godot/thirdparty/bullet/BulletCollision/BroadphaseCollision/btQuantizedBvh.h

/*
Bullet Continuous Collision Detection and Physics Library
Copyright (c) 2003-2006 Erwin Coumans  https://bulletphysics.org

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 BT_QUANTIZED_BVH_H
#define BT_QUANTIZED_BVH_H

class btSerializer;

//#define DEBUG_CHECK_DEQUANTIZATION 1
#ifdef DEBUG_CHECK_DEQUANTIZATION
#ifdef __SPU__
#define printf spu_printf
#endif  //__SPU__

#include <stdio.h>
#include <stdlib.h>
#endif  //DEBUG_CHECK_DEQUANTIZATION

#include "LinearMath/btVector3.h"
#include "LinearMath/btAlignedAllocator.h"

#ifdef BT_USE_DOUBLE_PRECISION
#define btQuantizedBvhData btQuantizedBvhDoubleData
#define btOptimizedBvhNodeData btOptimizedBvhNodeDoubleData
#define btQuantizedBvhDataName "btQuantizedBvhDoubleData"
#else
#define btQuantizedBvhData btQuantizedBvhFloatData
#define btOptimizedBvhNodeData btOptimizedBvhNodeFloatData
#define btQuantizedBvhDataName "btQuantizedBvhFloatData"
#endif

//http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vclang/html/vclrf__m128.asp

//Note: currently we have 16 bytes per quantized node
#define MAX_SUBTREE_SIZE_IN_BYTES 2048

// 10 gives the potential for 1024 parts, with at most 2^21 (2097152) (minus one
// actually) triangles each (since the sign bit is reserved
#define MAX_NUM_PARTS_IN_BITS 10

///btQuantizedBvhNode is a compressed aabb node, 16 bytes.
///Node can be used for leafnode or internal node. Leafnodes can point to 32-bit triangle index (non-negative range).
ATTRIBUTE_ALIGNED16(struct)
btQuantizedBvhNode
{
	BT_DECLARE_ALIGNED_ALLOCATOR();

	//12 bytes
	unsigned short int m_quantizedAabbMin[3];
	unsigned short int m_quantizedAabbMax[3];
	//4 bytes
	int m_escapeIndexOrTriangleIndex;

	bool isLeafNode() const
	{
		//skipindex is negative (internal node), triangleindex >=0 (leafnode)
		return (m_escapeIndexOrTriangleIndex >= 0);
	}
	int getEscapeIndex() const
	{
		btAssert(!isLeafNode());
		return -m_escapeIndexOrTriangleIndex;
	}
	int getTriangleIndex() const
	{
		btAssert(isLeafNode());
		unsigned int x = 0;
		unsigned int y = (~(x & 0)) << (31 - MAX_NUM_PARTS_IN_BITS);
		// Get only the lower bits where the triangle index is stored
		return (m_escapeIndexOrTriangleIndex & ~(y));
	}
	int getPartId() const
	{
		btAssert(isLeafNode());
		// Get only the highest bits where the part index is stored
		return (m_escapeIndexOrTriangleIndex >> (31 - MAX_NUM_PARTS_IN_BITS));
	}
};

/// btOptimizedBvhNode contains both internal and leaf node information.
/// Total node size is 44 bytes / node. You can use the compressed version of 16 bytes.
ATTRIBUTE_ALIGNED16(struct)
btOptimizedBvhNode
{
	BT_DECLARE_ALIGNED_ALLOCATOR();

	//32 bytes
	btVector3 m_aabbMinOrg;
	btVector3 m_aabbMaxOrg;

	//4
	int m_escapeIndex;

	//8
	//for child nodes
	int m_subPart;
	int m_triangleIndex;

	//pad the size to 64 bytes
	char m_padding[20];
};

///btBvhSubtreeInfo provides info to gather a subtree of limited size
ATTRIBUTE_ALIGNED16(class)
btBvhSubtreeInfo
{
public:
	BT_DECLARE_ALIGNED_ALLOCATOR();

