Added a Window node, and made it the scene root.

Still a lot of work to do.

84 files changed, 1081 insertions, 621 deletions

diff --git a/drivers/vulkan/rendering_device_vulkan.cpp b/drivers/vulkan/rendering_device_vulkan.cpp
index 76541c3cd5..8ebf5b0f04 100644
--- a/drivers/vulkan/rendering_device_vulkan.cpp
+++ b/drivers/vulkan/rendering_device_vulkan.cpp
@@ -5150,12 +5150,12 @@ bool RenderingDeviceVulkan::compute_pipeline_is_valid(RID p_pipeline) {
 /**** SCREEN ****/
 /****************/
 
-int RenderingDeviceVulkan::screen_get_width(int p_screen) const {
+int RenderingDeviceVulkan::screen_get_width(DisplayServer::WindowID p_screen) const {
 	_THREAD_SAFE_METHOD_
 
 	return context->window_get_width(p_screen);
 }
-int RenderingDeviceVulkan::screen_get_height(int p_screen) const {
+int RenderingDeviceVulkan::screen_get_height(DisplayServer::WindowID p_screen) const {
 	_THREAD_SAFE_METHOD_
 
 	return context->window_get_height(p_screen);
@@ -5189,7 +5189,7 @@ RenderingDevice::FramebufferFormatID RenderingDeviceVulkan::screen_get_framebuff
 /**** DRAW LIST ****/
 /*******************/
 
-RenderingDevice::DrawListID RenderingDeviceVulkan::draw_list_begin_for_screen(int p_screen, const Color &p_clear_color) {
+RenderingDevice::DrawListID RenderingDeviceVulkan::draw_list_begin_for_screen(DisplayServer::WindowID p_screen, const Color &p_clear_color) {
 
 	_THREAD_SAFE_METHOD_
 
diff --git a/drivers/vulkan/rendering_device_vulkan.h b/drivers/vulkan/rendering_device_vulkan.h
index 4a224f0ceb..7f1697b2b5 100644
--- a/drivers/vulkan/rendering_device_vulkan.h
+++ b/drivers/vulkan/rendering_device_vulkan.h
@@ -1052,15 +1052,15 @@ public:
 	/**** SCREEN ****/
 	/****************/
 
-	virtual int screen_get_width(int p_screen = 0) const;
-	virtual int screen_get_height(int p_screen = 0) const;
+	virtual int screen_get_width(DisplayServer::WindowID p_screen = 0) const;
+	virtual int screen_get_height(DisplayServer::WindowID p_screen = 0) const;
 	virtual FramebufferFormatID screen_get_framebuffer_format() const;
 
 	/********************/
 	/**** DRAW LISTS ****/
 	/********************/
 
-	virtual DrawListID draw_list_begin_for_screen(int p_screen = 0, const Color &p_clear_color = Color());
+	virtual DrawListID draw_list_begin_for_screen(DisplayServer::WindowID p_screen = 0, const Color &p_clear_color = Color());
 
 	virtual DrawListID draw_list_begin(RID p_framebuffer, InitialAction p_initial_color_action, FinalAction p_final_color_action, InitialAction p_initial_depth_action, FinalAction p_final_depth_action, const Vector<Color> &p_clear_color_values = Vector<Color>(), float p_clear_depth = 1.0, uint32_t p_clear_stencil = 0, const Rect2 &p_region = Rect2());
 	virtual Error draw_list_begin_split(RID p_framebuffer, uint32_t p_splits, DrawListID *r_split_ids, InitialAction p_initial_color_action, FinalAction p_final_color_action, InitialAction p_initial_depth_action, FinalAction p_final_depth_action, const Vector<Color> &p_clear_color_values = Vector<Color>(), float p_clear_depth = 1.0, uint32_t p_clear_stencil = 0, const Rect2 &p_region = Rect2());
diff --git a/drivers/vulkan/vulkan_context.cpp b/drivers/vulkan/vulkan_context.cpp
index c8ff342713..494c64ff55 100644
--- a/drivers/vulkan/vulkan_context.cpp
+++ b/drivers/vulkan/vulkan_context.cpp
@@ -696,7 +696,9 @@ Error VulkanContext::_create_semaphores() {
 	return OK;
 }
 
-int VulkanContext::_window_create(VkSurfaceKHR p_surface, int p_width, int p_height) {
+Error VulkanContext::_window_create(DisplayServer::WindowID p_window_id, VkSurfaceKHR p_surface, int p_width, int p_height) {
+
+	ERR_FAIL_COND_V(windows.has(p_window_id), ERR_INVALID_PARAMETER);
 
 	if (!queues_initialized) {
 		// We use a single GPU, but we need a surface to initialize the
@@ -710,39 +712,37 @@ int VulkanContext::_window_create(VkSurfaceKHR p_surface, int p_width, int p_hei
 	window.width = p_width;
 	window.height = p_height;
 	Error err = _update_swap_chain(&window);
-	ERR_FAIL_COND_V(err != OK, -1);
+	ERR_FAIL_COND_V(err != OK, ERR_CANT_CREATE);
 
-	int id = last_window_id;
-	windows[id] = window;
-	last_window_id++;
-	return id;
+	windows[p_window_id] = window;
+	return OK;
 }
 
-void VulkanContext::window_resize(int p_window, int p_width, int p_height) {
+void VulkanContext::window_resize(DisplayServer::WindowID p_window, int p_width, int p_height) {
 	ERR_FAIL_COND(!windows.has(p_window));
 	windows[p_window].width = p_width;
 	windows[p_window].height = p_height;
 	_update_swap_chain(&windows[p_window]);
 }
 
-int VulkanContext::window_get_width(int p_window) {
+int VulkanContext::window_get_width(DisplayServer::WindowID p_window) {
 	ERR_FAIL_COND_V(!windows.has(p_window), -1);
 	return windows[p_window].width;
 }
 
-int VulkanContext::window_get_height(int p_window) {
+int VulkanContext::window_get_height(DisplayServer::WindowID p_window) {
 	ERR_FAIL_COND_V(!windows.has(p_window), -1);
 	return windows[p_window].height;
 }
 
-VkRenderPass VulkanContext::window_get_render_pass(int p_window) {
+VkRenderPass VulkanContext::window_get_render_pass(DisplayServer::WindowID p_window) {
 	ERR_FAIL_COND_V(!windows.has(p_window), VK_NULL_HANDLE);
 	Window *w = &windows[p_window];
 	//vulkan use of currentbuffer
 	return w->render_pass;
 }
 
-VkFramebuffer VulkanContext::window_get_framebuffer(int p_window) {
+VkFramebuffer VulkanContext::window_get_framebuffer(DisplayServer::WindowID p_window) {
 	ERR_FAIL_COND_V(!windows.has(p_window), VK_NULL_HANDLE);
 	ERR_FAIL_COND_V(!buffers_prepared, VK_NULL_HANDLE);
 	Window *w = &windows[p_window];
@@ -750,7 +750,7 @@ VkFramebuffer VulkanContext::window_get_framebuffer(int p_window) {
 	return w->swapchain_image_resources[w->current_buffer].framebuffer;
 }
 
-void VulkanContext::window_destroy(int p_window_id) {
+void VulkanContext::window_destroy(DisplayServer::WindowID p_window_id) {
 	ERR_FAIL_COND(!windows.has(p_window_id));
 	_clean_up_swap_chain(&windows[p_window_id]);
 	vkDestroySurfaceKHR(inst, windows[p_window_id].surface, NULL);
@@ -1497,7 +1497,6 @@ VulkanContext::VulkanContext() {
 
 	buffers_prepared = false;
 	swapchainImageCount = 0;
-	last_window_id = 0;
 }
 
 VulkanContext::~VulkanContext() {
diff --git a/drivers/vulkan/vulkan_context.h b/drivers/vulkan/vulkan_context.h
index 458cb6d793..2f10fbfdef 100644
--- a/drivers/vulkan/vulkan_context.h
+++ b/drivers/vulkan/vulkan_context.h
@@ -34,6 +34,7 @@
 #include "core/error_list.h"
 #include "core/map.h"
 #include "core/ustring.h"
+#include "servers/display_server.h"
 #include <vulkan/vulkan.h>
 
 class VulkanContext {
@@ -106,8 +107,7 @@ class VulkanContext {
 		}
 	};
 
-	Map<int, Window> windows;
-	int last_window_id;
+	Map<DisplayServer::WindowID, Window> windows;
 	uint32_t swapchainImageCount;
 
 	//commands
@@ -173,7 +173,7 @@ protected:
 	virtual const char *_get_platform_surface_extension() const = 0;
 	//	virtual VkResult _create_surface(VkSurfaceKHR *surface, VkInstance p_instance) = 0;
 
-	virtual int _window_create(VkSurfaceKHR p_surface, int p_width, int p_height);
+	virtual Error _window_create(DisplayServer::WindowID p_window_id, VkSurfaceKHR p_surface, int p_width, int p_height);
 
 	VkInstance _get_instance() {
 		return inst;
@@ -187,12 +187,12 @@ public:
 	int get_swapchain_image_count() const;
 	uint32_t get_graphics_queue() const;
 
-	void window_resize(int p_window_id, int p_width, int p_height);
-	int window_get_width(int p_window = 0);
-	int window_get_height(int p_window = 0);
-	void window_destroy(int p_window_id);
-	VkFramebuffer window_get_framebuffer(int p_window = 0);
-	VkRenderPass window_get_render_pass(int p_window = 0);
+	void window_resize(DisplayServer::WindowID p_window_id, int p_width, int p_height);
+	int window_get_width(DisplayServer::WindowID p_window = 0);
+	int window_get_height(DisplayServer::WindowID p_window = 0);
+	void window_destroy(DisplayServer::WindowID p_window_id);
+	VkFramebuffer window_get_framebuffer(DisplayServer::WindowID p_window = 0);
+	VkRenderPass window_get_render_pass(DisplayServer::WindowID p_window = 0);
 
 	VkFormat get_screen_format() const;
 	VkPhysicalDeviceLimits get_device_limits() const;
diff --git a/editor/animation_track_editor.cpp b/editor/animation_track_editor.cpp
index d3205ff147..7a6f43497e 100644
--- a/editor/animation_track_editor.cpp
+++ b/editor/animation_track_editor.cpp
@@ -37,7 +37,7 @@
 #include "editor/plugins/animation_player_editor_plugin.h"
 #include "editor_node.h"
 #include "editor_scale.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 #include "servers/audio/audio_stream.h"
 
 class AnimationTrackKeyEdit : public Object {
diff --git a/editor/editor_autoload_settings.cpp b/editor/editor_autoload_settings.cpp
index 83a1e2fca2..a02346c872 100644
--- a/editor/editor_autoload_settings.cpp
+++ b/editor/editor_autoload_settings.cpp
@@ -35,7 +35,7 @@
 #include "editor_node.h"
 #include "editor_scale.h"
 #include "project_settings_editor.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 #include "scene/resources/packed_scene.h"
 
 #define PREVIEW_LIST_MAX_SIZE 10
diff --git a/editor/editor_node.cpp b/editor/editor_node.cpp
index 48cd479fcf..5f00bc59ac 100644
--- a/editor/editor_node.cpp
+++ b/editor/editor_node.cpp
@@ -169,6 +169,7 @@
 #include "editor/register_exporters.h"
 #include "editor/run_settings_dialog.h"
 #include "editor/settings_config_dialog.h"
+#include "scene/main/window.h"
 #include "servers/display_server.h"
 #include <stdio.h>
 #include <stdlib.h>
@@ -346,7 +347,7 @@ void EditorNode::_notification(int p_what) {
 
 			editor_selection->update();
 
-			scene_root->set_size_override(true, Size2(ProjectSettings::get_singleton()->get("display/window/size/width"), ProjectSettings::get_singleton()->get("display/window/size/height")));
+			//scene_root->set_size_override(true, Size2(ProjectSettings::get_singleton()->get("display/window/size/width"), ProjectSettings::get_singleton()->get("display/window/size/height")));
 
 			{ //TODO should only happen on settings changed
 				int current_filter = GLOBAL_GET("rendering/canvas_textures/default_texture_filter");
@@ -2668,10 +2669,10 @@ void EditorNode::_screenshot(bool p_use_utc) {
 
 void EditorNode::_save_screenshot(NodePath p_path) {
 
-	Viewport *viewport = EditorInterface::get_singleton()->get_editor_viewport()->get_viewport();
-	viewport->set_clear_mode(Viewport::CLEAR_MODE_ONLY_NEXT_FRAME);
+	SubViewport *viewport = Object::cast_to<SubViewport>(EditorInterface::get_singleton()->get_editor_viewport()->get_viewport());
+	viewport->set_clear_mode(SubViewport::CLEAR_MODE_ONLY_NEXT_FRAME);
 	Ref<Image> img = viewport->get_texture()->get_data();
-	viewport->set_clear_mode(Viewport::CLEAR_MODE_ALWAYS);
+	viewport->set_clear_mode(SubViewport::CLEAR_MODE_ALWAYS);
 	Error error = img->save_png(p_path);
 	ERR_FAIL_COND_MSG(error != OK, "Cannot save screenshot to file '" + p_path + "'.");
 }
@@ -5941,7 +5942,7 @@ EditorNode::EditorNode() {
 	srt->add_child(scene_root_parent);
 	scene_root_parent->set_v_size_flags(Control::SIZE_EXPAND_FILL);
 
-	scene_root = memnew(Viewport);
+	scene_root = memnew(SubViewport);
 	//scene_root->set_usage(Viewport::USAGE_2D); canvas BG mode prevents usage of this as 2D
 
 	VisualServer::get_singleton()->viewport_set_hide_scenario(scene_root->get_viewport_rid(), true);
diff --git a/editor/editor_node.h b/editor/editor_node.h
index bd285db224..c670d4954b 100644
--- a/editor/editor_node.h
+++ b/editor/editor_node.h
@@ -84,6 +84,8 @@ class Tabs;
 class TextureProgress;
 class ToolButton;
 class VSplitContainer;
+class Window;
+class SubViewport;
 
 class EditorNode : public Node {
 
@@ -206,7 +208,7 @@ private:
 		TOOL_MENU_BASE = 1000
 	};
 
-	Viewport *scene_root; //root of the scene being edited
+	SubViewport *scene_root; //root of the scene being edited
 
 	PanelContainer *scene_root_parent;
 	Control *theme_base;
@@ -724,7 +726,7 @@ public:
 
 	Node *get_edited_scene() { return editor_data.get_edited_scene_root(); }
 
-	Viewport *get_scene_root() { return scene_root; } //root of the scene being edited
+	SubViewport *get_scene_root() { return scene_root; } //root of the scene being edited
 
 	void fix_dependencies(const String &p_for_file);
 	void clear_scene() { _cleanup_scene(); }
diff --git a/editor/editor_properties.cpp b/editor/editor_properties.cpp
index 9a474ed4af..cc89f1c16a 100644
--- a/editor/editor_properties.cpp
+++ b/editor/editor_properties.cpp
@@ -35,7 +35,7 @@
 #include "editor_node.h"
 #include "editor_properties_array_dict.h"
 #include "editor_scale.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 
 ///////////////////// NULL /////////////////////////
 
diff --git a/editor/editor_settings.cpp b/editor/editor_settings.cpp
index 18f0aba030..286ca7b184 100644
--- a/editor/editor_settings.cpp
+++ b/editor/editor_settings.cpp
@@ -49,7 +49,7 @@
 #include "editor/editor_translations.gen.h"
 #include "scene/main/node.h"
 #include "scene/main/scene_tree.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 
 // PRIVATE METHODS
 
diff --git a/editor/filesystem_dock.cpp b/editor/filesystem_dock.cpp
index 171bb4105d..d52a7f25be 100644
--- a/editor/filesystem_dock.cpp
+++ b/editor/filesystem_dock.cpp
@@ -42,7 +42,7 @@
 #include "editor_scale.h"
 #include "editor_settings.h"
 #include "import_dock.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 #include "scene/resources/packed_scene.h"
 #include "servers/display_server.h"
 
diff --git a/editor/plugins/animation_blend_space_2d_editor.cpp b/editor/plugins/animation_blend_space_2d_editor.cpp
index dc8f7f3724..156237a452 100644
--- a/editor/plugins/animation_blend_space_2d_editor.cpp
+++ b/editor/plugins/animation_blend_space_2d_editor.cpp
@@ -40,7 +40,7 @@
 #include "scene/animation/animation_player.h"
 #include "scene/gui/menu_button.h"
 #include "scene/gui/panel.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 
 bool AnimationNodeBlendSpace2DEditor::can_edit(const Ref<AnimationNode> &p_node) {
 
diff --git a/editor/plugins/animation_blend_tree_editor_plugin.cpp b/editor/plugins/animation_blend_tree_editor_plugin.cpp
index 931bce65d7..ecc5982fea 100644
--- a/editor/plugins/animation_blend_tree_editor_plugin.cpp
+++ b/editor/plugins/animation_blend_tree_editor_plugin.cpp
@@ -40,7 +40,7 @@
 #include "scene/gui/menu_button.h"
 #include "scene/gui/panel.h"
 #include "scene/gui/progress_bar.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 
 void AnimationNodeBlendTreeEditor::add_custom_type(const String &p_name, const Ref<Script> &p_script) {
 
diff --git a/editor/plugins/animation_player_editor_plugin.cpp b/editor/plugins/animation_player_editor_plugin.cpp
index 10d13f0188..dee595c119 100644
--- a/editor/plugins/animation_player_editor_plugin.cpp
+++ b/editor/plugins/animation_player_editor_plugin.cpp
@@ -40,7 +40,7 @@
 #include "editor/editor_settings.h"
 #include "editor/plugins/canvas_item_editor_plugin.h" // For onion skinning.
 #include "editor/plugins/spatial_editor_plugin.h" // For onion skinning.
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 #include "servers/visual_server.h"
 
 void AnimationPlayerEditor::_node_removed(Node *p_node) {
@@ -1420,7 +1420,7 @@ void AnimationPlayerEditor::_prepare_onion_layers_2() {
 
 	// Tweak the root viewport to ensure it's rendered before our target.
 	RID root_vp = get_tree()->get_root()->get_viewport_rid();
-	Rect2 root_vp_screen_rect = get_tree()->get_root()->get_attach_to_screen_rect();
+	Rect2 root_vp_screen_rect = Rect2(Vector2(), get_tree()->get_root()->get_size());
 	VS::get_singleton()->viewport_attach_to_screen(root_vp, Rect2());
 	VS::get_singleton()->viewport_set_update_mode(root_vp, VS::VIEWPORT_UPDATE_ALWAYS);
 
diff --git a/editor/plugins/animation_state_machine_editor.cpp b/editor/plugins/animation_state_machine_editor.cpp
index 1fe57665eb..3fd0cb94a2 100644
--- a/editor/plugins/animation_state_machine_editor.cpp
+++ b/editor/plugins/animation_state_machine_editor.cpp
@@ -40,7 +40,7 @@
 #include "scene/animation/animation_player.h"
 #include "scene/gui/menu_button.h"
 #include "scene/gui/panel.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 
 bool AnimationNodeStateMachineEditor::can_edit(const Ref<AnimationNode> &p_node) {
 
diff --git a/editor/plugins/animation_tree_editor_plugin.cpp b/editor/plugins/animation_tree_editor_plugin.cpp
index cf99d2ef78..795bd3eb1b 100644
--- a/editor/plugins/animation_tree_editor_plugin.cpp
+++ b/editor/plugins/animation_tree_editor_plugin.cpp
@@ -44,7 +44,7 @@
 #include "scene/animation/animation_player.h"
 #include "scene/gui/menu_button.h"
 #include "scene/gui/panel.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 #include "scene/scene_string_names.h"
 
 void AnimationTreeEditor::edit(AnimationTree *p_tree) {
diff --git a/editor/plugins/canvas_item_editor_plugin.cpp b/editor/plugins/canvas_item_editor_plugin.cpp
index 13f4979ba2..90d3bf0641 100644
--- a/editor/plugins/canvas_item_editor_plugin.cpp
+++ b/editor/plugins/canvas_item_editor_plugin.cpp
@@ -50,7 +50,7 @@
 #include "scene/gui/nine_patch_rect.h"
 #include "scene/gui/viewport_container.h"
 #include "scene/main/canvas_layer.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 #include "scene/resources/packed_scene.h"
 
