bool Wml::FindIntersection (const Ray3<Real>& rkRay,
const Cylinder3<Real>& rkCylinder, int& riQuantity,
Vector3<Real> akPoint[2])
{
Real afT[2];
if ( rkCylinder.Capped() )
{
riQuantity = Find(rkRay.Origin(),rkRay.Direction(),rkCylinder,afT);
}
else
{
riQuantity = FindHollow(rkRay.Origin(),rkRay.Direction(),
rkCylinder,afT);
}
int iClipQuantity = 0;
for (int i = 0; i < riQuantity; i++)
{
if ( afT[i] >= (Real)0.0 )
{
akPoint[iClipQuantity++] = rkRay.Origin() +
afT[i]*rkRay.Direction();
}
}
riQuantity = iClipQuantity;
return riQuantity > 0;
}
//----------------------------------------------------------------------------
bool Mgc::TestIntersection (const Ray3& rkRay, const Box3& rkBox)
{
Real fWdU[3], fAWdU[3], fDdU[3], fADdU[3], fAWxDdU[3], fRhs;
Vector3 kDiff = rkRay.Origin() - rkBox.Center();
fWdU[0] = rkRay.Direction().Dot(rkBox.Axis(0));
fAWdU[0] = Math::FAbs(fWdU[0]);
fDdU[0] = kDiff.Dot(rkBox.Axis(0));
fADdU[0] = Math::FAbs(fDdU[0]);
if ( fADdU[0] > rkBox.Extent(0) && fDdU[0]*fWdU[0] >= 0.0f )
return false;
fWdU[1] = rkRay.Direction().Dot(rkBox.Axis(1));
fAWdU[1] = Math::FAbs(fWdU[1]);
fDdU[1] = kDiff.Dot(rkBox.Axis(1));
fADdU[1] = Math::FAbs(fDdU[1]);
if ( fADdU[1] > rkBox.Extent(1) && fDdU[1]*fWdU[1] >= 0.0f )
return false;
fWdU[2] = rkRay.Direction().Dot(rkBox.Axis(2));
fAWdU[2] = Math::FAbs(fWdU[2]);
fDdU[2] = kDiff.Dot(rkBox.Axis(2));
fADdU[2] = Math::FAbs(fDdU[2]);
if ( fADdU[2] > rkBox.Extent(2) && fDdU[2]*fWdU[2] >= 0.0f )
return false;
Vector3 kWxD = rkRay.Direction().Cross(kDiff);
fAWxDdU[0] = Math::FAbs(kWxD.Dot(rkBox.Axis(0)));
fRhs = rkBox.Extent(1)*fAWdU[2] + rkBox.Extent(2)*fAWdU[1];
if ( fAWxDdU[0] > fRhs )
return false;
fAWxDdU[1] = Math::FAbs(kWxD.Dot(rkBox.Axis(1)));
fRhs = rkBox.Extent(0)*fAWdU[2] + rkBox.Extent(2)*fAWdU[0];
if ( fAWxDdU[1] > fRhs )
return false;
fAWxDdU[2] = Math::FAbs(kWxD.Dot(rkBox.Axis(2)));
fRhs = rkBox.Extent(0)*fAWdU[1] + rkBox.Extent(1)*fAWdU[0];
if ( fAWxDdU[2] > fRhs )
return false;
return true;
}
//----------------------------------------------------------------------------
bool Mgc::FindIntersection (const Ray3& rkRay, const Triangle3& rkTriangle,
Vector3& rkPoint)
{
Real fRayP;
if ( SqrDistance(rkRay,rkTriangle,&fRayP) <= gs_fEpsilon )
{
rkPoint = rkRay.Origin() + fRayP*rkRay.Direction();
return true;
}
return false;
}
Real Mgc::SqrDistance (const Vector3& rkPoint, const Ray3& rkRay,
Real* pfParam)
{
Vector3 kDiff = rkPoint - rkRay.Origin();
Real fT = kDiff.Dot(rkRay.Direction());
if ( fT <= 0.0f )
{
fT = 0.0f;
}
else
{
fT /= rkRay.Direction().SquaredLength();
kDiff -= fT*rkRay.Direction();
}
if ( pfParam )
*pfParam = fT;
return kDiff.SquaredLength();
}
//----------------------------------------------------------------------------
bool Mgc::FindIntersection (const Ray3& rkRay, const Box3& rkBox,
int& riQuantity, Vector3 akPoint[2])
{
// convert ray to box coordinates
Vector3 kDiff = rkRay.Origin() - rkBox.Center();
Vector3 kOrigin(
kDiff.Dot(rkBox.Axis(0)),
