source/geometry/transformedshape.h

   1 #ifndef MSP_GEOMETRY_TRANSFORMEDSHAPE_H_
   2 #define MSP_GEOMETRY_TRANSFORMEDSHAPE_H_
   3
   4 #include "affinetransformation.h"
   5 #include "boundingbox.h"
   6 #include "ray.h"
   7 #include "shape.h"
   8
   9 namespace Msp {
  10 namespace Geometry {
  11
  12 /**
  13 A shape modified by an affine transformation.
  14 */
  15 template<typename T, unsigned D>
  16 class TransformedShape: public Shape<T, D>
  17 {
  18 private:
  19         Shape<T, D> *shape;
  20         AffineTransformation<T, D> transformation;
  21         AffineTransformation<T, D> inverse_trans;
  22
  23 public:
  24         TransformedShape(const Shape<T, D> &, const AffineTransformation<T, D> &);
  25         TransformedShape(const TransformedShape &);
  26         TransformedShape &operator=(const TransformedShape &);
  27         ~TransformedShape();
  28
  29         virtual TransformedShape *clone() const;
  30
  31         const Shape<T, D> &get_shape() const { return *shape; }
  32         const AffineTransformation<T, D> &get_transformation() const { return transformation; }
  33
  34         virtual BoundingBox<T, D> get_axis_aligned_bounding_box() const;
  35         virtual bool contains(const LinAl::Vector<T, D> &) const;
  36 private:
  37         Ray<T, D> make_local_ray(const Ray<T, D> &) const;
  38 public:
  39         virtual unsigned get_max_ray_intersections() const { return shape->get_max_ray_intersections(); }
  40         virtual unsigned get_intersections(const Ray<T, D> &, SurfacePoint<T, D> *, unsigned) const;
  41 };
  42
  43 template<typename T, unsigned D>
  44 inline TransformedShape<T, D>::TransformedShape(const Shape<T, D> &s, const AffineTransformation<T, D> &t):
  45         shape(s.clone()),
  46         transformation(t),
  47         inverse_trans(invert(t))
  48 { }
  49
  50 template<typename T, unsigned D>
  51 inline TransformedShape<T, D>::TransformedShape(const TransformedShape<T, D> &other):
  52         shape(other.shape->clone()),
  53         transformation(other.transformation),
  54         inverse_trans(other.inverse_trans)
  55 { }
  56
  57 template<typename T, unsigned D>
  58 inline TransformedShape<T, D> &TransformedShape<T, D>::operator=(const TransformedShape<T, D> &other)
  59 {
  60         delete shape;
  61         shape = other.shape->clone();
  62         transformation = other.transformation;
  63         inverse_trans = other.inverse_trans;
  64 }
  65
  66 template<typename T, unsigned D>
  67 inline TransformedShape<T, D>::~TransformedShape()
  68 {
  69         delete shape;
  70 }
  71
  72 template<typename T, unsigned D>
  73 inline TransformedShape<T, D> *TransformedShape<T, D>::clone() const
  74 {
  75         return new TransformedShape<T, D>(*this);
  76 }
  77
  78 template<typename T, unsigned D>
  79 inline BoundingBox<T, D> TransformedShape<T, D>::get_axis_aligned_bounding_box() const
  80 {
  81         BoundingBox<T, D> inner_bbox = shape->get_axis_aligned_bounding_box();
  82
  83         LinAl::Vector<T, D> min_pt;
  84         LinAl::Vector<T, D> max_pt;
  85         for(unsigned i=0; i<(1<<D); ++i)
  86         {
  87                 LinAl::Vector<T, D> point;
  88                 for(unsigned j=0; j<D; ++j)
  89                         point[j] = ((i>>j)&1 ? inner_bbox.get_maximum_coordinate(j) : inner_bbox.get_minimum_coordinate(j));
  90
  91                 point = transformation.transform(point);
  92
  93                 for(unsigned j=0; j<D; ++j)
  94                 {
  95                         min_pt[j] = std::min(min_pt[j], point[j]);
  96                         max_pt[j] = std::max(min_pt[j], point[j]);
  97                 }
  98         }
  99
 100         return BoundingBox<T, D>(min_pt, max_pt);
 101 }
 102
 103 template<typename T, unsigned D>
 104 inline bool TransformedShape<T, D>::contains(const LinAl::Vector<T, D> &point) const
 105 {
 106         return shape->contains(inverse_trans.transform(point));
 107 }
 108
 109 template<typename T, unsigned D>
 110 inline Ray<T, D> TransformedShape<T, D>::make_local_ray(const Ray<T, D> &ray) const
 111 {
 112         LinAl::Vector<T, D> local_dir = inverse_trans.transform_linear(ray.get_direction());
 113         float distortion = local_dir.norm();
 114         return Ray<T, D>(inverse_trans.transform(ray.get_start()), local_dir, ray.get_limit()*distortion);
 115 }
 116
 117 template<typename T, unsigned D>
 118 inline unsigned TransformedShape<T, D>::get_intersections(const Ray<T, D> &ray, SurfacePoint<T, D> *points, unsigned size) const
 119 {
 120         Ray<T, D> local_ray = make_local_ray(ray);
 121
 122         unsigned count = shape->get_intersections(local_ray, points, size);
 123         if(points)
 124         {
 125                 for(unsigned i=0; i<count; ++i)
 126                 {
 127                         points[i].position = transformation.transform(points[i].position);
 128                         /* XXX This is not correct for nonuniform scaling.  Inverse of the
 129                         transpose of the upper DxD part of the matrix should be used. */
 130                         points[i].normal = transformation.transform_linear(points[i].normal);
 131                         points[i].distance = inner_product(points[i].position-ray.get_start(), ray.get_direction());
 132                 }
 133         }
 134         return count;
 135 }
 136
 137 } // namespace Geometry
 138 } // namespace Msp
 139
 140 #endif