Add an entry flag to SharedPoint

[libs/math.git] / source / geometry / hypersphere.h

diff --git a/source/geometry/hypersphere.h b/source/geometry/hypersphere.h
index 8b7d0a4cf91088f8e4e14028b5116698ca079fb5..6bb4352f4016840ca331ebfd2034f35a7090e7d2 100644 (file)
--- 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 +20,26 @@ 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() 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;
 };
 
-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 +48,51 @@ 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() 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;
 }
 
 } // namespace Geometry