ogc: avoid copying to XFB when clearing with a render target

If we are rendering to a texture, we must avoid writing to the XFB,
because the image we are rendering might not be intended to be shown
as-is on the XFB.
So, when clearing the display, pay attention to whether we are rendering
to a texture and, in that case, do not copy the EFB to the XFB. Instead,
copy it to the texture itself (not that we care a lot about this copy,
since the texture will anyway be overwitten once it stops being a render
target; but we do care about this operation causing a full clearing of
the EFB).

Author: mardy

src/render/ogc/SDL_render_ogc.c

@@ -384,7 +384,11 @@ static int OGC_RenderClear(SDL_Renderer *renderer, SDL_RenderCommand *cmd)
 
     data->clear_color = c;
     GX_SetCopyClear(c, GX_MAX_Z24);
-    GX_CopyDisp(OGC_video_get_xfb(SDL_GetVideoDevice()), GX_TRUE);
+    if (renderer->target) {
+        save_efb_to_texture(renderer->target);
+    } else {
+        GX_CopyDisp(OGC_video_get_xfb(SDL_GetVideoDevice()), GX_TRUE);
+    }
 
     return 0;
 }