Support SCREEN_TEXTURE in GLES2, fixes #25405

drivers/gles2/rasterizer_canvas_gles2.cpp

@@ -1172,7 +1172,7 @@ void RasterizerCanvasGLES2::_canvas_item_render_commands(Item *p_item, Item *cur
 	}
 }
 
-void RasterizerCanvasGLES2::_copy_texscreen(const Rect2 &p_rect) {
+void RasterizerCanvasGLES2::_copy_screen(const Rect2 &p_rect) {
 
 	if (storage->frame.current_rt->copy_screen_effect.color == 0) {
 		ERR_EXPLAIN("Can't use screen texture copying in a render target configured without copy buffers");
@@ -1181,8 +1181,6 @@ void RasterizerCanvasGLES2::_copy_texscreen(const Rect2 &p_rect) {
 
 	glDisable(GL_BLEND);
 
-	state.canvas_texscreen_used = true;
-
 	Vector2 wh(storage->frame.current_rt->width, storage->frame.current_rt->height);
 
 	Color copy_section(p_rect.position.x / wh.x, p_rect.position.y / wh.y, p_rect.size.x / wh.x, p_rect.size.y / wh.y);
@@ -1195,9 +1193,6 @@ void RasterizerCanvasGLES2::_copy_texscreen(const Rect2 &p_rect) {
 	glActiveTexture(GL_TEXTURE0);
 	glBindTexture(GL_TEXTURE_2D, storage->frame.current_rt->color);
 
-	glClearColor(1, 0, 1, 1);
-	glClear(GL_COLOR_BUFFER_BIT);
-
 	storage->shaders.copy.bind();
 	storage->shaders.copy.set_uniform(CopyShaderGLES2::COPY_SECTION, copy_section);
 
@@ -1225,14 +1220,20 @@ void RasterizerCanvasGLES2::_copy_texscreen(const Rect2 &p_rect) {
 	storage->shaders.copy.set_conditional(CopyShaderGLES2::USE_COPY_SECTION, false);
 
 	glBindFramebuffer(GL_FRAMEBUFFER, storage->frame.current_rt->fbo); //back to front
+	glEnable(GL_BLEND);
+}
+
+void RasterizerCanvasGLES2::_copy_texscreen(const Rect2 &p_rect) {
+
+	state.canvas_texscreen_used = true;
+
+	_copy_texscreen(p_rect);
 
 	// back to canvas, force rebind
 	state.using_texture_rect = false;
 	state.canvas_shader.bind();
 	_bind_canvas_texture(state.current_tex, state.current_normal);
 	_set_uniforms();
-
-	glEnable(GL_BLEND);
 }
 
 void RasterizerCanvasGLES2::canvas_render_items(Item *p_item_list, int p_z, const Color &p_modulate, Light *p_light, const Transform2D &p_base_transform) {

drivers/gles2/rasterizer_canvas_gles2.h

@@ -118,6 +118,7 @@ public:
 	_FORCE_INLINE_ void _draw_generic(GLuint p_primitive, int p_vertex_count, const Vector2 *p_vertices, const Vector2 *p_uvs, const Color *p_colors, bool p_singlecolor);
 
 	_FORCE_INLINE_ void _canvas_item_render_commands(Item *p_item, Item *current_clip, bool &reclip, RasterizerStorageGLES2::Material *p_material);
+	void _copy_screen(const Rect2 &p_rect);
 	_FORCE_INLINE_ void _copy_texscreen(const Rect2 &p_rect);
 
 	virtual void canvas_render_items(Item *p_item_list, int p_z, const Color &p_modulate, Light *p_light, const Transform2D &p_base_transform);

drivers/gles2/rasterizer_scene_gles2.cpp

@@ -1178,6 +1178,11 @@ bool RasterizerSceneGLES2::_setup_material(RasterizerStorageGLES2::Material *p_m
 
 	state.scene_shader.set_custom_shader(p_material->shader->custom_code_id);
 
+	if (p_material->shader->spatial.uses_screen_texture && storage->frame.current_rt) {
+		glActiveTexture(GL_TEXTURE0 + storage->config.max_texture_image_units - 4);
+		glBindTexture(GL_TEXTURE_2D, storage->frame.current_rt->copy_screen_effect.color);
+	}
+
 	bool shader_rebind = state.scene_shader.bind();
 
 	if (p_material->shader->spatial.no_depth_test) {
@@ -2593,6 +2598,7 @@ void RasterizerSceneGLES2::render_scene(const Transform &p_cam_transform, const
 		viewport_height = storage->frame.current_rt->height;
 	}
 
+	state.used_screen_texture = false;
 	state.viewport_size.x = viewport_width;
 	state.viewport_size.y = viewport_height;
 	state.screen_pixel_size.x = 1.0 / viewport_width;
@@ -2728,6 +2734,10 @@ void RasterizerSceneGLES2::render_scene(const Transform &p_cam_transform, const
 	render_list.sort_by_key(false);
 	_render_render_list(render_list.elements, render_list.element_count, cam_transform, p_cam_projection, p_shadow_atlas, env, env_radiance_tex, 0.0, 0.0, reverse_cull, false, false);
 
+	if (storage->frame.current_rt && state.used_screen_texture) {
+		//copy screen texture
+		storage->canvas->_copy_screen(Rect2());
+	}
 	// alpha pass
 
 	glBlendEquation(GL_FUNC_ADD);