Use the coverage function to calculate tighter bounding boxes

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

diff --git a/source/geometry/hyperbox.h b/source/geometry/hyperbox.h
index 0e4efd81995508de416d37cffd6ad12e3bbf2184..e3236e8cfaf03d69877fdfe94f7a75dc8e9f811e 100644 (file)
--- a/source/geometry/hyperbox.h
+++ b/source/geometry/hyperbox.h
@@ -5,9 +5,7 @@
 #include <cmath>
 #include <stdexcept>
 #include <msp/linal/vector.h>
-#include "ray.h"
 #include "shape.h"
-#include "surfacepoint.h"
 
 namespace Msp {
 namespace Geometry {
@@ -31,11 +29,11 @@ public:
        const LinAl::Vector<T, D> &get_dimensions() const { return dimensions; }
        T get_dimension(unsigned) const;
 
-       virtual HyperBox<T, D> get_axis_aligned_bounding_box() const { return *this; }
+       virtual BoundingBox<T, D> get_axis_aligned_bounding_box(unsigned = 0) 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;
+       virtual Coverage get_coverage(const BoundingBox<T, D> &) const;
 };
 
 template<typename T, unsigned D>
@@ -66,36 +64,40 @@ inline T HyperBox<T, D>::get_dimension(unsigned i) const
        return dimensions[i];
 }
 
+template<typename T, unsigned D>
+inline BoundingBox<T, D> HyperBox<T, D>::get_axis_aligned_bounding_box(unsigned) const
+{
+       LinAl::Vector<T, D> half_dim = dimensions/T(2);
+       return BoundingBox<T, D>(-half_dim, half_dim);
+}
+
 template<typename T, unsigned D>
 inline bool HyperBox<T, D>::contains(const LinAl::Vector<T, D> &point) const
 {
        using std::abs;
 
        for(unsigned i=0; i<D; ++i)
-               if(abs(point[i])>dimensions[i]/2)
+               if(abs(point[i])>dimensions[i]/T(2))
                        return false;
        return true;
 }
 
-template<typename T, unsigned D>
-inline bool HyperBox<T, D>::check_intersection(const Ray<T, D> &ray) const
-{
-       return get_intersections(ray, 0, 1);
-}
-
 template<typename T, unsigned D>
 inline unsigned HyperBox<T, D>::get_intersections(const Ray<T, D> &ray, SurfacePoint<T, D> *points, unsigned size) const
 {
        using std::abs;
 
+       if(size>2)
+               size = 2;
+
        LinAl::Vector<T, D> half_dim = dimensions/T(2);
        unsigned n = 0;
-       for(unsigned i=0; i<D; ++i)
+       for(unsigned i=0; (n<size && i<D); ++i)
        {
                if(!ray.get_direction()[i])
                        continue;
 
-               for(int j=-1; j<=1; j+=2)
+               for(int j=-1; (n<size && j<=1); j+=2)
                {
                        T x = (T(j)*half_dim[i]-ray.get_start()[i])/ray.get_direction()[i];
                        if(!ray.check_limits(x))
@@ -107,22 +109,30 @@ inline unsigned HyperBox<T, D>::get_intersections(const Ray<T, D> &ray, SurfaceP
                        for(unsigned k=0; (inside && k<D); ++k)
                                inside = (k==i || abs(p[k])<=half_dim[k]);
 
-                       if(inside && n<size)
+                       if(inside)
                        {
                                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;
-                               if(n==size || n==2)
-                                       return n;
                        }
                }
        }
@@ -130,6 +140,25 @@ inline unsigned HyperBox<T, D>::get_intersections(const Ray<T, D> &ray, SurfaceP
        return n;
 }
 
+template<typename T, unsigned D>
+inline Coverage HyperBox<T, D>::get_coverage(const BoundingBox<T, D> &bbox) const
+{
+       const LinAl::Vector<T, D> &min_pt = bbox.get_minimum_point();
+       const LinAl::Vector<T, D> &max_pt = bbox.get_maximum_point();
+       LinAl::Vector<T, D> half_dim = dimensions/T(2);
+
+       Coverage coverage = FULL_COVERAGE;
+       for(unsigned i=0; i<D; ++i)
+       {
+               if(max_pt[i]<-half_dim[i] || min_pt[i]>half_dim[i])
+                       return NO_COVERAGE;
+               if(min_pt[i]<-half_dim[i] || max_pt[i]>half_dim[i])
+                       coverage = PARTIAL_COVERAGE;
+       }
+
+       return coverage;
+}
+
 } // namespace Geometry
 } // namespace Msp