pelya 2010-07-12 03:53:48 PDT

In function GLES_RenderCopy() in SDL_renderer_gles.c:819 there is one memcpy()
that can be avoided if we're updating whole texture.
Because of that the SDL 1.3 in compatibility mode is working even slower than
software rendering in SDL 1.2.

src/video/SDL_renderer_gles.c

@@ -822,20 +822,25 @@ GLES_RenderCopy(SDL_Renderer * renderer, SDL_Texture * texture,
                maybe it'd be a good idea to keep a temp buffer around
                for this purpose rather than allocating it each time
              */
-            temp_buffer = SDL_malloc(rect->w * rect->h * bpp);
-            temp_ptr = temp_buffer;
-            for (i = 0; i < rect->h; i++) {
-                SDL_memcpy(temp_ptr, pixels, rect->w * bpp);
-                temp_ptr += rect->w * bpp;
-                pixels += pitch;
+            if( rect->x == 0 && rect->w * bpp == pitch ) {
+                temp_buffer = pixels; /* Updating whole texture, no need to reformat */
+            } else {
+                temp_buffer = SDL_malloc(rect->w * rect->h * bpp);
+                temp_ptr = temp_buffer;
+                for (i = 0; i < rect->h; i++) {
+                    SDL_memcpy(temp_ptr, pixels, rect->w * bpp);
+                    temp_ptr += rect->w * bpp;
+                    pixels += pitch;
+                }
             }
 
             data->glTexSubImage2D(texturedata->type, 0, rect->x, rect->y,
                                   rect->w, rect->h, texturedata->format,
                                   texturedata->formattype, temp_buffer);
 
-            SDL_free(temp_buffer);
-
+            if( temp_buffer != pixels ) {
+                SDL_free(temp_buffer);
+            }
         }
         SDL_ClearDirtyRects(&texturedata->dirty);
     }