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99 lines
4.2 KiB
Plaintext
99 lines
4.2 KiB
Plaintext
/* Copyright (c) 2022, NVIDIA CORPORATION. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* * Neither the name of NVIDIA CORPORATION nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ``AS IS'' AND ANY
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* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
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* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "common.h"
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///////////////////////////////////////////////////////////////////////////////
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/// \brief downscale image
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///
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/// CUDA kernel, relies heavily on texture unit
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/// \param[in] width image width
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/// \param[in] height image height
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/// \param[in] stride image stride
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/// \param[out] out result
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///////////////////////////////////////////////////////////////////////////////
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__global__ void DownscaleKernel(int width, int height, int stride, float *out,
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cudaTextureObject_t texFine) {
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const int ix = threadIdx.x + blockIdx.x * blockDim.x;
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const int iy = threadIdx.y + blockIdx.y * blockDim.y;
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if (ix >= width || iy >= height) {
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return;
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}
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float dx = 1.0f / (float)width;
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float dy = 1.0f / (float)height;
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float x = ((float)ix + 0.5f) * dx;
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float y = ((float)iy + 0.5f) * dy;
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out[ix + iy * stride] = 0.25f * (tex2D<float>(texFine, x - dx * 0.25f, y) +
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tex2D<float>(texFine, x + dx * 0.25f, y) +
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tex2D<float>(texFine, x, y - dy * 0.25f) +
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tex2D<float>(texFine, x, y + dy * 0.25f));
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}
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///////////////////////////////////////////////////////////////////////////////
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/// \brief downscale image
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///
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/// \param[in] src image to downscale
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/// \param[in] width image width
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/// \param[in] height image height
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/// \param[in] stride image stride
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/// \param[out] out result
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///////////////////////////////////////////////////////////////////////////////
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static void Downscale(const float *src, int width, int height, int stride,
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int newWidth, int newHeight, int newStride, float *out) {
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dim3 threads(32, 8);
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dim3 blocks(iDivUp(newWidth, threads.x), iDivUp(newHeight, threads.y));
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cudaTextureObject_t texFine;
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cudaResourceDesc texRes;
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memset(&texRes, 0, sizeof(cudaResourceDesc));
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texRes.resType = cudaResourceTypePitch2D;
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texRes.res.pitch2D.devPtr = (void *)src;
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texRes.res.pitch2D.desc = cudaCreateChannelDesc<float>();
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texRes.res.pitch2D.width = width;
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texRes.res.pitch2D.height = height;
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texRes.res.pitch2D.pitchInBytes = stride * sizeof(float);
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cudaTextureDesc texDescr;
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memset(&texDescr, 0, sizeof(cudaTextureDesc));
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texDescr.normalizedCoords = true;
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texDescr.filterMode = cudaFilterModeLinear;
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texDescr.addressMode[0] = cudaAddressModeMirror;
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texDescr.addressMode[1] = cudaAddressModeMirror;
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texDescr.readMode = cudaReadModeElementType;
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checkCudaErrors(cudaCreateTextureObject(&texFine, &texRes, &texDescr, NULL));
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DownscaleKernel<<<blocks, threads>>>(newWidth, newHeight, newStride, out,
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texFine);
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}
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