	//12 bytes
	unsigned short int m_quantizedAabbMin[3];
	unsigned short int m_quantizedAabbMax[3];
	//4 bytes, points to the root of the subtree
	int m_rootNodeIndex;
	//4 bytes
	int m_subtreeSize;
	int m_padding[3];

	btBvhSubtreeInfo()
	{
		//memset(&m_padding[0], 0, sizeof(m_padding));
	}

	void setAabbFromQuantizeNode(const btQuantizedBvhNode& quantizedNode)
	{
		m_quantizedAabbMin[0] = quantizedNode.m_quantizedAabbMin[0];
		m_quantizedAabbMin[1] = quantizedNode.m_quantizedAabbMin[1];
		m_quantizedAabbMin[2] = quantizedNode.m_quantizedAabbMin[2];
		m_quantizedAabbMax[0] = quantizedNode.m_quantizedAabbMax[0];
		m_quantizedAabbMax[1] = quantizedNode.m_quantizedAabbMax[1];
		m_quantizedAabbMax[2] = quantizedNode.m_quantizedAabbMax[2];
	}
};

class btNodeOverlapCallback
{
public:
	virtual ~btNodeOverlapCallback(){};

	virtual void processNode(int subPart, int triangleIndex) = 0;
};

#include "LinearMath/btAlignedAllocator.h"
#include "LinearMath/btAlignedObjectArray.h"

///for code readability:
typedef btAlignedObjectArray<btOptimizedBvhNode> NodeArray;
typedef btAlignedObjectArray<btQuantizedBvhNode> QuantizedNodeArray;
typedef btAlignedObjectArray<btBvhSubtreeInfo> BvhSubtreeInfoArray;

///The btQuantizedBvh class stores an AABB tree that can be quickly traversed on CPU and Cell SPU.
///It is used by the btBvhTriangleMeshShape as midphase.
///It is recommended to use quantization for better performance and lower memory requirements.
ATTRIBUTE_ALIGNED16(class)
btQuantizedBvh
{
public:
	enum btTraversalMode
	{
		TRAVERSAL_STACKLESS = 0,
		TRAVERSAL_STACKLESS_CACHE_FRIENDLY,
		TRAVERSAL_RECURSIVE
	};

protected:
	btVector3 m_bvhAabbMin;
	btVector3 m_bvhAabbMax;
	btVector3 m_bvhQuantization;

	int m_bulletVersion;  //for serialization versioning. It could also be used to detect endianess.

	int m_curNodeIndex;
	//quantization data
	bool m_useQuantization;

	NodeArray m_leafNodes;
	NodeArray m_contiguousNodes;
	QuantizedNodeArray m_quantizedLeafNodes;
	QuantizedNodeArray m_quantizedContiguousNodes;

	btTraversalMode m_traversalMode;
	BvhSubtreeInfoArray m_SubtreeHeaders;

	//This is only used for serialization so we don't have to add serialization directly to btAlignedObjectArray
	mutable int m_subtreeHeaderCount;

	///two versions, one for quantized and normal nodes. This allows code-reuse while maintaining readability (no template/macro!)
	///this might be refactored into a virtual, it is usually not calculated at run-time
	void setInternalNodeAabbMin(int nodeIndex, const btVector3& aabbMin)
	{
		if (m_useQuantization)
		{
			quantize(&m_quantizedContiguousNodes[nodeIndex].m_quantizedAabbMin[0], aabbMin, 0);
		}
		else
		{
			m_contiguousNodes[nodeIndex].m_aabbMinOrg = aabbMin;
		}
	}
	void setInternalNodeAabbMax(int nodeIndex, const btVector3& aabbMax)
	{
		if (m_useQuantization)
		{
			quantize(&m_quantizedContiguousNodes[nodeIndex].m_quantizedAabbMax[0], aabbMax, 1);
		}
		else
		{
			m_contiguousNodes[nodeIndex].m_aabbMaxOrg = aabbMax;
		}
	}

	btVector3 getAabbMin(int nodeIndex) const
	{
		if (m_useQuantization)
		{
			return unQuantize(&m_quantizedLeafNodes[nodeIndex].m_quantizedAabbMin[0]);
		}
		//non-quantized
		return m_leafNodes[nodeIndex].m_aabbMinOrg;
	}
	btVector3 getAabbMax(int nodeIndex) const
	{
		if (m_useQuantization)
		{
			return unQuantize(&m_quantizedLeafNodes[nodeIndex].m_quantizedAabbMax[0]);
		}
		//non-quantized
		return m_leafNodes[nodeIndex].m_aabbMaxOrg;
	}

	void setInternalNodeEscapeIndex(int nodeIndex, int escapeIndex)
	{
		if (m_useQuantization)
		{
			m_quantizedContiguousNodes[nodeIndex].m_escapeIndexOrTriangleIndex = -escapeIndex;
		}
		else
		{
			m_contiguousNodes[nodeIndex].m_escapeIndex = escapeIndex;
		}
	}

