source/geometry/transformedshape.h

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