Add dependency detection improvements to the render graph.

- Buffers changing their usage are no longer treated as write usage unless the API requires it.
- Draw lists are not treated as being dependent on each other if their regions do not intersect despite both being write commands.
- Particles were tweaked to use different unused buffers to reduce dependencies.

drivers/d3d12/rendering_device_driver_d3d12.cpp

@@ -6177,6 +6177,8 @@ uint64_t RenderingDeviceDriverD3D12::api_trait_get(ApiTrait p_trait) {
 			return false;
 		case API_TRAIT_USE_GENERAL_IN_COPY_QUEUES:
 			return true;
+		case API_TRAIT_BUFFERS_REQUIRE_TRANSITIONS:
+			return !barrier_capabilities.enhanced_barriers_supported;
 		default:
 			return RenderingDeviceDriver::api_trait_get(p_trait);
 	}

servers/rendering/renderer_rd/effects/copy_effects.cpp

@@ -1002,15 +1002,19 @@ void CopyEffects::copy_cubemap_to_dp(RID p_source_rd_texture, RID p_dst_framebuf
 	MaterialStorage *material_storage = MaterialStorage::get_singleton();
 	ERR_FAIL_NULL(material_storage);
 
+	Rect2i screen_rect;
+	float atlas_width = p_dst_size.width / p_rect.size.width;
+	float atlas_height = p_dst_size.height / p_rect.size.height;
+	screen_rect.position.x = (int32_t)(Math::round(p_rect.position.x * atlas_width));
+	screen_rect.position.y = (int32_t)(Math::round(p_rect.position.y * atlas_height));
+	screen_rect.size.width = (int32_t)(Math::round(p_dst_size.width));
+	screen_rect.size.height = (int32_t)(Math::round(p_dst_size.height));
+
 	CopyToDPPushConstant push_constant;
-	push_constant.screen_rect[0] = p_rect.position.x;
-	push_constant.screen_rect[1] = p_rect.position.y;
-	push_constant.screen_rect[2] = p_rect.size.width;
-	push_constant.screen_rect[3] = p_rect.size.height;
 	push_constant.z_far = p_z_far;
 	push_constant.z_near = p_z_near;
-	push_constant.texel_size[0] = 1.0f / p_dst_size.x;
-	push_constant.texel_size[1] = 1.0f / p_dst_size.y;
+	push_constant.texel_size[0] = 1.0f / p_dst_size.width;
+	push_constant.texel_size[1] = 1.0f / p_dst_size.height;
 	push_constant.texel_size[0] *= p_dp_flip ? -1.0f : 1.0f; // Encode dp flip as x size sign
 
 	// setup our uniforms
@@ -1021,7 +1025,7 @@ void CopyEffects::copy_cubemap_to_dp(RID p_source_rd_texture, RID p_dst_framebuf
 	RID shader = cube_to_dp.shader.version_get_shader(cube_to_dp.shader_version, 0);
 	ERR_FAIL_COND(shader.is_null());
 
-	RD::DrawListID draw_list = RD::get_singleton()->draw_list_begin(p_dst_framebuffer, RD::INITIAL_ACTION_DISCARD, RD::FINAL_ACTION_DISCARD, RD::INITIAL_ACTION_LOAD, RD::FINAL_ACTION_STORE);
+	RD::DrawListID draw_list = RD::get_singleton()->draw_list_begin(p_dst_framebuffer, RD::INITIAL_ACTION_DISCARD, RD::FINAL_ACTION_DISCARD, RD::INITIAL_ACTION_LOAD, RD::FINAL_ACTION_STORE, Vector<Color>(), 1.0f, 0, screen_rect);
 	RD::get_singleton()->draw_list_bind_render_pipeline(draw_list, cube_to_dp.pipeline.get_render_pipeline(RD::INVALID_ID, RD::get_singleton()->framebuffer_get_format(p_dst_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());

servers/rendering/renderer_rd/effects/copy_effects.h

@@ -217,7 +217,6 @@ private:
 		float z_far;
 		float z_near;
 		float texel_size[2];
-		float screen_rect[4];
 	};
 
 	struct CopyToDP {

servers/rendering/renderer_rd/shaders/effects/cube_to_dp.glsl

@@ -8,7 +8,6 @@ layout(push_constant, std430) uniform Params {
 	float z_far;
 	float z_near;
 	vec2 texel_size;
-	vec4 screen_rect;
 }
 params;
 
