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// Copyright (c) 2004-2008 AGEIA Technologies, Inc. All rights reserved.
// Copyright (c) 2001-2004 NovodeX AG. All rights reserved.  

#include "PxPhysXConfig.h"
#if PX_USE_CLOTH_API

#include "foundation/PxVec4.h"
#include "foundation/PxMemory.h"
#include "foundation/PxStrideIterator.h"
#include "extensions/PxClothTetherCooker.h"
#include "PsArray.h"
// from shared foundation
#include <PsFoundation.h>

using namespace physx;

struct physx::PxClothSimpleTetherCookerImpl
{
	PxClothSimpleTetherCookerImpl(const PxClothMeshDesc& desc);

	void	getTetherData(PxU32* userTetherAnchors, PxReal* userTetherLengths) const;

public:
	// output
	shdfnd::Array<PxU32>	mTetherAnchors;
	shdfnd::Array<PxReal>	mTetherLengths;

protected:
	void	createTetherData(const PxClothMeshDesc &desc);
};

PxClothSimpleTetherCooker::PxClothSimpleTetherCooker(const PxClothMeshDesc& desc)
: mImpl(new PxClothSimpleTetherCookerImpl(desc))
{
}

PxClothSimpleTetherCooker::~PxClothSimpleTetherCooker()
{
	delete mImpl;
}

void PxClothSimpleTetherCooker::getTetherData(PxU32* userTetherAnchors, PxReal* userTetherLengths) const
{
	mImpl->getTetherData(userTetherAnchors, userTetherLengths);
}

///////////////////////////////////////////////////////////////////////////////
PxClothSimpleTetherCookerImpl::PxClothSimpleTetherCookerImpl(const PxClothMeshDesc &desc)
{
	createTetherData(desc);
}

///////////////////////////////////////////////////////////////////////////////
void PxClothSimpleTetherCookerImpl::createTetherData(const PxClothMeshDesc &desc)
{
	PxU32 numParticles = desc.points.count;

	if (!desc.invMasses.data)
		return;

	// assemble points
	shdfnd::Array<PxVec4> particles;
	particles.reserve(numParticles);
	PxStrideIterator<const PxVec3> pIt(reinterpret_cast<const PxVec3*>(desc.points.data), desc.points.stride);
	PxStrideIterator<const PxReal> wIt(reinterpret_cast<const PxReal*>(desc.invMasses.data), desc.invMasses.stride);
	for(PxU32 i=0; i<numParticles; ++i)
		particles.pushBack(PxVec4(*pIt++, wIt.ptr() ? *wIt++ : 1.0f));

	// compute tether data
	shdfnd::Array<PxU32> attachedIndices;
	for(PxU32 i=0; i < numParticles; ++i)
		if(particles[i].w == 0.0f)
			attachedIndices.pushBack(i);

	PxU32 n = attachedIndices.empty() ? 0 : numParticles;
	for(PxU32 i=0; i < n; ++i)
	{
		mTetherAnchors.reserve(numParticles);
		mTetherLengths.reserve(numParticles);

		PxVec3 position = reinterpret_cast<const PxVec3&>(particles[i]);
		float minSqrDist = FLT_MAX;
		PxU32 minIndex = numParticles;
		const PxU32 *aIt, *aEnd = attachedIndices.end();
		for(aIt = attachedIndices.begin(); aIt != aEnd; ++aIt)
		{
			float sqrDist = (reinterpret_cast<const PxVec3&>(
				particles[*aIt]) - position).magnitudeSquared();
			if(minSqrDist > sqrDist)
			{
				minSqrDist = sqrDist;
				minIndex = *aIt;
			}
		}

		mTetherAnchors.pushBack(minIndex);
		mTetherLengths.pushBack(PxSqrt(minSqrDist));
	}

	PX_ASSERT(mTetherAnchors.size() == mTetherLengths.size());

}

///////////////////////////////////////////////////////////////////////////////
void  
PxClothSimpleTetherCookerImpl::getTetherData(PxU32* userTetherAnchors, PxReal* userTetherLengths) const
{
	PxMemCopy(userTetherAnchors, mTetherAnchors.begin(), mTetherAnchors.size() * sizeof(PxU32));
	PxMemCopy(userTetherLengths, mTetherLengths.begin(), mTetherLengths.size() * sizeof(PxReal));
}


#endif //PX_USE_CLOTH_API