CWE-ou-minkata/Sources/Plasma/PubUtilLib/plGLight/plPointShadowMaster.cpp

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*==LICENSE==*/

#include "HeadSpin.h"

#include "plPointShadowMaster.h"
#include "plShadowSlave.h"
#include "plShadowCaster.h"
#include "plMessage/plShadowCastMsg.h"

#include "plLightInfo.h"

#include "hsMatrix44.h"
#include "hsBounds.h"
#include "hsFastMath.h"

static const float kMinMinZ = 1.f; // totally random arbitrary number (has to be > 0).

static inline void QuickNorm( hsVector3& a, float& b ) 
{ 
    float len = hsFastMath::InvSqrtAppr((a).MagnitudeSquared()); 
    a *= len; 
    b *= len; 
}

static inline hsVector3 CrossProd(const hsVector3& a, const hsPoint3& b)
{
    return hsVector3(a.fY*b.fZ - a.fZ*b.fY, a.fZ*b.fX - a.fX*b.fZ, a.fX*b.fY - a.fY*b.fX);
}

static inline void InverseOfPureRotTran(const hsMatrix44& src, hsMatrix44& inv)
{
    inv = src;

    // We know this is a pure rotation and translation matrix, so
    // we won't have to do a full inverse. Okay kids, don't try this
    // at home.
    inv.fMap[0][1] = src.fMap[1][0];
    inv.fMap[0][2] = src.fMap[2][0];

    inv.fMap[1][0] = src.fMap[0][1];
    inv.fMap[1][2] = src.fMap[2][1];

    inv.fMap[2][0] = src.fMap[0][2];
    inv.fMap[2][1] = src.fMap[1][2];

    hsPoint3 newTran(-src.fMap[0][3], -src.fMap[1][3], -src.fMap[2][3]);
    inv.fMap[0][3] = newTran.InnerProduct((hsVector3*)&inv.fMap[0][0]);
    inv.fMap[1][3] = newTran.InnerProduct((hsVector3*)&inv.fMap[1][0]);
    inv.fMap[2][3] = newTran.InnerProduct((hsVector3*)&inv.fMap[2][0]);
}

////////////////////////////////////////////////////////////////////////////////////
// Point first
////////////////////////////////////////////////////////////////////////////////////
plPointShadowMaster::plPointShadowMaster()
{
    fLastUp.Set(0,0,0);
}

plPointShadowMaster::~plPointShadowMaster()
{
    fIsectPool.SetCount(fIsectPool.GetNumAlloc());
    int i;
    for( i = 0; i < fIsectPool.GetCount(); i++ )
        delete fIsectPool[i];
}

plShadowSlave* plPointShadowMaster::INewSlave(const plShadowCaster* caster)
{
    return new plPointShadowSlave;
}

void plPointShadowMaster::IBeginRender()
{
    plShadowMaster::IBeginRender();

    fIsectPool.SetCount(0);
}

void plPointShadowMaster::IComputeWorldToLight(const hsBounds3Ext& bnd, plShadowSlave* slave) const
{
    const float kMinMag = 0.5f;
    hsPoint3 from = fLightInfo->GetLightToWorld().GetTranslate();
    hsPoint3 at = bnd.GetCenter();

    hsVector3 atToFrom(&from, &at);
    float distSq = atToFrom.MagnitudeSquared();
    atToFrom *= hsFastMath::InvSqrtAppr(distSq);

    hsPoint2 depth;
    bnd.TestPlane(atToFrom, depth);

    float fromDepth = atToFrom.InnerProduct(from);

    float dist = fromDepth - depth.fY;

    static float kMinDist = 3.f;
    if( dist < kMinDist )
    {
        atToFrom *= kMinDist - dist;
        from += atToFrom;
    }

    hsVector3 up(0,0,1.f);
    if( CrossProd(up, (at - from)).MagnitudeSquared() < kMinMag )
    {
        up.Set(0, 1.f, 0);
    }
    hsMatrix44 w2light;
    w2light.MakeCamera(&from, &at, &up); // mf_flip_up - mf

    hsMatrix44 light2w;
    InverseOfPureRotTran(w2light, light2w);

#ifdef CHECK_INVERSE
    hsMatrix44 inv;
    w2light.GetInverse(&inv);
#endif // CHECK_INVERSE

    slave->fWorldToLight = w2light;
    slave->fLightToWorld = light2w;
}

void plPointShadowMaster::IComputeProjections(plShadowCastMsg* castMsg, plShadowSlave* slave) const
{

    slave->fView.SetPerspective(true);


}

void plPointShadowMaster::IComputeISect(const hsBounds3Ext& bnd, plShadowSlave* slave) const
{
    int iIsect = fIsectPool.GetCount();
    fIsectPool.ExpandAndZero(iIsect+1);
    if( !fIsectPool[iIsect] )
    {
        fIsectPool[iIsect] = new plBoundsIsect;
    }
    plBoundsIsect* isect = fIsectPool[iIsect];

    const hsBounds3Ext& wBnd = slave->fWorldBounds;

    isect->SetBounds(wBnd);

    slave->fIsect = isect;
}

void plPointShadowMaster::IComputeBounds(const hsBounds3Ext& wBnd, plShadowSlave* slave) const
{
    // Plan here is to look at the bounds in the slave's local space.
    // Our slave's bounds will clearly contain the shadow caster's bounds. It will also
    // contain the bnd's corners projected out along the ray from the slave's position
    // through each corner. They will extend fAttenDist farther than the center point
    // of the bound.

    hsBounds3Ext sBnd = wBnd;
    sBnd.Transform(&slave->fWorldToLight);

    hsBounds3Ext bnd = sBnd;

    float dist = sBnd.GetCenter().fZ;
    dist += slave->fAttenDist;

    float minZ = sBnd.GetMaxs().fZ;

    hsPoint3 p(sBnd.GetMins().fX * dist / minZ, sBnd.GetMins().fY * dist / minZ, dist);
    bnd.Union(&p);

    p.Set(sBnd.GetMaxs().fX * dist / minZ, sBnd.GetMaxs().fY * dist / minZ, dist);
    bnd.Union(&p);

    bnd.Transform(&slave->fLightToWorld);

    slave->fWorldBounds = bnd;

}