@@ -17,8 +16,7 @@ layout(location = 0) out vec2 uv_interp;
 void main() {
 	vec2 base_arr[4] = vec2[](vec2(0.0, 0.0), vec2(0.0, 1.0), vec2(1.0, 1.0), vec2(1.0, 0.0));
 	uv_interp = base_arr[gl_VertexIndex];
-	vec2 screen_pos = uv_interp * params.screen_rect.zw + params.screen_rect.xy;
-	gl_Position = vec4(screen_pos * 2.0 - 1.0, 0.0, 1.0);
+	gl_Position = vec4(uv_interp * 2.0 - 1.0, 0.0, 1.0);
 }
 
 #[fragment]
@@ -35,7 +33,6 @@ layout(push_constant, std430) uniform Params {
 	float z_far;
 	float z_near;
 	vec2 texel_size;
-	vec4 screen_rect;
 }
 params;
 

servers/rendering/renderer_rd/storage_rd/particles_storage.cpp

@@ -306,9 +306,14 @@ void ParticlesStorage::_particles_free_data(Particles *particles) {
 		particles->emission_storage_buffer = RID();
 	}
 
-	if (particles->unused_storage_buffer.is_valid()) {
-		RD::get_singleton()->free(particles->unused_storage_buffer);
-		particles->unused_storage_buffer = RID();
+	if (particles->unused_emission_storage_buffer.is_valid()) {
+		RD::get_singleton()->free(particles->unused_emission_storage_buffer);
+		particles->unused_emission_storage_buffer = RID();
+	}
+
+	if (particles->unused_trail_storage_buffer.is_valid()) {
+		RD::get_singleton()->free(particles->unused_trail_storage_buffer);
+		particles->unused_trail_storage_buffer = RID();
 	}
 
 	if (RD::get_singleton()->uniform_set_is_valid(particles->particles_material_uniform_set)) {
@@ -534,9 +539,15 @@ void ParticlesStorage::_particles_allocate_emission_buffer(Particles *particles)
 	}
 }
 
-void ParticlesStorage::_particles_ensure_unused_buffer(Particles *particles) {
-	if (particles->unused_storage_buffer.is_null()) {
-		particles->unused_storage_buffer = RD::get_singleton()->storage_buffer_create(sizeof(uint32_t) * 4);
+void ParticlesStorage::_particles_ensure_unused_emission_buffer(Particles *particles) {
+	if (particles->unused_emission_storage_buffer.is_null()) {
+		particles->unused_emission_storage_buffer = RD::get_singleton()->storage_buffer_create(sizeof(uint32_t) * 4);
+	}
+}
+
+void ParticlesStorage::_particles_ensure_unused_trail_buffer(Particles *particles) {
+	if (particles->unused_trail_storage_buffer.is_null()) {
+		particles->unused_trail_storage_buffer = RD::get_singleton()->storage_buffer_create(sizeof(uint32_t) * 4);
 	}
 }
 
@@ -763,8 +774,8 @@ void ParticlesStorage::_particles_process(Particles *p_particles, double p_delta
 			if (p_particles->emission_storage_buffer.is_valid()) {
 				u.append_id(p_particles->emission_storage_buffer);
 			} else {
-				_particles_ensure_unused_buffer(p_particles);
-				u.append_id(p_particles->unused_storage_buffer);
+				_particles_ensure_unused_emission_buffer(p_particles);
+				u.append_id(p_particles->unused_emission_storage_buffer);
 			}
 			uniforms.push_back(u);
 		}
@@ -779,8 +790,8 @@ void ParticlesStorage::_particles_process(Particles *p_particles, double p_delta
 				}
 				u.append_id(sub_emitter->emission_storage_buffer);
 			} else {
-				_particles_ensure_unused_buffer(p_particles);
-				u.append_id(p_particles->unused_storage_buffer);
+				_particles_ensure_unused_emission_buffer(p_particles);
+				u.append_id(p_particles->unused_emission_storage_buffer);
 			}
 			uniforms.push_back(u);
 		}
@@ -1481,8 +1492,8 @@ void ParticlesStorage::update_particles() {
 					if (particles->trail_bind_pose_buffer.is_valid()) {
 						u.append_id(particles->trail_bind_pose_buffer);
 					} else {
-						_particles_ensure_unused_buffer(particles);
-						u.append_id(particles->unused_storage_buffer);
+						_particles_ensure_unused_trail_buffer(particles);
+						u.append_id(particles->unused_trail_storage_buffer);
 					}
 					uniforms.push_back(u);
 				}

servers/rendering/renderer_rd/storage_rd/particles_storage.h

@@ -247,7 +247,8 @@ private:
 		ParticleEmissionBuffer *emission_buffer = nullptr;
 		RID emission_storage_buffer;
 
-		RID unused_storage_buffer;
+		RID unused_emission_storage_buffer;
+		RID unused_trail_storage_buffer;
 
 		HashSet<RID> collisions;
 
