CollisionReport Seg2Seg(const Seg& a, const Seg& b) {
CollisionReport report;
glm::vec2 r = a.B - a.A;
glm::vec2 s = b.B - b.A;
glm::vec2 PQ = b.A - a.A;
float rxs = cross2D(r, s);
if (isEqual(rxs, 0.0f))
{
// collinear or parallel
float PQxr = cross2D (PQ, r);
if (isEqual (PQxr, 0.0f, 1e-8f)) {
// collinear
float a0 = 0.0;
float a1 = glm::dot (r,r);
float b0 = glm::dot (PQ, r);
float b1 = glm::dot (b.B - a.A, r);
float am = std::min (a0, a1);
float aM = std::max (a0, a1);
float bm = std::min (b0, b1);
float bM = std::max (b0, b1);
if (bm >= aM || bM <= am)
return report;
report.collide = true;
report.distance = 0.0f;
}
return report;
}
// if we get here then we need to compute t and u
float t = cross2D(PQ, s) / rxs;
float u = cross2D(PQ, r) / rxs;
if (t >= 0.0f && t <=1.0f && u >= 0.0f && u <= 1.0f) {
// intersection
report.collide = true;
report.distance = t * glm::length(r);
}
return report;
}
bool Simplex::inside(Point * p) {
return (cross2D(*_A, *_B, *p) < 0
&& cross2D(*_B, *_C, *p) < 0
&& cross2D(*_C, *_A, *p) < 0);
}
