bool FloorFace::intersectRay(const Math::Ray &ray, Math::Vector3d &intersection) const {
// Compute the triangle plane normal
Math::Vector3d n = Math::Vector3d::crossProduct(_vertices[1] - _vertices[0], _vertices[2] - _vertices[0]);
if (n == Math::Vector3d()) {
return false; // We don't handle degenerate triangles
}
// Point on triangle plane: dot(P - _vertices[0], n) = 0
// Point on ray: P = origin + r * direction
// Point on both => r = - dot(n, origin - _vertices[0]) / dot(n, direction)
float num = -Math::Vector3d::dotProduct(n, ray.origin() - _vertices[0]);
float denom = Math::Vector3d::dotProduct(n, ray.direction());
if (fabs(denom) < 0.00001) {
// The ray is parallel to the plane
return false;
}
float r = num / denom;
if (r < 0.0) {
// The ray goes away from the triangle
return false;
}
// Compute the intersection point between the triangle plane and the ray
intersection = ray.origin() + r * ray.direction();
// Check the intersection point is inside the triangle
return isPointInside(intersection);
}
float FloorFace::distanceToRay(const Math::Ray &ray) const {
Math::Vector3d center = getCenter();
return Math::Vector3d::crossProduct(ray.direction(), center - ray.origin()).getMagnitude();
}