Adding Variable Rate Shading support to Godot

Improve GI renderer and add VRS support
Implement render device has_feature and move subgroup settings to limit_get

3 files changed, 251 insertions, 5 deletions

diff --git a/servers/rendering/renderer_rd/effects/copy_effects.cpp b/servers/rendering/renderer_rd/effects/copy_effects.cpp
index c30e8ed58f..cbf7046887 100644
--- a/servers/rendering/renderer_rd/effects/copy_effects.cpp
+++ b/servers/rendering/renderer_rd/effects/copy_effects.cpp
@@ -100,11 +100,11 @@ CopyEffects::CopyEffects(bool p_prefer_raster_effects) {
 
 	{
 		Vector<String> copy_modes;
-		copy_modes.push_back("\n");
-		copy_modes.push_back("\n#define MODE_PANORAMA_TO_DP\n");
-		copy_modes.push_back("\n#define MODE_TWO_SOURCES\n");
-		copy_modes.push_back("\n#define MULTIVIEW\n");
-		copy_modes.push_back("\n#define MULTIVIEW\n#define MODE_TWO_SOURCES\n");
+		copy_modes.push_back("\n"); // COPY_TO_FB_COPY
+		copy_modes.push_back("\n#define MODE_PANORAMA_TO_DP\n"); // COPY_TO_FB_COPY_PANORAMA_TO_DP
+		copy_modes.push_back("\n#define MODE_TWO_SOURCES\n"); // COPY_TO_FB_COPY2
+		copy_modes.push_back("\n#define MULTIVIEW\n"); // COPY_TO_FB_MULTIVIEW
+		copy_modes.push_back("\n#define MULTIVIEW\n#define MODE_TWO_SOURCES\n"); // COPY_TO_FB_MULTIVIEW_WITH_DEPTH
 
 		copy_to_fb.shader.initialize(copy_modes);
 
