X-Git-Url: http://git.tdb.fi/?a=blobdiff_plain;f=source%2Fgeometry%2Fhypersphere.h;h=ed2b49ff161141e4364a5bd81773ed0c9cc16632;hb=adb812a194961d542dcb0abd61258cbc8723ecd9;hp=8b7d0a4cf91088f8e4e14028b5116698ca079fb5;hpb=6ff13022b53830d35283905d562c2ef3af198cc1;p=libs%2Fmath.git

diff --git a/source/geometry/hypersphere.h b/source/geometry/hypersphere.h
index 8b7d0a4..ed2b49f 100644
--- a/source/geometry/hypersphere.h
+++ b/source/geometry/hypersphere.h
@@ -5,10 +5,15 @@
 #include "hyperbox.h"
 #include "ray.h"
 #include "shape.h"
+#include "surfacepoint.h"
 
 namespace Msp {
 namespace Geometry {
 
+/**
+A shape consisting of the points within a specific distance from the origin.
+Two- and three-dimensional cases are Circle and Sphere, respectively.
+*/
 template<typename T, unsigned D>
 class HyperSphere: public Shape<T, D>
 {
@@ -24,7 +29,10 @@ public:
 	T get_radius() const { return radius; }
 
 	virtual HyperBox<T, D> get_axis_aligned_bounding_box() const;
+	virtual bool contains(const LinAl::Vector<T, D> &) const;
 	virtual bool check_intersection(const Ray<T, D> &) const;
+	virtual unsigned get_max_ray_intersections() const { return 2; }
+	virtual unsigned get_intersections(const Ray<T, D> &, SurfacePoint<T, D> *, unsigned) const;
 };
 
 template<typename T, unsigned D>
@@ -52,17 +60,51 @@ inline HyperBox<T, D> HyperSphere<T, D>::get_axis_aligned_bounding_box() const
 	return HyperBox<T, D>(dimensions);
 }
 
+template<typename T, unsigned D>
+inline bool HyperSphere<T, D>::contains(const LinAl::Vector<T, D> &point) const
+{
+	return inner_product(point, point)<=radius*radius;
+}
+
 template<typename T, unsigned D>
 inline bool HyperSphere<T, D>::check_intersection(const Ray<T, D> &ray) const
 {
 	T x = inner_product(ray.get_direction(), ray.get_start());
 	if(x>0)
-		return inner_product(ray.get_start(), ray.get_start())<=radius*radius;
+		return contains(ray.get_start());
 	else
+		return contains(ray.get_start()-ray.get_direction()*x);
+}
+
+template<typename T, unsigned D>
+inline unsigned HyperSphere<T, D>::get_intersections(const Ray<T, D> &ray, SurfacePoint<T, D> *points, unsigned size) const
+{
+	T mid = -inner_product(ray.get_direction(), ray.get_start());
+	LinAl::Vector<T, D> nearest = ray.get_start()+ray.get_direction()*mid;
+	T offset_sq = radius*radius-inner_product(nearest, nearest);
+	if(offset_sq<0)
+		return 0;
+	T offset = sqrt(offset_sq);
+
+	unsigned n = 0;
+	for(int i=-1; i<=1; i+=2)
 	{
-		LinAl::Vector<T, D> nearest = ray.get_start()-ray.get_direction()*x;
-		return inner_product(nearest, nearest)<=radius*radius;
+		T x = mid+offset*i;
+		if(x>0 && n<size)
+		{
+			if(points)
+			{
+				points[n].position = ray.get_start()+ray.get_direction()*x;
+				points[n].normal = normalize(points[n].position);
+			}
+
+			++n;
+			if(n==size)
+				return n;
+		}
 	}
+
+	return n;
 }
 
 } // namespace Geometry