source: code/branches/physics/src/bullet/BulletMultiThreaded/SpuDoubleBuffer.h @ 1971

#ifndef DOUBLE_BUFFER_H
#define DOUBLE_BUFFER_H

#include "SpuFakeDma.h"
#include <LinearMath/btScalar.h>


///DoubleBuffer
template<class T, int size>
class DoubleBuffer
{
#if defined(__SPU__) || defined(USE_LIBSPE2)
        ATTRIBUTE_ALIGNED128( T m_buffer0[size] ) ;
        ATTRIBUTE_ALIGNED128( T m_buffer1[size] ) ;
#else
        T m_buffer0[size];
        T m_buffer1[size];
#endif
        
        T *m_frontBuffer;
        T *m_backBuffer;

        unsigned int m_dmaTag;
        bool m_dmaPending;
public:
        bool    isPending() const { return m_dmaPending;}
        DoubleBuffer();

        void init ();

        // dma get and put commands
        void backBufferDmaGet(uint64_t ea, unsigned int numBytes, unsigned int tag);
        void backBufferDmaPut(uint64_t ea, unsigned int numBytes, unsigned int tag);

        // gets pointer to a buffer
        T *getFront();
        T *getBack();

        // if back buffer dma was started, wait for it to complete
        // then move back to front and vice versa
        T *swapBuffers();
};

template<class T, int size>
DoubleBuffer<T,size>::DoubleBuffer()
{
        init ();
}

template<class T, int size>
void DoubleBuffer<T,size>::init()
{
        this->m_dmaPending = false;
        this->m_frontBuffer = &this->m_buffer0[0];
        this->m_backBuffer = &this->m_buffer1[0];
}

template<class T, int size>
void
DoubleBuffer<T,size>::backBufferDmaGet(uint64_t ea, unsigned int numBytes, unsigned int tag)
{
        m_dmaPending = true;
        m_dmaTag = tag;
        cellDmaLargeGet(m_backBuffer, ea, numBytes, tag, 0, 0);
}

template<class T, int size>
void
DoubleBuffer<T,size>::backBufferDmaPut(uint64_t ea, unsigned int numBytes, unsigned int tag)
{
        m_dmaPending = true;
        m_dmaTag = tag;
        cellDmaLargePut(m_backBuffer, ea, numBytes, tag, 0, 0);
}

template<class T, int size>
T *
DoubleBuffer<T,size>::getFront()
{
        return m_frontBuffer;
}

template<class T, int size>
T *
DoubleBuffer<T,size>::getBack()
{
        return m_backBuffer;
}

template<class T, int size>
T *
DoubleBuffer<T,size>::swapBuffers()
{
        if (m_dmaPending)
        {
                cellDmaWaitTagStatusAll(1<<m_dmaTag);
                m_dmaPending = false;
        }

        T *tmp = m_backBuffer;
        m_backBuffer = m_frontBuffer;
        m_frontBuffer = tmp;

        return m_frontBuffer;
}

#endif