	void mergeInternalNodeAabb(int nodeIndex, const btVector3& newAabbMin, const btVector3& newAabbMax)
	{
		if (m_useQuantization)
		{
			unsigned short int quantizedAabbMin[3];
			unsigned short int quantizedAabbMax[3];
			quantize(quantizedAabbMin, newAabbMin, 0);
			quantize(quantizedAabbMax, newAabbMax, 1);
			for (int i = 0; i < 3; i++)
			{
				if (m_quantizedContiguousNodes[nodeIndex].m_quantizedAabbMin[i] > quantizedAabbMin[i])
					m_quantizedContiguousNodes[nodeIndex].m_quantizedAabbMin[i] = quantizedAabbMin[i];

				if (m_quantizedContiguousNodes[nodeIndex].m_quantizedAabbMax[i] < quantizedAabbMax[i])
					m_quantizedContiguousNodes[nodeIndex].m_quantizedAabbMax[i] = quantizedAabbMax[i];
			}
		}
		else
		{
			//non-quantized
			m_contiguousNodes[nodeIndex].m_aabbMinOrg.setMin(newAabbMin);
			m_contiguousNodes[nodeIndex].m_aabbMaxOrg.setMax(newAabbMax);
		}
	}

	void swapLeafNodes(int firstIndex, int secondIndex);

	void assignInternalNodeFromLeafNode(int internalNode, int leafNodeIndex);

protected:
	void buildTree(int startIndex, int endIndex);

	int calcSplittingAxis(int startIndex, int endIndex);

	int sortAndCalcSplittingIndex(int startIndex, int endIndex, int splitAxis);

	void walkStacklessTree(btNodeOverlapCallback * nodeCallback, const btVector3& aabbMin, const btVector3& aabbMax) const;

	void walkStacklessQuantizedTreeAgainstRay(btNodeOverlapCallback * nodeCallback, const btVector3& raySource, const btVector3& rayTarget, const btVector3& aabbMin, const btVector3& aabbMax, int startNodeIndex, int endNodeIndex) const;
	void walkStacklessQuantizedTree(btNodeOverlapCallback * nodeCallback, unsigned short int* quantizedQueryAabbMin, unsigned short int* quantizedQueryAabbMax, int startNodeIndex, int endNodeIndex) const;
	void walkStacklessTreeAgainstRay(btNodeOverlapCallback * nodeCallback, const btVector3& raySource, const btVector3& rayTarget, const btVector3& aabbMin, const btVector3& aabbMax, int startNodeIndex, int endNodeIndex) const;

	///tree traversal designed for small-memory processors like PS3 SPU
	void walkStacklessQuantizedTreeCacheFriendly(btNodeOverlapCallback * nodeCallback, unsigned short int* quantizedQueryAabbMin, unsigned short int* quantizedQueryAabbMax) const;

	///use the 16-byte stackless 'skipindex' node tree to do a recursive traversal
	void walkRecursiveQuantizedTreeAgainstQueryAabb(const btQuantizedBvhNode* currentNode, btNodeOverlapCallback* nodeCallback, unsigned short int* quantizedQueryAabbMin, unsigned short int* quantizedQueryAabbMax) const;

	///use the 16-byte stackless 'skipindex' node tree to do a recursive traversal
	void walkRecursiveQuantizedTreeAgainstQuantizedTree(const btQuantizedBvhNode* treeNodeA, const btQuantizedBvhNode* treeNodeB, btNodeOverlapCallback* nodeCallback) const;

	void updateSubtreeHeaders(int leftChildNodexIndex, int rightChildNodexIndex);

public:
	BT_DECLARE_ALIGNED_ALLOCATOR();

	btQuantizedBvh();

	virtual ~btQuantizedBvh();

	///***************************************** expert/internal use only *************************
	void setQuantizationValues(const btVector3& bvhAabbMin, const btVector3& bvhAabbMax, btScalar quantizationMargin = btScalar(1.0));
	QuantizedNodeArray& getLeafNodeArray() { return m_quantizedLeafNodes; }
	///buildInternal is expert use only: assumes that setQuantizationValues and LeafNodeArray are initialized
	void buildInternal();
	///***************************************** expert/internal use only *************************

	void reportAabbOverlappingNodex(btNodeOverlapCallback * nodeCallback, const btVector3& aabbMin, const btVector3& aabbMax) const;
	void reportRayOverlappingNodex(btNodeOverlapCallback * nodeCallback, const btVector3& raySource, const btVector3& rayTarget) const;
	void reportBoxCastOverlappingNodex(btNodeOverlapCallback * nodeCallback, const btVector3& raySource, const btVector3& rayTarget, const btVector3& aabbMin, const btVector3& aabbMax) const;

