bool Triangle::intersect(const Ray& r, Intersection *i) const {
// TODO:
// Implement ray - triangle intersection.
// When an intersection takes place, the Intersection data should
// be updated correspondingly.
Vector3D e1 = mesh->positions[v2]-mesh->positions[v1];
Vector3D e2 = mesh->positions[v3]-mesh->positions[v1];
Vector3D s = r.o - mesh->positions[v1];
// Matrix3x3 M;
// M.column(0) = e1;
// M.column(1) = e2;
// M.column(2) = -r.d;
//
// Vector3D x = M.inv()*s;
// double u = x[0];
// double v = x[1];
// double t = x[2];
double f = dot(cross(e1,r.d),e2);
if (f == 0) {
return false;
}
double u = dot(cross(s,r.d),e2)/f;
double v = dot(cross(e1,r.d),s)/f;
double t = dot(cross(e1,-s),e2)/f;
if (!(u >= 0 && v >= 0 && u+v <= 1 && t > r.min_t && t < r.max_t && t < i->t)) {
return false;
}
//cout << u <<" "<< v << " " << t << endl;
r.max_t = t;
i->bsdf = get_bsdf();
i->t = t;
i->primitive = this;
Vector3D n = (1-u-v)*mesh->normals[v1]+ u*mesh->normals[v2]+ v*mesh->normals[v3];
if (dot(r.d,n) > 0) {
n = -n;
}
i->n = n;
return true;
}
bool Triangle::intersect(const Ray& r, Intersection *isect) const {
// TODO:
// implement ray-triangle intersection. When an intersection takes
// place, the Intersection data should be updated accordingly
Vector3D p0 = mesh->positions[v1];
Vector3D p1 = mesh->positions[v2];
Vector3D p2 = mesh->positions[v3];
Vector3D e1 = p1 - p0;
Vector3D e2 = p2 - p0;
Vector3D s = r.o - p0;
Matrix3x3 A;
for (size_t i = 0; i < 3; i++) {
A(i,0) = e1[i];
A(i,1) = e2[i];
A(i,2) = -r.d[i];
}
if (A.det() == 0) {
return false;
}
bool tri_intersect = false;
Vector3D uvt = A.inv() * s;
if (uvt.z < r.min_t || uvt.z > r.max_t) {
return false;
}else if (uvt.x < 0 || uvt.x > 1) {
return false;
}else if (uvt.y < 0 || uvt.y > 1) {
return false;
}else if (uvt.x + uvt.y > 1) {
return false;
}else {
tri_intersect = true;
}
isect->t = uvt.z;
isect->bsdf = get_bsdf();
isect->primitive = this;
isect->n = (1 - uvt.x - uvt.y) * mesh->normals[v1] + uvt.x * mesh->normals[v2] + uvt.y * mesh->normals[v3];
r.max_t = uvt.z;
isect->n.normalize();
// bool tri_intersect = false;
// double u, v, t;
// double ede = 1 / dot(cross(e1, r.d), e2);
// t = - (dot(cross(s, e2), e1)) * ede;
// if (t < r.min_t || t > r.max_t) {
// return false;
// }else {
// u = - (dot(cross(s, e2), r.d)) * ede;
// if (u < 0 || u > 1) {
// return false;
// }else {
// v = (dot(cross(e1, r.d), s)) * ede;
// if (v < 0 || v > 1) {
// return false;
// }else{
// if (u + v > 1) {
// return false;
// }else{
// tri_intersect = true;
// }
// }
// }
// }
// isect->t = t;
// isect->bsdf = get_bsdf();
// isect->primitive = this;
// isect->n = (1 - u - v) * mesh->normals[v1] + u * mesh->normals[v2] + v * mesh->normals[v3];
// r.max_t = t;
// isect->n.normalize();
return tri_intersect;
}