preparation to receive camera image data from physics server

increase shadowmap world size default to 50 units (meter), 10 units (meter) was too small for most examples.

examples/OpenGLWindow/SimpleOpenGL3App.h

@@ -24,6 +24,7 @@ struct SimpleOpenGL3App : public CommonGraphicsApp
 	virtual void registerGrid(int xres, int yres, float color0[4], float color1[4]);
     void dumpNextFrameToPng(const char* pngFilename);
     void dumpFramesToVideo(const char* mp4Filename);
+    void getScreenPixels(unsigned char* rgbaBuffer, int bufferSizeInBytes);
     
 	void drawGrid(DrawGridData data=DrawGridData());
 	virtual void setUpAxis(int axis);