-/*******************************************************************************
-
- Copyright (c) 2009, Charles McGarvey
- All rights reserved.
-
- Redistribution and use in source and binary forms, with or without
- modification, are permitted provided that the following conditions are met:
-
- * Redistributions of source code must retain the above copyright notice,
- this list of conditions and the following disclaimer.
- * Redistributions in binary form must reproduce the above copyright notice,
- this list of conditions and the following disclaimer in the documentation
- and/or other materials provided with the distribution.
-
- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
- AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
- DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
- FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
- SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
- CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
-*******************************************************************************/
+/*] Copyright (c) 2009-2010, Charles McGarvey [**************************
+**] All rights reserved.
+*
+* vi:ts=4 sw=4 tw=75
+*
+* Distributable under the terms and conditions of the 2-clause BSD license;
+* see the file COPYING for a complete text of the license.
+*
+**************************************************************************/
#ifndef _MOOF_PLANE_HH_
#define _MOOF_PLANE_HH_
-
+
#include <Moof/Math.hh>
+#include <Moof/Shape.hh>
namespace Mf {
-class Plane
+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 : public Shape<3>
{
- Vector4 components;
+ Vector3 normal;
+ Scalar d;
+
+ typedef enum
+ {
+ NEGATIVE = -1,
+ INTERSECT = 0,
+ POSITIVE = 1
+ } Halfspace;
+
+ Plane() {}
+ Plane(const Vector3& vector, Scalar scalar) :
+ normal(vector),
+ d(scalar) {}
+ Plane(Scalar a, Scalar b, Scalar c, Scalar scalar) :
+ normal(a, b, c),
+ d(scalar) {}
+
+
+ bool intersectRay(const Ray<3>& ray, Ray<3>::Contact& 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;
+ }
-public:
+ // 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.
+ */
+ void normalize()
+ {
+ Scalar mag = normal.length();
+
+ normal /= mag;
+ d /= mag;
+ }
+
+ /**
+ * Determine the shortest distance between a point and the plane.
+ */
+ Scalar getDistanceToPoint(const Vector3& point) const
+ {
+ return cml::dot(point, normal) + d;
+ }
+
+ Halfspace intersects(const Vector3& point) const
+ {
+ Scalar distance = getDistanceToPoint(point);
+
+ if (isEqual(distance, 0.0)) return INTERSECT;
+ else if (distance < 0.0) return NEGATIVE;
+ else return POSITIVE;
+ }
+
+ Halfspace intersects(const Aabb<3>& aabb) const;
+ Halfspace intersects(const Sphere<3>& sphere) const;
};
#endif // _MOOF_PLANE_HH_
-/** vim: set ts=4 sw=4 tw=80: *************************************************/
-