GlowEffect.h

#pragma once

namespace ParaEngine
{
    class CGlowEffect
    {
    public:
        CGlowEffect(void);
        ~CGlowEffect(void);
    public:
        HRESULT InvalidateDeviceObjects(); // called just before device is Reset
        HRESULT RestoreDeviceObjects();    // called when device is restored

        //the first and second parameter on longer stands for blend factor and we don't use bUseAlpha any more;
        //fGlowThreshold : pixel intensity less than fGlowThreshold has no glow effect.
        //fGlowAmount is related to glow area size and weight usually between [0,10] , 0 means no glow   --clayman 2011.7.19
        HRESULT Render(float fGlowThreshold = 0.7f, float fGlowAmount= 2.0f, bool bUseAlpha = false);

        void SaveGlowTexturesToFile(const string& filename);
    private:
        LPDIRECT3DSURFACE9 m_pBackBuffer, m_pZBuffer; 

        LPDIRECT3DTEXTURE9 m_pRTHalfSizeTexture;
        LPDIRECT3DTEXTURE9 m_pRTGlowSourceTexture;
        LPDIRECT3DTEXTURE9 m_pRTBlurHorizTexture;
        LPDIRECT3DTEXTURE9 m_pRTBlurVertTexture; // usually same RT texture as m_pRTGlowSourceTexture

        LPDIRECT3DSURFACE9 m_pRTHalfSizeSurface;
        LPDIRECT3DSURFACE9 m_pRTGlowSourceSurface;
        LPDIRECT3DSURFACE9 m_pRTBlurHorizSurface;
        LPDIRECT3DSURFACE9 m_pRTBlurVertSurface;
        
        float m_glowtextureWidth;
        float m_glowtextureHeight;

        //calculate blurring texture coordinate offset   --clayman 2011.7.19
        void SetBlurEffectParameters(float dx,float dy,float blurAmount,CEffectFile* effect);
        float ComputeGaussian(float n,float blurAmount);
    };

}