Implement bounding boxes with a separate class

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

diff --git a/source/geometry/transformedshape.h b/source/geometry/transformedshape.h
index ea7281f746067c8d0c4dcb757edd1120ee0c903b..58e571a9db389a058cdb8ab3de1343b4ee87cb3e 100644 (file)
--- a/source/geometry/transformedshape.h
+++ b/source/geometry/transformedshape.h
@@ -2,12 +2,16 @@
 #define MSP_GEOMETRY_TRANSFORMEDSHAPE_H_
 
 #include "affinetransformation.h"
+#include "boundingbox.h"
 #include "ray.h"
 #include "shape.h"
 
 namespace Msp {
 namespace Geometry {
 
+/**
+A shape modified by an affine transformation.
+*/
 template<typename T, unsigned D>
 class TransformedShape: public Shape<T, D>
 {
@@ -27,9 +31,11 @@ public:
        const Shape<T, D> &get_shape() const { return *shape; }
        const AffineTransformation<T, D> &get_transformation() const { return transformation; }
 
-       virtual HyperBox<T, D> get_axis_aligned_bounding_box() const;
+       virtual BoundingBox<T, D> get_axis_aligned_bounding_box() const;
        virtual bool contains(const LinAl::Vector<T, D> &) const;
-       virtual bool check_intersection(const Ray<T, D> &) const;
+private:
+       Ray<T, D> make_local_ray(const Ray<T, D> &) const;
+public:
        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;
 };
@@ -42,7 +48,7 @@ inline TransformedShape<T, D>::TransformedShape(const Shape<T, D> &s, const Affi
 { }
 
 template<typename T, unsigned D>
-inline TransformedShape<T, D>::TransformedShape(const TransformedShape &other):
+inline TransformedShape<T, D>::TransformedShape(const TransformedShape<T, D> &other):
        shape(other.shape->clone()),
        transformation(other.transformation),
        inverse_trans(other.inverse_trans)
@@ -70,10 +76,28 @@ inline TransformedShape<T, D> *TransformedShape<T, D>::clone() const
 }
 
 template<typename T, unsigned D>
-inline HyperBox<T, D> TransformedShape<T, D>::get_axis_aligned_bounding_box() const
+inline BoundingBox<T, D> TransformedShape<T, D>::get_axis_aligned_bounding_box() const
 {
-       // XXX This is not correct for most shapes
-       return shape->get_axis_aligned_bounding_box();
+       BoundingBox<T, D> inner_bbox = shape->get_axis_aligned_bounding_box();
+
+       LinAl::Vector<T, D> min_pt;
+       LinAl::Vector<T, D> max_pt;
+       for(unsigned i=0; i<(1<<D); ++i)
+       {
+               LinAl::Vector<T, D> point;
+               for(unsigned j=0; j<D; ++j)
+                       point[j] = ((i>>j)&1 ? inner_bbox.get_maximum_coordinate(j) : inner_bbox.get_minimum_coordinate(j));
+
+               point = transformation.transform(point);
+
+               for(unsigned j=0; j<D; ++j)
+               {
+                       min_pt[j] = std::min(min_pt[j], point[j]);
+                       max_pt[j] = std::max(min_pt[j], point[j]);
+               }
+       }
+
+       return BoundingBox<T, D>(min_pt, max_pt);
 }
 
 template<typename T, unsigned D>
@@ -83,18 +107,18 @@ inline bool TransformedShape<T, D>::contains(const LinAl::Vector<T, D> &point) c
 }
 
 template<typename T, unsigned D>
-inline bool TransformedShape<T, D>::check_intersection(const Ray<T, D> &ray) const
+inline Ray<T, D> TransformedShape<T, D>::make_local_ray(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);
+       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 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)
        {
@@ -103,7 +127,8 @@ inline unsigned TransformedShape<T, D>::get_intersections(const Ray<T, D> &ray,
                        points[i].position = transformation.transform(points[i].position);
                        /* 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].normal = transformation.transform_linear(points[i].normal);
+                       points[i].distance = inner_product(points[i].position-ray.get_start(), ray.get_direction());
                }
        }
        return count;