Use a cached inverse transformation in TransformedShape

[libs/math.git] / source / geometry / transformedshape.h

diff --git a/source/geometry/transformedshape.h b/source/geometry/transformedshape.h
index 10af1e7588a7c2efb357037113f9e22970fe887f..2168126242ab88d1823230ac3b56f34df0eaa564 100644 (file)
--- a/source/geometry/transformedshape.h
+++ b/source/geometry/transformedshape.h
@@ -14,6 +14,7 @@ class TransformedShape: public Shape<T, D>
 private:
        Shape<T, D> *shape;
        AffineTransformation<T, D> transformation;
+       AffineTransformation<T, D> inverse_trans;
 
 public:
        TransformedShape(const Shape<T, D> &, const AffineTransformation<T, D> &);
@@ -33,13 +34,15 @@ public:
 template<typename T, unsigned D>
 inline TransformedShape<T, D>::TransformedShape(const Shape<T, D> &s, const AffineTransformation<T, D> &t):
        shape(s.clone()),
-       transformation(t)
+       transformation(t),
+       inverse_trans(invert(t))
 { }
 
 template<typename T, unsigned D>
 inline TransformedShape<T, D>::TransformedShape(const TransformedShape &other):
        shape(other.shape->clone()),
-       transformation(other.transformation)
+       transformation(other.transformation),
+       inverse_trans(other.inverse_trans)
 { }
 
 template<typename T, unsigned D>
@@ -47,7 +50,8 @@ inline TransformedShape<T, D> &TransformedShape<T, D>::operator=(const Transform
 {
        delete shape;
        shape = other.shape->clone();
-       transformation = other.transformation();
+       transformation = other.transformation;
+       inverse_trans = other.inverse_trans;
 }
 
 template<typename T, unsigned D>
@@ -72,11 +76,9 @@ inline HyperBox<T, D> TransformedShape<T, D>::get_axis_aligned_bounding_box() co
 template<typename T, unsigned D>
 inline bool TransformedShape<T, D>::check_intersection(const Ray<T, D> &ray) const
 {
-       // TODO cache the inverse transformation for performance
-       LinAl::SquareMatrix<T, D+1> inverse_trans = LinAl::invert(transformation.get_matrix());
-       Ray<T, D> trans_ray(reduce_vector(inverse_trans*augment_vector(ray.get_start(), T(1))),
-               reduce_vector(inverse_trans*augment_vector(ray.get_direction(), T(0))));
-       return shape->check_intersection(trans_ray);
+       Ray<T, D> local_ray(inverse_trans.transform(ray.get_start()),
+               inverse_trans.transform_linear(ray.get_direction()));
+       return shape->check_intersection(local_ray);
 }
 
 } // namespace Geometry