source/geometry/transformedshape.h

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