Merge pull request #73300 from clayjohn/GL-clear_window

Clear Window before blitting Viewport in gl_compatibility renderer

drivers/gles3/rasterizer_gles3.cpp

@@ -306,6 +306,15 @@ void RasterizerGLES3::_blit_render_target_to_screen(RID p_render_target, Display
 
 	glReadBuffer(GL_COLOR_ATTACHMENT0);
 	glBindFramebuffer(GL_DRAW_FRAMEBUFFER, GLES3::TextureStorage::system_fbo);
+
+	if (p_screen_rect.position != Vector2()) {
+		// Viewport doesn't cover entire window so clear window to black before blitting.
+		Size2i win_size = DisplayServer::get_singleton()->window_get_size();
+		glViewport(0, 0, win_size.width, win_size.height);
+		glClearColor(0.0, 0.0, 0.0, 1.0);
+		glClear(GL_COLOR_BUFFER_BIT);
+	}
+
 	Vector2i screen_rect_end = p_screen_rect.get_end();
 	glBlitFramebuffer(0, 0, rt->size.x, rt->size.y,
 			p_screen_rect.position.x, flip_y ? screen_rect_end.y : p_screen_rect.position.y, screen_rect_end.x, flip_y ? p_screen_rect.position.y : screen_rect_end.y,

scene/main/window.cpp

@@ -984,17 +984,13 @@ void Window::_update_viewport_size() {
 
 		Size2 margin;
 		Size2 offset;
-		//black bars and margin
+
 		if (content_scale_aspect != CONTENT_SCALE_ASPECT_EXPAND && screen_size.x < video_mode.x) {
 			margin.x = Math::round((video_mode.x - screen_size.x) / 2.0);
-			//RenderingServer::get_singleton()->black_bars_set_margins(margin.x, 0, margin.x, 0);
 			offset.x = Math::round(margin.x * viewport_size.y / screen_size.y);
 		} else if (content_scale_aspect != CONTENT_SCALE_ASPECT_EXPAND && screen_size.y < video_mode.y) {
 			margin.y = Math::round((video_mode.y - screen_size.y) / 2.0);
-			//RenderingServer::get_singleton()->black_bars_set_margins(0, margin.y, 0, margin.y);
 			offset.y = Math::round(margin.y * viewport_size.x / screen_size.x);
-		} else {
-			//RenderingServer::get_singleton()->black_bars_set_margins(0, 0, 0, 0);
 		}
 
 		switch (content_scale_mode) {