Ensure that HyperBox does not produce duplicate intersections

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

diff --git a/source/geometry/hyperbox.h b/source/geometry/hyperbox.h
index da500910e4f100d57f865b644bd719d71a3ee34c..b9fad33d620d205f1a5043e002cb88556cbc6e32 100644 (file)
--- a/source/geometry/hyperbox.h
+++ b/source/geometry/hyperbox.h
@@ -5,10 +5,7 @@
 #include <cmath>
 #include <stdexcept>
 #include <msp/linal/vector.h>
-#include "boundingbox.h"
-#include "ray.h"
 #include "shape.h"
-#include "surfacepoint.h"
 
 namespace Msp {
 namespace Geometry {
@@ -115,13 +112,23 @@ inline unsigned HyperBox<T, D>::get_intersections(const Ray<T, D> &ray, SurfaceP
                        {
                                if(points)
                                {
-                                       points[n].position = p;
-                                       points[n].normal = LinAl::Vector<T, D>();
-                                       points[n].normal[i] = j;
-                                       points[n].distance = x;
-
-                                       if(n==1 && x<points[0].distance)
-                                               std::swap(points[0], points[1]);
+                                       bool entry = (T(j)*ray.get_direction()[i]<T(0));
+                                       unsigned k = 0;
+                                       if(n>0 && entry!=points[0].entry)
+                                       {
+                                               if(entry)
+                                                       points[1] = points[0];
+                                               else
+                                                       ++k;
+                                       }
+                                       if(k<n && entry==points[k].entry)
+                                               --n;
+
+                                       points[k].position = p;
+                                       points[k].normal = LinAl::Vector<T, D>();
+                                       points[k].normal[i] = j;
+                                       points[k].distance = x;
+                                       points[k].entry = (T(j)*ray.get_direction()[i]<T(0));
                                }
 
                                ++n;