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76 lines
2.5 KiB
C++
76 lines
2.5 KiB
C++
/*
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* Copyright (c) Contributors to the Open 3D Engine Project. For complete copyright and license terms please see the LICENSE at the root of this distribution.
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*
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* SPDX-License-Identifier: Apache-2.0 OR MIT
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*
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*/
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#include <Atom/ImageProcessing/PixelFormats.h>
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#include <Atom/ImageProcessing/ImageObject.h>
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#include <Converters/PixelOperation.h>
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#include <Processing/PixelFormatInfo.h>
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#include <Converters/Histogram.h>
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///////////////////////////////////////////////////////////////////////////////////
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namespace ImageProcessingAtom
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{
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float GetLuminance(const float& r, const float& g, const float& b)
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{
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return (r * 0.30f + g * 0.59f + b * 0.11f);
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}
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bool ComputeLuminanceHistogram(IImageObjectPtr imageObject, Histogram<256>& histogram)
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{
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EPixelFormat pixelFormat = imageObject->GetPixelFormat();
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if (!(CPixelFormats::GetInstance().IsPixelFormatUncompressed(pixelFormat)))
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{
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AZ_Assert(false, "%s function only works with uncompressed pixel format", __FUNCTION__);
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return false;
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}
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//create pixel operation function
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IPixelOperationPtr pixelOp = CreatePixelOperation(pixelFormat);
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//setup histogram bin
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static const size_t binCount = 256;
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Histogram<binCount>::Bins bins;
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Histogram<binCount>::clearBins(bins);
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//get count of bytes per pixel
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AZ::u32 pixelBytes = CPixelFormats::GetInstance().GetPixelFormatInfo(pixelFormat)->bitsPerBlock / 8;
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const AZ::u32 mipCount = imageObject->GetMipCount();
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float color[4];
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for (uint32 mip = 0; mip < mipCount; ++mip)
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{
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AZ::u8* pixelBuf;
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AZ::u32 pitch;
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imageObject->GetImagePointer(mip, pixelBuf, pitch);
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const uint32 pixelCount = imageObject->GetPixelCount(mip);
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for (uint32 i = 0; i < pixelCount; ++i, pixelBuf += pixelBytes)
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{
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pixelOp->GetRGBA(pixelBuf, color[0], color[1], color[2], color[3]);
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const float luminance = AZ::GetClamp(GetLuminance(color[0], color[1], color[2]), 0.0f, 1.0f);
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const float f = luminance * binCount;
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if (f <= 0)
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{
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++bins[0];
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}
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else
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{
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const int bin = int(f);
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++bins[(bin < binCount) ? bin : binCount - 1];
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}
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}
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}
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histogram.set(bins);
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return true;
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}
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} // end namespace ImageProcessingAtom
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