Moved the ambient occlusion calculation code from Thermite into PolyVox.

library/PolyVoxCore/CMakeLists.txt

@@ -15,6 +15,8 @@ SET(CORE_SRC_FILES
 
 #Projects headers files
 SET(CORE_INC_FILES
+	include/AmbientOcclusionCalculator.h
+	include/AmbientOcclusionCalculator.inl
 	include/Array.h
 	include/Array.inl
 	include/ArraySizes.h
@@ -53,6 +55,8 @@ SET(CORE_INC_FILES
 
 SET(IMPL_SRC_FILES
 	source/PolyVoxImpl/MarchingCubesTables.cpp
+	source/PolyVoxImpl/RandomUnitVectors.cpp
+	source/PolyVoxImpl/RandomVectors.cpp
 	source/PolyVoxImpl/Utility.cpp
 )
 
@@ -63,6 +67,8 @@ SET(IMPL_INC_FILES
 	include/PolyVoxImpl/Block.h
 	include/PolyVoxImpl/Block.inl
 	include/PolyVoxImpl/MarchingCubesTables.h
+	include/PolyVoxImpl/RandomUnitVectors.h
+	include/PolyVoxImpl/RandomVectors.h
 	include/PolyVoxImpl/SubArray.h
 	include/PolyVoxImpl/SubArray.inl
 	include/PolyVoxImpl/TypeDef.h

library/PolyVoxCore/include/AmbientOcclusionCalculator.h

@@ -0,0 +1,55 @@
+/*******************************************************************************
+Copyright (c) 2005-2009 David Williams
+
+This software is provided 'as-is', without any express or implied
+warranty. In no event will the authors be held liable for any damages
+arising from the use of this software.
+
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it
+freely, subject to the following restrictions:
+
+    1. The origin of this software must not be misrepresented; you must not
+    claim that you wrote the original software. If you use this software
+    in a product, an acknowledgment in the product documentation would be
+    appreciated but is not required.
+
+    2. Altered source versions must be plainly marked as such, and must not be
+    misrepresented as being the original software.
+
+    3. This notice may not be removed or altered from any source
+    distribution. 	
+*******************************************************************************/
+
+#ifndef __AmbientOcclusionCalculator_H__
+#define __AmbientOcclusionCalculator_H__
+
+#include "PolyVoxForwardDeclarations.h"
+
+namespace PolyVox
+{
+	template <typename VoxelType>
+	class AmbientOcclusionCalculator
+	{
+	public:
+		AmbientOcclusionCalculator(Volume<VoxelType>* volInput, Array<3, uint8_t>* arrayResult, Region region, float fRayLength);
+		~AmbientOcclusionCalculator();
+
+		void execute(void);
+
+	private:
+		Region m_region;
+		VolumeSampler<VoxelType> m_sampVolume;
+		Volume<VoxelType>* m_volInput;
+		Array<3, uint8_t>* m_arrayResult;
+		float m_fRayLength;
+
+		uint16_t mRandomUnitVectorIndex;
+		uint16_t mRandomVectorIndex;
+		uint16_t mIndexIncreament;
+	};
+}
+
+#include "AmbientOcclusionCalculator.inl"
+
+#endif //__AmbientOcclusionCalculator_H__

