X-Git-Url: https://git.dogcows.com/gitweb?p=chaz%2Fyoink;a=blobdiff_plain;f=src%2FMoof%2FPlane.hh;h=5ec59eab28e1c6115f4923b92892de9fd5e9d572;hp=4739bb825406d5599d853ea0e39671d387e8041e;hb=71bd9dbaf1c1e3c55a9f63392a73865d8aeee7d4;hpb=fe9614821670d9affcb68fb3e45723b9d40d0b7e

diff --git a/src/Moof/Plane.hh b/src/Moof/Plane.hh
index 4739bb8..5ec59ea 100644
--- a/src/Moof/Plane.hh
+++ b/src/Moof/Plane.hh
@@ -28,15 +28,16 @@
 
 #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;
 
 
 /*
@@ -44,7 +45,7 @@ class Sphere;
  * is normal to the plane.
  */
 
-struct Plane
+struct Plane : public Shape<3>
 {
 	Vector3	normal;
 	Scalar	d;
@@ -65,8 +66,41 @@ struct Plane
 		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. */
+	 * 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();
@@ -78,12 +112,12 @@ struct Plane
 	/**
 	 * Determine the shortest distance between a point and the plane. */
 
-	inline Scalar getDistanceToPoint(const Vector3& point) const
+	Scalar getDistanceToPoint(const Vector3& point) const
 	{
 		return cml::dot(point, normal) + d;
 	}
 
-	inline Halfspace intersects(const Vector3& point) const
+	Halfspace intersects(const Vector3& point) const
 	{
 		Scalar distance = getDistanceToPoint(point);
 
@@ -92,8 +126,8 @@ struct Plane
 		else                        return POSITIVE;
 	}
 
-	Halfspace intersects(const Aabb& aabb) const;
-	Halfspace intersects(const Sphere& sphere) const;
+	Halfspace intersects(const Aabb<3>& aabb) const;
+	Halfspace intersects(const Sphere<3>& sphere) const;
 };