add compute shader renderer properly to the GUI

also add option to toggle using high resolution vertex coordinates

src/GPU.h

@@ -160,6 +160,7 @@ struct RenderSettings
 
     int GL_ScaleFactor;
     bool GL_BetterPolygons;
+    bool GL_HiresCoordinates;
 };
 
 
@@ -170,6 +171,16 @@ void Stop();
 
 void DoSavestate(Savestate* file);
 
+enum
+{
+    renderer3D_Software = 0,
+#ifdef OGLRENDERER_ENABLED
+    renderer3D_OpenGL,
+    renderer3D_OpenGLCompute,
+#endif
+    renderer3D_Max,
+};
+
 void InitRenderer(int renderer);
 void DeInitRenderer();
 void ResetRenderer();