optimize a bit rootston renderer if there's no surface transform

rootston/output.c

@@ -63,24 +63,28 @@ static void render_surface(struct wlr_surface *surface,
 			float scale[16];
 			wlr_matrix_scale(&scale, render_width, render_height, 1);
 
-			float surface_translate_center[16];
-			wlr_matrix_translate(&surface_translate_center, 0.5, 0.5, 0);
-
-			float surface_transform[16];
-			wlr_matrix_transform(surface_transform,
-				wlr_output_transform_invert(surface->current->transform));
-
-			float surface_translate_origin[16];
-			wlr_matrix_translate(&surface_translate_origin, -0.5, -0.5, 0);
-
 			float transform[16];
 			wlr_matrix_mul(&translate_center, &rotate, &transform);
 			wlr_matrix_mul(&transform, &translate_origin, &transform);
 			wlr_matrix_mul(&transform, &scale, &transform);
 
-			wlr_matrix_mul(&transform, &surface_translate_center, &transform);
+			if (surface->current->transform != WL_OUTPUT_TRANSFORM_NORMAL) {
-			wlr_matrix_mul(&transform, &surface_transform, &transform);
+				float surface_translate_center[16];
-			wlr_matrix_mul(&transform, &surface_translate_origin, &transform);
+				wlr_matrix_translate(&surface_translate_center, 0.5, 0.5, 0);
+
+				float surface_transform[16];
+				wlr_matrix_transform(surface_transform,
+					wlr_output_transform_invert(surface->current->transform));
+
+				float surface_translate_origin[16];
+				wlr_matrix_translate(&surface_translate_origin, -0.5, -0.5, 0);
+
+				wlr_matrix_mul(&transform, &surface_translate_center,
+					&transform);
+				wlr_matrix_mul(&transform, &surface_transform, &transform);
+				wlr_matrix_mul(&transform, &surface_translate_origin,
+					&transform);
+			}
 
 			wlr_matrix_mul(&wlr_output->transform_matrix, &transform, &matrix);