/**
Implemented but not tested
*/
Void CVector3f::SetFromReflectionVector( const CVector3f& input, const CVector3f& normal )
{
Float32
dot;
dot = input.DotProduct( normal );
x = input.GetX() - 2 * dot * normal.GetX();
y = input.GetY() - 2 * dot * normal.GetY();
z = input.GetZ() - 2 * dot * normal.GetZ();
}
/** "Intersecting a Ray with a Cylinder" by Joseph M. Cychosz and Warren N. Waggenspack, Jr., ([email protected], [email protected]) in "Graphics Gems IV", Academic Press, 1994 */ Float32 CCylinder::Intersect( const CRay& r ) { Float32 in, out; Bool hit; // True if ray intersects cyl CVector3f rc; // Ray base to cylinder base Float32 dist; // Shortest distance between Float32 t, s; // Distances along the ray CVector3f n, o; Float32 ln; CVector3f axis = GetAxis(); rc = r.Origin - PointA; n.CrossProduct( r.Direction, axis ); ln = n.GetLength(); if ( ln == 0.0f ) { CVector3f tmp; // ray parallel to cyl dist = rc.DotProduct( axis ); tmp = rc - axis * dist; dist = tmp.GetLength(); in = -FLOAT32_MAX_VAL; out = FLOAT32_MAX_VAL; if( dist <= Radius ) // true if ray is in cyl { return 1.0; } } n.Normalize(); dist = MathAbs( rc.DotProduct( n ) ); // shortest distance hit = (dist <= Radius); if (hit) { // if ray hits cylinder o.CrossProduct( rc, axis ); t = - o.DotProduct( n ) / ln; o.CrossProduct( n, axis ); o.Normalize(); s = MathAbs( MathSqrt( Radius*Radius - dist*dist) / r.Direction.DotProduct( o ) ); in = t - s; // entering distance out = t + s; // exiting distance // Test for capped cylinder CVector3f intersection = r.Origin + r.Direction * in; CVector3f cylBaseToInter = intersection - PointA; ln = cylBaseToInter.GetLength(); cylBaseToInter.Normalize(); if( axis.DotProduct( cylBaseToInter ) >= 0.0f ) { Float32 cylLength = CVector3f( PointA-PointB ).GetLength(); if( ln <= cylLength ) return in; } } return -1.0f; }
