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POOpenCL - Empty result when loading a specific amount of input data
 

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    <p>Right now I am programming some samples to understand OpenCL for future use. In the sample with the problem, I load some big 8bit Images and calculate pixelwise mean values.</p> <p>Result[X,Y] = (Image1[X,Y] + Image2[X,Y] + ... ) / ImageCount</p> <p>This works very well for 0 to 9 pictures. But when i load 10 or more images, the result is just a black image (all Pixels 0).</p> <p>I thought that it may be a problem with the amount of memory. But with 10 pictures the image data is only 100MB. The graphic card is a 8600GTS with 256MB RAM. </p> <p>Also i checked all of the error code returns and don't get anything different than a CL_SUCCESS.</p> <p>Host program (Delphi, but I thing also C people can read it):</p> <pre><code>//Settings MaxImg := 4; //Images from 0..4 Count = 5 SetLength(InImgs,MaxImg+1); //Array for images in Host memory SetLength(GPUInMems,MaxImg+1); //Array for images in GPU memory //Create Kernel CLKernel := clCreateKernel(CLProgram, PChar('MainKernel'), @LastError); //Create Queue CLQueue := clCreateCommandQueue(CLContext, CLDevices[0].DeviceID, 0, @LastError); //Load images for I := 0 to MaxImg do begin InImgs[I] := TImageMem.Create; InImgs[I].LoadFile('C:\Test\Img-' + IntToStr(I) + '.bmp'); GPUInMems[I] := clCreateBuffer(CLContext, CL_MEM_READ_ONLY or CL_MEM_COPY_HOST_PTR, InImgs[I].MemSize, InImgs[I].Memory, @LastError); end; //Prepare Outputimage OutImg := TImageMem.Create; OutImg.LoadFile('C:\Test\CLTestOut.bmp');//Temporary solution to get right memory size and headers GPUOutMem := clCreateBuffer(CLContext, CL_MEM_WRITE_ONLY, OutImg.MemSize, nil, @LastError); //Set parameter for kernel call LastError := clSetKernelArg(CLKernel, 0, sizeof(cl_mem), @GPUOutMem); //Output image LastError := clSetKernelArg(CLKernel, 1, sizeof(integer), @OutImg.Width); LastError := clSetKernelArg(CLKernel, 2, sizeof(integer), @OutImg.Height); //Add pointer to memory from images as parameters for I := 0 to MaxImg do begin LastError := clSetKernelArg(CLKernel, I+3, sizeof(cl_mem), @GPUInMems[I]); end; //Specify Group and Grid sizes GlobalWSize[0]:= (OutImg.Width div 512 + 1) * 512; //Calc groups needed for resolution LocalWSize[0] := 512; //Max WorkItems per group possible //Execute and transfer ouput to host memory LastError := clEnqueueNDRangeKernel(CLQueue, CLKernel, 1, nil, @GlobalWSize, @LocalWSize, 0, nil, nil); LastError := clEnqueueReadBuffer(CLQueue, GPUOutMem, CL_TRUE, 0, OutImg.MemSize, OutImg.Memory, 0, nil, nil); //Write output OutImg.SaveFile('C:\Test\CLTestOut.bmp'); </code></pre> <p>Kernel:</p> <pre><code>__kernel void MainKernel( __global uchar* ret, int xRes, int yRes, __global uchar* I0, __global uchar* I1, __global uchar* I2, __global uchar* I3, __global uchar* I4) { //Get line position int y = get_global_id(0); //Check inbound if (y &gt;= yRes) return; //Set pointers to position ret += xRes * y; I0 += xRes * y; I1 += xRes * y; I2 += xRes * y; I3 += xRes * y; I4 += xRes * y; //Set val for each pixel in line for (int x = 0; x &lt; xRes; ++x) { ret[x] = (I0[x] + I1[x] + I2[x] + I3[x] + I4[x]) / 5 ; } } </code></pre> <p>It would be great if somebody can tell me, why it is not working with more than 9 Images and why I don't get an errorcode.</p> <p>Thanks for any help.</p>
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