
metal performance shader 实现直方图均衡化,直方图计算部分没问题,到了执行 encodeTransformToCommandBuffer 计算累加直方图的时候报错: -[MTLDebugComputeCommandEncoder setBuffer:offset:atIndex:]:283: failed assertionoffset(4096) must be < buffer length.'`
代码:
// histogram MPSImageHistogramInfo info; info.histogramForAlpha = true; info.numberOfHistogramEntries = 256; info.minPixelValue = simd_make_float4(0, 0, 0, 0); info.maxPixelValue = simd_make_float4(1, 1, 1, 1); MPSImageHistogram *histogram = [[MPSImageHistogram alloc] initWithDevice:_device histogramInfo:&info]; size_t length = [histogram histogramSizeForSourceFormat:sourceTexture.pixelFormat]; id<MTLBuffer> histogramInfoBuffer = [_device newBufferWithLength:length options:MTLResourceStorageModePrivate]; [histogram encodeToCommandBuffer:commandBuffer sourceTexture:sourceTexture histogram:histogramInfoBuffer histogramOffset:0]; MPSImageHistogramEqualization *equalization = [[MPSImageHistogramEqualization alloc] initWithDevice:_device histogramInfo:&info]; // accumulative distribution function of the histogram [equalization encodeTransformToCommandBuffer:commandBuffer sourceTexture:sourceTexture histogram:histogramInfoBuffer histogramOffset:0]; // apply equalisation [equalization encodeToCommandBuffer:commandBuffer sourceImage:sourceTexture destinationImage:destTexture];