source/geometry/boundingbox.h

   1 #ifndef MSP_GEOMETRY_BOUNDINGBOX_H_
   2 #define MSP_GEOMETRY_BOUNDINGBOX_H_
   3
   4 #include <algorithm>
   5 #include <stdexcept>
   6 #include <msp/linal/vector.h>
   7
   8 namespace Msp {
   9 namespace Geometry {
  10
  11 template<typename T, unsigned D>
  12 class BoundingBox
  13 {
  14 private:
  15         LinAl::Vector<T, D> min_pt;
  16         LinAl::Vector<T, D> max_pt;
  17         bool empty;
  18         bool negated;
  19
  20 public:
  21         BoundingBox();
  22         BoundingBox(const LinAl::Vector<T, D> &, const LinAl::Vector<T, D> &);
  23
  24         static BoundingBox negate(const BoundingBox &);
  25
  26         const LinAl::Vector<T, D> &get_minimum_point() const { return min_pt; }
  27         T get_minimum_coordinate(unsigned i) const { return min_pt[i]; }
  28         const LinAl::Vector<T, D> &get_maximum_point() const { return max_pt; }
  29         T get_maximum_coordinate(unsigned i) const { return max_pt[i]; }
  30         bool is_empty() const { return empty && !negated; }
  31         bool is_space() const { return empty && negated; }
  32         bool is_negated() const { return negated; }
  33 };
  34
  35 template<typename T, unsigned D>
  36 inline BoundingBox<T, D>::BoundingBox():
  37         empty(true),
  38         negated(false)
  39 { }
  40
  41 template<typename T, unsigned D>
  42 inline BoundingBox<T, D>::BoundingBox(const LinAl::Vector<T, D> &n, const LinAl::Vector<T, D> &x):
  43         min_pt(n),
  44         max_pt(x),
  45         empty(false),
  46         negated(false)
  47 {
  48         for(unsigned i=0; i<D; ++i)
  49                 if(min_pt[i]>max_pt[i])
  50                         throw std::invalid_argument("BoundingBox::BoundingBox");
  51 }
  52
  53 template<typename T, unsigned D>
  54 inline BoundingBox<T, D> BoundingBox<T, D>::negate(const BoundingBox<T, D> &bb)
  55 {
  56         BoundingBox<T, D> result = bb;
  57         result.negated = !bb.negated;
  58         return result;
  59 }
  60
  61 template<typename T, unsigned D>
  62 inline BoundingBox<T, D> operator&(const BoundingBox<T, D> &bb1, const BoundingBox<T, D> &bb2)
  63 {
  64         if(bb1.is_empty() || bb2.is_empty())
  65                 return BoundingBox<T, D>();
  66
  67         if(bb1.is_negated())
  68         {
  69                 if(bb2.is_negated())
  70                         return ~((~bb1)|(~bb2));
  71                 else
  72                         return bb2&bb1;
  73         }
  74
  75         LinAl::Vector<T, D> result_min;
  76         LinAl::Vector<T, D> result_max;
  77
  78         if(bb2.is_negated())
  79         {
  80                 // This is effectively subtraction of (non-negated) bb2 from bb1
  81                 int uncovered_axis = -1;
  82                 for(unsigned i=0; i<D; ++i)
  83                         if(bb1.get_minimum_coordinate(i)<bb2.get_minimum_coordinate(i) || bb1.get_maximum_coordinate(i)>bb2.get_maximum_coordinate(i))
  84                         {
  85                                 if(uncovered_axis!=-1)
  86                                         return bb1;
  87                                 uncovered_axis = i;
  88                         }
  89
  90                 if(uncovered_axis==-1)
  91                         return BoundingBox<T, D>();
  92
  93                 result_min = bb1.get_minimum_point();
  94                 result_max = bb1.get_maximum_point();
  95                 if(bb2.get_minimum_coordinate(uncovered_axis)<bb1.get_minimum_coordinate(uncovered_axis))
  96                         result_min[uncovered_axis] = bb2.get_maximum_coordinate(uncovered_axis);
  97                 else
  98                         result_max[uncovered_axis] = bb2.get_minimum_coordinate(uncovered_axis);
  99         }
 100         else
 101         {
 102                 for(unsigned i=0; i<D; ++i)
 103                 {
 104                         result_min[i] = std::max(bb1.get_minimum_coordinate(i), bb2.get_minimum_coordinate(i));
 105                         result_max[i] = std::min(bb1.get_maximum_coordinate(i), bb2.get_maximum_coordinate(i));
 106                         if(result_min[i]>result_max[i])
 107                                 return BoundingBox<T, D>();
 108                 }
 109         }
 110
 111         return BoundingBox<T, D>(result_min, result_max);
 112 }
 113
 114 template<typename T, unsigned D>
 115 inline BoundingBox<T, D> operator|(const BoundingBox<T, D> &bb1, const BoundingBox<T, D> &bb2)
 116 {
 117         if(bb1.is_empty())
 118                 return bb2;
 119         if(bb2.is_empty())
 120                 return bb1;
 121
 122         if(bb1.is_negated())
 123                 return ~((~bb1)&(~bb2));
 124         else if(bb2.is_negated())
 125                 return ~((~bb2)&(~bb1));
 126
 127         LinAl::Vector<T, D> result_min;
 128         LinAl::Vector<T, D> result_max;
 129         for(unsigned i=0; i<D; ++i)
 130         {
 131                 result_min[i] = std::min(bb1.get_minimum_coordinate(i), bb2.get_minimum_coordinate(i));
 132                 result_max[i] = std::max(bb1.get_maximum_coordinate(i), bb2.get_maximum_coordinate(i));
 133         }
 134
 135         return BoundingBox<T, D>(result_min, result_max);
 136 }
 137
 138 template<typename T, unsigned D>
 139 inline BoundingBox<T, D> operator~(const BoundingBox<T, D> &bb)
 140 {
 141         return BoundingBox<T, D>::negate(bb);
 142 }
 143
 144 } // namespace Geometry
 145 } // namespace Msp
 146
 147 #endif