ShadowVolume.h

#pragma once

namespace ParaEngine
{
struct LightParams 
{
    Vector3       Position;     /* Position in world space */
    Vector3       Direction;        /* Direction in world space */
    LinearColor Diffuse;        /* Diffuse color of light */
    float           Range;          /* Cutoff range */
    bool            bIsDirectional; /* true if it is a directional light */
    LightParams(){
        bIsDirectional = true;
    }
};

class ShadowVolume;

class ShadowCaster
{
public:
    virtual bool IsShadowEnabled(){return false;};
    virtual void BuildShadowVolume(SceneState * sceneState, ShadowVolume * pShadowVolume, LightParams* pLight) = 0;
};

class CAutoCamera;
class CBaseObject;
class ShadowVolume
{
public:
    enum ShadowMethod {
        SHADOW_NONE = 0,
        SHADOW_Z_PASS,
        SHADOW_Z_FAIL
    };
    static float m_fMinShadowCastDistance; 

#define INITIAL_SHADOWVOLUME_SIZE       32000
    ShadowVolume(void);
    ~ShadowVolume(void);
    
    int             m_nVertexArraySize;     
    Vector3*    m_pVertices;            
    int             m_nNumVertices;         
    LinearColor     m_shadowColor;          
    ShadowMethod    m_shadowMethod;         
    LightParams*    m_pLightParam;          
    Plane       occlusionPyramid[5];    
protected:
    ParaViewport    m_viewport;             
    Matrix4     m_matProjection;        
    Matrix4     m_matView;              

public:
    void Reset() { 
        m_nNumVertices = 0L; 
        m_shadowMethod = SHADOW_NONE;
    }
    
    void ReserveNewBlock(Vector3** pVertices, int nSize);
    void CommitBlock(int nSize);
    
    void BuildFromShadowCaster( ShadowCaster* pCaster, LightParams* pLight);
    
    void ReCalculateOcclusionPyramid(CAutoCamera* pCamera);

    void UpdateProjectionInfo(const ParaViewport* pViewport,
        const Matrix4 *pProj,
        const Matrix4 *pView);

    void ProjectPoint(Vector3 *pOut,        const Vector3 *pV,      const Matrix4 *pWorld);
    bool PointsInsideOcclusionPyramid(Vector3* pVecBounds, int nCount);

    void SetLightParams(LightParams* l){m_pLightParam = l;};
    
    HRESULT Render( SceneState * sceneState );

    HRESULT RenderZPassShadow( SceneState * sceneState );
    HRESULT RenderZFailShadow( SceneState * sceneState );
};
}