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