godot/thirdparty/bullet/Bullet3OpenCL/ParallelPrimitives/b3PrefixScanCL.cpp

#include "b3PrefixScanCL.h"
#include "b3FillCL.h"
#define B3_PREFIXSCAN_PROG_PATH "src/Bullet3OpenCL/ParallelPrimitives/kernels/PrefixScanKernels.cl"

#include "b3LauncherCL.h"
#include "Bullet3OpenCL/Initialize/b3OpenCLUtils.h"
#include "kernels/PrefixScanKernelsCL.h"

b3PrefixScanCL::b3PrefixScanCL(cl_context ctx, cl_device_id device, cl_command_queue queue, int size)
:m_commandQueue(queue)
{
	const char* scanKernelSource = prefixScanKernelsCL;
	cl_int pErrNum;
	char* additionalMacros=0;

	m_workBuffer = new b3OpenCLArray<unsigned int>(ctx,queue,size);
	cl_program scanProg = b3OpenCLUtils::compileCLProgramFromString( ctx, device, scanKernelSource, &pErrNum,additionalMacros, B3_PREFIXSCAN_PROG_PATH);
	b3Assert(scanProg);

	m_localScanKernel = b3OpenCLUtils::compileCLKernelFromString( ctx, device, scanKernelSource, "LocalScanKernel", &pErrNum, scanProg,additionalMacros );
	b3Assert(m_localScanKernel );
	m_blockSumKernel = b3OpenCLUtils::compileCLKernelFromString( ctx, device, scanKernelSource, "TopLevelScanKernel", &pErrNum, scanProg,additionalMacros );
	b3Assert(m_blockSumKernel );
	m_propagationKernel = b3OpenCLUtils::compileCLKernelFromString( ctx, device, scanKernelSource, "AddOffsetKernel", &pErrNum, scanProg,additionalMacros );
	b3Assert(m_propagationKernel );
}


b3PrefixScanCL::~b3PrefixScanCL()
{
	delete m_workBuffer;
	clReleaseKernel(m_localScanKernel);
	clReleaseKernel(m_blockSumKernel);
	clReleaseKernel(m_propagationKernel);
}

template<class T>
T b3NextPowerOf2(T n)
{
	n -= 1;
	for(int i=0; i<sizeof(T)*8; i++)
		n = n | (n>>i);
	return n+1;
}

void b3PrefixScanCL::execute(b3OpenCLArray<unsigned int>& src, b3OpenCLArray<unsigned int>& dst, int n, unsigned int* sum)
{
	
//	b3Assert( data->m_option == EXCLUSIVE );
	const unsigned int numBlocks = (const unsigned int)( (n+BLOCK_SIZE*2-1)/(BLOCK_SIZE*2) );

	dst.resize(src.size());
	m_workBuffer->resize(src.size());

	b3Int4 constBuffer;
	constBuffer.x = n;
	constBuffer.y = numBlocks;
	constBuffer.z = (int)b3NextPowerOf2( numBlocks );

	b3OpenCLArray<unsigned int>* srcNative = &src;
	b3OpenCLArray<unsigned int>* dstNative = &dst;
	
	{
		b3BufferInfoCL bInfo[] = { b3BufferInfoCL( dstNative->getBufferCL() ), b3BufferInfoCL( srcNative->getBufferCL() ), b3BufferInfoCL( m_workBuffer->getBufferCL() ) };

		b3LauncherCL launcher( m_commandQueue, m_localScanKernel,"m_localScanKernel" );
		launcher.setBuffers( bInfo, sizeof(bInfo)/sizeof(b3BufferInfoCL) );
		launcher.setConst(  constBuffer );
		launcher.launch1D( numBlocks*BLOCK_SIZE, BLOCK_SIZE );
	}

	{
		b3BufferInfoCL bInfo[] = { b3BufferInfoCL( m_workBuffer->getBufferCL() ) };

		b3LauncherCL launcher( m_commandQueue, m_blockSumKernel,"m_blockSumKernel" );
		launcher.setBuffers( bInfo, sizeof(bInfo)/sizeof(b3BufferInfoCL) );
		launcher.setConst( constBuffer );
		launcher.launch1D( BLOCK_SIZE, BLOCK_SIZE );
	}
	

	if( numBlocks > 1 )
	{
		b3BufferInfoCL bInfo[] = { b3BufferInfoCL( dstNative->getBufferCL() ), b3BufferInfoCL( m_workBuffer->getBufferCL() ) };
		b3LauncherCL launcher( m_commandQueue, m_propagationKernel,"m_propagationKernel" );
		launcher.setBuffers( bInfo, sizeof(bInfo)/sizeof(b3BufferInfoCL) );
		launcher.setConst( constBuffer );
		launcher.launch1D( (numBlocks-1)*BLOCK_SIZE, BLOCK_SIZE );
	}


	if( sum )
	{
		clFinish(m_commandQueue);
		dstNative->copyToHostPointer(sum,1,n-1,true);
	}

}


void b3PrefixScanCL::executeHost(b3AlignedObjectArray<unsigned int>& src, b3AlignedObjectArray<unsigned int>& dst, int n, unsigned int* sum)
{
	unsigned int s = 0;
	//if( data->m_option == EXCLUSIVE )
	{
		for(int i=0; i<n; i++)
		{
			dst[i] = s;
			s += src[i];
		}
	}
	/*else
	{
		for(int i=0; i<n; i++)
		{
			s += hSrc[i];
			hDst[i] = s;
		}
	}
	*/

	if( sum )
	{
		*sum = dst[n-1];
	}
}