	SIMD_FORCE_INLINE void quantize(unsigned short* out, const btVector3& point, int isMax) const
	{
		btAssert(m_useQuantization);

		btAssert(point.getX() <= m_bvhAabbMax.getX());
		btAssert(point.getY() <= m_bvhAabbMax.getY());
		btAssert(point.getZ() <= m_bvhAabbMax.getZ());

		btAssert(point.getX() >= m_bvhAabbMin.getX());
		btAssert(point.getY() >= m_bvhAabbMin.getY());
		btAssert(point.getZ() >= m_bvhAabbMin.getZ());

		btVector3 v = (point - m_bvhAabbMin) * m_bvhQuantization;
		///Make sure rounding is done in a way that unQuantize(quantizeWithClamp(...)) is conservative
		///end-points always set the first bit, so that they are sorted properly (so that neighbouring AABBs overlap properly)
		///@todo: double-check this
		if (isMax)
		{
			out[0] = (unsigned short)(((unsigned short)(v.getX() + btScalar(1.)) | 1));
			out[1] = (unsigned short)(((unsigned short)(v.getY() + btScalar(1.)) | 1));
			out[2] = (unsigned short)(((unsigned short)(v.getZ() + btScalar(1.)) | 1));
		}
		else
		{
			out[0] = (unsigned short)(((unsigned short)(v.getX()) & 0xfffe));
			out[1] = (unsigned short)(((unsigned short)(v.getY()) & 0xfffe));
			out[2] = (unsigned short)(((unsigned short)(v.getZ()) & 0xfffe));
		}

#ifdef DEBUG_CHECK_DEQUANTIZATION
		btVector3 newPoint = unQuantize(out);
		if (isMax)
		{
			if (newPoint.getX() < point.getX())
			{
				printf("unconservative X, diffX = %f, oldX=%f,newX=%f\n", newPoint.getX() - point.getX(), newPoint.getX(), point.getX());
			}
			if (newPoint.getY() < point.getY())
			{
				printf("unconservative Y, diffY = %f, oldY=%f,newY=%f\n", newPoint.getY() - point.getY(), newPoint.getY(), point.getY());
			}
			if (newPoint.getZ() < point.getZ())
			{
				printf("unconservative Z, diffZ = %f, oldZ=%f,newZ=%f\n", newPoint.getZ() - point.getZ(), newPoint.getZ(), point.getZ());
			}
		}
		else
		{
			if (newPoint.getX() > point.getX())
			{
				printf("unconservative X, diffX = %f, oldX=%f,newX=%f\n", newPoint.getX() - point.getX(), newPoint.getX(), point.getX());
			}
			if (newPoint.getY() > point.getY())
			{
				printf("unconservative Y, diffY = %f, oldY=%f,newY=%f\n", newPoint.getY() - point.getY(), newPoint.getY(), point.getY());
			}
			if (newPoint.getZ() > point.getZ())
			{
				printf("unconservative Z, diffZ = %f, oldZ=%f,newZ=%f\n", newPoint.getZ() - point.getZ(), newPoint.getZ(), point.getZ());
			}
		}
#endif  //DEBUG_CHECK_DEQUANTIZATION
	}

	SIMD_FORCE_INLINE void quantizeWithClamp(unsigned short* out, const btVector3& point2, int isMax) const
	{
		btAssert(m_useQuantization);

		btVector3 clampedPoint(point2);
		clampedPoint.setMax(m_bvhAabbMin);
		clampedPoint.setMin(m_bvhAabbMax);

		quantize(out, clampedPoint, isMax);
	}

	SIMD_FORCE_INLINE btVector3 unQuantize(const unsigned short* vecIn) const
	{
		btVector3 vecOut;
		vecOut.setValue(
			(btScalar)(vecIn[0]) / (m_bvhQuantization.getX()),
			(btScalar)(vecIn[1]) / (m_bvhQuantization.getY()),
			(btScalar)(vecIn[2]) / (m_bvhQuantization.getZ()));
		vecOut += m_bvhAabbMin;
		return vecOut;
	}

	///setTraversalMode let's you choose between stackless, recursive or stackless cache friendly tree traversal. Note this is only implemented for quantized trees.
	void setTraversalMode(btTraversalMode traversalMode)
	{
		m_traversalMode = traversalMode;
	}

	SIMD_FORCE_INLINE QuantizedNodeArray& getQuantizedNodeArray()
	{
		return m_quantizedContiguousNodes;
	}