library/PolyVoxCore/include/AmbientOcclusionCalculator.inl

@@ -0,0 +1,128 @@
+/*******************************************************************************
+Copyright (c) 2005-2009 David Williams
+
+This software is provided 'as-is', without any express or implied
+warranty. In no event will the authors be held liable for any damages
+arising from the use of this software.
+
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it
+freely, subject to the following restrictions:
+
+    1. The origin of this software must not be misrepresented; you must not
+    claim that you wrote the original software. If you use this software
+    in a product, an acknowledgment in the product documentation would be
+    appreciated but is not required.
+
+    2. Altered source versions must be plainly marked as such, and must not be
+    misrepresented as being the original software.
+
+    3. This notice may not be removed or altered from any source
+    distribution. 	
+*******************************************************************************/
+
+#include "Array.h"
+#include "Raycast.h"
+#include "Volume.h"
+#include "VolumeSampler.h"
+
+#include "PolyVoxImpl/RandomUnitVectors.h"
+#include "PolyVoxImpl/RandomVectors.h"
+
+namespace PolyVox
+{
+	template <typename VoxelType>
+	AmbientOcclusionCalculator<VoxelType>::AmbientOcclusionCalculator(Volume<VoxelType>* volInput, Array<3, uint8_t>* arrayResult, Region region, float fRayLength)
+		:m_region(region)
+		,m_sampVolume(volInput)
+		,m_volInput(volInput)
+		,m_arrayResult(arrayResult)
+		,m_fRayLength(fRayLength)
+	{
+		//Make sure that the size of the volume is an exact multiple of the size of the array.
+		assert(m_volInput.getWidth() % arrayResult.getDimension(0) == 0);
+		assert(m_volInput.getHeight() % arrayResult.getDimension(1) == 0);
+		assert(m_volInput.getDepth() % arrayResult.getDimension(2) == 0);
+
+		//Our initial indices. It doesn't matter exactly what we set here, but the code below makes 
+		//sure they are different for different regions which helps reduce tiling patterns is the results.
+		mRandomUnitVectorIndex += m_region.getLowerCorner().getX() + m_region.getLowerCorner().getY() + m_region.getLowerCorner().getZ();
+		mRandomVectorIndex += m_region.getLowerCorner().getX() + m_region.getLowerCorner().getY() + m_region.getLowerCorner().getZ();
+
+		//This value helps us jump around in the array a bit more, so the
+		//nth 'random' value isn't always followed by the n+1th 'random' value.
+		mIndexIncreament = 1;
+	}
+
+	template <typename VoxelType>
+	AmbientOcclusionCalculator<VoxelType>::~AmbientOcclusionCalculator()
+	{
+	}
+
+	template <typename VoxelType>
+	void AmbientOcclusionCalculator<VoxelType>::execute(void)
+	{
+		const int iRatioX = m_volInput->getWidth()  / m_arrayResult->getDimension(0);
+		const int iRatioY = m_volInput->getHeight() / m_arrayResult->getDimension(1);
+		const int iRatioZ = m_volInput->getDepth()  / m_arrayResult->getDimension(2);
+		const int iRatioMax = std::max(std::max(iRatioX, iRatioY), iRatioZ);
+
+		const float fRatioX = iRatioX;
+		const float fRatioY = iRatioY;
+		const float fRatioZ = iRatioZ;
+		const float fRatioMax = iRatioMax;
+		const Vector3DFloat v3dRatio(fRatioX, fRatioY, fRatioZ);
+
+		const float fHalfRatioX = fRatioX * 0.5f;
+		const float fHalfRatioY = fRatioY * 0.5f;
+		const float fHalfRatioZ = fRatioZ * 0.5f;
+		const float fHalfRatioMax = fRatioMax * 0.5f;
+		const Vector3DFloat v3dHalfRatio(fHalfRatioX, fHalfRatioY, fHalfRatioZ);
+
+		const Vector3DFloat v3dOffset(0.5f,0.5f,0.5f);
+
+		RaycastResult raycastResult;
+		Raycast<VoxelType> raycast(m_volInput, Vector3DFloat(0.0f,0.0f,0.0f), Vector3DFloat(1.0f,1.0f,1.0f), raycastResult);
+
+		//This loop iterates over the bottom-lower-left voxel in each of the cells in the output array
+		for(uint16_t z = m_region.getLowerCorner().getZ(); z <= m_region.getUpperCorner().getZ(); z += iRatioZ)
+		{
+			for(uint16_t y = m_region.getLowerCorner().getY(); y <= m_region.getUpperCorner().getY(); y += iRatioY)
+			{
+				for(uint16_t x = m_region.getLowerCorner().getX(); x <= m_region.getUpperCorner().getX(); x += iRatioX)
+				{
+					//Compute a start position corresponding to 
+					//the centre of the cell in the output array.
+					Vector3DFloat v3dStart(x, y, z);
+					v3dStart -= v3dOffset;
+					v3dStart += v3dHalfRatio;
+
+					//Keep track of how many rays did not hit anything
+					uint8_t uVisibleDirections = 0;
+
+					for(int ct = 0; ct < 255; ct++)
+					{						
+						//We take a random vector with components going from -1 to 1 and scale it to go from -haflRatio to +halfRatio.
+						//This jitter value moves our sample point from the center of the array cell to somewhere else in the array cell
+						Vector3DFloat v3dJitter = randomVectors[(mRandomVectorIndex += (++mIndexIncreament)) % 1019]; //Prime number helps avoid repetition on sucessive loops.
+						v3dJitter *= v3dHalfRatio;
+						const Vector3DFloat v3dRayStart = v3dStart + v3dJitter;
+
+						Vector3DFloat v3dRayDirection = randomUnitVectors[(mRandomUnitVectorIndex += (++mIndexIncreament)) % 1021]; //Differenct prime number.
+						v3dRayDirection *= m_fRayLength;
+						
+						raycast.setStart(v3dRayStart);
+						raycast.setDirection(v3dRayDirection);
+						raycast.execute();
+
+						if(raycastResult.foundIntersection == false)
+						{
+							++uVisibleDirections;
+						}
+					}
+					(*m_arrayResult)[z / iRatioZ][y / iRatioY][x / iRatioX] = uVisibleDirections;
+				}
+			}
+		}
+	}
+}

