Add a distance limit to Ray

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

diff --git a/source/geometry/transformedshape.h b/source/geometry/transformedshape.h
index ea7281f746067c8d0c4dcb757edd1120ee0c903b..90c37b0bb0a2b234c0e7929796846c25cc7e4648 100644 (file)
--- a/source/geometry/transformedshape.h
+++ b/source/geometry/transformedshape.h
@@ -8,6 +8,9 @@
 namespace Msp {
 namespace Geometry {
 
+/**
+A shape modified by an affine transformation.
+*/
 template<typename T, unsigned D>
 class TransformedShape: public Shape<T, D>
 {
@@ -29,6 +32,9 @@ public:
 
        virtual HyperBox<T, D> get_axis_aligned_bounding_box() const;
        virtual bool contains(const LinAl::Vector<T, D> &) const;
+private:
+       Ray<T, D> make_local_ray(const Ray<T, D> &) const;
+public:
        virtual bool check_intersection(const Ray<T, D> &) const;
        virtual unsigned get_max_ray_intersections() const { return shape->get_max_ray_intersections(); }
        virtual unsigned get_intersections(const Ray<T, D> &, SurfacePoint<T, D> *, unsigned) const;
@@ -82,19 +88,25 @@ inline bool TransformedShape<T, D>::contains(const LinAl::Vector<T, D> &point) c
        return shape->contains(inverse_trans.transform(point));
 }
 
+template<typename T, unsigned D>
+inline Ray<T, D> TransformedShape<T, D>::make_local_ray(const Ray<T, D> &ray) const
+{
+       LinAl::Vector<T, D> local_dir = inverse_trans.transform_linear(ray.get_direction());
+       float distortion = local_dir.norm();
+       return Ray<T, D>(inverse_trans.transform(ray.get_start()), local_dir, ray.get_limit()*distortion);
+}
+
 template<typename T, unsigned D>
 inline bool TransformedShape<T, D>::check_intersection(const Ray<T, D> &ray) const
 {
-       Ray<T, D> local_ray(inverse_trans.transform(ray.get_start()),
-               inverse_trans.transform_linear(ray.get_direction()));
-       return shape->check_intersection(local_ray);
+       return shape->check_intersection(make_local_ray(ray));
 }
 
 template<typename T, unsigned D>
 inline unsigned TransformedShape<T, D>::get_intersections(const Ray<T, D> &ray, SurfacePoint<T, D> *points, unsigned size) const
 {
-       Ray<T, D> local_ray(inverse_trans.transform(ray.get_start()),
-               inverse_trans.transform_linear(ray.get_direction()));
+       Ray<T, D> local_ray = make_local_ray(ray);
+
        unsigned count = shape->get_intersections(local_ray, points, size);
        if(points)
        {
@@ -104,6 +116,7 @@ inline unsigned TransformedShape<T, D>::get_intersections(const Ray<T, D> &ray,
                        /* XXX This is not correct for nonuniform scaling.  Inverse of the
                        transpose of the upper DxD part of the matrix should be used. */
                        points[i].normal = transformation.transform(points[i].normal);
+                       points[i].distance = inner_product(points[i].position-ray.get_start(), ray.get_direction());
                }
        }
        return count;