diff --git a/servers/rendering/renderer_rd/effects/vrs.cpp b/servers/rendering/renderer_rd/effects/vrs.cpp
new file mode 100644
index 0000000000..505a35a269
--- /dev/null
+++ b/servers/rendering/renderer_rd/effects/vrs.cpp
@@ -0,0 +1,171 @@
+/*************************************************************************/
+/*  vrs.cpp                                                              */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2022 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2022 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 "vrs.h"
+#include "../renderer_compositor_rd.h"
+#include "../storage_rd/texture_storage.h"
+#include "../uniform_set_cache_rd.h"
+#include "servers/xr_server.h"
+
+using namespace RendererRD;
+
+VRS::VRS() {
+	{
+		Vector<String> vrs_modes;
+		vrs_modes.push_back("\n"); // VRS_DEFAULT
+		vrs_modes.push_back("\n#define MULTIVIEW\n"); // VRS_MULTIVIEW
+
+		vrs_shader.shader.initialize(vrs_modes);
+
+		if (!RendererCompositorRD::singleton->is_xr_enabled()) {
+			vrs_shader.shader.set_variant_enabled(VRS_MULTIVIEW, false);
+		}
+
+		vrs_shader.shader_version = vrs_shader.shader.version_create();
+
+		//use additive
+
+		for (int i = 0; i < VRS_MAX; i++) {
+			if (vrs_shader.shader.is_variant_enabled(i)) {
+				vrs_shader.pipelines[i].setup(vrs_shader.shader.version_get_shader(vrs_shader.shader_version, i), RD::RENDER_PRIMITIVE_TRIANGLES, RD::PipelineRasterizationState(), RD::PipelineMultisampleState(), RD::PipelineDepthStencilState(), RD::PipelineColorBlendState::create_disabled(), 0);
+			} else {
+				vrs_shader.pipelines[i].clear();
+			}
+		}
+	}
+}
+
+VRS::~VRS() {
+	vrs_shader.shader.version_free(vrs_shader.shader_version);
+}
+
+void VRS::copy_vrs(RID p_source_rd_texture, RID p_dest_framebuffer, bool p_multiview) {
+	UniformSetCacheRD *uniform_set_cache = UniformSetCacheRD::get_singleton();
+	ERR_FAIL_NULL(uniform_set_cache);
+	MaterialStorage *material_storage = MaterialStorage::get_singleton();
+	ERR_FAIL_NULL(material_storage);
+
+	// setup our uniforms
+	RID default_sampler = material_storage->sampler_rd_get_default(RS::CANVAS_ITEM_TEXTURE_FILTER_NEAREST, RS::CANVAS_ITEM_TEXTURE_REPEAT_DISABLED);
+
+	RD::Uniform u_source_rd_texture(RD::UNIFORM_TYPE_SAMPLER_WITH_TEXTURE, 0, Vector<RID>({ default_sampler, p_source_rd_texture }));
+
+	VRSMode mode = p_multiview ? VRS_MULTIVIEW : VRS_DEFAULT;
+
+	RID shader = vrs_shader.shader.version_get_shader(vrs_shader.shader_version, mode);
+	ERR_FAIL_COND(shader.is_null());
+
+	RD::DrawListID draw_list = RD::get_singleton()->draw_list_begin(p_dest_framebuffer, RD::INITIAL_ACTION_KEEP, RD::FINAL_ACTION_READ, RD::INITIAL_ACTION_KEEP, RD::FINAL_ACTION_DISCARD, Vector<Color>());
+	RD::get_singleton()->draw_list_bind_render_pipeline(draw_list, vrs_shader.pipelines[mode].get_render_pipeline(RD::INVALID_ID, RD::get_singleton()->framebuffer_get_format(p_dest_framebuffer)));
+	RD::get_singleton()->draw_list_bind_uniform_set(draw_list, uniform_set_cache->get_cache(shader, 0, u_source_rd_texture), 0);
+	RD::get_singleton()->draw_list_bind_index_array(draw_list, material_storage->get_quad_index_array());
+	// RD::get_singleton()->draw_list_set_push_constant(draw_list, &vrs_shader.push_constant, sizeof(VRSPushConstant));
+	RD::get_singleton()->draw_list_draw(draw_list, true);
+	RD::get_singleton()->draw_list_end();
+}
+
+void VRS::create_vrs_texture(const int p_base_width, const int p_base_height, const uint32_t p_view_count, RID &p_vrs_texture, RID &p_vrs_fb) {
+	// TODO find a way to skip this if VRS is not supported, but we don't have access to VulkanContext here, even though we're in vulkan.. hmmm
+
+	// TODO we should find some way to store this properly, we're assuming 16x16 as this seems to be the standard but in our vrs_capacities we
+	// obtain a minimum and maximum size, and we should choose something within this range and then make sure that is consistantly set when creating
+	// our frame buffer. Also it is important that we make the resulting size we calculate down below available to the end user so they know the size
+	// of the VRS buffer to supply.