 #define MIN_ZOOM 0.01
diff --git a/editor/plugins/material_editor_plugin.cpp b/editor/plugins/material_editor_plugin.cpp
index d388296927..a13a594d95 100644
--- a/editor/plugins/material_editor_plugin.cpp
+++ b/editor/plugins/material_editor_plugin.cpp
@@ -114,7 +114,7 @@ MaterialEditor::MaterialEditor() {
 	vc->set_stretch(true);
 	add_child(vc);
 	vc->set_anchors_and_margins_preset(PRESET_WIDE);
-	viewport = memnew(Viewport);
+	viewport = memnew(SubViewport);
 	Ref<World> world;
 	world.instance();
 	viewport->set_world(world); //use own world
diff --git a/editor/plugins/material_editor_plugin.h b/editor/plugins/material_editor_plugin.h
index 84e69425d0..895c3f80bd 100644
--- a/editor/plugins/material_editor_plugin.h
+++ b/editor/plugins/material_editor_plugin.h
@@ -48,7 +48,7 @@ class MaterialEditor : public Control {
 	GDCLASS(MaterialEditor, Control);
 
 	ViewportContainer *vc;
-	Viewport *viewport;
+	SubViewport *viewport;
 	MeshInstance *sphere_instance;
 	MeshInstance *box_instance;
 	DirectionalLight *light1;
diff --git a/editor/plugins/mesh_editor_plugin.cpp b/editor/plugins/mesh_editor_plugin.cpp
index 5a17f0d4f1..c921ca46cd 100644
--- a/editor/plugins/mesh_editor_plugin.cpp
+++ b/editor/plugins/mesh_editor_plugin.cpp
@@ -115,7 +115,7 @@ void MeshEditor::_bind_methods() {
 
 MeshEditor::MeshEditor() {
 
-	viewport = memnew(Viewport);
+	viewport = memnew(SubViewport);
 	Ref<World> world;
 	world.instance();
 	viewport->set_world(world); //use own world
diff --git a/editor/plugins/mesh_editor_plugin.h b/editor/plugins/mesh_editor_plugin.h
index 87c4a1776b..6d39d49de1 100644
--- a/editor/plugins/mesh_editor_plugin.h
+++ b/editor/plugins/mesh_editor_plugin.h
@@ -46,7 +46,7 @@ class MeshEditor : public ViewportContainer {
 	float rot_x;
 	float rot_y;
 
-	Viewport *viewport;
+	SubViewport *viewport;
 	MeshInstance *mesh_instance;
 	Spatial *rotation;
 	DirectionalLight *light1;
diff --git a/editor/plugins/mesh_library_editor_plugin.cpp b/editor/plugins/mesh_library_editor_plugin.cpp
index 4e63a498b8..f341d9ca86 100644
--- a/editor/plugins/mesh_library_editor_plugin.cpp
+++ b/editor/plugins/mesh_library_editor_plugin.cpp
@@ -36,7 +36,7 @@
 #include "scene/3d/mesh_instance.h"
 #include "scene/3d/navigation_region.h"
 #include "scene/3d/physics_body.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 #include "scene/resources/packed_scene.h"
 #include "spatial_editor_plugin.h"
 
diff --git a/editor/plugins/root_motion_editor_plugin.cpp b/editor/plugins/root_motion_editor_plugin.cpp
index d932305c63..daea2eec6b 100644
--- a/editor/plugins/root_motion_editor_plugin.cpp
+++ b/editor/plugins/root_motion_editor_plugin.cpp
@@ -30,7 +30,7 @@
 
 #include "root_motion_editor_plugin.h"
 #include "editor/editor_node.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 
 void EditorPropertyRootMotion::_confirmed() {
 
diff --git a/editor/plugins/script_editor_plugin.cpp b/editor/plugins/script_editor_plugin.cpp
index 06d1c664b5..f435856cdf 100644
--- a/editor/plugins/script_editor_plugin.cpp
+++ b/editor/plugins/script_editor_plugin.cpp
@@ -45,7 +45,7 @@
 #include "editor/find_in_files.h"
 #include "editor/node_dock.h"
 #include "editor/plugins/shader_editor_plugin.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 #include "scene/scene_string_names.h"
 #include "script_text_editor.h"
 #include "servers/display_server.h"
diff --git a/editor/plugins/spatial_editor_plugin.cpp b/editor/plugins/spatial_editor_plugin.cpp
index d514b50460..2af64b6ed6 100644
--- a/editor/plugins/spatial_editor_plugin.cpp
+++ b/editor/plugins/spatial_editor_plugin.cpp
@@ -3834,7 +3834,7 @@ SpatialEditorViewport::SpatialEditorViewport(SpatialEditor *p_spatial_editor, Ed
 	c->set_stretch(true);
 	add_child(c);
 	c->set_anchors_and_margins_preset(Control::PRESET_WIDE);
-	viewport = memnew(Viewport);
+	viewport = memnew(SubViewport);
 	viewport->set_disable_input(true);
 
 	c->add_child(viewport);
diff --git a/editor/plugins/spatial_editor_plugin.h b/editor/plugins/spatial_editor_plugin.h
index b67459b9d0..9dad66b647 100644
--- a/editor/plugins/spatial_editor_plugin.h
+++ b/editor/plugins/spatial_editor_plugin.h
@@ -262,7 +262,7 @@ private:
 	PopupMenu *display_submenu;
 
 	Control *surface;
-	Viewport *viewport;
+	SubViewport *viewport;
 	Camera *camera;
 	bool transforming;
 	bool orthogonal;
@@ -467,7 +467,7 @@ public:
 			AABB *p_preview_bounds,
 			AcceptDialog *p_accept);
 
-	Viewport *get_viewport_node() { return viewport; }
+	SubViewport *get_viewport_node() { return viewport; }
 	Camera *get_camera() { return camera; } // return the default camera object.
 
 	SpatialEditorViewport(SpatialEditor *p_spatial_editor, EditorNode *p_editor, int p_index);
diff --git a/editor/plugins/visual_shader_editor_plugin.cpp b/editor/plugins/visual_shader_editor_plugin.cpp
index 8070e2b4d5..3b7c4897b2 100644
--- a/editor/plugins/visual_shader_editor_plugin.cpp
+++ b/editor/plugins/visual_shader_editor_plugin.cpp
@@ -42,7 +42,7 @@
 #include "scene/animation/animation_player.h"
 #include "scene/gui/menu_button.h"
 #include "scene/gui/panel.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 #include "scene/resources/visual_shader_nodes.h"
 #include "servers/display_server.h"
 #include "servers/visual/shader_types.h"
diff --git a/editor/property_editor.cpp b/editor/property_editor.cpp
index feef274d33..7ba43d1246 100644
--- a/editor/property_editor.cpp
+++ b/editor/property_editor.cpp
@@ -53,7 +53,7 @@
 #include "editor/multi_node_edit.h"
 #include "editor/property_selector.h"
 #include "scene/gui/label.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 #include "scene/resources/font.h"
 #include "scene/resources/packed_scene.h"
 #include "scene/scene_string_names.h"
diff --git a/editor/scene_tree_dock.cpp b/editor/scene_tree_dock.cpp
index 4382b63747..3df4367b43 100644
--- a/editor/scene_tree_dock.cpp
+++ b/editor/scene_tree_dock.cpp
@@ -44,7 +44,7 @@
 #include "editor/plugins/canvas_item_editor_plugin.h"
 #include "editor/plugins/script_editor_plugin.h"
 #include "editor/plugins/spatial_editor_plugin.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 #include "scene/resources/packed_scene.h"
 #include "servers/display_server.h"
 #include "servers/visual_server.h"
diff --git a/editor/scene_tree_editor.cpp b/editor/scene_tree_editor.cpp
index 782df12d4b..0f8e748dfb 100644
--- a/editor/scene_tree_editor.cpp
+++ b/editor/scene_tree_editor.cpp
@@ -37,7 +37,7 @@
 #include "editor/plugins/animation_player_editor_plugin.h"
 #include "editor/plugins/canvas_item_editor_plugin.h"
 #include "scene/gui/label.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 #include "scene/resources/packed_scene.h"
 
 Node *SceneTreeEditor::get_scene_node() {
diff --git a/main/main.cpp b/main/main.cpp
index 53bb336b1f..d748aad9a7 100644
--- a/main/main.cpp
+++ b/main/main.cpp
@@ -58,7 +58,7 @@
 #include "modules/register_module_types.h"
 #include "platform/register_platform_apis.h"
 #include "scene/main/scene_tree.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 #include "scene/register_scene_types.h"
 #include "scene/resources/packed_scene.h"
 #include "servers/arvr_server.h"
@@ -1819,25 +1819,26 @@ bool Main::start() {
 			String stretch_mode = GLOBAL_DEF("display/window/stretch/mode", "disabled");
 			String stretch_aspect = GLOBAL_DEF("display/window/stretch/aspect", "ignore");
 			Size2i stretch_size = Size2(GLOBAL_DEF("display/window/size/width", 0), GLOBAL_DEF("display/window/size/height", 0));
-			real_t stretch_shrink = GLOBAL_DEF("display/window/stretch/shrink", 1.0);
 
-			SceneTree::StretchMode sml_sm = SceneTree::STRETCH_MODE_DISABLED;
-			if (stretch_mode == "2d")
-				sml_sm = SceneTree::STRETCH_MODE_2D;
-			else if (stretch_mode == "viewport")
-				sml_sm = SceneTree::STRETCH_MODE_VIEWPORT;
+			Window::ContentScaleMode cs_sm = Window::CONTENT_SCALE_MODE_DISABLED;
+			if (stretch_mode == "objects")
+				cs_sm = Window::CONTENT_SCALE_MODE_OBJECTS;
+			else if (stretch_mode == "pixels")
+				cs_sm = Window::CONTENT_SCALE_MODE_PIXELS;
 
-			SceneTree::StretchAspect sml_aspect = SceneTree::STRETCH_ASPECT_IGNORE;
+			Window::ContentScaleAspect cs_aspect = Window::CONTENT_SCALE_ASPECT_IGNORE;
 			if (stretch_aspect == "keep")
-				sml_aspect = SceneTree::STRETCH_ASPECT_KEEP;
+				cs_aspect = Window::CONTENT_SCALE_ASPECT_KEEP;
 			else if (stretch_aspect == "keep_width")
-				sml_aspect = SceneTree::STRETCH_ASPECT_KEEP_WIDTH;
+				cs_aspect = Window::CONTENT_SCALE_ASPECT_KEEP_WIDTH;
 			else if (stretch_aspect == "keep_height")
-				sml_aspect = SceneTree::STRETCH_ASPECT_KEEP_HEIGHT;
+				cs_aspect = Window::CONTENT_SCALE_ASPECT_KEEP_HEIGHT;
 			else if (stretch_aspect == "expand")
-				sml_aspect = SceneTree::STRETCH_ASPECT_EXPAND;
+				cs_aspect = Window::CONTENT_SCALE_ASPECT_EXPAND;
 
-			sml->set_screen_stretch(sml_sm, sml_aspect, stretch_size, stretch_shrink);
+			sml->get_root()->set_content_scale_mode(cs_sm);
+			sml->get_root()->set_content_scale_aspect(cs_aspect);
+			sml->get_root()->set_content_scale_size(stretch_size);
 
 			sml->set_auto_accept_quit(GLOBAL_DEF("application/config/auto_accept_quit", true));
 			sml->set_quit_on_go_back(GLOBAL_DEF("application/config/quit_on_go_back", true));
@@ -1861,7 +1862,7 @@ bool Main::start() {
 			sml->get_root()->set_snap_controls_to_pixels(snap_controls);
 
 			bool font_oversampling = GLOBAL_DEF("rendering/quality/dynamic_fonts/use_oversampling", true);
-			sml->set_use_font_oversampling(font_oversampling);
+			sml->get_root()->set_use_font_oversampling(font_oversampling);
 
 			int texture_filter = GLOBAL_DEF("rendering/canvas_textures/default_texture_filter", 1);
 			int texture_repeat = GLOBAL_DEF("rendering/canvas_textures/default_texture_repeat", 0);
diff --git a/main/tests/test_gui.cpp b/main/tests/test_gui.cpp
index f0b00aeeae..645588529f 100644
--- a/main/tests/test_gui.cpp
+++ b/main/tests/test_gui.cpp
@@ -54,7 +54,7 @@
 #include "scene/main/scene_tree.h"
 
 #include "scene/3d/camera.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 
 namespace TestGUI {
 
diff --git a/modules/gridmap/grid_map_editor_plugin.cpp b/modules/gridmap/grid_map_editor_plugin.cpp
index aa470105e0..bb27f946a2 100644
--- a/modules/gridmap/grid_map_editor_plugin.cpp
+++ b/modules/gridmap/grid_map_editor_plugin.cpp
@@ -37,6 +37,7 @@
 
 #include "core/math/geometry.h"
 #include "core/os/keyboard.h"
+#include "scene/main/window.h"
 
 void GridMapEditor::_node_removed(Node *p_node) {
 
diff --git a/modules/visual_script/visual_script_editor.cpp b/modules/visual_script/visual_script_editor.cpp
index 14c37bd375..8600dcbbf5 100644
--- a/modules/visual_script/visual_script_editor.cpp
+++ b/modules/visual_script/visual_script_editor.cpp
@@ -38,7 +38,7 @@
 #include "editor/editor_node.h"
 #include "editor/editor_resource_preview.h"
 #include "editor/editor_scale.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 #include "visual_script_expression.h"
 #include "visual_script_flow_control.h"
 #include "visual_script_func_nodes.h"
diff --git a/modules/visual_script/visual_script_property_selector.cpp b/modules/visual_script/visual_script_property_selector.cpp
index d799f19143..6e0d662be9 100644
--- a/modules/visual_script/visual_script_property_selector.cpp
+++ b/modules/visual_script/visual_script_property_selector.cpp
@@ -39,7 +39,7 @@
 #include "modules/visual_script/visual_script_func_nodes.h"
 #include "modules/visual_script/visual_script_nodes.h"
 #include "scene/main/node.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 
 void VisualScriptPropertySelector::_text_changed(const String &p_newtext) {
 	_update_search();
diff --git a/platform/linuxbsd/display_server_x11.cpp b/platform/linuxbsd/display_server_x11.cpp
index ace07a3ac6..0b4a6b19d8 100644
--- a/platform/linuxbsd/display_server_x11.cpp
+++ b/platform/linuxbsd/display_server_x11.cpp
@@ -47,8 +47,7 @@
 #include "servers/visual/rasterizer_rd/rasterizer_rd.h"
 #endif
 
-#include "servers/visual/visual_server_raster.h"
-#include "servers/visual/visual_server_wrap_mt.h"
+#include "scene/resources/texture.h"
 
 #ifdef HAVE_MNTENT
 #include <mntent.h>
@@ -89,6 +88,8 @@
 
 #include <X11/XKBlib.h>
 
+#include "core/project_settings.h"
+
 // 2.2 is the first release with multitouch
 #define XINPUT_CLIENT_VERSION_MAJOR 2
 #define XINPUT_CLIENT_VERSION_MINOR 2
@@ -641,7 +642,7 @@ void DisplayServerX11::delete_sub_window(WindowID p_id) {
 
 #ifdef VULKAN_ENABLED
 	if (rendering_driver == "vulkan") {
-		context_vulkan->window_destroy(wd.vulkan_window);
+		context_vulkan->window_destroy(p_id);
 	}
 #endif
 	XUnmapWindow(x11_display, wd.x11_window);
@@ -665,6 +666,13 @@ void DisplayServerX11::window_set_title(const String &p_title, WindowID p_window
 	XChangeProperty(x11_display, wd.x11_window, _net_wm_name, utf8_string, 8, PropModeReplace, (unsigned char *)p_title.utf8().get_data(), p_title.utf8().length());
 }
 
+void DisplayServerX11::window_set_resize_callback(const Callable &p_callable, WindowID p_window) {
+
+	ERR_FAIL_COND(!windows.has(p_window));
+	WindowData &wd = windows[p_window];
+	wd.resize_callback = p_callable;
+}
+
 int DisplayServerX11::window_get_current_screen(WindowID p_window) const {
 	ERR_FAIL_COND_V(!windows.has(p_window), -1);
 	const WindowData &wd = windows[p_window];
@@ -2020,9 +2028,17 @@ void DisplayServerX11::_window_changed(XEvent *event) {
 
 #if defined(VULKAN_ENABLED)
 	if (rendering_driver == "vulkan") {
-		context_vulkan->window_resize(wd.vulkan_window, wd.size.width, wd.size.height);
+		context_vulkan->window_resize(window_id, wd.size.width, wd.size.height);
 	}
 #endif
+
+	if (!wd.resize_callback.is_null()) {
+		Variant size = wd.size;
+		Variant *sizep = &size;
+		Variant ret;
+		Callable::CallError ce;
+		wd.resize_callback.call((const Variant **)&sizep, 1, ret, ce);
+	}
 }
 
 void DisplayServerX11::process_events() {
@@ -2764,8 +2780,8 @@ DisplayServerX11::WindowID DisplayServerX11::_create_window(WindowMode p_mode, c
 
 #if defined(VULKAN_ENABLED)
 		if (context_vulkan) {
-			wd.vulkan_window = context_vulkan->window_create(wd.x11_window, x11_display, p_resolution.width, p_resolution.height);
-			ERR_FAIL_COND_V_MSG(wd.vulkan_window == -1, INVALID_WINDOW_ID, "Can't create a Vulkan window");
+			Error err = context_vulkan->window_create(window_id_counter, wd.x11_window, x11_display, p_resolution.width, p_resolution.height);
+			ERR_FAIL_COND_V_MSG(err != OK, INVALID_WINDOW_ID, "Can't create a Vulkan window");
 		}
 #endif
 
