+ bool intersectRay(const Ray<3>& ray, Ray<3>::Intersection& hit)
+ {
+ // solve: [(ray.point + t*ray.direction) dot normal] + d = 0
+
+ Scalar denom = cml::dot(ray.direction, normal);
+
+ // check for parallel condition
+ if (denom == SCALAR(0.0))
+ {
+ if (isEqual(cml::dot(ray.point, normal), -d))
+ {
+ // the ray lies on the plane
+ hit.distance = SCALAR(0.0);
+ hit.normal.set(0.0, 0.0, 0.0);
+ return true;
+ }
+
+ // no solution
+ return false;
+ }
+
+ Scalar numer = cml::dot(ray.point, normal) + d;
+ hit.distance = -numer / denom;
+ if (hit.distance < SCALAR(0.0)) return false;
+
+ if (numer >= 0.0) hit.normal = normal;
+ else hit.normal = -normal;
+ return true;
+ }
+
+
+ /* Causes the normal of the plane to become normalized. The scalar may also
+ * be changed to keep the equation true. Word to the wise: don't normalize
+ * a plane if the normal is the zero vector. */