private static unsafe void AggregateSlabByIntensity(IntensityProjectionMethod method, IntPtr pSlabData, byte[] pixelData, int subsamples, int subsamplePixels, int maxThreads)
{
fixed(byte *pPixelData = pixelData)
{
var ptrPixelData = new IntPtr(pPixelData);
// only parallelize if requested, and there's enough work for multiple threads to do stuff (otherwise overhead would just kill performance)
if (maxThreads > 1 && subsamplePixels > 32768 * maxThreads)
{
// determine the number of pixels to process per thread job
var jobSize = subsamplePixels / maxThreads;
// first MAX_THREADS-1 jobs will have exactly JOB_SIZE pixels, and the last will be everything else (thus including any remainder caused by the determination of JOB_SIZE)
var lastJob = maxThreads - 1;
Enumerable.Range(0, maxThreads).Select(g => new KeyValuePair <int, int>(g * jobSize, g == lastJob ? subsamplePixels - lastJob * jobSize : jobSize))
.AsParallel().WithDegreeOfParallelism(maxThreads)
.ForAll(r => method(pSlabData, ptrPixelData, subsamples, subsamplePixels, r.Key, r.Value));
}
else
{
method(pSlabData, ptrPixelData, subsamples, subsamplePixels, 0, subsamplePixels);
}
}
}
private static unsafe void AggregateSlabByIntensity(IntensityProjectionMethod method, IntPtr pSlabData, byte[] pixelData, int subsamples, int subsamplePixels, int maxThreads)
{
fixed (byte* pPixelData = pixelData)
{
var ptrPixelData = new IntPtr(pPixelData);
// only parallelize if requested, and there's enough work for multiple threads to do stuff (otherwise overhead would just kill performance)
if (maxThreads > 1 && subsamplePixels > 32768*maxThreads)
{
// determine the number of pixels to process per thread job
var jobSize = subsamplePixels/maxThreads;
// first MAX_THREADS-1 jobs will have exactly JOB_SIZE pixels, and the last will be everything else (thus including any remainder caused by the determination of JOB_SIZE)
var lastJob = maxThreads - 1;
Enumerable.Range(0, maxThreads).Select(g => new KeyValuePair<int, int>(g*jobSize, g == lastJob ? subsamplePixels - lastJob*jobSize : jobSize))
.AsParallel().WithDegreeOfParallelism(maxThreads)
.ForAll(r => method(pSlabData, ptrPixelData, subsamples, subsamplePixels, r.Key, r.Value));
}
else
{
method(pSlabData, ptrPixelData, subsamples, subsamplePixels, 0, subsamplePixels);
}
}
}
