Properly sort intersection points for complex shapes

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

diff --git a/source/geometry/hypersphere.h b/source/geometry/hypersphere.h
index ed2b49ff161141e4364a5bd81773ed0c9cc16632..cbec2d99af744e7182f4b5f0081379b059a14d95 100644 (file)
--- a/source/geometry/hypersphere.h
+++ b/source/geometry/hypersphere.h
@@ -1,6 +1,8 @@
 #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"
@@ -21,7 +23,7 @@ private:
        T radius;
 
 public:
-       HyperSphere();
+       HyperSphere(): radius(1) { }
        explicit HyperSphere(T);
 
        virtual HyperSphere *clone() const;
@@ -35,15 +37,13 @@ public:
        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
@@ -79,6 +79,8 @@ inline bool HyperSphere<T, D>::check_intersection(const Ray<T, D> &ray) const
 template<typename T, unsigned D>
 inline unsigned HyperSphere<T, D>::get_intersections(const Ray<T, D> &ray, SurfacePoint<T, D> *points, unsigned size) const
 {
+       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);
@@ -87,20 +89,19 @@ inline unsigned HyperSphere<T, D>::get_intersections(const Ray<T, D> &ray, Surfa
        T offset = sqrt(offset_sq);
 
        unsigned n = 0;
-       for(int i=-1; i<=1; i+=2)
+       for(int i=-1; (n<size && i<=1); i+=2)
        {
                T x = mid+offset*i;
-               if(x>0 && n<size)
+               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;
                        }
 
                        ++n;
-                       if(n==size)
-                               return n;
                }
        }