source: GTP/trunk/App/Demos/Vis/FriendlyCulling/src/SsaoShader.h @ 2859

#ifndef _SsaoShader_H__
#define _SsaoShader_H__

#include "common.h"
#include "glInterface.h"
#include <Cg/cg.h>
#include <Cg/cgGL.h>


namespace CHCDemoEngine 
{ 

class FrameBufferObject;


/** This class implements a deferred shading algorithm that takes
        a frame buffer object as input and outputs an image in the given size
*/
class SsaoShader
{
public:
        /** constructor for a deferred shader taking the requested output image size,
                the exponential smoothing factor for temporal reprojection.
                
                The last parameter is a just a scale factor
                for the scene depth in order to get better floating point precision in the shader
                This must be reciprocal value of the scale factor used in the mrt shader.
        */
        SsaoShader(int w, int h, float expFactor, float scaleFactor);
        /** The algorithm renders the scene given an fbo.
                The fbo must have color buffer, position buffer, normal buffer.
        */
        void Render(FrameBufferObject *fbo, FrameBufferObject *fbo2);

        /** Initialises the deferred shader and loads the required shaders:
                This function has to be called only once.
        */
        static void Init(CGcontext context);


protected:

        void FirstPass(FrameBufferObject *fbo, FrameBufferObject *fbo2);

        void SecondPass(FrameBufferObject *fbo, FrameBufferObject *fbo2);


        ////////////

        int mWidth;
        int mHeight;

        /// the temporal smoothing factor
        float mExpFactor;
        /// this is just a scale factor for the scene depth in order to get better float precision in the shader
        float mScaleFactor;
};

} // namespace 
#endif // _SsaoShader_H__