@@ -3295,7 +3311,7 @@ DisplayServerX11::~DisplayServerX11() {
 	for (Map<WindowID, WindowData>::Element *E = windows.front(); E; E = E->next()) {
 #ifdef VULKAN_ENABLED
 		if (rendering_driver == "vulkan") {
-			context_vulkan->window_destroy(E->get().vulkan_window);
+			context_vulkan->window_destroy(E->key());
 		}
 #endif
 
diff --git a/platform/linuxbsd/display_server_x11.h b/platform/linuxbsd/display_server_x11.h
index 6964447be2..b1ecde30d9 100644
--- a/platform/linuxbsd/display_server_x11.h
+++ b/platform/linuxbsd/display_server_x11.h
@@ -113,14 +113,13 @@ class DisplayServerX11 : public DisplayServer {
 	struct WindowData {
 		Window x11_window;
 		::XIC xic;
-#if defined(VULKAN_ENABLED)
-		int vulkan_window;
-#endif
+
 		Size2i min_size;
 		Size2i max_size;
 		Size2i size;
 		Size2i im_position;
 		bool im_active = false;
+		Callable resize_callback;
 
 		//better to guess on the fly, given WM can change it
 		//WindowMode mode;
@@ -256,6 +255,7 @@ public:
 	virtual void delete_sub_window(WindowID p_id);
 
 	virtual void window_set_title(const String &p_title, WindowID p_window = MAIN_WINDOW_ID);
+	virtual void window_set_resize_callback(const Callable &p_callable, WindowID p_window = MAIN_WINDOW_ID);
 
 	virtual int window_get_current_screen(WindowID p_window = MAIN_WINDOW_ID) const;
 	virtual void window_set_current_screen(int p_screen, WindowID p_window = MAIN_WINDOW_ID);
diff --git a/platform/linuxbsd/vulkan_context_x11.cpp b/platform/linuxbsd/vulkan_context_x11.cpp
index 602dbc77a2..d0e1b1678c 100644
--- a/platform/linuxbsd/vulkan_context_x11.cpp
+++ b/platform/linuxbsd/vulkan_context_x11.cpp
@@ -35,7 +35,7 @@ const char *VulkanContextX11::_get_platform_surface_extension() const {
 	return VK_KHR_XLIB_SURFACE_EXTENSION_NAME;
 }
 
-int VulkanContextX11::window_create(::Window p_window, Display *p_display, int p_width, int p_height) {
+Error VulkanContextX11::window_create(DisplayServer::WindowID p_window_id, ::Window p_window, Display *p_display, int p_width, int p_height) {
 
 	VkXlibSurfaceCreateInfoKHR createInfo;
 	createInfo.sType = VK_STRUCTURE_TYPE_XLIB_SURFACE_CREATE_INFO_KHR;
@@ -46,8 +46,8 @@ int VulkanContextX11::window_create(::Window p_window, Display *p_display, int p
 
 	VkSurfaceKHR surface;
 	VkResult err = vkCreateXlibSurfaceKHR(_get_instance(), &createInfo, NULL, &surface);
-	ERR_FAIL_COND_V(err, -1);
-	return _window_create(surface, p_width, p_height);
+	ERR_FAIL_COND_V(err, ERR_CANT_CREATE);
+	return _window_create(p_window_id, surface, p_width, p_height);
 }
 
 VulkanContextX11::VulkanContextX11() {
diff --git a/platform/linuxbsd/vulkan_context_x11.h b/platform/linuxbsd/vulkan_context_x11.h
index 573f994ea6..6e144ab2d9 100644
--- a/platform/linuxbsd/vulkan_context_x11.h
+++ b/platform/linuxbsd/vulkan_context_x11.h
@@ -39,7 +39,7 @@ class VulkanContextX11 : public VulkanContext {
 	virtual const char *_get_platform_surface_extension() const;
 
 public:
-	int window_create(::Window p_window, Display *p_display, int p_width, int p_height);
+	Error window_create(DisplayServer::WindowID p_window_id, ::Window p_window, Display *p_display, int p_width, int p_height);
 
 	VulkanContextX11();
 	~VulkanContextX11();
diff --git a/scene/2d/audio_stream_player_2d.cpp b/scene/2d/audio_stream_player_2d.cpp
index 3ef4dfe5f1..df0b17800f 100644
--- a/scene/2d/audio_stream_player_2d.cpp
+++ b/scene/2d/audio_stream_player_2d.cpp
@@ -32,7 +32,7 @@
 
 #include "core/engine.h"
 #include "scene/2d/area_2d.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 
 void AudioStreamPlayer2D::_mix_audio() {
 
diff --git a/scene/2d/camera_2d.h b/scene/2d/camera_2d.h
index 04b5260444..7a106ef79a 100644
--- a/scene/2d/camera_2d.h
+++ b/scene/2d/camera_2d.h
@@ -32,7 +32,7 @@
 #define CAMERA_2D_H
 
 #include "scene/2d/node_2d.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 
 class Camera2D : public Node2D {
 
diff --git a/scene/2d/canvas_item.cpp b/scene/2d/canvas_item.cpp
index 0f93a61b09..959be53028 100644
--- a/scene/2d/canvas_item.cpp
+++ b/scene/2d/canvas_item.cpp
@@ -34,7 +34,7 @@
 #include "core/message_queue.h"
 #include "core/method_bind_ext.gen.inc"
 #include "scene/main/canvas_layer.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 #include "scene/resources/font.h"
 #include "scene/resources/style_box.h"
 #include "scene/resources/texture.h"
diff --git a/scene/2d/node_2d.cpp b/scene/2d/node_2d.cpp
index df21538609..0b0b9820d3 100644
--- a/scene/2d/node_2d.cpp
+++ b/scene/2d/node_2d.cpp
@@ -32,7 +32,7 @@
 
 #include "core/message_queue.h"
 #include "scene/gui/control.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 #include "servers/visual_server.h"
 
 #ifdef TOOLS_ENABLED
diff --git a/scene/2d/sprite.cpp b/scene/2d/sprite.cpp
index 7eaafe5348..a6fb6f7435 100644
--- a/scene/2d/sprite.cpp
+++ b/scene/2d/sprite.cpp
@@ -32,7 +32,7 @@
 
 #include "core/core_string_names.h"
 #include "core/os/os.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 #include "scene/scene_string_names.h"
 
 #ifdef TOOLS_ENABLED
diff --git a/scene/2d/touch_screen_button.cpp b/scene/2d/touch_screen_button.cpp
index 0f79e12275..7efc6479f9 100644
--- a/scene/2d/touch_screen_button.cpp
+++ b/scene/2d/touch_screen_button.cpp
@@ -33,7 +33,7 @@
 #include "core/input/input.h"
 #include "core/input/input_map.h"
 #include "core/os/os.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 
 void TouchScreenButton::set_texture(const Ref<Texture2D> &p_texture) {
 
diff --git a/scene/2d/visibility_notifier_2d.cpp b/scene/2d/visibility_notifier_2d.cpp
index 54511bbe1b..65dabb92b1 100644
--- a/scene/2d/visibility_notifier_2d.cpp
+++ b/scene/2d/visibility_notifier_2d.cpp
@@ -35,7 +35,7 @@
 #include "scene/2d/animated_sprite.h"
 #include "scene/2d/physics_body_2d.h"
 #include "scene/animation/animation_player.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 #include "scene/scene_string_names.h"
 
 #ifdef TOOLS_ENABLED
diff --git a/scene/3d/audio_stream_player_3d.cpp b/scene/3d/audio_stream_player_3d.cpp
index f0a61a905c..f3020d4044 100644
--- a/scene/3d/audio_stream_player_3d.cpp
+++ b/scene/3d/audio_stream_player_3d.cpp
@@ -33,7 +33,7 @@
 #include "scene/3d/area.h"
 #include "scene/3d/camera.h"
 #include "scene/3d/listener.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 
 // Based on "A Novel Multichannel Panning Method for Standard and Arbitrary Loudspeaker Configurations" by Ramy Sadek and Chris Kyriakakis (2004)
 // Speaker-Placement Correction Amplitude Panning (SPCAP)
diff --git a/scene/3d/camera.h b/scene/3d/camera.h
index 6ac3ece798..feb7b39b1e 100644
--- a/scene/3d/camera.h
+++ b/scene/3d/camera.h
@@ -33,7 +33,7 @@
 
 #include "scene/3d/spatial.h"
 #include "scene/3d/spatial_velocity_tracker.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 #include "scene/resources/environment.h"
 
 class Camera : public Spatial {
diff --git a/scene/3d/listener.h b/scene/3d/listener.h
index 287e67f31e..17ff1d9397 100644
--- a/scene/3d/listener.h
+++ b/scene/3d/listener.h
@@ -32,7 +32,7 @@
 #define LISTENER_H
 
 #include "scene/3d/spatial.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 
 class Listener : public Spatial {
 
diff --git a/scene/3d/spatial.cpp b/scene/3d/spatial.cpp
index f1911348ce..c6225dd291 100644
--- a/scene/3d/spatial.cpp
+++ b/scene/3d/spatial.cpp
@@ -33,7 +33,7 @@
 #include "core/engine.h"
 #include "core/message_queue.h"
 #include "scene/main/scene_tree.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 #include "scene/scene_string_names.h"
 
 /*
diff --git a/scene/3d/world_environment.cpp b/scene/3d/world_environment.cpp
index 83a7243906..9276432ba9 100644
--- a/scene/3d/world_environment.cpp
+++ b/scene/3d/world_environment.cpp
@@ -29,7 +29,7 @@
 /*************************************************************************/
 
 #include "world_environment.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 
 void WorldEnvironment::_notification(int p_what) {
 
diff --git a/scene/debugger/scene_debugger.cpp b/scene/debugger/scene_debugger.cpp
index 7a184adc55..359f936793 100644
--- a/scene/debugger/scene_debugger.cpp
+++ b/scene/debugger/scene_debugger.cpp
@@ -34,7 +34,7 @@
 #include "core/io/marshalls.h"
 #include "core/script_language.h"
 #include "scene/main/scene_tree.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 #include "scene/resources/packed_scene.h"
 
 void SceneDebugger::initialize() {
diff --git a/scene/gui/base_button.cpp b/scene/gui/base_button.cpp
index b2020d44e8..07bc91e7e7 100644
--- a/scene/gui/base_button.cpp
+++ b/scene/gui/base_button.cpp
@@ -31,7 +31,7 @@
 #include "base_button.h"
 
 #include "core/os/keyboard.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 #include "scene/scene_string_names.h"
 
 void BaseButton::_unpress_group() {
diff --git a/scene/gui/color_picker.cpp b/scene/gui/color_picker.cpp
index 29900def80..4959781de4 100644
--- a/scene/gui/color_picker.cpp
+++ b/scene/gui/color_picker.cpp
@@ -38,7 +38,7 @@
 #include "editor/editor_scale.h"
 #include "editor/editor_settings.h"
 #endif
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 
 void ColorPicker::_notification(int p_what) {
 
diff --git a/scene/gui/control.cpp b/scene/gui/control.cpp
index 1a231e368b..8f62d9c009 100644
--- a/scene/gui/control.cpp
+++ b/scene/gui/control.cpp
@@ -38,7 +38,7 @@
 #include "scene/gui/label.h"
 #include "scene/gui/panel.h"
 #include "scene/main/canvas_layer.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 #include "scene/scene_string_names.h"
 #include "servers/visual_server.h"
 
diff --git a/scene/gui/dialogs.cpp b/scene/gui/dialogs.cpp
index 6cadd0a63e..290cff6888 100644
--- a/scene/gui/dialogs.cpp
+++ b/scene/gui/dialogs.cpp
@@ -36,7 +36,7 @@
 #ifdef TOOLS_ENABLED
 #include "editor/editor_node.h"
 #include "editor/editor_scale.h"
-#include "scene/main/viewport.h" // Only used to check for more modals when dimming the editor.
+#include "scene/main/window.h" // Only used to check for more modals when dimming the editor.
 #endif
 
 // WindowDialog
diff --git a/scene/gui/line_edit.cpp b/scene/gui/line_edit.cpp
index 8466612c85..41a9905d0b 100644
--- a/scene/gui/line_edit.cpp
+++ b/scene/gui/line_edit.cpp
@@ -41,7 +41,7 @@
 #include "editor/editor_scale.h"
 #include "editor/editor_settings.h"
 #endif
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 static bool _is_text_char(CharType c) {
 
 	return !is_symbol(c);
diff --git a/scene/gui/menu_button.cpp b/scene/gui/menu_button.cpp
index 2b163187c5..7f2ea7d3ed 100644
--- a/scene/gui/menu_button.cpp
+++ b/scene/gui/menu_button.cpp
@@ -31,7 +31,7 @@
 #include "menu_button.h"
 
 #include "core/os/keyboard.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 
 void MenuButton::_unhandled_key_input(Ref<InputEvent> p_event) {
 
diff --git a/scene/gui/scroll_bar.cpp b/scene/gui/scroll_bar.cpp
index 4750853c3b..7fc83703c3 100644
--- a/scene/gui/scroll_bar.cpp
+++ b/scene/gui/scroll_bar.cpp
@@ -33,7 +33,7 @@
 #include "core/os/keyboard.h"
 #include "core/os/os.h"
 #include "core/print_string.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 
 bool ScrollBar::focus_by_default = false;
 
diff --git a/scene/gui/scroll_container.cpp b/scene/gui/scroll_container.cpp
index 8bd741f4d8..32943e04e0 100644
--- a/scene/gui/scroll_container.cpp
+++ b/scene/gui/scroll_container.cpp
@@ -30,7 +30,7 @@
 
 #include "scroll_container.h"
 #include "core/os/os.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 
 bool ScrollContainer::clips_input() const {
 
diff --git a/scene/gui/text_edit.cpp b/scene/gui/text_edit.cpp
index dd535ba76f..09878f07cf 100644
--- a/scene/gui/text_edit.cpp
+++ b/scene/gui/text_edit.cpp
@@ -36,7 +36,7 @@
 #include "core/os/os.h"
 #include "core/project_settings.h"
 #include "core/script_language.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 
 #ifdef TOOLS_ENABLED
 #include "editor/editor_scale.h"
diff --git a/scene/gui/tree.cpp b/scene/gui/tree.cpp
index cecfb07edb..74b394e51c 100644
--- a/scene/gui/tree.cpp
+++ b/scene/gui/tree.cpp
@@ -36,7 +36,7 @@
 #include "core/os/os.h"
 #include "core/print_string.h"
 #include "core/project_settings.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 
 #ifdef TOOLS_ENABLED
 #include "editor/editor_scale.h"
diff --git a/scene/gui/viewport_container.cpp b/scene/gui/viewport_container.cpp
index a76f2924d3..7ce1d9e551 100644
--- a/scene/gui/viewport_container.cpp
+++ b/scene/gui/viewport_container.cpp
@@ -40,7 +40,7 @@ Size2 ViewportContainer::get_minimum_size() const {
 	Size2 ms;
 	for (int i = 0; i < get_child_count(); i++) {
 
-		Viewport *c = Object::cast_to<Viewport>(get_child(i));
+		SubViewport *c = Object::cast_to<SubViewport>(get_child(i));
 		if (!c)
 			continue;
 
@@ -77,7 +77,7 @@ void ViewportContainer::set_stretch_shrink(int p_shrink) {
 
 	for (int i = 0; i < get_child_count(); i++) {
 
-		Viewport *c = Object::cast_to<Viewport>(get_child(i));
+		SubViewport *c = Object::cast_to<SubViewport>(get_child(i));
 		if (!c)
 			continue;
 
@@ -101,7 +101,7 @@ void ViewportContainer::_notification(int p_what) {
 
 		for (int i = 0; i < get_child_count(); i++) {
 
-			Viewport *c = Object::cast_to<Viewport>(get_child(i));
+			SubViewport *c = Object::cast_to<SubViewport>(get_child(i));
 			if (!c)
 				continue;
 
@@ -113,14 +113,14 @@ void ViewportContainer::_notification(int p_what) {
 
 		for (int i = 0; i < get_child_count(); i++) {
 
-			Viewport *c = Object::cast_to<Viewport>(get_child(i));
+			SubViewport *c = Object::cast_to<SubViewport>(get_child(i));
 			if (!c)
 				continue;
 
 			if (is_visible_in_tree())
-				c->set_update_mode(Viewport::UPDATE_ALWAYS);
+				c->set_update_mode(SubViewport::UPDATE_ALWAYS);
 			else
-				c->set_update_mode(Viewport::UPDATE_DISABLED);
+				c->set_update_mode(SubViewport::UPDATE_DISABLED);
 
 			c->set_handle_input_locally(false); //do not handle input locally here
 		}
@@ -130,7 +130,7 @@ void ViewportContainer::_notification(int p_what) {
 
 		for (int i = 0; i < get_child_count(); i++) {
 
-			Viewport *c = Object::cast_to<Viewport>(get_child(i));
+			SubViewport *c = Object::cast_to<SubViewport>(get_child(i));
 			if (!c)
 				continue;
 
@@ -159,7 +159,7 @@ void ViewportContainer::_input(const Ref<InputEvent> &p_event) {
 
 	for (int i = 0; i < get_child_count(); i++) {
 
-		Viewport *c = Object::cast_to<Viewport>(get_child(i));
+		SubViewport *c = Object::cast_to<SubViewport>(get_child(i));
 		if (!c || c->is_input_disabled())
 			continue;
 
@@ -184,7 +184,7 @@ void ViewportContainer::_unhandled_input(const Ref<InputEvent> &p_event) {
 
 	for (int i = 0; i < get_child_count(); i++) {
 
-		Viewport *c = Object::cast_to<Viewport>(get_child(i));
+		SubViewport *c = Object::cast_to<SubViewport>(get_child(i));
 		if (!c || c->is_input_disabled())
 			continue;
 
diff --git a/scene/main/scene_tree.cpp b/scene/main/scene_tree.cpp
index b0708b70b8..77eb445afa 100644
--- a/scene/main/scene_tree.cpp
+++ b/scene/main/scene_tree.cpp
@@ -51,7 +51,7 @@
 #include "servers/navigation_server.h"
 #include "servers/physics_2d_server.h"
 #include "servers/physics_server.h"
-#include "viewport.h"
+#include "window.h"
 
 #include <stdio.h>
 
@@ -494,14 +494,6 @@ bool SceneTree::iteration(float p_time) {
 	return _quit;
 }
 
-void SceneTree::_update_font_oversampling(float p_ratio) {
-
-	if (use_font_oversampling) {
-		DynamicFontAtSize::font_oversampling = p_ratio;
-		DynamicFont::update_oversampling();
-	}
-}
-
 bool SceneTree::idle(float p_time) {
 
 	//print_line("ram: "+itos(OS::get_singleton()->get_static_memory_usage())+" sram: "+itos(OS::get_singleton()->get_dynamic_memory_usage()));
@@ -527,15 +519,6 @@ bool SceneTree::idle(float p_time) {
 	_notify_group_pause("idle_process_internal", Node::NOTIFICATION_INTERNAL_PROCESS);
 	_notify_group_pause("idle_process", Node::NOTIFICATION_PROCESS);
 
-	Size2 win_size = Size2(DisplayServer::get_singleton()->window_get_size().width, DisplayServer::get_singleton()->window_get_size().height);
-
-	if (win_size != last_screen_size) {
-
-		last_screen_size = win_size;
-		_update_root_rect();
-		emit_signal("screen_resized");
-	}
-
 	_flush_ugc();
 	MessageQueue::get_singleton()->flush(); //small little hack
 	flush_transform_notifications(); //transforms after world update, to avoid unnecessary enter/exit notifications
@@ -1130,129 +1113,6 @@ int SceneTree::get_node_count() const {
 	return node_count;
 }
 