+	Size2i texel_size = Size2i(16, 16);
+
+	RD::TextureFormat tf;
+	if (p_view_count > 1) {
+		tf.texture_type = RD::TEXTURE_TYPE_2D_ARRAY;
+	} else {
+		tf.texture_type = RD::TEXTURE_TYPE_2D;
+	}
+	tf.format = RD::DATA_FORMAT_R8_UINT;
+	tf.width = p_base_width / texel_size.x;
+	if (p_base_width % texel_size.x != 0) {
+		tf.width++;
+	}
+	tf.height = p_base_height / texel_size.y;
+	if (p_base_height % texel_size.y != 0) {
+		tf.height++;
+	}
+	tf.array_layers = p_view_count; // create a layer for every view
+	tf.usage_bits = RD::TEXTURE_USAGE_COLOR_ATTACHMENT_BIT | RD::TEXTURE_USAGE_VRS_ATTACHMENT_BIT | RD::TEXTURE_USAGE_SAMPLING_BIT | RD::TEXTURE_USAGE_STORAGE_BIT;
+	tf.samples = RD::TEXTURE_SAMPLES_1;
+
+	p_vrs_texture = RD::get_singleton()->texture_create(tf, RD::TextureView());
+
+	// by default VRS is assumed to be our VRS attachment, but if we need to write into it, we need a bit more control
+	Vector<RID> fb;
+	fb.push_back(p_vrs_texture);
+
+	RD::FramebufferPass pass;
+	pass.color_attachments.push_back(0);
+
+	Vector<RD::FramebufferPass> passes;
+	passes.push_back(pass);
+
+	p_vrs_fb = RD::get_singleton()->framebuffer_create_multipass(fb, passes, RenderingDevice::INVALID_ID, p_view_count);
+}
+
+void VRS::update_vrs_texture(RID p_vrs_fb, RID p_render_target) {
+	TextureStorage *texture_storage = TextureStorage::get_singleton();
+	RS::ViewportVRSMode vrs_mode = texture_storage->render_target_get_vrs_mode(p_render_target);
+
+	if (vrs_mode != RS::VIEWPORT_VRS_DISABLED) {
+		RD::get_singleton()->draw_command_begin_label("VRS Setup");
+
+		// TODO figure out if image has changed since it was last copied so we can save some resources..
+
+		if (vrs_mode == RS::VIEWPORT_VRS_TEXTURE) {
+			RID vrs_texture = texture_storage->render_target_get_vrs_texture(p_render_target);
+			if (vrs_texture.is_valid()) {
+				Texture *texture = texture_storage->get_texture(vrs_texture);
+				if (texture) {
+					// Copy into our density buffer
+					copy_vrs(texture->rd_texture, p_vrs_fb, texture->layers > 1);
+				}
+			}
+		} else if (vrs_mode == RS::VIEWPORT_VRS_XR) {
+			Ref<XRInterface> interface = XRServer::get_singleton()->get_primary_interface();
+			if (interface.is_valid()) {
+				RID vrs_texture = interface->get_vrs_texture();
+				if (vrs_texture.is_valid()) {
+					Texture *texture = texture_storage->get_texture(vrs_texture);
+					if (texture) {
+						// Copy into our density buffer
+						copy_vrs(texture->rd_texture, p_vrs_fb, texture->layers > 1);
+					}
+				}
+			}
+		}
+
+		RD::get_singleton()->draw_command_end_label();
+	}
+}
diff --git a/servers/rendering/renderer_rd/effects/vrs.h b/servers/rendering/renderer_rd/effects/vrs.h
new file mode 100644
index 0000000000..0f2bdd31b6
--- /dev/null
+++ b/servers/rendering/renderer_rd/effects/vrs.h
@@ -0,0 +1,75 @@
+/*************************************************************************/
+/*  vrs.h                                                                */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2022 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2022 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 VRS_RD_H
+#define VRS_RD_H
+
+#include "servers/rendering/renderer_rd/pipeline_cache_rd.h"
+#include "servers/rendering/renderer_rd/shaders/effects/vrs.glsl.gen.h"
+#include "servers/rendering/renderer_scene_render.h"
+
+#include "servers/rendering_server.h"
+
+namespace RendererRD {
+
+class VRS {
+private:
+	enum VRSMode {
+		VRS_DEFAULT,
+		VRS_MULTIVIEW,
+		VRS_MAX,
+	};
+
+	/* we have no push constant here (yet)
+	struct VRSPushConstant {
+
+	};
+	*/
+
+	struct VRSShader {
+		// VRSPushConstant push_constant;
+		VrsShaderRD shader;
+		RID shader_version;
+		PipelineCacheRD pipelines[VRS_MAX];
+	} vrs_shader;
+
+public:
+	VRS();
+	~VRS();
+
+	void copy_vrs(RID p_source_rd_texture, RID p_dest_framebuffer, bool p_multiview = false);
+
+	void create_vrs_texture(const int p_base_width, const int p_base_height, const uint32_t p_view_count, RID &p_vrs_texture, RID &p_vrs_fb);
+	void update_vrs_texture(RID p_vrs_fb, RID p_render_target);
+};
+
+} // namespace RendererRD
+
+#endif // !VRS_RD_H