Implement motion vectors in compatibility renderer

Author: devloglogan

drivers/gles3/rasterizer_canvas_gles3.cpp

@@ -1468,9 +1468,9 @@ void RasterizerCanvasGLES3::_render_batch(Light *p_lights, uint32_t p_index, Ren
 				uint64_t vertex_input_mask = state.canvas_instance_batches[p_index].vertex_input_mask;
 
 				if (mesh_instance.is_valid()) {
-					mesh_storage->mesh_instance_surface_get_vertex_arrays_and_format(mesh_instance, j, vertex_input_mask, vertex_array_gl);
+					mesh_storage->mesh_instance_surface_get_vertex_arrays_and_format(mesh_instance, j, vertex_input_mask, false, vertex_array_gl);
 				} else {
-					mesh_storage->mesh_surface_get_vertex_arrays_and_format(surface, vertex_input_mask, vertex_array_gl);
+					mesh_storage->mesh_surface_get_vertex_arrays_and_format(surface, vertex_input_mask, false, vertex_array_gl);
 				}
 
 				index_array_gl = mesh_storage->mesh_surface_get_index_buffer(surface, 0);

drivers/gles3/rasterizer_scene_gles3.cpp

@@ -62,6 +62,7 @@ enum PassMode {
 	PASS_MODE_SHADOW,
 	PASS_MODE_DEPTH,
 	PASS_MODE_MATERIAL,
+	PASS_MODE_MOTION_VECTORS,
 };
 
 // These should share as much as possible with SkyUniform Location
@@ -301,6 +302,10 @@ class RasterizerSceneGLES3 : public RendererSceneRender {
 		//used during rendering
 		bool store_transform_cache = true;
 
+		// Used for generating motion vectors.
+		Transform3D prev_transform;
+		bool is_prev_transform_stored = false;
+
 		int32_t instance_count = 0;
 
 		bool can_sdfgi = false;
@@ -454,12 +459,16 @@ class RasterizerSceneGLES3 : public RendererSceneRender {
 		};
 		static_assert(sizeof(TonemapUBO) % 16 == 0, "Tonemap UBO size must be a multiple of 16 bytes");
 
-		UBO ubo;
+		UBO data;
+		UBO prev_data;
 		GLuint ubo_buffer = 0;
-		MultiviewUBO multiview_ubo;
+		MultiviewUBO multiview_data;
+		MultiviewUBO prev_multiview_data;
 		GLuint multiview_buffer = 0;
 		GLuint tonemap_buffer = 0;
 
+		bool is_prev_data_stored = false;
+
 		bool used_depth_prepass = false;
 
 		GLES3::SceneShaderData::BlendMode current_blend_mode = GLES3::SceneShaderData::BLEND_MODE_MIX;