Add more collision check functions for shapes

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

diff --git a/source/geometry/hypersphere.h b/source/geometry/hypersphere.h
index 8b7d0a4cf91088f8e4e14028b5116698ca079fb5..f95ebe4182094667533e2cec0914210cb7b79337 100644 (file)
--- a/source/geometry/hypersphere.h
+++ b/source/geometry/hypersphere.h
@@ -5,6 +5,7 @@
 #include "hyperbox.h"
 #include "ray.h"
 #include "shape.h"
+#include "surfacepoint.h"
 
 namespace Msp {
 namespace Geometry {
@@ -24,7 +25,10 @@ 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 +56,51 @@ 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