//check if points of the triangle is counterclockwise
bool cclock( float x0, float y0,
float x1, float y1,
float x2, float y2 ) {
Matrix3x3 m;
m(0,0) = x0; m(0,1) = x1; m(0,2) = x2;
m(1,0) = y0; m(1,1) = y1; m(1,2) = y2;
m(2,0) = 1 ; m(2,1) = 1 ; m(2,2) = 1 ;
return m.det() >= 0.0;
/*
return lineSide(x2 - x0, y2 - y0, x0, y0, x1, y1);
*/
}
bool Triangle::intersect(const Ray& r) const {
// TODO: implement ray-triangle intersection
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;
}
double u, v, t;
double ede = 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{
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;
}