-void SceneTree::_update_root_rect() {
-
-	if (stretch_mode == STRETCH_MODE_DISABLED) {
-
-		_update_font_oversampling(1.0);
-		root->set_size((last_screen_size / stretch_shrink).floor());
-		root->set_attach_to_screen_rect(Rect2(Point2(), last_screen_size));
-		root->set_size_override_stretch(false);
-		root->set_size_override(false, Size2());
-		root->update_canvas_items();
-		return; //user will take care
-	}
-
-	//actual screen video mode
-	Size2 video_mode = Size2(DisplayServer::get_singleton()->window_get_size().width, DisplayServer::get_singleton()->window_get_size().height);
-	Size2 desired_res = stretch_min;
-
-	Size2 viewport_size;
-	Size2 screen_size;
-
-	float viewport_aspect = desired_res.aspect();
-	float video_mode_aspect = video_mode.aspect();
-
-	if (use_font_oversampling && stretch_aspect == STRETCH_ASPECT_IGNORE) {
-		WARN_PRINT("Font oversampling only works with the resize modes 'Keep Width', 'Keep Height', and 'Expand'.");
-	}
-
-	if (stretch_aspect == STRETCH_ASPECT_IGNORE || Math::is_equal_approx(viewport_aspect, video_mode_aspect)) {
-		//same aspect or ignore aspect
-		viewport_size = desired_res;
-		screen_size = video_mode;
-	} else if (viewport_aspect < video_mode_aspect) {
-		// screen ratio is smaller vertically
-
-		if (stretch_aspect == STRETCH_ASPECT_KEEP_HEIGHT || stretch_aspect == STRETCH_ASPECT_EXPAND) {
-
-			//will stretch horizontally
-			viewport_size.x = desired_res.y * video_mode_aspect;
-			viewport_size.y = desired_res.y;
-			screen_size = video_mode;
-
-		} else {
-			//will need black bars
-			viewport_size = desired_res;
-			screen_size.x = video_mode.y * viewport_aspect;
-			screen_size.y = video_mode.y;
-		}
-	} else {
-		//screen ratio is smaller horizontally
-		if (stretch_aspect == STRETCH_ASPECT_KEEP_WIDTH || stretch_aspect == STRETCH_ASPECT_EXPAND) {
-
-			//will stretch horizontally
-			viewport_size.x = desired_res.x;
-			viewport_size.y = desired_res.x / video_mode_aspect;
-			screen_size = video_mode;
-
-		} else {
-			//will need black bars
-			viewport_size = desired_res;
-			screen_size.x = video_mode.x;
-			screen_size.y = video_mode.x / viewport_aspect;
-		}
-	}
-
-	screen_size = screen_size.floor();
-	viewport_size = viewport_size.floor();
-
-	Size2 margin;
-	Size2 offset;
-	//black bars and margin
-	if (stretch_aspect != STRETCH_ASPECT_EXPAND && screen_size.x < video_mode.x) {
-		margin.x = Math::round((video_mode.x - screen_size.x) / 2.0);
-		VisualServer::get_singleton()->black_bars_set_margins(margin.x, 0, margin.x, 0);
-		offset.x = Math::round(margin.x * viewport_size.y / screen_size.y);
-	} else if (stretch_aspect != STRETCH_ASPECT_EXPAND && screen_size.y < video_mode.y) {
-		margin.y = Math::round((video_mode.y - screen_size.y) / 2.0);
-		VisualServer::get_singleton()->black_bars_set_margins(0, margin.y, 0, margin.y);
-		offset.y = Math::round(margin.y * viewport_size.x / screen_size.x);
-	} else {
-		VisualServer::get_singleton()->black_bars_set_margins(0, 0, 0, 0);
-	}
-
-	switch (stretch_mode) {
-		case STRETCH_MODE_DISABLED: {
-			// Already handled above
-			_update_font_oversampling(1.0);
-		} break;
-		case STRETCH_MODE_2D: {
-
-			_update_font_oversampling(screen_size.x / viewport_size.x); //screen / viewport radio drives oversampling
-			root->set_size((screen_size / stretch_shrink).floor());
-			root->set_attach_to_screen_rect(Rect2(margin, screen_size));
-			root->set_size_override_stretch(true);
-			root->set_size_override(true, (viewport_size / stretch_shrink).floor());
-			root->update_canvas_items(); //force them to update just in case
-
-		} break;
-		case STRETCH_MODE_VIEWPORT: {
-
-			_update_font_oversampling(1.0);
-			root->set_size((viewport_size / stretch_shrink).floor());
-			root->set_attach_to_screen_rect(Rect2(margin, screen_size));
-			root->set_size_override_stretch(false);
-			root->set_size_override(false, Size2());
-			root->update_canvas_items(); //force them to update just in case
-
-			if (use_font_oversampling) {
-				WARN_PRINT("Font oversampling does not work in 'Viewport' stretch mode, only '2D'.");
-			}
-
-		} break;
-	}
-}
-
-void SceneTree::set_screen_stretch(StretchMode p_mode, StretchAspect p_aspect, const Size2 &p_minsize, real_t p_shrink) {
-
-	stretch_mode = p_mode;
-	stretch_aspect = p_aspect;
-	stretch_min = p_minsize;
-	stretch_shrink = p_shrink;
-	_update_root_rect();
-}
-
 void SceneTree::set_edited_scene_root(Node *p_node) {
 #ifdef TOOLS_ENABLED
 	edited_scene_root = p_node;
@@ -1479,8 +1339,6 @@ void SceneTree::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("get_frame"), &SceneTree::get_frame);
 	ClassDB::bind_method(D_METHOD("quit", "exit_code"), &SceneTree::quit, DEFVAL(-1));
 
-	ClassDB::bind_method(D_METHOD("set_screen_stretch", "mode", "aspect", "minsize", "shrink"), &SceneTree::set_screen_stretch, DEFVAL(1));
-
 	ClassDB::bind_method(D_METHOD("queue_delete", "obj"), &SceneTree::queue_delete);
 
 	MethodInfo mi;
@@ -1530,15 +1388,11 @@ void SceneTree::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("set_refuse_new_network_connections", "refuse"), &SceneTree::set_refuse_new_network_connections);
 	ClassDB::bind_method(D_METHOD("is_refusing_new_network_connections"), &SceneTree::is_refusing_new_network_connections);
 
-	ClassDB::bind_method(D_METHOD("set_use_font_oversampling", "enable"), &SceneTree::set_use_font_oversampling);
-	ClassDB::bind_method(D_METHOD("is_using_font_oversampling"), &SceneTree::is_using_font_oversampling);
-
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "debug_collisions_hint"), "set_debug_collisions_hint", "is_debugging_collisions_hint");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "debug_navigation_hint"), "set_debug_navigation_hint", "is_debugging_navigation_hint");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "paused"), "set_pause", "is_paused");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "refuse_new_network_connections"), "set_refuse_new_network_connections", "is_refusing_new_network_connections");
 	ADD_PROPERTY_DEFAULT("refuse_new_network_connections", false);
-	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "use_font_oversampling"), "set_use_font_oversampling", "is_using_font_oversampling");
 	ADD_PROPERTY(PropertyInfo(Variant::OBJECT, "edited_scene_root", PROPERTY_HINT_RESOURCE_TYPE, "Node", 0), "set_edited_scene_root", "get_edited_scene_root");
 	ADD_PROPERTY(PropertyInfo(Variant::OBJECT, "current_scene", PROPERTY_HINT_RESOURCE_TYPE, "Node", 0), "set_current_scene", "get_current_scene");
 	ADD_PROPERTY(PropertyInfo(Variant::OBJECT, "network_peer", PROPERTY_HINT_RESOURCE_TYPE, "NetworkedMultiplayerPeer", 0), "set_network_peer", "get_network_peer");
@@ -1550,7 +1404,6 @@ void SceneTree::_bind_methods() {
 	ADD_SIGNAL(MethodInfo("node_added", PropertyInfo(Variant::OBJECT, "node", PROPERTY_HINT_RESOURCE_TYPE, "Node")));
 	ADD_SIGNAL(MethodInfo("node_removed", PropertyInfo(Variant::OBJECT, "node", PROPERTY_HINT_RESOURCE_TYPE, "Node")));
 	ADD_SIGNAL(MethodInfo("node_renamed", PropertyInfo(Variant::OBJECT, "node", PROPERTY_HINT_RESOURCE_TYPE, "Node")));
-	ADD_SIGNAL(MethodInfo("screen_resized"));
 	ADD_SIGNAL(MethodInfo("node_configuration_warning_changed", PropertyInfo(Variant::OBJECT, "node", PROPERTY_HINT_RESOURCE_TYPE, "Node")));
 
 	ADD_SIGNAL(MethodInfo("idle_frame"));
@@ -1568,16 +1421,6 @@ void SceneTree::_bind_methods() {
 	BIND_ENUM_CONSTANT(GROUP_CALL_REVERSE);
 	BIND_ENUM_CONSTANT(GROUP_CALL_REALTIME);
 	BIND_ENUM_CONSTANT(GROUP_CALL_UNIQUE);
-
-	BIND_ENUM_CONSTANT(STRETCH_MODE_DISABLED);
-	BIND_ENUM_CONSTANT(STRETCH_MODE_2D);
-	BIND_ENUM_CONSTANT(STRETCH_MODE_VIEWPORT);
-
-	BIND_ENUM_CONSTANT(STRETCH_ASPECT_IGNORE);
-	BIND_ENUM_CONSTANT(STRETCH_ASPECT_KEEP);
-	BIND_ENUM_CONSTANT(STRETCH_ASPECT_KEEP_WIDTH);
-	BIND_ENUM_CONSTANT(STRETCH_ASPECT_KEEP_HEIGHT);
-	BIND_ENUM_CONSTANT(STRETCH_ASPECT_EXPAND);
 }
 
 SceneTree *SceneTree::singleton = NULL;
@@ -1597,19 +1440,6 @@ void SceneTree::add_idle_callback(IdleCallback p_callback) {
 	idle_callbacks[idle_callback_count++] = p_callback;
 }
 
-void SceneTree::set_use_font_oversampling(bool p_oversampling) {
-
-	if (use_font_oversampling == p_oversampling)
-		return;
-
-	use_font_oversampling = p_oversampling;
-	_update_root_rect();
-}
-
-bool SceneTree::is_using_font_oversampling() const {
-	return use_font_oversampling;
-}
-
 void SceneTree::get_argument_options(const StringName &p_function, int p_idx, List<String> *r_options) const {
 
 	if (p_function == "change_scene") {
@@ -1649,7 +1479,6 @@ SceneTree::SceneTree() {
 	accept_quit = true;
 	quit_on_go_back = true;
 	initialized = false;
-	use_font_oversampling = false;
 #ifdef DEBUG_ENABLED
 	debug_collisions_hint = false;
 	debug_navigation_hint = false;
@@ -1681,7 +1510,7 @@ SceneTree::SceneTree() {
 
 	//create with mainloop
 
-	root = memnew(Viewport);
+	root = memnew(Window);
 	root->set_name("root");
 	root->set_handle_input_locally(false);
 	if (!root->get_world().is_valid())
@@ -1731,13 +1560,6 @@ SceneTree::SceneTree() {
 		}
 	}
 
-	stretch_mode = STRETCH_MODE_DISABLED;
-	stretch_aspect = STRETCH_ASPECT_IGNORE;
-	stretch_shrink = 1;
-
-	last_screen_size = Size2(DisplayServer::get_singleton()->window_get_size().width, DisplayServer::get_singleton()->window_get_size().height);
-	_update_root_rect();
-
 	root->set_physics_object_picking(GLOBAL_DEF("physics/common/enable_object_picking", true));
 
 #ifdef TOOLS_ENABLED
diff --git a/scene/main/scene_tree.h b/scene/main/scene_tree.h
index 2f805d074f..c51214b676 100644
--- a/scene/main/scene_tree.h
+++ b/scene/main/scene_tree.h
@@ -39,9 +39,11 @@
 #include "scene/resources/world.h"
 #include "scene/resources/world_2d.h"
 
+#undef Window
+
 class PackedScene;
 class Node;
-class Viewport;
+class Window;
 class Material;
 class Mesh;
 class SceneDebugger;
@@ -76,22 +78,6 @@ class SceneTree : public MainLoop {
 public:
 	typedef void (*IdleCallback)();
 
-	enum StretchMode {
-
-		STRETCH_MODE_DISABLED,
-		STRETCH_MODE_2D,
-		STRETCH_MODE_VIEWPORT,
-	};
-
-	enum StretchAspect {
-
-		STRETCH_ASPECT_IGNORE,
-		STRETCH_ASPECT_KEEP,
-		STRETCH_ASPECT_KEEP_WIDTH,
-		STRETCH_ASPECT_KEEP_HEIGHT,
-		STRETCH_ASPECT_EXPAND,
-	};
-
 private:
 	struct Group {
 
@@ -101,7 +87,7 @@ private:
 		Group() { changed = false; };
 	};
 
-	Viewport *root;
+	Window *root;
 
 	uint64_t tree_version;
 	float physics_process_time;
@@ -121,13 +107,11 @@ private:
 	bool initialized;
 	bool input_handled;
 
-	Size2 last_screen_size;
 	StringName tree_changed_name;
 	StringName node_added_name;
 	StringName node_removed_name;
 	StringName node_renamed_name;
 
-	bool use_font_oversampling;
 	int64_t current_frame;
 	int64_t current_event;
 	int node_count;
@@ -147,14 +131,6 @@ private:
 	int call_lock;
 	Set<Node *> call_skip; //skip erased nodes
 
-	StretchMode stretch_mode;
-	StretchAspect stretch_aspect;
-	Size2i stretch_min;
-	real_t stretch_shrink;
-
-	void _update_font_oversampling(float p_ratio);
-	void _update_root_rect();
-
 	List<ObjectID> delete_queue;
 
 	Map<UGCall, Vector<Variant>> unique_group_calls;
@@ -249,7 +225,7 @@ public:
 		GROUP_CALL_MULTILEVEL = 8,
 	};
 
-	_FORCE_INLINE_ Viewport *get_root() const { return root; }
+	_FORCE_INLINE_ Window *get_root() const { return root; }
 
 	void call_group_flags(uint32_t p_call_flags, const StringName &p_group, const StringName &p_function, VARIANT_ARG_LIST);
 	void notify_group_flags(uint32_t p_call_flags, const StringName &p_group, int p_notification);
@@ -335,11 +311,6 @@ public:
 	void get_nodes_in_group(const StringName &p_group, List<Node *> *p_list);
 	bool has_group(const StringName &p_identifier) const;
 
-	void set_screen_stretch(StretchMode p_mode, StretchAspect p_aspect, const Size2 &p_minsize, real_t p_shrink = 1);
-
-	void set_use_font_oversampling(bool p_oversampling);
-	bool is_using_font_oversampling() const;
-
 	//void change_scene(const String& p_path);
 	//Node *get_loaded_scene();
 
@@ -388,8 +359,6 @@ public:
 	~SceneTree();
 };
 
-VARIANT_ENUM_CAST(SceneTree::StretchMode);
-VARIANT_ENUM_CAST(SceneTree::StretchAspect);
 VARIANT_ENUM_CAST(SceneTree::GroupCallFlags);
 
 #endif
diff --git a/scene/main/viewport.cpp b/scene/main/viewport.cpp
index 20587f49b9..66faaf51b3 100644
--- a/scene/main/viewport.cpp
+++ b/scene/main/viewport.cpp
@@ -142,7 +142,7 @@ void ViewportTexture::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("set_viewport_path_in_scene", "path"), &ViewportTexture::set_viewport_path_in_scene);
 	ClassDB::bind_method(D_METHOD("get_viewport_path_in_scene"), &ViewportTexture::get_viewport_path_in_scene);
 
-	ADD_PROPERTY(PropertyInfo(Variant::NODE_PATH, "viewport_path", PROPERTY_HINT_NODE_PATH_VALID_TYPES, "Viewport", PROPERTY_USAGE_DEFAULT | PROPERTY_USAGE_NODE_PATH_FROM_SCENE_ROOT), "set_viewport_path_in_scene", "get_viewport_path_in_scene");
+	ADD_PROPERTY(PropertyInfo(Variant::NODE_PATH, "viewport_path", PROPERTY_HINT_NODE_PATH_VALID_TYPES, "SubViewport", PROPERTY_USAGE_DEFAULT | PROPERTY_USAGE_NODE_PATH_FROM_SCENE_ROOT), "set_viewport_path_in_scene", "get_viewport_path_in_scene");
 }
 
 ViewportTexture::ViewportTexture() {
@@ -185,6 +185,8 @@ public:
 
 Viewport::GUI::GUI() {
 
+	embed_subwindows_hint = false;
+
 	dragging = false;
 	mouse_focus = NULL;
 	mouse_click_grabber = NULL;
@@ -201,23 +203,6 @@ Viewport::GUI::GUI() {
 
 /////////////////////////////////////
 
-void Viewport::_update_stretch_transform() {
-
-	if (size_override_stretch && size_override) {
-
-		stretch_transform = Transform2D();
-		Size2 scale = size / (size_override_size + size_override_margin * 2);
-		stretch_transform.scale(scale);
-		stretch_transform.elements[2] = size_override_margin * scale;
-
-	} else {
-
-		stretch_transform = Transform2D();
-	}
-
-	_update_global_transform();
-}
-
 void Viewport::update_worlds() {
 
 	if (!is_inside_tree())
@@ -409,7 +394,7 @@ void Viewport::_notification(int p_what) {
 				VS::get_singleton()->multimesh_set_visible_instances(contact_3d_debug_multimesh, point_count);
 			}
 
-			if (physics_object_picking && (to_screen_rect == Rect2() || Input::get_singleton()->get_mouse_mode() != Input::MOUSE_MODE_CAPTURED)) {
+			if (physics_object_picking && (to_screen_rect == Rect2i() || Input::get_singleton()->get_mouse_mode() != Input::MOUSE_MODE_CAPTURED)) {
 
 #ifndef _3D_DISABLED
 				Vector2 last_pos(1e20, 1e20);
@@ -699,16 +684,6 @@ RID Viewport::get_viewport_rid() const {
 	return viewport;
 }
 
-void Viewport::set_use_arvr(bool p_use_arvr) {
-	arvr = p_use_arvr;
-
-	VS::get_singleton()->viewport_set_use_arvr(viewport, arvr);
-}
-
-bool Viewport::use_arvr() {
-	return arvr;
-}
-
 void Viewport::update_canvas_items() {
 	if (!is_inside_tree())
 		return;
@@ -716,18 +691,35 @@ void Viewport::update_canvas_items() {
 	_update_canvas_items(this);
 }
 
-void Viewport::set_size(const Size2 &p_size) {
+void Viewport::_set_size(const Size2i &p_size, const Size2i &p_size_override, const Rect2i &p_to_screen_rect, const Transform2D &p_stretch_transform, bool p_allocated) {
 
