static void calcTriNormal(const float* v0, const float* v1, const float* v2, float* norm)
{
float e0[3], e1[3];
rcVsub(e0, v1, v0);
rcVsub(e1, v2, v0);
rcVcross(norm, e0, e1);
rcVnormalize(norm);
}
static void calcTriNormal(const dtCoordinates& v0, const dtCoordinates& v1, const dtCoordinates& v2, dtCoordinates& norm)
{
dtCoordinates e0, e1;
rcVsub(e0, v1, v0);
rcVsub(e1, v2, v0);
rcVcross(norm, e0, e1);
rcVnormalize(norm);
}
static bool intersectSegmentTriangle(const float* sp, const float* sq,
const float* a, const float* b, const float* c,
float &t)
{
float v, w;
float ab[3], ac[3], qp[3], ap[3], norm[3], e[3];
rcVsub(ab, b, a);
rcVsub(ac, c, a);
rcVsub(qp, sp, sq);
// Compute triangle normal. Can be precalculated or cached if
// intersecting multiple segments against the same triangle
rcVcross(norm, ab, ac);
// Compute denominator d. If d <= 0, segment is parallel to or points
// away from triangle, so exit early
float d = rcVdot(qp, norm);
if (d <= 0.0f) return false;
// Compute intersection t value of pq with plane of triangle. A ray
// intersects iff 0 <= t. Segment intersects iff 0 <= t <= 1. Delay
// dividing by d until intersection has been found to pierce triangle
rcVsub(ap, sp, a);
t = rcVdot(ap, norm);
if (t < 0.0f) return false;
if (t > d) return false; // For segment; exclude this code line for a ray test
// Compute barycentric coordinate components and test if within bounds
rcVcross(e, qp, ap);
v = rcVdot(ac, e);
if (v < 0.0f || v > d) return false;
w = -rcVdot(ab, e);
if (w < 0.0f || v + w > d) return false;
// Segment/ray intersects triangle. Perform delayed division
t /= d;
return true;
}