@@ -265,7 +266,8 @@ private:
 
 	void _particles_process(Particles *p_particles, double p_delta);
 	void _particles_allocate_emission_buffer(Particles *particles);
-	void _particles_ensure_unused_buffer(Particles *particles);
+	void _particles_ensure_unused_emission_buffer(Particles *particles);
+	void _particles_ensure_unused_trail_buffer(Particles *particles);
 	void _particles_free_data(Particles *particles);
 	void _particles_update_buffers(Particles *particles);
 

servers/rendering/rendering_device_driver.cpp

@@ -376,6 +376,8 @@ uint64_t RenderingDeviceDriver::api_trait_get(ApiTrait p_trait) {
 			return true;
 		case API_TRAIT_USE_GENERAL_IN_COPY_QUEUES:
 			return false;
+		case API_TRAIT_BUFFERS_REQUIRE_TRANSITIONS:
+			return false;
 		default:
 			ERR_FAIL_V(0);
 	}

servers/rendering/rendering_device_driver.h

@@ -756,6 +756,7 @@ public:
 		API_TRAIT_SECONDARY_VIEWPORT_SCISSOR,
 		API_TRAIT_CLEARS_WITH_COPY_ENGINE,
 		API_TRAIT_USE_GENERAL_IN_COPY_QUEUES,
+		API_TRAIT_BUFFERS_REQUIRE_TRANSITIONS,
 	};
 
 	enum ShaderChangeInvalidation {

servers/rendering/rendering_device_graph.cpp

@@ -140,6 +140,25 @@ RDD::BarrierAccessBits RenderingDeviceGraph::_usage_to_access_bits(ResourceUsage
 #endif
 }
 
+bool RenderingDeviceGraph::_check_command_intersection(ResourceTracker *p_resource_tracker, int32_t p_previous_command_index, int32_t p_command_index) const {
+	if (p_resource_tracker->usage != RESOURCE_USAGE_ATTACHMENT_COLOR_READ_WRITE && p_resource_tracker->usage != RESOURCE_USAGE_ATTACHMENT_DEPTH_STENCIL_READ_WRITE) {
+		// We don't check possible intersections for usages that aren't consecutive color or depth writes.
+		return true;
+	}
+
+	const uint32_t previous_command_data_offset = command_data_offsets[p_previous_command_index];
+	const uint32_t current_command_data_offset = command_data_offsets[p_command_index];
+	const RecordedDrawListCommand &previous_draw_list_command = *reinterpret_cast<const RecordedDrawListCommand *>(&command_data[previous_command_data_offset]);
+	const RecordedDrawListCommand &current_draw_list_command = *reinterpret_cast<const RecordedDrawListCommand *>(&command_data[current_command_data_offset]);
+	if (previous_draw_list_command.type != RecordedCommand::TYPE_DRAW_LIST || current_draw_list_command.type != RecordedCommand::TYPE_DRAW_LIST) {
+		// We don't check possible intersections if both commands aren't draw lists.
+		return true;
+	}
+
+	// We check if the region used by both draw lists have an intersection.
+	return previous_draw_list_command.region.intersects(current_draw_list_command.region);
+}
+
 int32_t RenderingDeviceGraph::_add_to_command_list(int32_t p_command_index, int32_t p_list_index) {
 	DEV_ASSERT(p_command_index < int32_t(command_count));
 	DEV_ASSERT(p_list_index < int32_t(command_list_nodes.size()));
@@ -425,11 +444,9 @@ void RenderingDeviceGraph::_add_command_to_graph(ResourceTracker **p_resource_tr
 #if USE_BUFFER_BARRIERS
 				_add_buffer_barrier_to_command(resource_tracker->buffer_driver_id, resource_tracker->usage_access, new_usage_access, r_command->buffer_barrier_index, r_command->buffer_barrier_count);
 #endif
-				// FIXME: Memory barriers are currently pushed regardless of whether buffer barriers are being used or not. Refer to the comment on the
-				// definition of USE_BUFFER_BARRIERS for the reason behind this. This can be fixed to be one case or the other once it's been confirmed
-				// the buffer and memory barrier behavior discrepancy has been solved.
-				r_command->memory_barrier.src_access = resource_tracker->usage_access;
-				r_command->memory_barrier.dst_access = new_usage_access;
+				// Memory barriers are pushed regardless of buffer barriers being used or not.
+				r_command->memory_barrier.src_access = r_command->memory_barrier.src_access | resource_tracker->usage_access;
+				r_command->memory_barrier.dst_access = r_command->memory_barrier.dst_access | new_usage_access;
 			} else {
 				DEV_ASSERT(false && "Resource tracker does not contain a valid buffer or texture ID.");
 			}
@@ -449,10 +466,12 @@ void RenderingDeviceGraph::_add_command_to_graph(ResourceTracker **p_resource_tr
 
 		if (different_usage) {
 			// Even if the usage of the resource isn't a write usage explicitly, a different usage implies a transition and it should therefore be considered a write.
-			write_usage = true;
+			// In the case of buffers however, this is not exactly necessary if the driver does not consider different buffer usages as different states.
+			write_usage = write_usage || bool(resource_tracker->texture_driver_id) || driver_buffers_require_transitions;
 			resource_tracker->usage = new_resource_usage;
 		}
 
