Fixed loading textures when the window starts hidden.

The viewport automatically resets to the window size when you programmatically resize the window.

src/render/SDL_sysrender.h

@@ -100,7 +100,8 @@ struct SDL_Renderer
 
     /* The window associated with the renderer */
     SDL_Window *window;
-    SDL_bool minimized;
+    SDL_bool hidden;
+    SDL_bool resized;
 
     /* The drawable area within the window */
     SDL_Rect viewport;