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 private:
  36         Ray<T, D> make_local_ray(const Ray<T, D> &) const;
  37 public:
  38         virtual unsigned get_max_ray_intersections() const { return shape->get_max_ray_intersections(); }
  39         virtual unsigned get_intersections(const Ray<T, D> &, SurfacePoint<T, D> *, unsigned) const;
  40 };
  41
  42 template<typename T, unsigned D>
  43 inline TransformedShape<T, D>::TransformedShape(const Shape<T, D> &s, const AffineTransformation<T, D> &t):
  44         shape(s.clone()),
  45         transformation(t),
  46         inverse_trans(invert(t))
  47 { }
  48
  49 template<typename T, unsigned D>
  50 inline TransformedShape<T, D>::TransformedShape(const TransformedShape<T, D> &other):
  51         shape(other.shape->clone()),
  52         transformation(other.transformation),
  53         inverse_trans(other.inverse_trans)
  54 { }
  55
  56 template<typename T, unsigned D>
  57 inline TransformedShape<T, D> &TransformedShape<T, D>::operator=(const TransformedShape<T, D> &other)
  58 {
  59         delete shape;
  60         shape = other.shape->clone();
  61         transformation = other.transformation;
  62         inverse_trans = other.inverse_trans;
  63 }
  64
  65 template<typename T, unsigned D>
  66 inline TransformedShape<T, D>::~TransformedShape()
  67 {
  68         delete shape;
  69 }
  70
  71 template<typename T, unsigned D>
  72 inline TransformedShape<T, D> *TransformedShape<T, D>::clone() const
  73 {
  74         return new TransformedShape<T, D>(*this);
  75 }
  76
  77 template<typename T, unsigned D>
  78 inline HyperBox<T, D> TransformedShape<T, D>::get_axis_aligned_bounding_box() const
  79 {
  80         // XXX This is not correct for most shapes
  81         return shape->get_axis_aligned_bounding_box();
  82 }
  83
  84 template<typename T, unsigned D>
  85 inline bool TransformedShape<T, D>::contains(const LinAl::Vector<T, D> &point) const
  86 {
  87         return shape->contains(inverse_trans.transform(point));
  88 }
  89
  90 template<typename T, unsigned D>
  91 inline Ray<T, D> TransformedShape<T, D>::make_local_ray(const Ray<T, D> &ray) const
  92 {
  93         LinAl::Vector<T, D> local_dir = inverse_trans.transform_linear(ray.get_direction());
  94         float distortion = local_dir.norm();
  95         return Ray<T, D>(inverse_trans.transform(ray.get_start()), local_dir, ray.get_limit()*distortion);
  96 }
  97
  98 template<typename T, unsigned D>
  99 inline unsigned TransformedShape<T, D>::get_intersections(const Ray<T, D> &ray, SurfacePoint<T, D> *points, unsigned size) const
 100 {
 101         Ray<T, D> local_ray = make_local_ray(ray);
 102
 103         unsigned count = shape->get_intersections(local_ray, points, size);
 104         if(points)
 105         {
 106                 for(unsigned i=0; i<count; ++i)
 107                 {
 108                         points[i].position = transformation.transform(points[i].position);
 109                         /* XXX This is not correct for nonuniform scaling.  Inverse of the
 110                         transpose of the upper DxD part of the matrix should be used. */
 111                         points[i].normal = transformation.transform_linear(points[i].normal);
 112                         points[i].distance = inner_product(points[i].position-ray.get_start(), ray.get_direction());
 113                 }
 114         }
 115         return count;
 116 }
 117
 118 } // namespace Geometry
 119 } // namespace Msp
 120
 121 #endif