bool Triangle3::intersectsLocal(const Ray3D& ray) const {
Vector3D n = faceNormal();
double nd = n.dot(ray.direction);
if (nd < std::numeric_limits<double>::epsilon()) {
return false;
}
double d = n.dot(points[0]);
double t = (d - n.dot(ray.origin)) / nd;
if (t < 0.0) {
return false;
}
Vector3D q = ray.pointAt(t);
Vector3D q01 = (points[1] - points[0]).cross(q - points[0]);
if (n.dot(q01) <= 0.0) {
return false;
}
Vector3D q12 = (points[2] - points[1]).cross(q - points[1]);
if (n.dot(q12) <= 0.0) {
return false;
}
Vector3D q02 = (points[0] - points[2]).cross(q - points[2]);
if (n.dot(q02) <= 0.0) {
return false;
}
return true;
}
SurfaceRayIntersection3 Triangle3::closestIntersectionLocal(
const Ray3D& ray) const {
SurfaceRayIntersection3 intersection;
Vector3D n = faceNormal();
double nd = n.dot(ray.direction);
if (nd < std::numeric_limits<double>::epsilon()) {
intersection.isIntersecting = false;
return intersection;
}
double d = n.dot(points[0]);
double t = (d - n.dot(ray.origin)) / nd;
if (t < 0.0) {
intersection.isIntersecting = false;
return intersection;
}
Vector3D q = ray.pointAt(t);
Vector3D q01 = (points[1] - points[0]).cross(q - points[0]);
if (n.dot(q01) <= 0.0) {
intersection.isIntersecting = false;
return intersection;
}
Vector3D q12 = (points[2] - points[1]).cross(q - points[1]);
if (n.dot(q12) <= 0.0) {
intersection.isIntersecting = false;
return intersection;
}
Vector3D q02 = (points[0] - points[2]).cross(q - points[2]);
if (n.dot(q02) <= 0.0) {
intersection.isIntersecting = false;
return intersection;
}
double a = area();
double b0 = 0.5 * q12.length() / a;
double b1 = 0.5 * q02.length() / a;
double b2 = 0.5 * q01.length() / a;
Vector3D normal = b0 * normals[0] + b1 * normals[1] + b2 * normals[2];
intersection.isIntersecting = true;
intersection.distance = t;
intersection.point = q;
intersection.normal = normal.normalized();
return intersection;
}
SurfaceRayIntersection3 ImplicitSurfaceSet3::closestIntersectionLocal(
const Ray3D& ray) const {
buildBvh();
const auto testFunc = [](const Surface3Ptr& surface, const Ray3D& ray) {
SurfaceRayIntersection3 result = surface->closestIntersection(ray);
return result.distance;
};
const auto queryResult = _bvh.closestIntersection(ray, testFunc);
SurfaceRayIntersection3 result;
result.distance = queryResult.distance;
result.isIntersecting = queryResult.item != nullptr;
if (queryResult.item != nullptr) {
result.point = ray.pointAt(queryResult.distance);
result.normal = (*queryResult.item)->closestNormal(result.point);
}
return result;
}
TEST(Ray3, PointAt) {
Ray3D ray;
EXPECT_EQ(Vector3D(4.5, 0.0, 0.0), ray.pointAt(4.5));
}
