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

#ifndef __CASCADED_SHADOW_MAP_H__

#define __CASCADED_SHADOW_MAP_H__

#include "compute_types.h"

#include "texture.h"

#include "camera.h"

#include "aabb.h"

#include "fbo.h"

class CascadedShadowMapper

{

public:

    struct FrustumPartition

    {

        float near;

        float far;

        float fov;

        float aspect;

        float3 corners[8];

        FrustumPartition( void ):

            near(0),

            far(0),

            fov(0),

            aspect(0)

        {

            // EMPTY!

        }

        FrustumPartition( const FrustumPartition &rkOther ):

            near( rkOther.near ),

            far( rkOther.far ),

            fov( rkOther.fov ),

            aspect( rkOther.aspect )

        {

            for ( int i = 0 ; i < 8; i++ ) 

                corners[i] = rkOther.corners[i];

        }

        FrustumPartition &operator = ( const FrustumPartition &rkOther )

        {

            near = rkOther.near;

            far = rkOther.far;

            fov = rkOther.fov;

            aspect = rkOther.aspect;

            for ( int i = 0 ; i < 8; i++ ) 

                corners[i] = rkOther.corners[i];

            return *this;

        }

        aabbf3 getBounds( void ) const

        {

            aabbf3 kAABB;

            for ( int i = 0; i < 8; i++ ) 

                kAABB.extend( corners[i] );

            return kAABB;

        }

    };

public:

    typedef enum PassType 

    {

        PSSM_DEPTH_PASS,

        PSSM_SHADOW_PASS

    };

public:

    CascadedShadowMapper();

    ~CascadedShadowMapper();

    bool setup(

        uint uiWidth, uint uiHeight, 

        uint uiSplitCount, 

        float fNear, float fFar);

    void update(

        const Camera &rkCamera,         

        float fShadowNear = -150.0f, 

        float fShadowFar = +150.0f);

    bool enableDepthPass(uint uiSplit = 0, bool bUseActiveFramebuffer = false);

    bool disableDepthPass(uint uiSplit = 0);  

    bool enableShadowPass(uint uiSplit = 0);

    bool disableShadowPass(uint uiSplit = 0);  

    void setLightDirection(const float3 &rkV);

    void setShadowMapTextureUnit(GLenum eUnit)      { m_eShadowMapTextureUnit = eUnit; }

    uint getSplitCount() const                      { return m_uiSplitCount; }

    GLenum getShadowMapTextureUnit() const          { return m_eShadowMapTextureUnit; }

    Texture getDepthMap()                           { return m_kDepthMap; }

protected:

    void destroy();

    float16 computeProjectionMatrix(

        const float16 &rkOrthoCropMatrix,

        float fNear = -1500.0f, 

        float fFar = +1500.0f);

    float16 computeOrthoCropMatrix(

        const FrustumPartition &rkPartition, 

        const float16 &rkLightModelview,         

        float fShadowNear = -150.0f, 

        float fShadowFar = +150.0f);    

    void computeSplitDistances(

        FrustumPartition *akPartitions, 

        unsigned int uiCount, 

        float fNear, float fFar);

    void computeFrustumCorners(

        FrustumPartition &rkPartition, 

        const float3 &rkCenter, 

        const float3 &rkView, 

        const float3 &rkUp );

    void enableShadowMap(

        float16 &rkProjection, 

        float16 &rkModelView,

        GLenum eTextureUnit);

    void disableShadowMap(void);

    void enableDepthState();

    void disableDepthState();

    void enableDepthCapture(

        float16 &rkProjection,

        float16 &rkModelView,

        bool bUseActiveFramebuffer,

        bool bClear);

    void disableDepthCapture();

    void fillDepthMap(

        const float16 &rkProjection,

        const float16 &rkModelView);

    void renderSceneWithShadows(

        const float16 &rkProjection, 

        const float16 &rkModelView, 

        float fNear, float fFar);

    void renderSceneSplit(void);

protected:

    bool m_bInitialized;

    float* m_afSplitDistances;

    FrustumPartition *m_akSplitPartitions;

    float16 *m_akSplitProjections;

    float16 *m_akSplitBiases;

    uint m_uiSplitCount;

    uint m_uiShadowMapResolution;

    float m_fPolygonOffsetScale;

    float m_fPolygonOffsetBias;

    int m_aiViewport[4];

    float16 m_kLightModelView;

    float16 m_kCameraInverseModelView;

    Texture m_kDepthMap;

    FrameBufferObject m_kFrameBuffer;

    GLenum m_eShadowMapTextureUnit;

};

#endif