From 24f239e418599c13a9d0bdc4942c188ccf0a8437 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Mon, 20 May 2013 19:35:31 +0300
Subject: [PATCH] Add a distance limit to Ray

---
 source/geometry/hyperbox.h         |  2 +-
 source/geometry/hypersphere.h      |  2 +-
 source/geometry/ray.h              | 29 ++++++++++++++++++++++++++---
 source/geometry/transformedshape.h | 19 ++++++++++++++-----
 4 files changed, 42 insertions(+), 10 deletions(-)

diff --git a/source/geometry/hyperbox.h b/source/geometry/hyperbox.h
index 10c28d5..845ca34 100644
--- a/source/geometry/hyperbox.h
+++ b/source/geometry/hyperbox.h
@@ -91,7 +91,7 @@ inline unsigned HyperBox<T, D>::get_intersections(const Ray<T, D> &ray, SurfaceP
 		for(int j=-1; j<=1; j+=2)
 		{
 			T x = (T(j)*half_dim[i]-ray.get_start()[i])/ray.get_direction()[i];
-			if(x<0)
+			if(!ray.check_limits(x))
 				continue;
 
 			LinAl::Vector<T, D> p = ray.get_start()+ray.get_direction()*x;
diff --git a/source/geometry/hypersphere.h b/source/geometry/hypersphere.h
index 48fdb8a..ce424e1 100644
--- a/source/geometry/hypersphere.h
+++ b/source/geometry/hypersphere.h
@@ -90,7 +90,7 @@ inline unsigned HyperSphere<T, D>::get_intersections(const Ray<T, D> &ray, Surfa
 	for(int i=-1; i<=1; i+=2)
 	{
 		T x = mid+offset*i;
-		if(x>0 && n<size)
+		if(ray.check_limits(x) && n<size)
 		{
 			if(points)
 			{
diff --git a/source/geometry/ray.h b/source/geometry/ray.h
index 4825cfe..99f447b 100644
--- a/source/geometry/ray.h
+++ b/source/geometry/ray.h
@@ -1,6 +1,7 @@
 #ifndef MSP_GEOMETRY_RAY_H_
 #define MSP_GEOMETRY_RAY_H_
 
+#include <stdexcept>
 #include <msp/linal/vector.h>
 
 namespace Msp {
@@ -12,27 +13,49 @@ class Ray
 private:
 	LinAl::Vector<T, D> start;
 	LinAl::Vector<T, D> direction;
+	T limit;
 
 public:
 	Ray();
 	Ray(const LinAl::Vector<T, D> &, const LinAl::Vector<T, D> &);
+	Ray(const LinAl::Vector<T, D> &, const LinAl::Vector<T, D> &, T);
 
 	const LinAl::Vector<T, D> &get_start() const { return start; }
 	const LinAl::Vector<T, D> &get_direction() const { return direction; }
+	T get_limit() const { return limit; }
+	bool check_limits(T) const;
 };
 
 template<typename T, unsigned D>
-Ray<T, D>::Ray()
+inline Ray<T, D>::Ray():
+	limit(0)
 {
 	direction[0] = 1;
 }
 
 template<typename T, unsigned D>
-Ray<T, D>::Ray(const LinAl::Vector<T, D> &s, const LinAl::Vector<T, D> &d):
+inline Ray<T, D>::Ray(const LinAl::Vector<T, D> &s, const LinAl::Vector<T, D> &d):
 	start(s),
-	direction(normalize(d))
+	direction(normalize(d)),
+	limit(0)
 { }
 
+template<typename T, unsigned D>
+inline Ray<T, D>::Ray(const LinAl::Vector<T, D> &s, const LinAl::Vector<T, D> &d, T l):
+	start(s),
+	direction(normalize(d)),
+	limit(l)
+{
+	if(l<0)
+		throw std::invalid_argument("Ray::Ray");
+}
+
+template<typename T, unsigned D>
+inline bool Ray<T, D>::check_limits(T x) const
+{
+	return x>=0 && (!limit || x<=limit);
+}
+
 } // namespace Geometry
 } // namespace Msp
 
diff --git a/source/geometry/transformedshape.h b/source/geometry/transformedshape.h
index 34fd298..90c37b0 100644
--- a/source/geometry/transformedshape.h
+++ b/source/geometry/transformedshape.h
@@ -32,6 +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;
@@ -85,19 +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)
 	{
-- 
2.43.0