X-Git-Url: http://git.tdb.fi/?a=blobdiff_plain;f=source%2Fgeometry%2Fhypersphere.h;h=13e4278430b8b5e2a811974a1959d54dac8bd305;hb=44bd1d1ab256d397be4e2169c4ca5efdd0569d31;hp=8b7d0a4cf91088f8e4e14028b5116698ca079fb5;hpb=6ff13022b53830d35283905d562c2ef3af198cc1;p=libs%2Fmath.git

diff --git a/source/geometry/hypersphere.h b/source/geometry/hypersphere.h
index 8b7d0a4..13e4278 100644
--- a/source/geometry/hypersphere.h
+++ b/source/geometry/hypersphere.h
@@ -1,14 +1,18 @@
 #ifndef MSP_GEOMETRY_HYPERSPHERE_H_
 #define MSP_GEOMETRY_HYPERSPHERE_H_
 
+#include <cmath>
+#include <stdexcept>
 #include <msp/linal/vector.h>
-#include "hyperbox.h"
-#include "ray.h"
 #include "shape.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>
 {
@@ -16,26 +20,27 @@ private:
 	T radius;
 
 public:
-	HyperSphere();
+	HyperSphere(): radius(1) { }
 	explicit HyperSphere(T);
 
 	virtual HyperSphere *clone() const;
 
 	T get_radius() const { return radius; }
 
-	virtual HyperBox<T, D> get_axis_aligned_bounding_box() const;
-	virtual bool check_intersection(const Ray<T, D> &) const;
+	virtual BoundingBox<T, D> get_axis_aligned_bounding_box(unsigned = 0) const;
+	virtual bool contains(const LinAl::Vector<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;
+	virtual Coverage get_coverage(const BoundingBox<T, D> &) const;
 };
 
-template<typename T, unsigned D>
-inline HyperSphere<T, D>::HyperSphere():
-	radius(1)
-{ }
-
 template<typename T, unsigned D>
 inline HyperSphere<T, D>::HyperSphere(T r):
 	radius(r)
-{ }
+{
+	if(r<=T(0))
+		throw std::invalid_argument("HyperSphere::HyperShpere");
+}
 
 template<typename T, unsigned D>
 inline HyperSphere<T, D> *HyperSphere<T, D>::clone() const
@@ -44,25 +49,86 @@ inline HyperSphere<T, D> *HyperSphere<T, D>::clone() const
 }
 
 template<typename T, unsigned D>
-inline HyperBox<T, D> HyperSphere<T, D>::get_axis_aligned_bounding_box() const
+inline BoundingBox<T, D> HyperSphere<T, D>::get_axis_aligned_bounding_box(unsigned) const
 {
-	LinAl::Vector<T, D> dimensions;
+	LinAl::Vector<T, D> extent;
 	for(unsigned i=0; i<D; ++i)
-		dimensions[i] = radius;
-	return HyperBox<T, D>(dimensions);
+		extent[i] = radius;
+	return BoundingBox<T, D>(-extent, extent);
+}
+
+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
+inline unsigned HyperSphere<T, D>::get_intersections(const Ray<T, D> &ray, SurfacePoint<T, D> *points, unsigned size) 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;
-	else
+	using std::sqrt;
+
+	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<T(0))
+		return 0;
+	T offset = sqrt(offset_sq);
+
+	unsigned n = 0;
+	for(int i=-1; (n<size && 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(ray.check_limits(x))
+		{
+			if(points)
+			{
+				points[n].position = ray.get_start()+ray.get_direction()*x;
+				points[n].normal = normalize(points[n].position);
+				points[n].distance = x;
+				points[n].entry = (i<0);
+			}
+
+			++n;
+		}
 	}
+
+	return n;
+}
+
+template<typename T, unsigned D>
+inline Coverage HyperSphere<T, D>::get_coverage(const BoundingBox<T, D> &bbox) const
+{
+	const LinAl::Vector<T, D> &min_pt = bbox.get_minimum_point();
+	const LinAl::Vector<T, D> &max_pt = bbox.get_maximum_point();
+
+	LinAl::Vector<T, D> far_point;
+	for(unsigned i=0; i<D; ++i)
+		far_point[i] = std::max(std::abs(min_pt[i]), std::abs(max_pt[i]));
+
+	if(contains(far_point))
+		return FULL_COVERAGE;
+
+	unsigned spanned_dimensions = 0;
+	for(unsigned i=0; i<D; ++i)
+		if(min_pt[i]<T(0) && max_pt[i]>T(0))
+			spanned_dimensions |= 1<<i;
+
+	for(unsigned i=0; i<(1<<D); ++i)
+	{
+		if(i&spanned_dimensions)
+			continue;
+
+		LinAl::Vector<T, D> point;
+		for(unsigned j=0; j<D; ++j)
+			if(!((spanned_dimensions>>j)&1))
+				point[j] = ((i>>j)&1 ? max_pt[j] : min_pt[j]);
+
+		if(contains(point))
+			return PARTIAL_COVERAGE;
+	}
+
+	return NO_COVERAGE;
 }
 
 } // namespace Geometry