-	if (size == p_size.floor())
+	if (size == p_size && size_allocated == p_allocated && stretch_transform == p_stretch_transform && p_size_override == size_override && to_screen_rect != p_to_screen_rect)
 		return;
-	size = p_size.floor();
-	VS::get_singleton()->viewport_set_size(viewport, size.width, size.height);
+	size = p_size;
+	size_allocated = p_allocated;
+	size_override = p_size_override;
+	stretch_transform = p_stretch_transform;
+	to_screen_rect = p_to_screen_rect;
+
+	if (p_allocated) {
+		VS::get_singleton()->viewport_set_size(viewport, size.width, size.height);
+	} else {
+		VS::get_singleton()->viewport_set_size(viewport, 0, 0);
+	}
+	_update_global_transform();
 
-	_update_stretch_transform();
+	update_canvas_items();
 
 	emit_signal("size_changed");
 }
 
+Size2i Viewport::_get_size() const {
+	return size;
+}
+bool Viewport::_is_size_allocated() const {
+	return size_allocated;
+}
+
 Rect2 Viewport::get_visible_rect() const {
 
 	Rect2 r;
@@ -738,18 +730,13 @@ Rect2 Viewport::get_visible_rect() const {
 		r = Rect2(Point2(), size);
 	}
 
-	if (size_override) {
-		r.size = size_override_size;
+	if (size_override != Size2i()) {
+		r.size = size_override;
 	}
 
 	return r;
 }
 
-Size2 Viewport::get_size() const {
-
-	return size;
-}
-
 void Viewport::_update_listener() {
 	/*
 	if (is_inside_tree() && audio_listener && (camera || listener) && (!get_parent() || (Object::cast_to<Control>(get_parent()) && Object::cast_to<Control>(get_parent())->is_visible_in_tree())))  {
@@ -1279,70 +1266,11 @@ void Viewport::_update_canvas_items(Node *p_node) {
 	}
 }
 
-void Viewport::set_size_override(bool p_enable, const Size2 &p_size, const Vector2 &p_margin) {
-
-	if (size_override == p_enable && p_size == size_override_size)
-		return;
-
-	size_override = p_enable;
-	if (p_size.x >= 0 || p_size.y >= 0) {
-		size_override_size = p_size;
-	}
-	size_override_margin = p_margin;
-
-	_update_stretch_transform();
-	emit_signal("size_changed");
-}
-
-Size2 Viewport::get_size_override() const {
-
-	return size_override_size;
-}
-bool Viewport::is_size_override_enabled() const {
-
-	return size_override;
-}
-void Viewport::set_size_override_stretch(bool p_enable) {
-
-	if (p_enable == size_override_stretch)
-		return;
-
-	size_override_stretch = p_enable;
-
-	_update_stretch_transform();
-}
-
-bool Viewport::is_size_override_stretch_enabled() const {
-
-	return size_override_stretch;
-}
-
-void Viewport::set_update_mode(UpdateMode p_mode) {
-
-	update_mode = p_mode;
-	VS::get_singleton()->viewport_set_update_mode(viewport, VS::ViewportUpdateMode(p_mode));
-}
-Viewport::UpdateMode Viewport::get_update_mode() const {
-
-	return update_mode;
-}
-
 Ref<ViewportTexture> Viewport::get_texture() const {
 
 	return default_texture;
 }
 
-void Viewport::set_clear_mode(ClearMode p_mode) {
-
-	clear_mode = p_mode;
-	VS::get_singleton()->viewport_set_clear_mode(viewport, VS::ViewportClearMode(p_mode));
-}
-
-Viewport::ClearMode Viewport::get_clear_mode() const {
-
-	return clear_mode;
-}
-
 void Viewport::set_shadow_atlas_size(int p_size) {
 
 	if (shadow_atlas_size == p_size)
@@ -1380,7 +1308,7 @@ Transform2D Viewport::_get_input_pre_xform() const {
 
 	Transform2D pre_xf;
 
-	if (to_screen_rect != Rect2()) {
+	if (to_screen_rect != Rect2i()) {
 
 		pre_xf.elements[2] = -to_screen_rect.position;
 		pre_xf.scale(size / to_screen_rect.size);
@@ -1423,8 +1351,12 @@ void Viewport::_vp_input(const Ref<InputEvent> &p_ev) {
 	}
 #endif
 
-	if (to_screen_rect == Rect2())
-		return; //if render target, can't get input events
+	Ref<InputEventFromWindow> window_event = p_ev;
+	if (window_event.is_valid()) {
+		if (window_event->get_window_id() != get_window_id()) {
+			return;
+		}
+	}
 
 	//this one handles system input, p_ev are in system coordinates
 	//they are converted to viewport coordinates
@@ -1448,8 +1380,12 @@ void Viewport::_vp_unhandled_input(const Ref<InputEvent> &p_ev) {
 		return;
 	*/
 
-	if (to_screen_rect == Rect2())
-		return; //if render target, can't get input events
+	Ref<InputEventFromWindow> window_event = p_ev;
+	if (window_event.is_valid()) {
+		if (window_event->get_window_id() != get_window_id()) {
+			return;
+		}
+	}
 
 	//this one handles system input, p_ev are in system coordinates
 	//they are converted to viewport coordinates
@@ -2878,30 +2814,6 @@ bool Viewport::is_using_own_world() const {
 	return own_world.is_valid();
 }
 
-void Viewport::set_attach_to_screen_rect(const Rect2 &p_rect) {
-
-	VS::get_singleton()->viewport_attach_to_screen(viewport, p_rect);
-	to_screen_rect = p_rect;
-}
-
-Rect2 Viewport::get_attach_to_screen_rect() const {
-
-	return to_screen_rect;
-}
-
-void Viewport::set_use_render_direct_to_screen(bool p_render_direct_to_screen) {
-
-	if (p_render_direct_to_screen == render_direct_to_screen)
-		return;
-
-	render_direct_to_screen = p_render_direct_to_screen;
-	VS::get_singleton()->viewport_set_render_direct_to_screen(viewport, p_render_direct_to_screen);
-}
-
-bool Viewport::is_using_render_direct_to_screen() const {
-	return render_direct_to_screen;
-}
-
 void Viewport::set_physics_object_picking(bool p_enable) {
 
 	physics_object_picking = p_enable;
@@ -3091,13 +3003,27 @@ DisplayServer::WindowID Viewport::get_window_id() const {
 	return DisplayServer::MAIN_WINDOW_ID;
 }
 
-void Viewport::_bind_methods() {
+Viewport *Viewport::get_parent_viewport() const {
+	ERR_FAIL_COND_V(!is_inside_tree(), nullptr);
+	if (!get_parent()) {
+		return nullptr; //root viewport
+	}
+
+	return get_parent()->get_viewport();
+}
 
-	ClassDB::bind_method(D_METHOD("set_use_arvr", "use"), &Viewport::set_use_arvr);
-	ClassDB::bind_method(D_METHOD("use_arvr"), &Viewport::use_arvr);
+void Viewport::set_embed_subwindows_hint(bool p_embed) {
+	gui.embed_subwindows_hint = p_embed;
+}
+bool Viewport::get_embed_subwindows_hint() const {
+	return gui.embed_subwindows_hint;
+}
+bool Viewport::is_embedding_subwindows() const {
+	return gui.embed_subwindows_hint;
+}
+
+void Viewport::_bind_methods() {
 
-	ClassDB::bind_method(D_METHOD("set_size", "size"), &Viewport::set_size);
-	ClassDB::bind_method(D_METHOD("get_size"), &Viewport::get_size);
 	ClassDB::bind_method(D_METHOD("set_world_2d", "world_2d"), &Viewport::set_world_2d);
 	ClassDB::bind_method(D_METHOD("get_world_2d"), &Viewport::get_world_2d);
 	ClassDB::bind_method(D_METHOD("find_world_2d"), &Viewport::find_world_2d);
@@ -3120,18 +3046,6 @@ void Viewport::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("_vp_input_text", "text"), &Viewport::_vp_input_text);
 	ClassDB::bind_method(D_METHOD("_vp_unhandled_input"), &Viewport::_vp_unhandled_input);
 
-	ClassDB::bind_method(D_METHOD("set_size_override", "enable", "size", "margin"), &Viewport::set_size_override, DEFVAL(Size2(-1, -1)), DEFVAL(Size2(0, 0)));
-	ClassDB::bind_method(D_METHOD("get_size_override"), &Viewport::get_size_override);
-	ClassDB::bind_method(D_METHOD("is_size_override_enabled"), &Viewport::is_size_override_enabled);
-	ClassDB::bind_method(D_METHOD("set_size_override_stretch", "enabled"), &Viewport::set_size_override_stretch);
-	ClassDB::bind_method(D_METHOD("is_size_override_stretch_enabled"), &Viewport::is_size_override_stretch_enabled);
-
-	ClassDB::bind_method(D_METHOD("set_clear_mode", "mode"), &Viewport::set_clear_mode);
-	ClassDB::bind_method(D_METHOD("get_clear_mode"), &Viewport::get_clear_mode);
-
-	ClassDB::bind_method(D_METHOD("set_update_mode", "mode"), &Viewport::set_update_mode);
-	ClassDB::bind_method(D_METHOD("get_update_mode"), &Viewport::get_update_mode);
-
 	ClassDB::bind_method(D_METHOD("set_msaa", "msaa"), &Viewport::set_msaa);
 	ClassDB::bind_method(D_METHOD("get_msaa"), &Viewport::get_msaa);
 
@@ -3161,9 +3075,6 @@ void Viewport::_bind_methods() {
 
 	ClassDB::bind_method(D_METHOD("set_as_audio_listener_2d", "enable"), &Viewport::set_as_audio_listener_2d);
 	ClassDB::bind_method(D_METHOD("is_audio_listener_2d"), &Viewport::is_audio_listener_2d);
-	ClassDB::bind_method(D_METHOD("set_attach_to_screen_rect", "rect"), &Viewport::set_attach_to_screen_rect);
-	ClassDB::bind_method(D_METHOD("set_use_render_direct_to_screen", "enable"), &Viewport::set_use_render_direct_to_screen);
-	ClassDB::bind_method(D_METHOD("is_using_render_direct_to_screen"), &Viewport::is_using_render_direct_to_screen);
 
 	ClassDB::bind_method(D_METHOD("get_mouse_position"), &Viewport::get_mouse_position);
 	ClassDB::bind_method(D_METHOD("warp_mouse", "to_position"), &Viewport::warp_mouse);
@@ -3199,13 +3110,13 @@ void Viewport::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("set_default_canvas_item_texture_filter", "mode"), &Viewport::set_default_canvas_item_texture_filter);
 	ClassDB::bind_method(D_METHOD("get_default_canvas_item_texture_filter"), &Viewport::get_default_canvas_item_texture_filter);
 
+	ClassDB::bind_method(D_METHOD("set_embed_subwindows_hint", "enable"), &Viewport::set_embed_subwindows_hint);
+	ClassDB::bind_method(D_METHOD("get_embed_subwindows_hint"), &Viewport::get_embed_subwindows_hint);
+	ClassDB::bind_method(D_METHOD("is_embedding_subwindows"), &Viewport::is_embedding_subwindows);
+
 	ClassDB::bind_method(D_METHOD("set_default_canvas_item_texture_repeat", "mode"), &Viewport::set_default_canvas_item_texture_repeat);
 	ClassDB::bind_method(D_METHOD("get_default_canvas_item_texture_repeat"), &Viewport::get_default_canvas_item_texture_repeat);
 
-	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "arvr"), "set_use_arvr", "use_arvr");
-
-	ADD_PROPERTY(PropertyInfo(Variant::VECTOR2, "size"), "set_size", "get_size");
-	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "size_override_stretch"), "set_size_override_stretch", "is_size_override_stretch_enabled");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "own_world"), "set_use_own_world", "is_using_own_world");
 	ADD_PROPERTY(PropertyInfo(Variant::OBJECT, "world", PROPERTY_HINT_RESOURCE_TYPE, "World"), "set_world", "get_world");
 	ADD_PROPERTY(PropertyInfo(Variant::OBJECT, "world_2d", PROPERTY_HINT_RESOURCE_TYPE, "World2D", 0), "set_world_2d", "get_world_2d");
@@ -3213,11 +3124,7 @@ void Viewport::_bind_methods() {
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "handle_input_locally"), "set_handle_input_locally", "is_handling_input_locally");
 	ADD_GROUP("Rendering", "");
 	ADD_PROPERTY(PropertyInfo(Variant::INT, "msaa", PROPERTY_HINT_ENUM, "Disabled,2x,4x,8x,16x,AndroidVR 2x,AndroidVR 4x"), "set_msaa", "get_msaa");
-	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "render_direct_to_screen"), "set_use_render_direct_to_screen", "is_using_render_direct_to_screen");
 	ADD_PROPERTY(PropertyInfo(Variant::INT, "debug_draw", PROPERTY_HINT_ENUM, "Disabled,Unshaded,Overdraw,Wireframe"), "set_debug_draw", "get_debug_draw");
-	ADD_GROUP("Render Target", "render_target_");
-	ADD_PROPERTY(PropertyInfo(Variant::INT, "render_target_clear_mode", PROPERTY_HINT_ENUM, "Always,Never,Next Frame"), "set_clear_mode", "get_clear_mode");
-	ADD_PROPERTY(PropertyInfo(Variant::INT, "render_target_update_mode", PROPERTY_HINT_ENUM, "Disabled,Once,When Visible,Always"), "set_update_mode", "get_update_mode");
 	ADD_GROUP("Canvas Items", "canvas_item_");
 	ADD_PROPERTY(PropertyInfo(Variant::INT, "canvas_item_default_texture_filter", PROPERTY_HINT_ENUM, "Nearest,Linear,MipmapLinear,MipmapNearest"), "set_default_canvas_item_texture_filter", "get_default_canvas_item_texture_filter");
 	ADD_PROPERTY(PropertyInfo(Variant::INT, "canvas_item_default_texture_repeat", PROPERTY_HINT_ENUM, "Disabled,Enabled,Mirror"), "set_default_canvas_item_texture_repeat", "get_default_canvas_item_texture_repeat");
@@ -3229,6 +3136,7 @@ void Viewport::_bind_methods() {
 	ADD_GROUP("GUI", "gui_");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "gui_disable_input"), "set_disable_input", "is_input_disabled");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "gui_snap_controls_to_pixels"), "set_snap_controls_to_pixels", "is_snap_controls_to_pixels_enabled");
+	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "gui_embed_subwindows"), "set_embed_subwindows_hint", "get_embed_subwindows_hint");
 	ADD_GROUP("Shadow Atlas", "shadow_atlas_");
 	ADD_PROPERTY(PropertyInfo(Variant::INT, "shadow_atlas_size"), "set_shadow_atlas_size", "get_shadow_atlas_size");
 	ADD_PROPERTYI(PropertyInfo(Variant::INT, "shadow_atlas_quad_0", PROPERTY_HINT_ENUM, "Disabled,1 Shadow,4 Shadows,16 Shadows,64 Shadows,256 Shadows,1024 Shadows"), "set_shadow_atlas_quadrant_subdiv", "get_shadow_atlas_quadrant_subdiv", 0);
@@ -3241,11 +3149,6 @@ void Viewport::_bind_methods() {
 	ADD_SIGNAL(MethodInfo("size_changed"));
 	ADD_SIGNAL(MethodInfo("gui_focus_changed", PropertyInfo(Variant::OBJECT, "node", PROPERTY_HINT_RESOURCE_TYPE, "Control")));
 
-	BIND_ENUM_CONSTANT(UPDATE_DISABLED);
-	BIND_ENUM_CONSTANT(UPDATE_ONCE);
-	BIND_ENUM_CONSTANT(UPDATE_WHEN_VISIBLE);
-	BIND_ENUM_CONSTANT(UPDATE_ALWAYS);
-
 	BIND_ENUM_CONSTANT(SHADOW_ATLAS_QUADRANT_SUBDIV_DISABLED);
 	BIND_ENUM_CONSTANT(SHADOW_ATLAS_QUADRANT_SUBDIV_1);
 	BIND_ENUM_CONSTANT(SHADOW_ATLAS_QUADRANT_SUBDIV_4);
@@ -3282,10 +3185,6 @@ void Viewport::_bind_methods() {
 	BIND_ENUM_CONSTANT(MSAA_8X);
 	BIND_ENUM_CONSTANT(MSAA_16X);
 
-	BIND_ENUM_CONSTANT(CLEAR_MODE_ALWAYS);
-	BIND_ENUM_CONSTANT(CLEAR_MODE_NEVER);
-	BIND_ENUM_CONSTANT(CLEAR_MODE_ONLY_NEXT_FRAME);
-
 	BIND_ENUM_CONSTANT(DEFAULT_CANVAS_ITEM_TEXTURE_FILTER_NEAREST);
 	BIND_ENUM_CONSTANT(DEFAULT_CANVAS_ITEM_TEXTURE_FILTER_LINEAR);
 	BIND_ENUM_CONSTANT(DEFAULT_CANVAS_ITEM_TEXTURE_FILTER_LINEAR_WITH_MIPMAPS);
@@ -3312,8 +3211,6 @@ Viewport::Viewport() {
 	viewport = VisualServer::get_singleton()->viewport_create();
 	texture_rid = VisualServer::get_singleton()->viewport_get_texture(viewport);
 
-	render_direct_to_screen = false;
-
 	default_texture.instance();
 	default_texture->vp = const_cast<Viewport *>(this);
 	viewport_textures.insert(default_texture.ptr());
@@ -3329,14 +3226,10 @@ Viewport::Viewport() {
 	camera = NULL;
 	override_canvas_transform = false;
 	canvas_layers.insert(NULL); // This eases picking code (interpreted as the canvas of the Viewport)
-	arvr = false;
-	size_override = false;
-	size_override_stretch = false;
-	size_override_size = Size2(1, 1);
+
 	gen_mipmaps = false;
 
 	//clear=true;
-	update_mode = UPDATE_WHEN_VISIBLE;
 
 	physics_object_picking = false;
 	physics_has_last_mousepos = false;
@@ -3378,7 +3271,6 @@ Viewport::Viewport() {
 	msaa = MSAA_DISABLED;
 
 	debug_draw = DEBUG_DRAW_DISABLED;
-	clear_mode = CLEAR_MODE_ALWAYS;
 
 	snap_controls_to_pixels = true;
 	physics_last_mouse_state.alt = false;
@@ -3389,6 +3281,8 @@ Viewport::Viewport() {
 	local_input_handled = false;
 	handle_input_locally = true;
 
