DyFrictionPatchStreamPair.h

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#ifndef DY_FRICTION_PATCH_STREAM_PAIR_H
#define DY_FRICTION_PATCH_STREAM_PAIR_H
 
#include "foundation/PxSimpleTypes.h"
#include "PxvConfig.h"
#include "foundation/PxMutex.h"
#include "foundation/PxArray.h"
 
// Each narrow phase thread has an input stream of friction patches from the
// previous frame and an output stream of friction patches which will be
// saved for next frame. The patches persist for exactly one frame at which
// point they get thrown away.
 
 
// There is a stream pair per thread. A contact callback reserves space
// for its friction patches and gets a cookie in return that can stash
// for next frame. Cookies are valid for one frame only.
//
// note that all friction patches reserved are guaranteed to be contiguous;
// this might turn out to be a bit inefficient if we often have a large
// number of friction patches
 
#include "PxcNpMemBlockPool.h"
 
namespace physx
{
 
class FrictionPatchStreamPair
{
public:
    FrictionPatchStreamPair(PxcNpMemBlockPool& blockPool);
 
    // reserve can fail and return null. Read should never fail
    template<class FrictionPatch>
    FrictionPatch*      reserve(const PxU32 size);
 
    template<class FrictionPatch>
    const FrictionPatch* findInputPatches(const PxU8* ptr) const;
    void                    reset();
 
    PxcNpMemBlockPool& getBlockPool() { return mBlockPool;}
private:
    PxcNpMemBlockPool&  mBlockPool;
    PxcNpMemBlock*      mBlock;
    PxU32               mUsed;
 
    FrictionPatchStreamPair& operator=(const FrictionPatchStreamPair&);
};
 
PX_FORCE_INLINE FrictionPatchStreamPair::FrictionPatchStreamPair(PxcNpMemBlockPool& blockPool):
  mBlockPool(blockPool), mBlock(NULL), mUsed(0)
{
}
 
PX_FORCE_INLINE void FrictionPatchStreamPair::reset()
{
    mBlock = NULL;
    mUsed = 0;
}
 
// reserve can fail and return null. Read should never fail
template <class FrictionPatch>
FrictionPatch* FrictionPatchStreamPair::reserve(const PxU32 size)
{
    if(size>PxcNpMemBlock::SIZE)
    {
        return reinterpret_cast<FrictionPatch*>(-1);
    }
 
    PX_ASSERT(size <= PxcNpMemBlock::SIZE);
 
    FrictionPatch* ptr = NULL;
 
    if(mBlock == NULL || mUsed + size > PxcNpMemBlock::SIZE)
    {
        mBlock = mBlockPool.acquireFrictionBlock();
        mUsed = 0;
    }
 
    if(mBlock)
    {
        ptr = reinterpret_cast<FrictionPatch*>(mBlock->data+mUsed);
        mUsed += size;
    }
 
    return ptr;
}
 
template <class FrictionPatch>
const FrictionPatch* FrictionPatchStreamPair::findInputPatches(const PxU8* ptr) const
{
    return reinterpret_cast<const FrictionPatch*>(ptr);
}
 
}
 
#endif