kDiff.Dot(rkBox.Axis(1)),
kDiff.Dot(rkBox.Axis(2))
);
Vector3 kDirection(
rkRay.Direction().Dot(rkBox.Axis(0)),
rkRay.Direction().Dot(rkBox.Axis(1)),
rkRay.Direction().Dot(rkBox.Axis(2))
);
Real fT0 = 0.0f, fT1 = Math::MAX_REAL;
bool bIntersects = FindIntersection(kOrigin,kDirection,rkBox.Extents(),
fT0,fT1);
if ( bIntersects )
{
if ( fT0 > 0.0f )
{
riQuantity = 2;
akPoint[0] = rkRay.Origin() + fT0*rkRay.Direction();
akPoint[1] = rkRay.Origin() + fT1*rkRay.Direction();
}
else // fT0 == 0
{
riQuantity = 1;
akPoint[0] = rkRay.Origin() + fT1*rkRay.Direction();
}
}
else
{
riQuantity = 0;
}
return bIntersects;
}
Real Wml::SqrDistance (const Vector3<Real>& rkPoint, const Ray3<Real>& rkRay,
Real* pfParam)
{
Vector3<Real> kDiff = rkPoint - rkRay.Origin();
Real fT = kDiff.Dot(rkRay.Direction());
if ( fT <= (Real)0.0 )
{
fT = (Real)0.0;
}
else
{
fT /= rkRay.Direction().SquaredLength();
kDiff -= fT*rkRay.Direction();
}
if ( pfParam )
*pfParam = fT;
return kDiff.SquaredLength();
}
//----------------------------------------------------------------------------
Real Mgc::SqrDistance (const Ray3& rkRay, const Box3& rkBox, Real* pfLParam,
Real* pfBParam0, Real* pfBParam1, Real* pfBParam2)
{
#ifdef _DEBUG
// The four parameters pointers are either all non-null or all null.
if ( pfLParam )
{
assert( pfBParam0 && pfBParam1 && pfBParam2 );
}
else
{
assert( !pfBParam0 && !pfBParam1 && !pfBParam2 );
}
#endif
Line3 kLine;
kLine.Origin() = rkRay.Origin();
kLine.Direction() = rkRay.Direction();
Real fLP, fBP0, fBP1, fBP2;
Real fSqrDistance = SqrDistance(kLine,rkBox,&fLP,&fBP0,&fBP1,&fBP2);
if ( fLP >= 0.0f )
{
if ( pfLParam )
{
*pfLParam = fLP;
*pfBParam0 = fBP0;
*pfBParam1 = fBP1;
*pfBParam2 = fBP2;
}
return fSqrDistance;
}
else
{
fSqrDistance = SqrDistance(rkRay.Origin(),rkBox,pfBParam0,
pfBParam1,pfBParam2);
if ( pfLParam )
*pfLParam = 0.0f;
return fSqrDistance;
}
}
bool Mgc::FindIntersection (const Ray3& rkRay, const Sphere& rkSphere,
int& riQuantity, Vector3 akPoint[2])
{
// set up quadratic Q(t) = a*t^2 + 2*b*t + c
Vector3 kDiff = rkRay.Origin() - rkSphere.Center();
Real fA = rkRay.Direction().SquaredLength();
Real fB = kDiff.Dot(rkRay.Direction());
Real fC = kDiff.SquaredLength() -
rkSphere.Radius()*rkSphere.Radius();
Real afT[2];
Real fDiscr = fB*fB - fA*fC;
if ( fDiscr < 0.0f )
{
riQuantity = 0;
return false;
}
else if ( fDiscr > 0.0f )
{
Real fRoot = Math::Sqrt(fDiscr);
Real fInvA = 1.0f/fA;
afT[0] = (-fB - fRoot)*fInvA;
afT[1] = (-fB + fRoot)*fInvA;
if ( afT[0] >= 0.0f )
{
riQuantity = 2;
akPoint[0] = rkRay.Origin() + afT[0]*rkRay.Direction();
akPoint[1] = rkRay.Origin() + afT[1]*rkRay.Direction();
return true;
}
else if ( afT[1] >= 0.0f )
{
riQuantity = 1;
akPoint[0] = rkRay.Origin() + afT[1]*rkRay.Direction();
return true;
}
else
{
riQuantity = 0;
return false;
}
}
else
{
afT[0] = -fB/fA;
if ( afT[0] >= 0.0f )
{
riQuantity = 1;
akPoint[0] = rkRay.Origin() + afT[0]*rkRay.Direction();
return true;
}
else
{
riQuantity = 0;
return false;
}
}
}