	SIMD_FORCE_INLINE BvhSubtreeInfoArray& getSubtreeInfoArray()
	{
		return m_SubtreeHeaders;
	}

	////////////////////////////////////////////////////////////////////

	/////Calculate space needed to store BVH for serialization
	unsigned calculateSerializeBufferSize() const;

	/// Data buffer MUST be 16 byte aligned
	virtual bool serialize(void* o_alignedDataBuffer, unsigned i_dataBufferSize, bool i_swapEndian) const;

	///deSerializeInPlace loads and initializes a BVH from a buffer in memory 'in place'
	static btQuantizedBvh* deSerializeInPlace(void* i_alignedDataBuffer, unsigned int i_dataBufferSize, bool i_swapEndian);

	static unsigned int getAlignmentSerializationPadding();
	//////////////////////////////////////////////////////////////////////

	virtual int calculateSerializeBufferSizeNew() const;

	///fills the dataBuffer and returns the struct name (and 0 on failure)
	virtual const char* serialize(void* dataBuffer, btSerializer* serializer) const;

	virtual void deSerializeFloat(struct btQuantizedBvhFloatData & quantizedBvhFloatData);

	virtual void deSerializeDouble(struct btQuantizedBvhDoubleData & quantizedBvhDoubleData);

	////////////////////////////////////////////////////////////////////

	SIMD_FORCE_INLINE bool isQuantized()
	{
		return m_useQuantization;
	}

private:
	// Special "copy" constructor that allows for in-place deserialization
	// Prevents btVector3's default constructor from being called, but doesn't inialize much else
	// ownsMemory should most likely be false if deserializing, and if you are not, don't call this (it also changes the function signature, which we need)
	btQuantizedBvh(btQuantizedBvh & other, bool ownsMemory);
};

// clang-format off
// parser needs * with the name
struct btBvhSubtreeInfoData
{
	int m_rootNodeIndex;
	int m_subtreeSize;
	unsigned short m_quantizedAabbMin[3];
	unsigned short m_quantizedAabbMax[3];
};

struct btOptimizedBvhNodeFloatData
{
	btVector3FloatData m_aabbMinOrg;
	btVector3FloatData m_aabbMaxOrg;
	int m_escapeIndex;
	int m_subPart;
	int m_triangleIndex;
	char m_pad[4];
};

struct btOptimizedBvhNodeDoubleData
{
	btVector3DoubleData m_aabbMinOrg;
	btVector3DoubleData m_aabbMaxOrg;
	int m_escapeIndex;
	int m_subPart;
	int m_triangleIndex;
	char m_pad[4];
};


struct btQuantizedBvhNodeData
{
	unsigned short m_quantizedAabbMin[3];
	unsigned short m_quantizedAabbMax[3];
	int	m_escapeIndexOrTriangleIndex;
};

struct	btQuantizedBvhFloatData
{
	btVector3FloatData			m_bvhAabbMin;
	btVector3FloatData			m_bvhAabbMax;
	btVector3FloatData			m_bvhQuantization;
	int					m_curNodeIndex;
	int					m_useQuantization;
	int					m_numContiguousLeafNodes;
	int					m_numQuantizedContiguousNodes;
	btOptimizedBvhNodeFloatData	*m_contiguousNodesPtr;
	btQuantizedBvhNodeData		*m_quantizedContiguousNodesPtr;
	btBvhSubtreeInfoData	*m_subTreeInfoPtr;
	int					m_traversalMode;
	int					m_numSubtreeHeaders;
	
};

struct	btQuantizedBvhDoubleData
{
	btVector3DoubleData			m_bvhAabbMin;
	btVector3DoubleData			m_bvhAabbMax;
	btVector3DoubleData			m_bvhQuantization;
	int							m_curNodeIndex;
	int							m_useQuantization;
	int							m_numContiguousLeafNodes;
	int							m_numQuantizedContiguousNodes;
	btOptimizedBvhNodeDoubleData	*m_contiguousNodesPtr;
	btQuantizedBvhNodeData			*m_quantizedContiguousNodesPtr;

	int							m_traversalMode;
	int							m_numSubtreeHeaders;
	btBvhSubtreeInfoData		*m_subTreeInfoPtr;
};
// clang-format on

SIMD_FORCE_INLINE int btQuantizedBvh::calculateSerializeBufferSizeNew() const
{
	return sizeof(btQuantizedBvhData);
}

#endif  //BT_QUANTIZED_BVH_H