#ifndef _MOOF_PLANE_HH_
#define _MOOF_PLANE_HH_
-
+
#include <Moof/Math.hh>
+#include <Moof/Shape.hh>
namespace Mf {
-class Aabb;
-class Sphere;
+template <int D> class Aabb;
+template <int D> class Sphere;
+
+/*
+ * A plane in 3-space defined by the equation Ax + By + Cz = D, where [A, B, C]
+ * is normal to the plane.
+ */
-struct Plane
+struct Plane : public Shape<3>
{
Vector3 normal;
Scalar d;
d(scalar) {}
+ Scalar intersectRay(const Ray<3>& ray, Ray<3>::Intersection& intersection)
+ {
+ // solve: [(ray.point + t*ray.direction) dot normal] + d = 0
+
+ Scalar denominator = cml::dot(ray.direction, normal);
+
+ // check for parallel condition
+ if (denominator == SCALAR(0.0))
+ {
+ if (isEqual(cml::dot(ray.point, normal), -d))
+ {
+ // the ray lies on the plane
+ intersection.point = ray.point;
+ intersection.normal = normal;
+ return SCALAR(0.0);
+ }
+
+ // no solution
+ return SCALAR(-1.0);
+ }
+
+ Scalar t = (cml::dot(ray.point, normal) + d) / denominator;
+ if (t > SCALAR(0.0))
+ {
+ ray.solve(intersection.point, t);
+ intersection.normal = normal;
+ }
+
+ return t;
+ }
+
+
+ /* 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. */
void normalize()
{
Scalar mag = normal.length();
d /= mag;
}
- inline Scalar getDistanceToPoint(const Vector3& point) const
+ /**
+ * Determine the shortest distance between a point and the plane. */
+
+ Scalar getDistanceToPoint(const Vector3& point) const
{
return cml::dot(point, normal) + d;
}
- inline Halfspace intersectsPoint(const Vector3& point) const
+ Halfspace intersects(const Vector3& point) const
{
Scalar distance = getDistanceToPoint(point);
else return POSITIVE;
}
- Halfspace intersectsAabb(const Aabb& aabb) const;
- Halfspace intersectsSphere(const Sphere& sphere) const;
+ Halfspace intersects(const Aabb<3>& aabb) const;
+ Halfspace intersects(const Sphere<3>& sphere) const;
};