bullet3/Extras/ConvexDecomposition/vlookup.cpp

#include "float_math.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>

#pragma warning(disable : 4786)

#include <vector>
#include <map>
#include <set>

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		INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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-----------------------------------------------------------------------*/

// http://codesuppository.blogspot.com
//
// mailto: jratcliff@infiniplex.net
//
// http://www.amillionpixels.us
//

// CodeSnippet provided by John W. Ratcliff
// on March 23, 2006.
//
// mailto: jratcliff@infiniplex.net
//
// Personal website: http://jratcliffscarab.blogspot.com
// Coding Website:   http://codesuppository.blogspot.com
// FundRaising Blog: http://amillionpixels.blogspot.com
// Fundraising site: http://www.amillionpixels.us
// New Temple Site:  http://newtemple.blogspot.com
//
// This snippet shows how to 'hide' the complexity of
// the STL by wrapping some useful piece of functionality
// around a handful of discrete API calls.
//
// This API allows you to create an indexed triangle list
// from a collection of raw input triangles.  Internally
// it uses an STL set to build the lookup table very rapidly.
//
// Here is how you would use it to build an indexed triangle
// list from a raw list of triangles.
//
// (1) create a 'VertexLookup' interface by calling
//
//     VertexLook vl = Vl_createVertexLookup();
//
// (2) For each vertice in each triangle call:
//
//     unsigned int i1 = Vl_getIndex(vl,p1);
//     unsigned int i2 = Vl_getIndex(vl,p2);
//     unsigned int i3 = Vl_getIndex(vl,p3);
//
//     save the 3 indices into your triangle list array.
//
// (3) Get the vertex array by calling:
//
//     const float *vertices = Vl_getVertices(vl);
//
// (4) Get the number of vertices so you can copy them into
//     your own buffer.
//     unsigned int vcount = Vl_getVcount(vl);
//
// (5) Release the VertexLookup interface when you are done with it.
//     Vl_releaseVertexLookup(vl);
//
// Teaches the following lessons:
//
//    How to wrap the complexity of STL and C++ classes around a
//    simple API interface.
//
//    How to use an STL set and custom comparator operator for
//    a complex data type.
//
//    How to create a template class.
//
//    How to achieve significant performance improvements by
//    taking advantage of built in STL containers in just
//    a few lines of code.
//
//    You could easily modify this code to support other vertex
//    formats with any number of interpolants.

#include "vlookup.h"

namespace Vlookup
{
class VertexPosition
{
public:
	VertexPosition(void){};
	VertexPosition(const float *p)
	{
		mPos[0] = p[0];
		mPos[1] = p[1];
		mPos[2] = p[2];
	};

	void Set(int index, const float *pos)
	{
		const float *p = &pos[index * 3];

		mPos[0] = p[0];
		mPos[1] = p[1];
		mPos[2] = p[2];
	};

	float GetX(void) const { return mPos[0]; };
	float GetY(void) const { return mPos[1]; };
	float GetZ(void) const { return mPos[2]; };

	float mPos[3];
};

typedef std::vector<VertexPosition> VertexVector;

struct Tracker
{
	VertexPosition mFind;  // vertice to locate.
	VertexVector *mList;

	Tracker()
	{
		mList = 0;
	}

	void SetSearch(const VertexPosition &match, VertexVector *list)
	{
		mFind = match;
		mList = list;
	};
};

struct VertexID
{
	int mID;
	Tracker *mTracker;

	VertexID(int ID, Tracker *Tracker)
	{
		mID = ID;
		mTracker = Tracker;
	}
};

class VertexLess
{
public:
	bool operator()(VertexID v1, VertexID v2) const;

private:
	const VertexPosition &Get(VertexID index) const
	{
		if (index.mID == -1) return index.mTracker->mFind;
		VertexVector &vlist = *index.mTracker->mList;
		return vlist[index.mID];
	}
};

template <class Type>
class VertexPool
{
public:
	typedef std::set<VertexID, VertexLess> VertexSet;
	typedef std::vector<Type> VertexVector;

	int getVertex(const Type &vtx)
	{
		mTracker.SetSearch(vtx, &mVtxs);
		VertexSet::iterator found;
		found = mVertSet.find(VertexID(-1, &mTracker));
		if (found != mVertSet.end())
		{
			return found->mID;
		}
		int idx = (int)mVtxs.size();
		mVtxs.push_back(vtx);
		mVertSet.insert(VertexID(idx, &mTracker));
		return idx;
	};

	const float *GetPos(int idx) const
	{
		return mVtxs[idx].mPos;
	}

	const Type &Get(int idx) const
	{
		return mVtxs[idx];
	};

	unsigned int GetSize(void) const
	{
		return mVtxs.size();
	};

	void Clear(int reservesize)  // clear the vertice pool.
	{
		mVertSet.clear();
		mVtxs.clear();
		mVtxs.reserve(reservesize);
	};

	const VertexVector &GetVertexList(void) const { return mVtxs; };

	void Set(const Type &vtx)
	{
		mVtxs.push_back(vtx);
	}

	unsigned int GetVertexCount(void) const
	{
		return mVtxs.size();
	};

	Type *getBuffer(void)
	{
		return &mVtxs[0];
	};

private:
	VertexSet mVertSet;  // ordered list.
	VertexVector mVtxs;  // set of vertices.
	Tracker mTracker;
};

bool VertexLess::operator()(VertexID v1, VertexID v2) const
{
	const VertexPosition &a = Get(v1);
	const VertexPosition &b = Get(v2);

	int ixA = (int)(a.GetX() * 10000.0f);
	int ixB = (int)(b.GetX() * 10000.0f);

	if (ixA < ixB) return true;
	if (ixA > ixB) return false;

	int iyA = (int)(a.GetY() * 10000.0f);
	int iyB = (int)(b.GetY() * 10000.0f);

	if (iyA < iyB) return true;
	if (iyA > iyB) return false;

	int izA = (int)(a.GetZ() * 10000.0f);
	int izB = (int)(b.GetZ() * 10000.0f);

	if (izA < izB) return true;
	if (izA > izB) return false;

	return false;
}

}  // namespace Vlookup

using namespace Vlookup;

VertexLookup Vl_createVertexLookup(void)
{
	VertexLookup ret = new VertexPool<VertexPosition>;
	return ret;
}

void Vl_releaseVertexLookup(VertexLookup vlook)
{
	VertexPool<VertexPosition> *vp = (VertexPool<VertexPosition> *)vlook;
	delete vp;
}

unsigned int Vl_getIndex(VertexLookup vlook, const float *pos)  // get index.
{
	VertexPool<VertexPosition> *vp = (VertexPool<VertexPosition> *)vlook;
	VertexPosition p(pos);
	return vp->getVertex(p);
}

const float *Vl_getVertices(VertexLookup vlook)
{
	VertexPool<VertexPosition> *vp = (VertexPool<VertexPosition> *)vlook;
	return vp->GetPos(0);
}

unsigned int Vl_getVcount(VertexLookup vlook)
{
	VertexPool<VertexPosition> *vp = (VertexPool<VertexPosition> *)vlook;
	return vp->GetVertexCount();
}