+	size_allocated = false;
+
 	default_canvas_item_texture_filter = DEFAULT_CANVAS_ITEM_TEXTURE_FILTER_LINEAR;
 	default_canvas_item_texture_repeat = DEFAULT_CANVAS_ITEM_TEXTURE_REPEAT_DISABLED;
 }
@@ -3403,3 +3297,84 @@ Viewport::~Viewport() {
 	//SpatialSoundServer::get_singleton()->free(internal_listener);
 	//SpatialSound2DServer::get_singleton()->free(internal_listener_2d);
 }
+
+/////////////////////////////////
+
+void SubViewport::set_use_arvr(bool p_use_arvr) {
+	arvr = p_use_arvr;
+
+	VS::get_singleton()->viewport_set_use_arvr(get_viewport_rid(), arvr);
+}
+
+bool SubViewport::is_using_arvr() {
+	return arvr;
+}
+
+void SubViewport::set_size(const Size2i &p_size) {
+	_set_size(p_size, Size2i(), Rect2i(), Transform2D(), true);
+}
+Size2i SubViewport::get_size() const {
+	return _get_size();
+}
+
+void SubViewport::set_update_mode(UpdateMode p_mode) {
+
+	update_mode = p_mode;
+	VS::get_singleton()->viewport_set_update_mode(get_viewport_rid(), VS::ViewportUpdateMode(p_mode));
+}
+SubViewport::UpdateMode SubViewport::get_update_mode() const {
+
+	return update_mode;
+}
+
+void SubViewport::set_clear_mode(ClearMode p_mode) {
+
+	clear_mode = p_mode;
+	VS::get_singleton()->viewport_set_clear_mode(get_viewport_rid(), VS::ViewportClearMode(p_mode));
+}
+
+SubViewport::ClearMode SubViewport::get_clear_mode() const {
+
+	return clear_mode;
+}
+
+DisplayServer::WindowID SubViewport::get_window_id() const {
+	return DisplayServer::INVALID_WINDOW_ID;
+}
+
+void SubViewport::_bind_methods() {
+	ClassDB::bind_method(D_METHOD("set_use_arvr", "use"), &SubViewport::set_use_arvr);
+	ClassDB::bind_method(D_METHOD("is_using_arvr"), &SubViewport::is_using_arvr);
+
+	ClassDB::bind_method(D_METHOD("set_size", "size"), &SubViewport::set_size);
+	ClassDB::bind_method(D_METHOD("get_size"), &SubViewport::get_size);
+
+	ClassDB::bind_method(D_METHOD("set_update_mode", "mode"), &SubViewport::set_update_mode);
+	ClassDB::bind_method(D_METHOD("get_update_mode"), &SubViewport::get_update_mode);
+
+	ClassDB::bind_method(D_METHOD("set_clear_mode", "mode"), &SubViewport::set_clear_mode);
+	ClassDB::bind_method(D_METHOD("get_clear_mode"), &SubViewport::get_clear_mode);
+
+	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "arvr"), "set_use_arvr", "is_using_arvr");
+	ADD_GROUP("Render Target", "render_target_");
+	ADD_PROPERTY(PropertyInfo(Variant::INT, "render_target_clear_mode", PROPERTY_HINT_ENUM, "Always,Never,Next Frame"), "set_clear_mode", "get_clear_mode");
+	ADD_PROPERTY(PropertyInfo(Variant::INT, "render_target_update_mode", PROPERTY_HINT_ENUM, "Disabled,Once,When Visible,Always"), "set_update_mode", "get_update_mode");
+
+	BIND_ENUM_CONSTANT(UPDATE_DISABLED);
+	BIND_ENUM_CONSTANT(UPDATE_ONCE);
+	BIND_ENUM_CONSTANT(UPDATE_WHEN_VISIBLE);
+	BIND_ENUM_CONSTANT(UPDATE_ALWAYS);
+
+	BIND_ENUM_CONSTANT(CLEAR_MODE_ALWAYS);
+	BIND_ENUM_CONSTANT(CLEAR_MODE_NEVER);
+	BIND_ENUM_CONSTANT(CLEAR_MODE_ONLY_NEXT_FRAME);
+}
+
+SubViewport::SubViewport() {
+	arvr = false;
+	update_mode = UPDATE_WHEN_VISIBLE;
+	clear_mode = CLEAR_MODE_ALWAYS;
+}
+
+SubViewport::~SubViewport() {
+}
diff --git a/scene/main/viewport.h b/scene/main/viewport.h
index b2a25fe0e9..1fa08e6cd0 100644
--- a/scene/main/viewport.h
+++ b/scene/main/viewport.h
@@ -89,13 +89,6 @@ class Viewport : public Node {
 	GDCLASS(Viewport, Node);
 
 public:
-	enum UpdateMode {
-		UPDATE_DISABLED,
-		UPDATE_ONCE, //then goes to disabled
-		UPDATE_WHEN_VISIBLE, // default
-		UPDATE_ALWAYS
-	};
-
 	enum ShadowAtlasQuadrantSubdiv {
 		SHADOW_ATLAS_QUADRANT_SUBDIV_DISABLED,
 		SHADOW_ATLAS_QUADRANT_SUBDIV_1,
@@ -143,13 +136,6 @@ public:
 		DEBUG_DRAW_ROUGHNESS_LIMITER
 	};
 
-	enum ClearMode {
-
-		CLEAR_MODE_ALWAYS,
-		CLEAR_MODE_NEVER,
-		CLEAR_MODE_ONLY_NEXT_FRAME
-	};
-
 	enum DefaultCanvasItemTextureFilter {
 		DEFAULT_CANVAS_ITEM_TEXTURE_FILTER_NEAREST,
 		DEFAULT_CANVAS_ITEM_TEXTURE_FILTER_LINEAR,
@@ -173,8 +159,6 @@ private:
 	Listener *listener;
 	Set<Listener *> listeners;
 
-	bool arvr;
-
 	struct CameraOverrideData {
 		Transform transform;
 		enum Projection {
@@ -213,23 +197,17 @@ private:
 	Transform2D global_canvas_transform;
 	Transform2D stretch_transform;
 
-	Size2 size;
-	Rect2 to_screen_rect;
-	bool render_direct_to_screen;
+	Size2i size;
+	Size2i size_override;
+	bool size_allocated;
 
 	RID contact_2d_debug;
 	RID contact_3d_debug_multimesh;
 	RID contact_3d_debug_instance;
 
-	bool size_override;
-	bool size_override_stretch;
-	Size2 size_override_size;
-	Size2 size_override_margin;
-
 	Rect2 last_vp_rect;
 
 	bool transparent_bg;
-	ClearMode clear_mode;
 	bool filter;
 	bool gen_mipmaps;
 
@@ -265,6 +243,7 @@ private:
 	Ref<World> world;
 	Ref<World> own_world;
 
+	Rect2i to_screen_rect;
 	StringName input_group;
 	StringName gui_input_group;
 	StringName unhandled_input_group;
@@ -277,10 +256,8 @@ private:
 	void _propagate_exit_world(Node *p_node);
 	void _propagate_viewport_notification(Node *p_node, int p_what);
 
-	void _update_stretch_transform();
 	void _update_global_transform();
 
-	UpdateMode update_mode;
 	RID texture_rid;
 
 	DebugDraw debug_draw;
@@ -323,6 +300,7 @@ private:
 		List<Control *> roots;
 		int canvas_sort_index; //for sorting items with canvas as root
 		bool dragging;
+		bool embed_subwindows_hint;
 
 		GUI();
 	} gui;
@@ -422,6 +400,11 @@ private:
 	void _own_world_changed();
 
 protected:
+	void _set_size(const Size2i &p_size, const Size2i &p_size_override, const Rect2i &p_to_screen_rect, const Transform2D &p_stretch_transform, bool p_allocated);
+
+	Size2i _get_size() const;
+	bool _is_size_allocated() const;
+
 	void _notification(int p_what);
 	static void _bind_methods();
 	virtual void _validate_property(PropertyInfo &property) const;
@@ -439,19 +422,14 @@ public:
 	void set_camera_override_perspective(float p_fovy_degrees, float p_z_near, float p_z_far);
 	void set_camera_override_orthogonal(float p_size, float p_z_near, float p_z_far);
 
-	void set_use_arvr(bool p_use_arvr);
-	bool use_arvr();
-
 	void set_as_audio_listener(bool p_enable);
 	bool is_audio_listener() const;
 
 	void set_as_audio_listener_2d(bool p_enable);
 	bool is_audio_listener_2d() const;
 
-	void set_size(const Size2 &p_size);
 	void update_canvas_items();
 
-	Size2 get_size() const;
 	Rect2 get_visible_rect() const;
 	RID get_viewport_rid() const;
 
@@ -480,18 +458,6 @@ public:
 	void set_transparent_background(bool p_enable);
 	bool has_transparent_background() const;
 
-	void set_size_override(bool p_enable, const Size2 &p_size = Size2(-1, -1), const Vector2 &p_margin = Vector2());
-	Size2 get_size_override() const;
-
-	bool is_size_override_enabled() const;
-	void set_size_override_stretch(bool p_enable);
-	bool is_size_override_stretch_enabled() const;
-
-	void set_clear_mode(ClearMode p_mode);
-	ClearMode get_clear_mode() const;
-
-	void set_update_mode(UpdateMode p_mode);
-	UpdateMode get_update_mode() const;
 	Ref<ViewportTexture> get_texture() const;
 
 	void set_shadow_atlas_size(int p_size);
@@ -515,12 +481,6 @@ public:
 	void set_disable_input(bool p_disable);
 	bool is_input_disabled() const;
 
-	void set_attach_to_screen_rect(const Rect2 &p_rect);
-	Rect2 get_attach_to_screen_rect() const;
-
-	void set_use_render_direct_to_screen(bool p_render_direct_to_screen);
-	bool is_using_render_direct_to_screen() const;
-
 	Vector2 get_mouse_position() const;
 	void warp_mouse(const Vector2 &p_pos);
 
@@ -561,17 +521,66 @@ public:
 	void set_default_canvas_item_texture_repeat(DefaultCanvasItemTextureRepeat p_repeat);
 	DefaultCanvasItemTextureRepeat get_default_canvas_item_texture_repeat() const;
 
-	DisplayServer::WindowID get_window_id() const;
+	virtual DisplayServer::WindowID get_window_id() const = 0;
+
+	void set_embed_subwindows_hint(bool p_embed);
+	bool get_embed_subwindows_hint() const;
+	bool is_embedding_subwindows() const;
 
+	Viewport *get_parent_viewport() const;
 	Viewport();
 	~Viewport();
 };
 
