Update README-vita.md

docs/README-vita.md

@@ -22,6 +22,9 @@ Notes
 * gles1/gles2 support and renderers are disabled by default and can be enabled by configuring with `-DVIDEO_VITA_PVR=ON`
   These renderers support 720p and 1080i resolutions. These can be specified with: 
   `SDL_setenv("VITA_RESOLUTION", "720", 1);` and `SDL_setenv("VITA_RESOLUTION", "1080", 1);`
+* Desktop GL 1.X and 2.X support and renderers are also disabled by default and also can be enabled with `-DVIDEO_VITA_PVR=ON` as long as gl4es4vita is present in your SDK.
+  They support the same resolutions as the gles1/gles2 backends and require specifying `SDL_setenv("VITA_PVR_OGL", "1", 1);`
+  anytime before window creation.
 * gles2 support via PIB is disabled by default and can be enabled by configuring with `-DVIDEO_VITA_PIB=ON`
 * By default SDL emits mouse events for touch events on every touchscreen.  
   Vita has two touchscreens, so it's recommended to use `SDL_SetHint(SDL_HINT_TOUCH_MOUSE_EVENTS, "0");` and handle touch events instead.