static int
circle2segment(const cpCircleShape *circleShape, const cpSegmentShape *segmentShape, cpContact *con)
{
cpVect seg_a = segmentShape->ta;
cpVect seg_b = segmentShape->tb;
cpVect center = circleShape->tc;
cpVect seg_delta = cpvsub(seg_b, seg_a);
cpFloat closest_t = cpfclamp01(cpvdot(seg_delta, cpvsub(center, seg_a))/cpvlengthsq(seg_delta));
cpVect closest = cpvadd(seg_a, cpvmult(seg_delta, closest_t));
if(circle2circleQuery(center, closest, circleShape->r, segmentShape->r, con)){
cpVect n = con[0].n;
// Reject endcap collisions if tangents are provided.
if(
(closest_t == 0.0f && cpvdot(n, segmentShape->a_tangent) < 0.0) ||
(closest_t == 1.0f && cpvdot(n, segmentShape->b_tangent) < 0.0)
) return 0;
return 1;
} else {
return 0;
}
}
static void
cpSegmentShapePointQuery(cpSegmentShape *seg, cpVect p, cpPointQueryExtendedInfo *info){
if(!cpBBContainsVect(seg->shape.bb, p)) return;
cpVect a = seg->ta;
cpVect b = seg->tb;
cpVect seg_delta = cpvsub(b, a);
cpFloat closest_t = cpfclamp01(cpvdot(seg_delta, cpvsub(p, a))/cpvlengthsq(seg_delta));
cpVect closest = cpvadd(a, cpvmult(seg_delta, closest_t));
cpVect delta = cpvsub(p, closest);
cpFloat distsq = cpvlengthsq(delta);
cpFloat r = seg->r;
if(distsq < r*r){
info->shape = (cpShape *)seg;
cpFloat dist = cpfsqrt(distsq);
info->d = r - dist;
info->n = cpvmult(delta, 1.0/dist);
}
}