library/PolyVoxCore/include/PolyVoxImpl/RandomUnitVectors.h

@@ -0,0 +1,34 @@
+/*******************************************************************************
+Copyright (c) 2005-2009 David Williams
+
+This software is provided 'as-is', without any express or implied
+warranty. In no event will the authors be held liable for any damages
+arising from the use of this software.
+
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it
+freely, subject to the following restrictions:
+
+    1. The origin of this software must not be misrepresented; you must not
+    claim that you wrote the original software. If you use this software
+    in a product, an acknowledgment in the product documentation would be
+    appreciated but is not required.
+
+    2. Altered source versions must be plainly marked as such, and must not be
+    misrepresented as being the original software.
+
+    3. This notice may not be removed or altered from any source
+    distribution. 	
+*******************************************************************************/
+
+#ifndef __PolyVox_RandomUnitVectors_H__
+#define __PolyVox_RandomUnitVectors_H__
+
+#include "Vector.h"
+
+namespace PolyVox
+{	
+	extern POLYVOXCORE_API const Vector3DFloat randomUnitVectors[];
+}
+
+#endif //__PolyVox_RandomUnitVectors_H__

library/PolyVoxCore/include/PolyVoxImpl/RandomVectors.h

@@ -0,0 +1,34 @@
+/*******************************************************************************
+Copyright (c) 2005-2009 David Williams
+
+This software is provided 'as-is', without any express or implied
+warranty. In no event will the authors be held liable for any damages
+arising from the use of this software.
+
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it
+freely, subject to the following restrictions:
+
+    1. The origin of this software must not be misrepresented; you must not
+    claim that you wrote the original software. If you use this software
+    in a product, an acknowledgment in the product documentation would be
+    appreciated but is not required.
+
+    2. Altered source versions must be plainly marked as such, and must not be
+    misrepresented as being the original software.
+
+    3. This notice may not be removed or altered from any source
+    distribution. 	
+*******************************************************************************/
+
+#ifndef __PolyVox_RandomVectors_H__
+#define __PolyVox_RandomVectors_H__
+
+#include "Vector.h"
+
+namespace PolyVox
+{	
+	extern POLYVOXCORE_API const Vector3DFloat randomVectors[];
+}
+
+#endif //__PolyVox_RandomVectors_H__