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 bool check_intersection(const Ray<T, D> &) const;
  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 &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 HyperBox<T, D> TransformedShape<T, D>::get_axis_aligned_bounding_box() const
  80 {
  81         // XXX This is not correct for most shapes
  82         return shape->get_axis_aligned_bounding_box();
  83 }
  84
  85 template<typename T, unsigned D>
  86 inline bool TransformedShape<T, D>::contains(const LinAl::Vector<T, D> &point) const
  87 {
  88         return shape->contains(inverse_trans.transform(point));
  89 }
  90
  91 template<typename T, unsigned D>
  92 inline Ray<T, D> TransformedShape<T, D>::make_local_ray(const Ray<T, D> &ray) const
  93 {
  94         LinAl::Vector<T, D> local_dir = inverse_trans.transform_linear(ray.get_direction());
  95         float distortion = local_dir.norm();
  96         return Ray<T, D>(inverse_trans.transform(ray.get_start()), local_dir, ray.get_limit()*distortion);
  97 }
  98
  99 template<typename T, unsigned D>
 100 inline bool TransformedShape<T, D>::check_intersection(const Ray<T, D> &ray) const
 101 {
 102         return shape->check_intersection(make_local_ray(ray));
 103 }
 104
 105 template<typename T, unsigned D>
 106 inline unsigned TransformedShape<T, D>::get_intersections(const Ray<T, D> &ray, SurfacePoint<T, D> *points, unsigned size) const
 107 {
 108         Ray<T, D> local_ray = make_local_ray(ray);
 109
 110         unsigned count = shape->get_intersections(local_ray, points, size);
 111         if(points)
 112         {
 113                 for(unsigned i=0; i<count; ++i)
 114                 {
 115                         points[i].position = transformation.transform(points[i].position);
 116                         /* XXX This is not correct for nonuniform scaling.  Inverse of the
 117                         transpose of the upper DxD part of the matrix should be used. */
 118                         points[i].normal = transformation.transform_linear(points[i].normal);
 119                         points[i].distance = inner_product(points[i].position-ray.get_start(), ray.get_direction());
 120                 }
 121         }
 122         return count;
 123 }
 124
 125 } // namespace Geometry
 126 } // namespace Msp
 127
 128 #endif