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160 lines
6.4 KiB
Plaintext
160 lines
6.4 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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///////////////////////////////////////////////////////////////////////////////
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#include <cufft.h>
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#include <math_constants.h>
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// Round a / b to nearest higher integer value
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int cuda_iDivUp(int a, int b) { return (a + (b - 1)) / b; }
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// complex math functions
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__device__ float2 conjugate(float2 arg) { return make_float2(arg.x, -arg.y); }
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__device__ float2 complex_exp(float arg) {
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return make_float2(cosf(arg), sinf(arg));
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}
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__device__ float2 complex_add(float2 a, float2 b) {
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return make_float2(a.x + b.x, a.y + b.y);
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}
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__device__ float2 complex_mult(float2 ab, float2 cd) {
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return make_float2(ab.x * cd.x - ab.y * cd.y, ab.x * cd.y + ab.y * cd.x);
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}
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// generate wave heightfield at time t based on initial heightfield and
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// dispersion relationship
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__global__ void generateSpectrumKernel(float2 *h0, float2 *ht,
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unsigned int in_width,
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unsigned int out_width,
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unsigned int out_height, float t,
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float patchSize) {
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unsigned int x = blockIdx.x * blockDim.x + threadIdx.x;
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unsigned int y = blockIdx.y * blockDim.y + threadIdx.y;
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unsigned int in_index = y * in_width + x;
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unsigned int in_mindex =
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(out_height - y) * in_width + (out_width - x); // mirrored
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unsigned int out_index = y * out_width + x;
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// calculate wave vector
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float2 k;
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k.x = (-(int)out_width / 2.0f + x) * (2.0f * CUDART_PI_F / patchSize);
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k.y = (-(int)out_width / 2.0f + y) * (2.0f * CUDART_PI_F / patchSize);
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// calculate dispersion w(k)
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float k_len = sqrtf(k.x * k.x + k.y * k.y);
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float w = sqrtf(9.81f * k_len);
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if ((x < out_width) && (y < out_height)) {
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float2 h0_k = h0[in_index];
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float2 h0_mk = h0[in_mindex];
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// output frequency-space complex values
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ht[out_index] =
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complex_add(complex_mult(h0_k, complex_exp(w * t)),
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complex_mult(conjugate(h0_mk), complex_exp(-w * t)));
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// ht[out_index] = h0_k;
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}
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}
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// update height map values based on output of FFT
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__global__ void updateHeightmapKernel(float *heightMap, float2 *ht,
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unsigned int width) {
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unsigned int x = blockIdx.x * blockDim.x + threadIdx.x;
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unsigned int y = blockIdx.y * blockDim.y + threadIdx.y;
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unsigned int i = y * width + x;
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// cos(pi * (m1 + m2))
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float sign_correction = ((x + y) & 0x01) ? -1.0f : 1.0f;
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heightMap[i] = ht[i].x * sign_correction;
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}
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// update height map values based on output of FFT
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__global__ void updateHeightmapKernel_y(float *heightMap, float2 *ht,
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unsigned int width) {
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unsigned int x = blockIdx.x * blockDim.x + threadIdx.x;
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unsigned int y = blockIdx.y * blockDim.y + threadIdx.y;
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unsigned int i = y * width + x;
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// cos(pi * (m1 + m2))
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float sign_correction = ((x + y) & 0x01) ? -1.0f : 1.0f;
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heightMap[i] = ht[i].y * sign_correction;
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}
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// generate slope by partial differences in spatial domain
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__global__ void calculateSlopeKernel(float *h, float2 *slopeOut,
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unsigned int width, unsigned int height) {
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unsigned int x = blockIdx.x * blockDim.x + threadIdx.x;
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unsigned int y = blockIdx.y * blockDim.y + threadIdx.y;
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unsigned int i = y * width + x;
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float2 slope = make_float2(0.0f, 0.0f);
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if ((x > 0) && (y > 0) && (x < width - 1) && (y < height - 1)) {
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slope.x = h[i + 1] - h[i - 1];
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slope.y = h[i + width] - h[i - width];
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}
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slopeOut[i] = slope;
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}
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// wrapper functions
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extern "C" void cudaGenerateSpectrumKernel(float2 *d_h0, float2 *d_ht,
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unsigned int in_width,
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unsigned int out_width,
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unsigned int out_height,
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float animTime, float patchSize) {
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dim3 block(8, 8, 1);
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dim3 grid(cuda_iDivUp(out_width, block.x), cuda_iDivUp(out_height, block.y),
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1);
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generateSpectrumKernel<<<grid, block>>>(d_h0, d_ht, in_width, out_width,
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out_height, animTime, patchSize);
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}
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extern "C" void cudaUpdateHeightmapKernel(float *d_heightMap, float2 *d_ht,
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unsigned int width,
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unsigned int height, bool autoTest) {
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dim3 block(8, 8, 1);
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dim3 grid(cuda_iDivUp(width, block.x), cuda_iDivUp(height, block.y), 1);
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if (autoTest) {
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updateHeightmapKernel_y<<<grid, block>>>(d_heightMap, d_ht, width);
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} else {
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updateHeightmapKernel<<<grid, block>>>(d_heightMap, d_ht, width);
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}
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}
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extern "C" void cudaCalculateSlopeKernel(float *hptr, float2 *slopeOut,
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unsigned int width,
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unsigned int height) {
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dim3 block(8, 8, 1);
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dim3 grid2(cuda_iDivUp(width, block.x), cuda_iDivUp(height, block.y), 1);
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calculateSlopeKernel<<<grid2, block>>>(hptr, slopeOut, width, height);
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}
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