Avoid division by zero in HalfSpace::get_intersections

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

diff --git a/source/geometry/halfspace.h b/source/geometry/halfspace.h
index 60f040350b0f63ac3ac48409701db028cece4353..4adc0dff45694726f399b7a07a3afff0cedcdb2c 100644 (file)
--- a/source/geometry/halfspace.h
+++ b/source/geometry/halfspace.h
@@ -1,7 +1,6 @@
 #ifndef MSP_GEOMETRY_HALFSPACE_H_
 #define MSP_GEOMETRY_HALFSPACE_H_
 
-#include "boundingbox.h"
 #include "shape.h"
 
 namespace Msp {
@@ -34,7 +33,7 @@ public:
 template<typename T, unsigned D>
 inline HalfSpace<T, D>::HalfSpace()
 {
-       normal[0] = 1;
+       normal[0] = T(1);
 }
 
 template<typename T, unsigned D>
@@ -58,13 +57,18 @@ inline BoundingBox<T, D> HalfSpace<T, D>::get_axis_aligned_bounding_box() const
 template<typename T, unsigned D>
 inline bool HalfSpace<T, D>::contains(const LinAl::Vector<T, D> &point) const
 {
-       return inner_product(point, normal)<=0;
+       return inner_product(point, normal)<=T(0);
 }
 
 template<typename T, unsigned D>
 inline unsigned HalfSpace<T, D>::get_intersections(const Ray<T, D> &ray, SurfacePoint<T, D> *points, unsigned size) const
 {
-       T x = -inner_product(ray.get_start(), normal)/inner_product(ray.get_direction(), normal);
+       T d = inner_product(ray.get_start(), normal);
+       T c = inner_product(ray.get_direction(), normal);
+       if(c==T(0))
+               return 0;
+
+       T x = -d/c;
        if(ray.check_limits(x))
        {
                if(points && size>0)