-VARIANT_ENUM_CAST(Viewport::UpdateMode);
+class SubViewport : public Viewport {
+
+	GDCLASS(SubViewport, Viewport);
+
+public:
+	enum ClearMode {
+
+		CLEAR_MODE_ALWAYS,
+		CLEAR_MODE_NEVER,
+		CLEAR_MODE_ONLY_NEXT_FRAME
+	};
+
+	enum UpdateMode {
+		UPDATE_DISABLED,
+		UPDATE_ONCE, //then goes to disabled
+		UPDATE_WHEN_VISIBLE, // default
+		UPDATE_ALWAYS
+	};
+
+private:
+	UpdateMode update_mode;
+	ClearMode clear_mode;
+	bool arvr;
+
+protected:
+	static void _bind_methods();
+	virtual DisplayServer::WindowID get_window_id() const;
+
+public:
+	void set_size(const Size2i &p_size);
+	Size2i get_size() const;
+
+	void set_use_arvr(bool p_use_arvr);
+	bool is_using_arvr();
+
+	void set_update_mode(UpdateMode p_mode);
+	UpdateMode get_update_mode() const;
+
+	void set_clear_mode(ClearMode p_mode);
+	ClearMode get_clear_mode() const;
+
+	SubViewport();
+	~SubViewport();
+};
+VARIANT_ENUM_CAST(SubViewport::UpdateMode);
 VARIANT_ENUM_CAST(Viewport::ShadowAtlasQuadrantSubdiv);
 VARIANT_ENUM_CAST(Viewport::MSAA);
 VARIANT_ENUM_CAST(Viewport::DebugDraw);
-VARIANT_ENUM_CAST(Viewport::ClearMode);
+VARIANT_ENUM_CAST(SubViewport::ClearMode);
 VARIANT_ENUM_CAST(Viewport::RenderInfo);
 VARIANT_ENUM_CAST(Viewport::DefaultCanvasItemTextureFilter);
 VARIANT_ENUM_CAST(Viewport::DefaultCanvasItemTextureRepeat);
diff --git a/scene/main/window.cpp b/scene/main/window.cpp
new file mode 100644
index 0000000000..21e7450b9f
--- /dev/null
+++ b/scene/main/window.cpp
@@ -0,0 +1,489 @@
+/*************************************************************************/
+/*  window.cpp                                                           */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2020 Godot Engine contributors (cf. AUTHORS.md).   */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#include "window.h"
+
+#include "scene/resources/dynamic_font.h"
+
+void Window::set_title(const String &p_title) {
+	title = p_title;
+	if (window_id == DisplayServer::INVALID_WINDOW_ID)
+		return;
+	DisplayServer::get_singleton()->window_set_title(p_title, window_id);
+}
+String Window::get_title() const {
+	return title;
+}
+
+void Window::set_current_screen(int p_screen) {
+	current_screen = p_screen;
+	if (window_id == DisplayServer::INVALID_WINDOW_ID)
+		return;
+	DisplayServer::get_singleton()->window_set_current_screen(p_screen, window_id);
+}
+int Window::get_current_screen() const {
+	if (window_id != DisplayServer::INVALID_WINDOW_ID) {
+		current_screen = DisplayServer::get_singleton()->window_get_current_screen(window_id);
+	}
+	return current_screen;
+}
+
+void Window::set_position(const Point2i &p_position) {
+
+	position = p_position;
+	if (window_id == DisplayServer::INVALID_WINDOW_ID)
+		return;
+	DisplayServer::get_singleton()->window_set_position(p_position, window_id);
+}
+Point2i Window::get_position() const {
+	if (window_id != DisplayServer::INVALID_WINDOW_ID) {
+		position = DisplayServer::get_singleton()->window_get_position(window_id);
+	}
+	return position;
+}
+
+void Window::set_size(const Size2i &p_size) {
+	size = p_size;
+	if (window_id == DisplayServer::INVALID_WINDOW_ID) {
+		DisplayServer::get_singleton()->window_set_size(p_size, window_id);
+	}
+	_update_size();
+}
+Size2i Window::get_size() const {
+	if (window_id != DisplayServer::INVALID_WINDOW_ID) {
+		size = DisplayServer::get_singleton()->window_get_size(window_id);
+	}
+	return size;
+}
+
+Size2i Window::get_real_size() const {
+
+	if (window_id != DisplayServer::INVALID_WINDOW_ID) {
+		return DisplayServer::get_singleton()->window_get_real_size(window_id);
+	}
+	return size;
+}
+
+void Window::set_max_size(const Size2i &p_max_size) {
+	max_size = p_max_size;
+	if (window_id == DisplayServer::INVALID_WINDOW_ID)
+		return;
+	DisplayServer::get_singleton()->window_set_max_size(p_max_size, window_id);
+}
+Size2i Window::get_max_size() const {
+	if (window_id != DisplayServer::INVALID_WINDOW_ID) {
+		max_size = DisplayServer::get_singleton()->window_get_max_size(window_id);
+	}
+	return max_size;
+}
+
+void Window::set_min_size(const Size2i &p_min_size) {
+	min_size = p_min_size;
+	if (window_id == DisplayServer::INVALID_WINDOW_ID)
+		return;
+	DisplayServer::get_singleton()->window_set_min_size(p_min_size, window_id);
+}
+Size2i Window::get_min_size() const {
+	if (window_id != DisplayServer::INVALID_WINDOW_ID) {
+		min_size = DisplayServer::get_singleton()->window_get_min_size(window_id);
+	}
+	return min_size;
+}
+
+void Window::set_mode(Mode p_mode) {
+
+	mode = p_mode;
+	if (window_id == DisplayServer::INVALID_WINDOW_ID)
+		return;
+	DisplayServer::get_singleton()->window_set_mode(DisplayServer::WindowMode(p_mode), window_id);
+}
+
+Window::Mode Window::get_mode() const {
+
+	if (window_id != DisplayServer::INVALID_WINDOW_ID) {
+		mode = (Mode)DisplayServer::get_singleton()->window_get_mode(window_id);
+	}
+	return mode;
+}
+
+void Window::set_flag(Flags p_flag, bool p_enabled) {
+	ERR_FAIL_INDEX(p_flag, FLAG_MAX);
+	flags[p_flag] = p_enabled;
+	if (window_id == DisplayServer::INVALID_WINDOW_ID)
+		return;
+	DisplayServer::get_singleton()->window_set_flag(DisplayServer::WindowFlags(p_flag), p_enabled, window_id);
+}
+
+bool Window::get_flag(Flags p_flag) const {
+	ERR_FAIL_INDEX_V(p_flag, FLAG_MAX, false);
+	if (window_id != DisplayServer::INVALID_WINDOW_ID) {
+		flags[p_flag] = DisplayServer::get_singleton()->window_get_flag(DisplayServer::WindowFlags(p_flag), window_id);
+	}
+	return flags[p_flag];
+}
+
+bool Window::is_maximize_allowed() const {
+	if (window_id != DisplayServer::INVALID_WINDOW_ID) {
+		return DisplayServer::get_singleton()->window_is_maximize_allowed(window_id);
+	}
+	return true;
+}
+
+void Window::request_attention() {
+	if (window_id != DisplayServer::INVALID_WINDOW_ID) {
+		DisplayServer::get_singleton()->window_request_attention(window_id);
+	}
+}
+void Window::move_to_foreground() {
+	if (window_id != DisplayServer::INVALID_WINDOW_ID) {
+		DisplayServer::get_singleton()->window_move_to_foreground(window_id);
+	}
+}
+
+bool Window::can_draw() const {
+	if (!is_inside_tree()) {
+		return false;
+	}
+	if (window_id != DisplayServer::INVALID_WINDOW_ID) {
+		return DisplayServer::get_singleton()->window_can_draw(window_id);
+	}
+
+	return true;
+}
+
+void Window::set_ime_active(bool p_active) {
+	if (window_id != DisplayServer::INVALID_WINDOW_ID) {
+		DisplayServer::get_singleton()->window_set_ime_active(p_active, window_id);
+	}
+}
+void Window::set_ime_position(const Point2i &p_pos) {
+	if (window_id != DisplayServer::INVALID_WINDOW_ID) {
+		DisplayServer::get_singleton()->window_set_ime_position(p_pos, window_id);
+	}
+}
+
+bool Window::is_embedded() const {
+	ERR_FAIL_COND_V(!is_inside_tree(), false);
+	if (get_parent_viewport()) {
+		return get_parent_viewport()->is_embedding_subwindows();
+	} else {
+		return false;
+	}
+}
+
+void Window::_make_window() {
+	ERR_FAIL_COND(window_id != DisplayServer::INVALID_WINDOW_ID);
+
+	uint32_t f = 0;
+	for (int i = 0; i < FLAG_MAX; i++) {
+		if (flags[i]) {
+			f |= (1 << i);
+		}
+	}
+	window_id = DisplayServer::get_singleton()->create_sub_window(DisplayServer::WindowMode(mode), f, Rect2i(position, size));
+	ERR_FAIL_COND(window_id == DisplayServer::INVALID_WINDOW_ID);
+	DisplayServer::get_singleton()->window_set_current_screen(current_screen, window_id);
+	DisplayServer::get_singleton()->window_set_max_size(max_size, window_id);
+	DisplayServer::get_singleton()->window_set_min_size(min_size, window_id);
+	DisplayServer::get_singleton()->window_set_title(title, window_id);
+
+	_update_size();
+}
+void Window::_update_from_window() {
+
+	ERR_FAIL_COND(window_id == DisplayServer::INVALID_WINDOW_ID);
+	mode = (Mode)DisplayServer::get_singleton()->window_get_mode(window_id);
+	for (int i = 0; i < FLAG_MAX; i++) {
+		flags[i] = DisplayServer::get_singleton()->window_get_flag(DisplayServer::WindowFlags(i), window_id);
+	}
+	position = DisplayServer::get_singleton()->window_get_position(window_id);
+	size = DisplayServer::get_singleton()->window_get_size(window_id);
+	max_size = DisplayServer::get_singleton()->window_get_max_size(window_id);
+	min_size = DisplayServer::get_singleton()->window_get_min_size(window_id);
+}
+
+void Window::_clear_window() {
+	ERR_FAIL_COND(window_id == DisplayServer::INVALID_WINDOW_ID);
+	_update_from_window();
+	DisplayServer::get_singleton()->delete_sub_window(window_id);
+	window_id = DisplayServer::INVALID_WINDOW_ID;
+	_update_size();
+}
+
+void Window::_resize_callback(const Size2i &p_callback) {
+	size = p_callback;
+	_update_size();
+}
+
+void Window::set_visible(bool p_visible) {
+	if (visible == p_visible) {
+		return;
+	}
+
+	if (!is_inside_tree()) {
+		return;
+	}
+
+	bool subwindow = get_parent() && get_parent()->get_viewport()->is_embedding_subwindows();
+
+	visible = p_visible;
+
+	if (!subwindow) {
+		if (p_visible && window_id != DisplayServer::INVALID_WINDOW_ID) {
+			_clear_window();
+		}
+		if (!p_visible && window_id == DisplayServer::INVALID_WINDOW_ID) {
+			_make_window();
+		}
+	} else {
+		_update_size();
+	}
+}
+bool Window::is_visible() const {
+	return visible;
+}
+
+void Window::_update_size() {
+
+	Size2i final_size;
+	Size2i final_size_override;
+	Rect2i attach_to_screen_rect(Point2i(), size);
+	Transform2D stretch_transform;
+	float font_oversampling = 1.0;
+
+	if (content_scale_mode == CONTENT_SCALE_MODE_DISABLED || content_scale_size.x == 0 || content_scale_size.y == 0) {
+
+		stretch_transform = Transform2D();
+		final_size = size;
+
+	} else {
+
+		//actual screen video mode
+		Size2 video_mode = size;
+		Size2 desired_res = content_scale_size;
+
+		Size2 viewport_size;
+		Size2 screen_size;
+
+		float viewport_aspect = desired_res.aspect();
+		float video_mode_aspect = video_mode.aspect();
+
+		if (content_scale_aspect == CONTENT_SCALE_ASPECT_IGNORE || Math::is_equal_approx(viewport_aspect, video_mode_aspect)) {
+			//same aspect or ignore aspect
+			viewport_size = desired_res;
+			screen_size = video_mode;
+		} else if (viewport_aspect < video_mode_aspect) {
+			// screen ratio is smaller vertically
+
+			if (content_scale_aspect == CONTENT_SCALE_ASPECT_KEEP_HEIGHT || content_scale_aspect == CONTENT_SCALE_ASPECT_EXPAND) {
+
+				//will stretch horizontally
+				viewport_size.x = desired_res.y * video_mode_aspect;
+				viewport_size.y = desired_res.y;
+				screen_size = video_mode;
+
+			} else {
+				//will need black bars
+				viewport_size = desired_res;
+				screen_size.x = video_mode.y * viewport_aspect;
+				screen_size.y = video_mode.y;
+			}
+		} else {
+			//screen ratio is smaller horizontally
+			if (content_scale_aspect == CONTENT_SCALE_ASPECT_KEEP_WIDTH || content_scale_aspect == CONTENT_SCALE_ASPECT_EXPAND) {
+
+				//will stretch horizontally
+				viewport_size.x = desired_res.x;
+				viewport_size.y = desired_res.x / video_mode_aspect;
+				screen_size = video_mode;
+
+			} else {
+				//will need black bars
+				viewport_size = desired_res;
+				screen_size.x = video_mode.x;
+				screen_size.y = video_mode.x / viewport_aspect;
+			}
+		}
+
+		screen_size = screen_size.floor();
+		viewport_size = viewport_size.floor();
+
+		Size2 margin;
+		Size2 offset;
+		//black bars and margin
+		if (content_scale_aspect != CONTENT_SCALE_ASPECT_EXPAND && screen_size.x < video_mode.x) {
+			margin.x = Math::round((video_mode.x - screen_size.x) / 2.0);
+			//VisualServer::get_singleton()->black_bars_set_margins(margin.x, 0, margin.x, 0);
+			offset.x = Math::round(margin.x * viewport_size.y / screen_size.y);
+		} else if (content_scale_aspect != CONTENT_SCALE_ASPECT_EXPAND && screen_size.y < video_mode.y) {
+			margin.y = Math::round((video_mode.y - screen_size.y) / 2.0);
+			//VisualServer::get_singleton()->black_bars_set_margins(0, margin.y, 0, margin.y);
+			offset.y = Math::round(margin.y * viewport_size.x / screen_size.x);
+		} else {
+			//VisualServer::get_singleton()->black_bars_set_margins(0, 0, 0, 0);
+		}
+
+		switch (content_scale_mode) {
+			case CONTENT_SCALE_MODE_DISABLED: {
+				// Already handled above
+				//_update_font_oversampling(1.0);
+			} break;
+			case CONTENT_SCALE_MODE_OBJECTS: {
+
+				final_size = screen_size;
+				final_size_override = viewport_size;
+				attach_to_screen_rect = Rect2(margin, screen_size);
+				font_oversampling = screen_size.x / viewport_size.x;
+			} break;
+			case CONTENT_SCALE_MODE_PIXELS: {
+
+				final_size = viewport_size;
+				attach_to_screen_rect = Rect2(margin, screen_size);
+
+			} break;
+		}
+
+		Size2 scale = size / (Vector2(final_size) + margin * 2);
+		stretch_transform.scale(scale);
+		stretch_transform.elements[2] = margin * scale;
+	}
+
+	bool allocate = is_inside_tree() && visible && (window_id != DisplayServer::INVALID_WINDOW_ID || (get_parent() && get_parent()->get_viewport()->is_embedding_subwindows()));
+
+	_set_size(final_size, final_size_override, attach_to_screen_rect, stretch_transform, allocate);
+
+	if (window_id != DisplayServer::INVALID_WINDOW_ID) {
+		VisualServer::get_singleton()->viewport_attach_to_screen(get_viewport_rid(), attach_to_screen_rect, window_id);
+	} else {
+		VisualServer::get_singleton()->viewport_attach_to_screen(get_viewport_rid(), Rect2i(), DisplayServer::INVALID_WINDOW_ID);
+	}
+
+	if (window_id == DisplayServer::MAIN_WINDOW_ID) {
+
+		if (!use_font_oversampling) {
+			font_oversampling = 1.0;
+		}
+		if (DynamicFontAtSize::font_oversampling != font_oversampling) {
+
+			DynamicFontAtSize::font_oversampling = font_oversampling;
+			DynamicFont::update_oversampling();
+		}
+	}
+}
+
+void Window::_notification(int p_what) {
+	if (p_what == NOTIFICATION_ENTER_TREE) {
+		if (is_embedded()) {
+			//create as embedded
+			_update_size();
+		} else {
+			if (get_parent() == nullptr) {
+				//it's the root window!
+				window_id = DisplayServer::MAIN_WINDOW_ID;
+				_update_from_window();
+				_update_size();
+				DisplayServer::get_singleton()->window_set_resize_callback(callable_mp(this, &Window::_resize_callback), window_id);
+			} else {
+				//create
+				_make_window();
+				DisplayServer::get_singleton()->window_set_resize_callback(callable_mp(this, &Window::_resize_callback), window_id);
+			}
+		}
+	}
+
+	if (p_what == NOTIFICATION_EXIT_TREE) {
+		if (!is_embedded() && window_id != DisplayServer::INVALID_WINDOW_ID) {
+
+			if (window_id == DisplayServer::MAIN_WINDOW_ID) {
+
+				DisplayServer::get_singleton()->window_set_resize_callback(Callable(), window_id);
+			} else {
+				_clear_window();
+			}
+		} else {
+			_update_size();
+		}
+	}
+}
+
+void Window::set_content_scale_size(const Size2i &p_size) {
+	ERR_FAIL_COND(p_size.x < 0);
+	ERR_FAIL_COND(p_size.y < 0);
+	content_scale_size = p_size;
+	_update_size();
+}
+
+Size2i Window::get_content_scale_size() const {
+	return content_scale_size;
+}
+
+void Window::set_content_scale_mode(const ContentScaleMode &p_mode) {
+	content_scale_mode = p_mode;
+	_update_size();
+}
+Window::ContentScaleMode Window::get_content_scale_mode() const {
+	return content_scale_mode;
+}
+
+void Window::set_content_scale_aspect(const ContentScaleAspect &p_aspect) {
+	content_scale_aspect = p_aspect;
+	_update_size();
+}
+Window::ContentScaleAspect Window::get_content_scale_aspect() const {
+	return content_scale_aspect;
+}
+
+void Window::set_use_font_oversampling(bool p_oversampling) {
+	if (is_inside_tree() && window_id != DisplayServer::MAIN_WINDOW_ID) {
+		ERR_FAIL_MSG("Only the root window can set and use font oversampling.");
+	}
+	use_font_oversampling = p_oversampling;
+	_update_size();
+}
+bool Window::is_using_font_oversampling() const {
+	return use_font_oversampling;
+}
+
+DisplayServer::WindowID Window::get_window_id() const {
+	return window_id;
+}
+
+void Window::_bind_methods() {
+}
+
+Window::Window() {
+	for (int i = 0; i < FLAG_MAX; i++) {
+		flags[i] = false;
+	}
+	content_scale_mode = CONTENT_SCALE_MODE_DISABLED;
+	content_scale_aspect = CONTENT_SCALE_ASPECT_IGNORE;
+}
+Window::~Window() {
+}
diff --git a/scene/main/window.h b/scene/main/window.h
new file mode 100644
index 0000000000..2fd6d993a9
--- /dev/null
+++ b/scene/main/window.h
@@ -0,0 +1,169 @@
+/*************************************************************************/
+/*  window.h                                                             */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2020 Godot Engine contributors (cf. AUTHORS.md).   */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#ifndef WINDOW_H
+#define WINDOW_H
+
+#include "scene/main/viewport.h"
+#include "servers/display_server.h"
+
+class Window : public Viewport {
+	GDCLASS(Window, Viewport)
+public:
+	enum Mode {
+		MODE_WINDOWED = DisplayServer::WINDOW_MODE_WINDOWED,
+		MODE_MINIMIZED = DisplayServer::WINDOW_MODE_MINIMIZED,
+		MODE_MAXIMIZED = DisplayServer::WINDOW_MODE_MAXIMIZED,
+		MODE_FULLSCREEN = DisplayServer::WINDOW_MODE_FULLSCREEN
+	};
+
+	enum Flags {
+		FLAG_RESIZE_DISABLED = DisplayServer::WINDOW_FLAG_RESIZE_DISABLED,
+		FLAG_BORDERLESS = DisplayServer::WINDOW_FLAG_BORDERLESS,
+		FLAG_ALWAYS_ON_TOP = DisplayServer::WINDOW_FLAG_ALWAYS_ON_TOP,
+		FLAG_TRANSPARENT = DisplayServer::WINDOW_FLAG_TRANSPARENT,
+		FLAG_MAX = DisplayServer::WINDOW_FLAG_MAX,
+	};
+
+	enum ContentScaleMode {
+		CONTENT_SCALE_MODE_DISABLED,
+		CONTENT_SCALE_MODE_OBJECTS,
+		CONTENT_SCALE_MODE_PIXELS,
+
+	};
+
+	enum ContentScaleAspect {
+		CONTENT_SCALE_ASPECT_IGNORE,
+		CONTENT_SCALE_ASPECT_KEEP,
+		CONTENT_SCALE_ASPECT_KEEP_WIDTH,
+		CONTENT_SCALE_ASPECT_KEEP_HEIGHT,
+		CONTENT_SCALE_ASPECT_EXPAND,
+
+	};
+	enum {
+		DEFAULT_WINDOW_SIZE = 100
+	};
+
+private:
+	DisplayServer::WindowID window_id = DisplayServer::INVALID_WINDOW_ID;
+
+	String title;
+	mutable int current_screen = 0;
+	mutable Vector2i position;
+	mutable Size2i size = Size2i(DEFAULT_WINDOW_SIZE, DEFAULT_WINDOW_SIZE);
+	mutable Size2i min_size;
+	mutable Size2i max_size;
+	mutable Mode mode = MODE_WINDOWED;
+	mutable bool flags[FLAG_MAX];
+	bool visible = true;
+
+	bool use_font_oversampling = false;
+
+	Size2i content_scale_size;
+	ContentScaleMode content_scale_mode;
+	ContentScaleAspect content_scale_aspect;
+
+	void _make_window();
+	void _clear_window();
+	void _update_from_window();
+
+	void _resize_callback(const Size2i &p_callback);
+
+	void _update_size();
+
+	virtual DisplayServer::WindowID get_window_id() const;
+
+protected:
+	static void _bind_methods();
+	void _notification(int p_what);
+
+public:
+	void set_title(const String &p_title);
+	String get_title() const;
+
+	void set_current_screen(int p_screen);
+	int get_current_screen() const;
+
+	void set_position(const Point2i &p_position);
+	Point2i get_position() const;
+
+	void set_size(const Size2i &p_size);
+	Size2i get_size() const;
+
+	Size2i get_real_size() const;
+
+	void set_max_size(const Size2i &p_max_size);
+	Size2i get_max_size() const;
+
+	void set_min_size(const Size2i &p_min_size);
+	Size2i get_min_size() const;
+
+	void set_mode(Mode p_mode);
+	Mode get_mode() const;
+
+	void set_flag(Flags p_flag, bool p_enabled);
+	bool get_flag(Flags p_flag) const;
+
+	bool is_maximize_allowed() const;
+
+	void request_attention();
+	void move_to_foreground();
+
+	void set_visible(bool p_visible);
+	bool is_visible() const;
+
+	bool can_draw() const;
+
+	void set_ime_active(bool p_active);
+	void set_ime_position(const Point2i &p_pos);
+
+	bool is_embedded() const;
+
+	void set_content_scale_size(const Size2i &p_size);
+	Size2i get_content_scale_size() const;
+
+	void set_content_scale_mode(const ContentScaleMode &p_mode);
+	ContentScaleMode get_content_scale_mode() const;
+
+	void set_content_scale_aspect(const ContentScaleAspect &p_aspect);
+	ContentScaleAspect get_content_scale_aspect() const;
+
+	void set_use_font_oversampling(bool p_oversampling);
+	bool is_using_font_oversampling() const;
+	Window();
+	~Window();
+};
+
+VARIANT_ENUM_CAST(Window::Window::Mode);
+VARIANT_ENUM_CAST(Window::Window::Flags);
+VARIANT_ENUM_CAST(Window::ContentScaleMode);
+VARIANT_ENUM_CAST(Window::ContentScaleAspect);
+
+#endif // WINDOW_H
diff --git a/scene/register_scene_types.cpp b/scene/register_scene_types.cpp
index 5b33277fa0..8c4bff16a0 100644
--- a/scene/register_scene_types.cpp
+++ b/scene/register_scene_types.cpp
@@ -128,6 +128,7 @@
 #include "scene/main/scene_tree.h"
 #include "scene/main/timer.h"
 #include "scene/main/viewport.h"
+#include "scene/main/window.h"
 #include "scene/resources/audio_stream_sample.h"
 #include "scene/resources/bit_map.h"
 #include "scene/resources/box_shape.h"
@@ -267,13 +268,14 @@ void register_scene_types() {
 	ClassDB::register_class<Node>();
 	ClassDB::register_virtual_class<InstancePlaceholder>();
 
-	ClassDB::register_class<Viewport>();
+	ClassDB::register_virtual_class<Viewport>();
 	ClassDB::register_class<ViewportTexture>();
 	ClassDB::register_class<HTTPRequest>();
 	ClassDB::register_class<Timer>();
 	ClassDB::register_class<CanvasLayer>();
 	ClassDB::register_class<CanvasModulate>();
 	ClassDB::register_class<ResourcePreloader>();
+	ClassDB::register_class<Window>();
 
 	/* REGISTER GUI */
 	ClassDB::register_class<ButtonGroup>();
diff --git a/scene/resources/world_2d.cpp b/scene/resources/world_2d.cpp
index 6bdc4cf6f0..75bdeeac07 100644
--- a/scene/resources/world_2d.cpp
+++ b/scene/resources/world_2d.cpp
@@ -33,7 +33,7 @@
 #include "core/project_settings.h"
 #include "scene/2d/camera_2d.h"
 #include "scene/2d/visibility_notifier_2d.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 #include "servers/physics_2d_server.h"
 #include "servers/visual_server.h"
 
diff --git a/servers/arvr/arvr_interface.h b/servers/arvr/arvr_interface.h
index f33ddb2411..861061cbf5 100644
--- a/servers/arvr/arvr_interface.h
+++ b/servers/arvr/arvr_interface.h
@@ -33,7 +33,7 @@
 
 #include "core/math/camera_matrix.h"
 #include "core/os/thread_safe.h"
-#include "scene/main/viewport.h"
+#include "scene/main/window.h"
 #include "servers/arvr_server.h"
 
 /**
diff --git a/servers/display_server.cpp b/servers/display_server.cpp
index b1ace561df..598d1734ad 100644
--- a/servers/display_server.cpp
+++ b/servers/display_server.cpp
@@ -93,7 +93,7 @@ bool DisplayServer::screen_is_kept_on() const {
 	return false;
 }
 
-DisplayServer::WindowID DisplayServer::create_sub_window(WindowMode p_mode, uint32_t p_flags, const Rect2i) {
+DisplayServer::WindowID DisplayServer::create_sub_window(WindowMode p_mode, uint32_t p_flags, const Rect2i &) {
 	ERR_FAIL_V_MSG(INVALID_WINDOW_ID, "Sub-windows not supported by this display server.");
 }
 void DisplayServer::delete_sub_window(WindowID p_id) {
@@ -274,6 +274,7 @@ void DisplayServer::_bind_methods() {
 
 	ClassDB::bind_method(D_METHOD("window_get_size", "window_id"), &DisplayServer::window_get_size, DEFVAL(MAIN_WINDOW_ID));
 	ClassDB::bind_method(D_METHOD("window_set_size", "size", "window_id"), &DisplayServer::window_set_size, DEFVAL(MAIN_WINDOW_ID));
+	ClassDB::bind_method(D_METHOD("window_set_resize_callback", "callback", "window_id"), &DisplayServer::window_set_resize_callback, DEFVAL(MAIN_WINDOW_ID));
 
