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

Still a lot of work to do.

13 files changed, 57 insertions, 52 deletions

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,