X-Git-Url: http://git.tdb.fi/?a=blobdiff_plain;f=source%2Fgeometry%2Fhalfspace.h;h=9fdcdadfbd02b0dec41ef88c3e97539013cf2cbd;hb=44bd1d1ab256d397be4e2169c4ca5efdd0569d31;hp=5fdea34c885eaf2dbf17296b07d4677984589fef;hpb=7353dc087872cdb93bd57cbaf2b6f0dcc21f9a03;p=libs%2Fmath.git

diff --git a/source/geometry/halfspace.h b/source/geometry/halfspace.h
index 5fdea34..9fdcdad 100644
--- a/source/geometry/halfspace.h
+++ b/source/geometry/halfspace.h
@@ -7,8 +7,8 @@ namespace Msp {
 namespace Geometry {
 
 /**
-An infinite shape consisting of the space on one side of a plane.  Mostly
-useful when composited with other shapes.
+An unbounded shape consisting of the space on one side of a plane.  Mostly
+useful when intersected with other shapes.
 */
 template<typename T, unsigned D>
 class HalfSpace: public Shape<T, D>
@@ -24,16 +24,17 @@ public:
 
 	const LinAl::Vector<T, D> &get_normal() const { return normal; }
 
-	virtual BoundingBox<T, D> get_axis_aligned_bounding_box() const;
+	virtual BoundingBox<T, D> get_axis_aligned_bounding_box(unsigned = 0) const;
 	virtual bool contains(const LinAl::Vector<T, D> &) const;
 	virtual unsigned get_max_ray_intersections() const { return 1; }
 	virtual unsigned get_intersections(const Ray<T, D> &, SurfacePoint<T, D> *, unsigned) const;
+	virtual Coverage get_coverage(const BoundingBox<T, D> &) const;
 };
 
 template<typename T, unsigned D>
 inline HalfSpace<T, D>::HalfSpace()
 {
-	normal[0] = 1;
+	normal[0] = T(1);
 }
 
 template<typename T, unsigned D>
@@ -48,7 +49,7 @@ inline HalfSpace<T, D> *HalfSpace<T, D>::clone() const
 }
 
 template<typename T, unsigned D>
-inline BoundingBox<T, D> HalfSpace<T, D>::get_axis_aligned_bounding_box() const
+inline BoundingBox<T, D> HalfSpace<T, D>::get_axis_aligned_bounding_box(unsigned) const
 {
 	// XXX If the normal is aligned to an axis, should the bounding box reflect that?
 	return ~BoundingBox<T, D>();
@@ -57,13 +58,18 @@ inline BoundingBox<T, D> HalfSpace<T, D>::get_axis_aligned_bounding_box() const
 template<typename T, unsigned D>
 inline bool HalfSpace<T, D>::contains(const LinAl::Vector<T, D> &point) const
 {
-	return inner_product(point, normal)<=0;
+	return inner_product(point, normal)<=T(0);
 }
 
 template<typename T, unsigned D>
 inline unsigned HalfSpace<T, D>::get_intersections(const Ray<T, D> &ray, SurfacePoint<T, D> *points, unsigned size) const
 {
-	T x = -inner_product(ray.get_start(), normal)/inner_product(ray.get_direction(), normal);
+	T d = inner_product(ray.get_start(), normal);
+	T c = inner_product(ray.get_direction(), normal);
+	if(c==T(0))
+		return 0;
+
+	T x = -d/c;
 	if(ray.check_limits(x))
 	{
 		if(points && size>0)
@@ -71,6 +77,7 @@ inline unsigned HalfSpace<T, D>::get_intersections(const Ray<T, D> &ray, Surface
 			points[0].position = ray.get_start()+ray.get_direction()*x;
 			points[0].normal = normal;
 			points[0].distance = x;
+			points[0].entry = (c<T(0));
 		}
 
 		return 1;
@@ -79,6 +86,25 @@ inline unsigned HalfSpace<T, D>::get_intersections(const Ray<T, D> &ray, Surface
 	return 0;
 }
 
+template<typename T, unsigned D>
+inline Coverage HalfSpace<T, D>::get_coverage(const BoundingBox<T, D> &bbox) const
+{
+	LinAl::Vector<T, D> low_point;
+	LinAl::Vector<T, D> high_point;
+	for(unsigned i=0; i<D; ++i)
+	{
+		low_point[i] = (normal[i]>=T(0) ? bbox.get_minimum_coordinate(i) : bbox.get_maximum_coordinate(i));
+		high_point[i] = (normal[i]>=T(0) ? bbox.get_maximum_coordinate(i) : bbox.get_minimum_coordinate(i));
+	}
+
+	if(contains(high_point))
+		return FULL_COVERAGE;
+	else if(contains(low_point))
+		return PARTIAL_COVERAGE;
+	else
+		return NO_COVERAGE;
+}
+
 } // namespace Geometry
 } // namespace Msp