From 47e8f4a86dc17a6d5908cbda0dac134b486c86c9 Mon Sep 17 00:00:00 2001
From: David Williams <david@david-williams.info>
Date: Sun, 2 Dec 2012 17:33:59 +0100
Subject: [PATCH] Improved raycast unit test so that it exits early if the ray
 leaves the volume.

---
 .../include/PolyVoxCore/BaseVolume.h          |  3 +-
 .../include/PolyVoxCore/BaseVolumeSampler.inl | 14 ++++----
 tests/TestRaycast.cpp                         | 34 +++++++++++++------
 3 files changed, 33 insertions(+), 18 deletions(-)

diff --git a/library/PolyVoxCore/include/PolyVoxCore/BaseVolume.h b/library/PolyVoxCore/include/PolyVoxCore/BaseVolume.h
index 0622a823..f44fbc7d 100644
--- a/library/PolyVoxCore/include/PolyVoxCore/BaseVolume.h
+++ b/library/PolyVoxCore/include/PolyVoxCore/BaseVolume.h
@@ -65,6 +65,8 @@ namespace PolyVox
 			Vector3DInt32 getPosition(void) const;
 			inline VoxelType getVoxel(void) const;	
 
+			bool isCurrentPositionValid(void) const;
+
 			void setPosition(const Vector3DInt32& v3dNewPos);
 			void setPosition(int32_t xPos, int32_t yPos, int32_t zPos);
 			inline bool setVoxel(VoxelType tValue);
@@ -110,7 +112,6 @@ namespace PolyVox
 
 		protected:
 			VoxelType getVoxelAt(int32_t uXPos, int32_t uYPos, int32_t uZPos) const;
-			bool isCurrentPositionValid(void) const;
 
 			DerivedVolumeType* mVolume;
 
diff --git a/library/PolyVoxCore/include/PolyVoxCore/BaseVolumeSampler.inl b/library/PolyVoxCore/include/PolyVoxCore/BaseVolumeSampler.inl
index b82aff5e..b3004074 100644
--- a/library/PolyVoxCore/include/PolyVoxCore/BaseVolumeSampler.inl
+++ b/library/PolyVoxCore/include/PolyVoxCore/BaseVolumeSampler.inl
@@ -60,6 +60,13 @@ namespace PolyVox
 		return mVolume->getVoxelAt(mXPosInVolume, mYPosInVolume, mZPosInVolume);
 	}
 
+	template <typename VoxelType>
+	template <typename DerivedVolumeType>
+	bool inline BaseVolume<VoxelType>::Sampler<DerivedVolumeType>::isCurrentPositionValid(void) const
+	{
+		return m_bIsCurrentPositionValidInX && m_bIsCurrentPositionValidInY && m_bIsCurrentPositionValidInZ;
+	}
+
 	template <typename VoxelType>
 	template <typename DerivedVolumeType>
 	void BaseVolume<VoxelType>::Sampler<DerivedVolumeType>::setPosition(const Vector3DInt32& v3dNewPos)
@@ -374,11 +381,4 @@ namespace PolyVox
 			}
 		}
 	}
-
-	template <typename VoxelType>
-	template <typename DerivedVolumeType>
-	bool inline BaseVolume<VoxelType>::Sampler<DerivedVolumeType>::isCurrentPositionValid(void) const
-	{
-		return m_bIsCurrentPositionValidInX && m_bIsCurrentPositionValidInY && m_bIsCurrentPositionValidInZ;
-	}
 }
diff --git a/tests/TestRaycast.cpp b/tests/TestRaycast.cpp
index 96fb2ce8..364bff04 100644
--- a/tests/TestRaycast.cpp
+++ b/tests/TestRaycast.cpp
@@ -42,18 +42,30 @@ class RaycastTestFunctor
 {
 public:
 	RaycastTestFunctor()
-		:m_uTotalVoxelsTouched(0)
+		:m_uVoxelsTouched(0)
+		,m_bRayLeftVolume(false)
 	{
 	}
 
 	bool operator()(const SimpleVolume<int8_t>::Sampler& sampler)
 	{
-		m_uTotalVoxelsTouched++;
+		m_uVoxelsTouched++;
 
+		// For this particular test we know that we are always starting a ray inside the volume,
+		// so if it ever leaves the volume we know it can't go back in and so we can terminate early.
+		// This optimisation is worthwhile because samplers get slow once outside the volume.
+		if(!sampler.isCurrentPositionValid())
+		{
+			m_bRayLeftVolume = true;
+			return false;
+		}
+
+		// We are in the volume, so decide whether to continue based on the voxel value.
 		return sampler.getVoxel() <= 0;
 	}
 
-	uint32_t m_uTotalVoxelsTouched;
+	uint32_t m_uVoxelsTouched;
+	bool m_bRayLeftVolume;
 };
 
 void TestRaycast::testExecute()
@@ -81,23 +93,25 @@ void TestRaycast::testExecute()
 	}
 
 	//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.
-	RaycastTestFunctor raycastTestFunctor;
+	Vector3DFloat start (uVolumeSideLength / 2, uVolumeSideLength / 2, uVolumeSideLength / 2);	
 
 	// 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;
+	uint32_t uTotalVoxelsTouched = 0;
 
 	// Cast a large number of random rays
 	for(int ct = 0; ct < 1000000; ct++)
 	{
+		RaycastTestFunctor raycastTestFunctor;
 		RaycastResult result = raycastWithDirection(&volData, start, randomUnitVectors[ct % 1024] * 1000.0f, raycastTestFunctor);
 
-		if(result == RaycastResults::Interupted)
+		uTotalVoxelsTouched += raycastTestFunctor.m_uVoxelsTouched;
+
+		// If the raycast completed then we know it did not hit anything.If it was interupted then it
+		// probably hit something, unless we noted that the reason it was interupted was that it left the volume.
+		if((result == RaycastResults::Interupted) && (raycastTestFunctor.m_bRayLeftVolume == false))
 		{
 			hits++;
 		}
@@ -107,7 +121,7 @@ void TestRaycast::testExecute()
 	QCOMPARE(hits, 687494);
 
 	// Check the total number of voxels touched
-	QCOMPARE(raycastTestFunctor.m_uTotalVoxelsTouched, static_cast<uint32_t>(486219343));
+	QCOMPARE(uTotalVoxelsTouched, static_cast<uint32_t>(29783248));
 }
 
 QTEST_MAIN(TestRaycast)