/*
====================
sdTraceSurface::RayIntersection
====================
*/
bool sdTraceSurface::RayIntersection( const idVec3& start, const idVec3& end, idDrawVert& dv ) const {
idVec3 p;
int linkNum;
unsigned int i;
unsigned int maxTraceBins;
int hashBin[3];
int separatorAxis;
float faceDist, traceDist;
float separatorDist;
idVec3 normal, invNormal;
// clear the result in case nothing is hit
dv.Clear();
if ( numLinkBlocks == 0 ) {
return false;
}
// get trace normal and normalize
normal = end - start;
faceDist = traceDist = normal.Normalize();
// inverse normal
invNormal[0] = ( normal[0] != 0.0f ) ? 1.0f / normal[0] : 1.0f;
invNormal[1] = ( normal[1] != 0.0f ) ? 1.0f / normal[1] : 1.0f;
invNormal[2] = ( normal[2] != 0.0f ) ? 1.0f / normal[2] : 1.0f;
// maximum number of hash bins the trace can go through
maxTraceBins = 1 + idMath::Ftoi( traceDist * (
fabs( normal[0] ) * invBinSize[0] +
fabs( normal[1] ) * invBinSize[1] +
fabs( normal[2] ) * invBinSize[2] ) );
// get the first hash bin for the trace
p = start - _bounds[0];
hashBin[0] = idMath::Ftoi( idMath::Floor( p[0] * invBinSize[0] ) );
hashBin[1] = idMath::Ftoi( idMath::Floor( p[1] * invBinSize[1] ) );
hashBin[2] = idMath::Ftoi( idMath::Floor( p[2] * invBinSize[2] ) );
separatorAxis = 0;
separatorDist = 0.0f;
bool insideHash = false;
for ( i = 0; i < maxTraceBins; i++, GetNextHashBin( start, normal, hashBin, separatorAxis, separatorDist ) ) {
// if this bin is outside the valid hash space
if ( ( hashBin[0] | hashBin[1] | hashBin[2] ) & ~( binsPerAxis - 1 ) ) {
if ( insideHash ) {
break; // left valid hash space
}
continue; // not yet in valid hash space
}
insideHash = true;
// if a triangle was hit before the plane that separates this hash bin from the previous hash bin
if ( faceDist < traceDist && faceDist < separatorDist * invNormal[separatorAxis] ) {
break;
}
const triLink_t *link;
// test all the triangles in this hash bin
for ( linkNum = binLinks[hashBin[0]][hashBin[1]][hashBin[2]]; linkNum != -1; linkNum = link->nextLink ) {
link = &linkBlocks[ linkNum / MAX_LINKS_PER_BLOCK ][ linkNum % MAX_LINKS_PER_BLOCK ];
faceDist = TraceToMeshFace( link->faceNum, start, normal, faceDist, traceDist, dv );
}
}
// FIXME: SD_USE_DRAWVERT_SIZE_32
#if defined( SD_USE_DRAWVERT_SIZE_32 )
idVec3 n = dv.GetNormal();
n.Normalize();
dv.SetNormal( n );
#else
dv._normal.Normalize();
#endif
return ( faceDist < traceDist );
}
