X-Git-Url: https://git.dogcows.com/gitweb?p=chaz%2Fyoink;a=blobdiff_plain;f=src%2FMoof%2FPlane.hh;h=262a6bd281bfb796eb1832b3f2e68c54761e0dd4;hp=797edc05c39fe13283c4a52088502fcb6e2f132c;hb=837bae9f2bf7b25e1d3d2625eeaf39c1d2f48827;hpb=29e3d45f7bbbf31eadf793c41ff2b3d9c47b7539

diff --git a/src/Moof/Plane.hh b/src/Moof/Plane.hh
index 797edc0..262a6bd 100644
--- a/src/Moof/Plane.hh
+++ b/src/Moof/Plane.hh
@@ -1,45 +1,116 @@
 
-/*******************************************************************************
-
- 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>::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;
+			}
 
-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;
 };
 
 
@@ -47,5 +118,3 @@ public:
 
 #endif // _MOOF_PLANE_HH_
 
-/** vim: set ts=4 sw=4 tw=80: *************************************************/
-