cudaAlphaBlend.cuh

/*
 * Copyright (c) 2019, NVIDIA CORPORATION. All rights reserved.
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#ifndef __CUDA_ALPHA_BLEND_CUH__
#define __CUDA_ALPHA_BLEND_CUH__


#include "cudaUtility.h"
#include "cudaVector.h"


/**
 * CUDA device function for alpha blending two pixels.
 * The alpha blending of the `src` and `dst` pixels is
 * computed by the equation: `dst * dst.w + src * (1.0 - dst.w)`
 *
 * @note cudaAlphaBlend() is for use inside of other CUDA kernels.
 * @ingroup cuda
 */
template<typename T1, typename T2>
__device__ inline T1 cudaAlphaBlend( const T1& src, const T2& dst )
{
	const float alph = dst.w / 255.0f;
	const float inva = 1.0f - alph;

	return make_vec<T1>(alph * dst.x + inva * src.x,
				     alph * dst.y + inva * src.y,
				     alph * dst.z + inva * src.z,
				     255);
}


#endif