HACK: make compositor work. Get glname from undistorted texture and put to compositor. need vr_use_offscreen_rendering enabled and multicore rendering disabled to work

public/materialsystem/imaterialsystem.h

@@ -1093,6 +1093,7 @@ public:
 
 	// Performs final verification of all compositor templates (after they've all been initially loaded).
 	virtual bool				VerifyTextureCompositorTemplates( ) = 0;
+	virtual uint32_t GetShaderAPIGLTexture( ITexture *pTexture, int nFrame, int nTextureChannel ) = 0;
 };