+		bool command_intersection_failed = false;
 		if (search_tracker->write_command_or_list_index >= 0) {
 			if (search_tracker->write_command_list_enabled) {
 				// Make this command adjacent to any commands that wrote to this resource and intersect with the slice if it applies.
@@ -464,7 +483,7 @@ void RenderingDeviceGraph::_add_command_to_graph(ResourceTracker **p_resource_tr
 					if (!resource_has_parent || search_tracker_rect.intersects(write_list_node.subresources)) {
 						if (write_list_node.command_index == p_command_index) {
 							ERR_FAIL_COND_MSG(!resource_has_parent, "Command can't have itself as a dependency.");
-						} else {
+						} else if (_check_command_intersection(resource_tracker, write_list_node.command_index, p_command_index)) {
 							// Command is dependent on this command. Add this command to the adjacency list of the write command.
 							_add_adjacent_command(write_list_node.command_index, p_command_index, r_command);
 
@@ -480,6 +499,8 @@ void RenderingDeviceGraph::_add_command_to_graph(ResourceTracker **p_resource_tr
 								write_list_index = write_list_node.next_list_index;
 								continue;
 							}
+						} else {
+							command_intersection_failed = true;
 						}
 					}
 
@@ -490,14 +511,16 @@ void RenderingDeviceGraph::_add_command_to_graph(ResourceTracker **p_resource_tr
 				// The index is just the latest command index that wrote to the resource.
 				if (search_tracker->write_command_or_list_index == p_command_index) {
 					ERR_FAIL_MSG("Command can't have itself as a dependency.");
-				} else {
+				} else if (_check_command_intersection(resource_tracker, search_tracker->write_command_or_list_index, p_command_index)) {
 					_add_adjacent_command(search_tracker->write_command_or_list_index, p_command_index, r_command);
+				} else {
+					command_intersection_failed = true;
 				}
 			}
 		}
 
 		if (write_usage) {
-			if (resource_has_parent) {
+			if (resource_has_parent || command_intersection_failed) {
 				if (!search_tracker->write_command_list_enabled && search_tracker->write_command_or_list_index >= 0) {
 					// Write command list was not being used but there was a write command recorded. Add a new node with the entire parent resource's subresources and the recorded command index to the list.
 					const RDD::TextureSubresourceRange &tracker_subresources = search_tracker->texture_subresources;
@@ -1318,6 +1341,7 @@ void RenderingDeviceGraph::initialize(RDD *p_driver, RenderingContextDriver::Dev
 
 	driver_honors_barriers = driver->api_trait_get(RDD::API_TRAIT_HONORS_PIPELINE_BARRIERS);
 	driver_clears_with_copy_engine = driver->api_trait_get(RDD::API_TRAIT_CLEARS_WITH_COPY_ENGINE);
+	driver_buffers_require_transitions = driver->api_trait_get(RDD::API_TRAIT_BUFFERS_REQUIRE_TRANSITIONS);
 }
 
 void RenderingDeviceGraph::finalize() {

servers/rendering/rendering_device_graph.h

@@ -637,6 +637,7 @@ private:
 	BarrierGroup barrier_group;
 	bool driver_honors_barriers : 1;
 	bool driver_clears_with_copy_engine : 1;
+	bool driver_buffers_require_transitions : 1;
 	WorkaroundsState workarounds_state;
 	TightLocalVector<Frame> frames;
 	uint32_t frame = 0;
@@ -648,6 +649,7 @@ private:
 	static bool _is_write_usage(ResourceUsage p_usage);
 	static RDD::TextureLayout _usage_to_image_layout(ResourceUsage p_usage);
 	static RDD::BarrierAccessBits _usage_to_access_bits(ResourceUsage p_usage);
+	bool _check_command_intersection(ResourceTracker *p_resource_tracker, int32_t p_previous_command_index, int32_t p_command_index) const;
 	int32_t _add_to_command_list(int32_t p_command_index, int32_t p_list_index);
 	void _add_adjacent_command(int32_t p_previous_command_index, int32_t p_command_index, RecordedCommand *r_command);
 	int32_t _add_to_slice_read_list(int32_t p_command_index, Rect2i p_subresources, int32_t p_list_index);