 	ClassDB::bind_method(D_METHOD("window_get_max_size", "window_id"), &DisplayServer::window_get_max_size, DEFVAL(MAIN_WINDOW_ID));
 	ClassDB::bind_method(D_METHOD("window_set_max_size", "max_size", "window_id"), &DisplayServer::window_set_max_size, DEFVAL(MAIN_WINDOW_ID));
diff --git a/servers/display_server.h b/servers/display_server.h
index 94848153ce..8dc2497762 100644
--- a/servers/display_server.h
+++ b/servers/display_server.h
@@ -31,6 +31,7 @@
 #ifndef DISPLAY_SERVER_H
 #define DISPLAY_SERVER_H
 
+#include "core/callable.h"
 #include "core/input/input.h"
 #include "core/os/os.h"
 #include "core/resource.h"
@@ -177,9 +178,10 @@ public:
 		WINDOW_FLAG_TRANSPARENT_BIT = (1 << WINDOW_FLAG_TRANSPARENT)
 	};
 
-	virtual WindowID create_sub_window(WindowMode p_mode, uint32_t p_flags, const Rect2i = Rect2i());
+	virtual WindowID create_sub_window(WindowMode p_mode, uint32_t p_flags, const Rect2i & = Rect2i());
 	virtual void delete_sub_window(WindowID p_id);
 
+	virtual void window_set_resize_callback(const Callable &p_callable, WindowID p_window = MAIN_WINDOW_ID) = 0;
 	virtual void window_set_title(const String &p_title, WindowID p_window = MAIN_WINDOW_ID) = 0;
 
 	virtual int window_get_current_screen(WindowID p_window = MAIN_WINDOW_ID) const = 0;
diff --git a/servers/visual/rasterizer.h b/servers/visual/rasterizer.h
index 84eda2d80c..d5d32c8d47 100644
--- a/servers/visual/rasterizer.h
+++ b/servers/visual/rasterizer.h
@@ -1294,7 +1294,7 @@ public:
 	};
 
 	virtual void prepare_for_blitting_render_targets() = 0;
-	virtual void blit_render_targets_to_screen(int p_screen, const BlitToScreen *p_render_targets, int p_amount) = 0;
+	virtual void blit_render_targets_to_screen(DisplayServer::WindowID p_screen, const BlitToScreen *p_render_targets, int p_amount) = 0;
 
 	virtual void end_frame(bool p_swap_buffers) = 0;
 	virtual void finalize() = 0;
diff --git a/servers/visual/rasterizer_rd/rasterizer_rd.cpp b/servers/visual/rasterizer_rd/rasterizer_rd.cpp
index 206320376b..9c54f0caae 100644
--- a/servers/visual/rasterizer_rd/rasterizer_rd.cpp
+++ b/servers/visual/rasterizer_rd/rasterizer_rd.cpp
@@ -34,7 +34,7 @@ void RasterizerRD::prepare_for_blitting_render_targets() {
 	RD::get_singleton()->prepare_screen_for_drawing();
 }
 
-void RasterizerRD::blit_render_targets_to_screen(int p_screen, const BlitToScreen *p_render_targets, int p_amount) {
+void RasterizerRD::blit_render_targets_to_screen(DisplayServer::WindowID p_screen, const BlitToScreen *p_render_targets, int p_amount) {
 
 	RD::DrawListID draw_list = RD::get_singleton()->draw_list_begin_for_screen(p_screen);
 
diff --git a/servers/visual/rasterizer_rd/rasterizer_rd.h b/servers/visual/rasterizer_rd/rasterizer_rd.h
index d14e9fb36e..bbcf9bfefe 100644
--- a/servers/visual/rasterizer_rd/rasterizer_rd.h
+++ b/servers/visual/rasterizer_rd/rasterizer_rd.h
@@ -66,7 +66,7 @@ public:
 	void initialize();
 	void begin_frame(double frame_step);
 	void prepare_for_blitting_render_targets();
-	void blit_render_targets_to_screen(int p_screen, const BlitToScreen *p_render_targets, int p_amount);
+	void blit_render_targets_to_screen(DisplayServer::WindowID p_screen, const BlitToScreen *p_render_targets, int p_amount);
 
 	void end_frame(bool p_swap_buffers);
 	void finalize();
diff --git a/servers/visual/rendering_device.h b/servers/visual/rendering_device.h
index ed55afd961..4705bcaa75 100644
--- a/servers/visual/rendering_device.h
+++ b/servers/visual/rendering_device.h
@@ -32,6 +32,7 @@
 #define RENDERING_DEVICE_H
 
 #include "core/object.h"
+#include "servers/display_server.h"
 
 class RenderingDevice : public Object {
 	GDCLASS(RenderingDevice, Object)
@@ -896,8 +897,8 @@ public:
 	/**** SCREEN ****/
 	/****************/
 
-	virtual int screen_get_width(int p_screen = 0) const = 0;
-	virtual int screen_get_height(int p_screen = 0) const = 0;
+	virtual int screen_get_width(DisplayServer::WindowID p_screen = 0) const = 0;
+	virtual int screen_get_height(DisplayServer::WindowID p_screen = 0) const = 0;
 	virtual FramebufferFormatID screen_get_framebuffer_format() const = 0;
 
 	/********************/
@@ -920,7 +921,7 @@ public:
 
 	typedef int64_t DrawListID;
 
-	virtual DrawListID draw_list_begin_for_screen(int p_screen = 0, const Color &p_clear_color = Color()) = 0;
+	virtual DrawListID draw_list_begin_for_screen(DisplayServer::WindowID p_screen = 0, const Color &p_clear_color = Color()) = 0;
 	virtual DrawListID draw_list_begin(RID p_framebuffer, InitialAction p_initial_color_action, FinalAction p_final_color_action, InitialAction p_initial_depth_action, FinalAction p_final_depth_action, const Vector<Color> &p_clear_color_values = Vector<Color>(), float p_clear_depth = 1.0, uint32_t p_clear_stencil = 0, const Rect2 &p_region = Rect2()) = 0;
 	virtual Error draw_list_begin_split(RID p_framebuffer, uint32_t p_splits, DrawListID *r_split_ids, InitialAction p_initial_color_action, FinalAction p_final_color_action, InitialAction p_initial_depth_action, FinalAction p_final_depth_action, const Vector<Color> &p_clear_color_values = Vector<Color>(), float p_clear_depth = 1.0, uint32_t p_clear_stencil = 0, const Rect2 &p_region = Rect2()) = 0;
 
diff --git a/servers/visual/visual_server_raster.h b/servers/visual/visual_server_raster.h
index b6afbbff93..1a40fc96a2 100644
--- a/servers/visual/visual_server_raster.h
+++ b/servers/visual/visual_server_raster.h
@@ -466,7 +466,6 @@ public:
 
 	BIND3(viewport_attach_to_screen, RID, const Rect2 &, int)
 	BIND2(viewport_set_render_direct_to_screen, RID, bool)
-	BIND1(viewport_detach, RID)
 
 	BIND2(viewport_set_update_mode, RID, ViewportUpdateMode)
 	BIND2(viewport_set_vflip, RID, bool)
diff --git a/servers/visual/visual_server_viewport.cpp b/servers/visual/visual_server_viewport.cpp
index 43262042cc..aca96d6552 100644
--- a/servers/visual/visual_server_viewport.cpp
+++ b/servers/visual/visual_server_viewport.cpp
@@ -312,7 +312,7 @@ void VisualServerViewport::draw_viewports() {
 	//sort viewports
 	active_viewports.sort_custom<ViewportSort>();
 
-	Map<int, Vector<Rasterizer::BlitToScreen>> blit_to_screen_list;
+	Map<DisplayServer::WindowID, Vector<Rasterizer::BlitToScreen>> blit_to_screen_list;
 	//draw viewports
 	RENDER_TIMESTAMP(">Render Viewports");
 
@@ -389,11 +389,16 @@ void VisualServerViewport::draw_viewports() {
 			vp->render_info[VS::VIEWPORT_RENDER_INFO_SURFACE_CHANGES_IN_FRAME] = VSG::storage->get_captured_render_info(VS::INFO_SURFACE_CHANGES_IN_FRAME);
 			vp->render_info[VS::VIEWPORT_RENDER_INFO_DRAW_CALLS_IN_FRAME] = VSG::storage->get_captured_render_info(VS::INFO_DRAW_CALLS_IN_FRAME);
 
-			if (vp->viewport_to_screen_rect != Rect2() && (!vp->viewport_render_direct_to_screen || !VSG::rasterizer->is_low_end())) {
+			if (vp->viewport_to_screen != DisplayServer::INVALID_WINDOW_ID && (!vp->viewport_render_direct_to_screen || !VSG::rasterizer->is_low_end())) {
 				//copy to screen if set as such
 				Rasterizer::BlitToScreen blit;
 				blit.render_target = vp->render_target;
-				blit.rect = vp->viewport_to_screen_rect;
+				if (vp->viewport_to_screen_rect != Rect2()) {
+					blit.rect = vp->viewport_to_screen_rect;
+				} else {
+					blit.rect.position = Vector2();
+					blit.rect.size = vp->size;
+				}
 
 				if (!blit_to_screen_list.has(vp->viewport_to_screen)) {
 					blit_to_screen_list[vp->viewport_to_screen] = Vector<Rasterizer::BlitToScreen>();
@@ -450,13 +455,15 @@ void VisualServerViewport::viewport_set_size(RID p_viewport, int p_width, int p_
 	Viewport *viewport = viewport_owner.getornull(p_viewport);
 	ERR_FAIL_COND(!viewport);
 
-	//	if (viewport->size.width == p_width && viewport->size.height == p_height) {
-	//		return; //nothing to do
-	//	}
 	viewport->size = Size2(p_width, p_height);
 	VSG::storage->render_target_set_size(viewport->render_target, p_width, p_height);
 	if (viewport->render_buffers.is_valid()) {
-		VSG::scene_render->render_buffers_configure(viewport->render_buffers, viewport->render_target, viewport->size.width, viewport->size.height, viewport->msaa);
+		if (p_width == 0 || p_height == 0) {
+			VSG::scene_render->free(viewport->render_buffers);
+			viewport->render_buffers = RID();
+		} else {
+			VSG::scene_render->render_buffers_configure(viewport->render_buffers, viewport->render_target, viewport->size.width, viewport->size.height, viewport->msaa);
+		}
 	}
 }
 
@@ -489,21 +496,34 @@ void VisualServerViewport::viewport_set_clear_mode(RID p_viewport, VS::ViewportC
 	viewport->clear_mode = p_clear_mode;
 }
 
-void VisualServerViewport::viewport_attach_to_screen(RID p_viewport, const Rect2 &p_rect, int p_screen) {
+void VisualServerViewport::viewport_attach_to_screen(RID p_viewport, const Rect2 &p_rect, DisplayServer::WindowID p_screen) {
 
 	Viewport *viewport = viewport_owner.getornull(p_viewport);
 	ERR_FAIL_COND(!viewport);
 
-	// If using GLES2 we can optimize this operation by rendering directly to system_fbo
-	// instead of rendering to fbo and copying to system_fbo after
-	if (VSG::rasterizer->is_low_end() && viewport->viewport_render_direct_to_screen) {
+	if (p_screen != DisplayServer::INVALID_WINDOW_ID) {
+		// If using GLES2 we can optimize this operation by rendering directly to system_fbo
+		// instead of rendering to fbo and copying to system_fbo after
+		if (VSG::rasterizer->is_low_end() && viewport->viewport_render_direct_to_screen) {
 
-		VSG::storage->render_target_set_size(viewport->render_target, p_rect.size.x, p_rect.size.y);
-		VSG::storage->render_target_set_position(viewport->render_target, p_rect.position.x, p_rect.position.y);
-	}
+			VSG::storage->render_target_set_size(viewport->render_target, p_rect.size.x, p_rect.size.y);
+			VSG::storage->render_target_set_position(viewport->render_target, p_rect.position.x, p_rect.position.y);
+		}
+
+		viewport->viewport_to_screen_rect = p_rect;
+		viewport->viewport_to_screen = p_screen;
+	} else {
+
+		// if render_direct_to_screen was used, reset size and position
+		if (VSG::rasterizer->is_low_end() && viewport->viewport_render_direct_to_screen) {
+
+			VSG::storage->render_target_set_position(viewport->render_target, 0, 0);
+			VSG::storage->render_target_set_size(viewport->render_target, viewport->size.x, viewport->size.y);
+		}
 
-	viewport->viewport_to_screen_rect = p_rect;
-	viewport->viewport_to_screen = p_screen;
+		viewport->viewport_to_screen_rect = Rect2();
+		viewport->viewport_to_screen = DisplayServer::INVALID_WINDOW_ID;
+	}
 }
 
 void VisualServerViewport::viewport_set_render_direct_to_screen(RID p_viewport, bool p_enable) {
@@ -531,22 +551,6 @@ void VisualServerViewport::viewport_set_render_direct_to_screen(RID p_viewport,
 	}
 }
 
-void VisualServerViewport::viewport_detach(RID p_viewport) {
-
-	Viewport *viewport = viewport_owner.getornull(p_viewport);
-	ERR_FAIL_COND(!viewport);
-
-	// if render_direct_to_screen was used, reset size and position
-	if (VSG::rasterizer->is_low_end() && viewport->viewport_render_direct_to_screen) {
-
-		VSG::storage->render_target_set_position(viewport->render_target, 0, 0);
-		VSG::storage->render_target_set_size(viewport->render_target, viewport->size.x, viewport->size.y);
-	}
-
-	viewport->viewport_to_screen_rect = Rect2();
-	viewport->viewport_to_screen = 0;
-}
-
 void VisualServerViewport::viewport_set_update_mode(RID p_viewport, VS::ViewportUpdateMode p_mode) {
 
 	Viewport *viewport = viewport_owner.getornull(p_viewport);
diff --git a/servers/visual/visual_server_viewport.h b/servers/visual/visual_server_viewport.h
index 30b53f3935..38983d5e8a 100644
--- a/servers/visual/visual_server_viewport.h
+++ b/servers/visual/visual_server_viewport.h
@@ -60,7 +60,7 @@ public:
 
 		VS::ViewportMSAA msaa;
 
-		int viewport_to_screen;
+		DisplayServer::WindowID viewport_to_screen;
 		Rect2 viewport_to_screen_rect;
 		bool viewport_render_direct_to_screen;
 
@@ -117,7 +117,7 @@ public:
 			clear_mode = VS::VIEWPORT_CLEAR_ALWAYS;
 			transparent_bg = false;
 			disable_environment = false;
-			viewport_to_screen = 0;
+			viewport_to_screen = DisplayServer::INVALID_WINDOW_ID;
 			shadow_atlas_size = 0;
 			keep_3d_linear = false;
 			debug_draw = VS::VIEWPORT_DEBUG_DRAW_DISABLED;
@@ -158,9 +158,8 @@ public:
 
 	void viewport_set_size(RID p_viewport, int p_width, int p_height);
 
-	void viewport_attach_to_screen(RID p_viewport, const Rect2 &p_rect = Rect2(), int p_screen = 0);
+	void viewport_attach_to_screen(RID p_viewport, const Rect2 &p_rect = Rect2(), DisplayServer::WindowID p_screen = DisplayServer::MAIN_WINDOW_ID);
 	void viewport_set_render_direct_to_screen(RID p_viewport, bool p_enable);
-	void viewport_detach(RID p_viewport);
 
 	void viewport_set_active(RID p_viewport, bool p_active);
 	void viewport_set_parent_viewport(RID p_viewport, RID p_parent_viewport);
diff --git a/servers/visual/visual_server_wrap_mt.h b/servers/visual/visual_server_wrap_mt.h
index 0d4683e43d..e043ac5214 100644
--- a/servers/visual/visual_server_wrap_mt.h
+++ b/servers/visual/visual_server_wrap_mt.h
@@ -379,9 +379,8 @@ public:
 
 	FUNC2(viewport_set_clear_mode, RID, ViewportClearMode)
 
-	FUNC3(viewport_attach_to_screen, RID, const Rect2 &, int)
+	FUNC3(viewport_attach_to_screen, RID, const Rect2 &, DisplayServer::WindowID)
 	FUNC2(viewport_set_render_direct_to_screen, RID, bool)
-	FUNC1(viewport_detach, RID)
 
 	FUNC2(viewport_set_update_mode, RID, ViewportUpdateMode)
 
diff --git a/servers/visual_server.cpp b/servers/visual_server.cpp
index b50ad89b1e..62c3704f5b 100644
--- a/servers/visual_server.cpp
+++ b/servers/visual_server.cpp
@@ -1769,9 +1769,9 @@ void VisualServer::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("viewport_set_size", "viewport", "width", "height"), &VisualServer::viewport_set_size);
 	ClassDB::bind_method(D_METHOD("viewport_set_active", "viewport", "active"), &VisualServer::viewport_set_active);
 	ClassDB::bind_method(D_METHOD("viewport_set_parent_viewport", "viewport", "parent_viewport"), &VisualServer::viewport_set_parent_viewport);
-	ClassDB::bind_method(D_METHOD("viewport_attach_to_screen", "viewport", "rect", "screen"), &VisualServer::viewport_attach_to_screen, DEFVAL(Rect2()), DEFVAL(0));
+	ClassDB::bind_method(D_METHOD("viewport_attach_to_screen", "viewport", "rect", "screen"), &VisualServer::viewport_attach_to_screen, DEFVAL(Rect2()), DEFVAL(DisplayServer::MAIN_WINDOW_ID));
 	ClassDB::bind_method(D_METHOD("viewport_set_render_direct_to_screen", "viewport", "enabled"), &VisualServer::viewport_set_render_direct_to_screen);
-	ClassDB::bind_method(D_METHOD("viewport_detach", "viewport"), &VisualServer::viewport_detach);
+
 	ClassDB::bind_method(D_METHOD("viewport_set_update_mode", "viewport", "update_mode"), &VisualServer::viewport_set_update_mode);
 	ClassDB::bind_method(D_METHOD("viewport_set_clear_mode", "viewport", "clear_mode"), &VisualServer::viewport_set_clear_mode);
 	ClassDB::bind_method(D_METHOD("viewport_get_texture", "viewport"), &VisualServer::viewport_get_texture);
diff --git a/servers/visual_server.h b/servers/visual_server.h
index dfe5e7feed..d41c80dfa1 100644
--- a/servers/visual_server.h
+++ b/servers/visual_server.h
@@ -37,6 +37,7 @@
 #include "core/object.h"
 #include "core/rid.h"
 #include "core/variant.h"
+#include "servers/display_server.h"
 
 class VisualServer : public Object {
 
@@ -584,9 +585,8 @@ public:
 	virtual void viewport_set_active(RID p_viewport, bool p_active) = 0;
 	virtual void viewport_set_parent_viewport(RID p_viewport, RID p_parent_viewport) = 0;
 
-	virtual void viewport_attach_to_screen(RID p_viewport, const Rect2 &p_rect = Rect2(), int p_screen = 0) = 0;
+	virtual void viewport_attach_to_screen(RID p_viewport, const Rect2 &p_rect = Rect2(), DisplayServer::WindowID p_screen = DisplayServer::MAIN_WINDOW_ID) = 0;
 	virtual void viewport_set_render_direct_to_screen(RID p_viewport, bool p_enable) = 0;
-	virtual void viewport_detach(RID p_viewport) = 0;
 
 	enum ViewportUpdateMode {
 		VIEWPORT_UPDATE_DISABLED,