From 7af38d83a33c9171aad0adaf5b917e41323cc9bd Mon Sep 17 00:00:00 2001
From: David Williams <david@volumesoffun.com>
Date: Tue, 2 Oct 2012 16:52:43 +0200
Subject: [PATCH] Added meaningful raycast return values and improved tests.

---
 CHANGELOG.txt                                 |  5 +-
 .../PolyVoxCore/include/PolyVoxCore/Raycast.h | 16 ++++-
 tests/TestRaycast.cpp                         | 62 +++++++++----------
 3 files changed, 46 insertions(+), 37 deletions(-)

diff --git a/CHANGELOG.txt b/CHANGELOG.txt
index ba4954eb..027e419c 100644
--- a/CHANGELOG.txt
+++ b/CHANGELOG.txt
@@ -29,4 +29,7 @@ Changes to Raycast
 It's been unclassed (makes sense, removes template parameters).
 Switch from std::function to STL approach.
 Note functor is passed by reference rather than by value.
-Remove 0.5 offset?
\ No newline at end of file
+Remove 0.5 offset?
+Resolved endpoints vs direction confusion
+Prevent short directions
+Prevent infinite loops (by preventing long directions?
\ No newline at end of file
diff --git a/library/PolyVoxCore/include/PolyVoxCore/Raycast.h b/library/PolyVoxCore/include/PolyVoxCore/Raycast.h
index 4d77658e..e645dcbf 100644
--- a/library/PolyVoxCore/include/PolyVoxCore/Raycast.h
+++ b/library/PolyVoxCore/include/PolyVoxCore/Raycast.h
@@ -121,8 +121,18 @@ namespace PolyVox
 		float m_fMaxDistance;
 	};
 
+	namespace MyRaycastResults
+	{
+		enum MyRaycastResult
+		{
+			Completed,
+			Interupted
+		};
+	}
+	typedef MyRaycastResults::MyRaycastResult MyRaycastResult;
+
 	template<typename VolumeType, typename Callback>
-	void raycast(VolumeType* volData, /*const*/ Vector3DFloat/*&*/ v3dStart, const Vector3DFloat& v3dDirectionAndLength, Callback& callback)
+	MyRaycastResult raycast(VolumeType* volData, /*const*/ Vector3DFloat/*&*/ v3dStart, const Vector3DFloat& v3dDirectionAndLength, Callback& callback)
 	{
 		VolumeType::Sampler sampler(volData);
 
@@ -173,7 +183,7 @@ namespace PolyVox
 			{
 				//m_result.foundIntersection = true;
 				//m_result.intersectionVoxel = Vector3DInt32(i,j,k);
-				return;
+				return MyRaycastResults::Interupted;
 			}
 			//m_result.previousVoxel = Vector3DInt32(i,j,k);
 
@@ -203,6 +213,8 @@ namespace PolyVox
 				if(dk == -1) sampler.moveNegativeZ();
 			}
 		}
+
+		return MyRaycastResults::Completed;
 	}
 }
 
diff --git a/tests/TestRaycast.cpp b/tests/TestRaycast.cpp
index 0e49e79a..ca79af7e 100644
--- a/tests/TestRaycast.cpp
+++ b/tests/TestRaycast.cpp
@@ -33,31 +33,27 @@ freely, subject to the following restrictions:
 
 using namespace PolyVox;
 
-bool foundIntersection;
-
-bool isPassableByRay(const SimpleVolume<int8_t>::Sampler& sampler)
-{
-	if(sampler.getVoxel() > 0)
-	{
-		foundIntersection = true;
-	}
-	return sampler.getVoxel() <= 0;
-}
-
 // This is the callback functor which is called by the raycast() function for every voxel it touches.
 // It's primary purpose is to tell the raycast whether or not to continue (i.e. it tests whether the
-// ray has hit a solid voxel). Because the instance of this class is passed to the raycast() function by reference we can also use it to encapsulate some state.
+// ray has hit a solid voxel). Because the instance of this class is passed to the raycast() function
+// by reference we can also use it to encapsulate some state. We're testing this by counting the total
+// number of voxels touched.
 class MyFunctor
 {
 public:
+	MyFunctor()
+		:m_uTotalVoxelsTouched(0)
+	{
+	}
+
 	bool operator()(const SimpleVolume<int8_t>::Sampler& sampler)
 	{
-		if(sampler.getVoxel() > 0)
-		{
-			foundIntersection = true;
-		}
+		m_uTotalVoxelsTouched++;
+
 		return sampler.getVoxel() <= 0;
 	}
+
+	uint32_t m_uTotalVoxelsTouched;
 };
 
 void TestRaycast::testExecute()
@@ -84,36 +80,34 @@ void TestRaycast::testExecute()
 		}
 	}
 
-	QTime timer;
-	timer.start();
-
 	//Cast rays from the centre. Roughly 2/3 should escape.
 	Vector3DFloat start (uVolumeSideLength / 2, uVolumeSideLength / 2, uVolumeSideLength / 2);
+	
+	// For demonstration purposes we are using the same function object for all raycasts.
+	// Therefore, the state it maintains (total voxels touched) is accumulated over all raycsts.
+	MyFunctor myFunctor;
+
+	// We could have counted the total number of hits in the same way as the total number of voxels
+	// touched, but for demonstration and testing purposes we are making use of the raycast return value
+	// and counting them seperatly in this variable.
 	int hits = 0;
+
+	// Cast a large number of random rays
 	for(int ct = 0; ct < 1000000; ct++)
 	{
-		/*RaycastResult result;
-		Raycast< SimpleVolume<int8_t> > raycast(&volData, start, randomUnitVectors[ct % 1024] * 1000.0f, result, isPassableByRay);
-		raycast.execute();
-		if(result.foundIntersection)
-		{
-			hits++;
-		}*/
+		MyRaycastResult result = raycast(&volData, start, randomUnitVectors[ct % 1024] * 1000.0f, myFunctor);
 
-		foundIntersection = false;
-		MyFunctor myFunctor;
-		raycast(&volData, start, randomUnitVectors[ct % 1024] * 1000.0f, myFunctor);
-
-		if(foundIntersection)
+		if(result == MyRaycastResults::Interupted)
 		{
 			hits++;
 		}
 	}	
 
-	std::cout << "Finished in " << timer.elapsed() << "ms" << std::endl;
-
-	//Check the number of hits.
+	// Check the number of hits.
 	QCOMPARE(hits, 687494);
+
+	// Check the total number of voxels touched
+	QCOMPARE(myFunctor.m_uTotalVoxelsTouched, static_cast<uint32_t>(486219343));
 }
 
 QTEST_MAIN(TestRaycast)