84 lines
2.4 KiB
C++
84 lines
2.4 KiB
C++
/*
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Copyright (c) 2016 yvt
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This file is part of OpenSpades.
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OpenSpades is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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OpenSpades is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with OpenSpades. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "NoiseSampler.h"
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#include <Core/Math.h>
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using namespace std;
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namespace spades {
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namespace client {
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CoherentNoiseSampler1D::CoherentNoiseSampler1D() {
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values.resize(1024);
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for (float &value : values) {
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value = GetRandom() - GetRandom();
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}
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}
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CoherentNoiseSampler1D::~CoherentNoiseSampler1D() {}
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float CoherentNoiseSampler1D::Sample(float x) {
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// Wrap around
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x /= static_cast<float>(values.size());
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x -= floor(x);
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x *= static_cast<float>(values.size());
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int intCoord = static_cast<int>(floor(x));
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float fracCoord = x - floor(x);
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// Sample values
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const int mask = static_cast<int>(values.size() - 1);
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float v1 = values[intCoord & mask];
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float v2 = values[(intCoord + 1) & mask];
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// Create and evaluate a polynomial with given values
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return Mix(v1, v2, SmoothStep(fracCoord)) + gcns.Sample(x);
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}
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GradientCoherentNoiseSampler1D::GradientCoherentNoiseSampler1D() {
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derivatives.resize(1024);
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for (float &derivative : derivatives) {
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derivative = (GetRandom() - GetRandom()) * 4.f;
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}
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}
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GradientCoherentNoiseSampler1D::~GradientCoherentNoiseSampler1D() {}
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float GradientCoherentNoiseSampler1D::Sample(float x) {
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// Wrap around
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x /= static_cast<float>(derivatives.size());
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x -= floor(x);
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x *= static_cast<float>(derivatives.size());
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int intCoord = static_cast<int>(floor(x));
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float fracCoord = x - floor(x);
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// Sample derivatives
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const int mask = static_cast<int>(derivatives.size() - 1);
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float d1 = derivatives[intCoord & mask];
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float d2 = derivatives[(intCoord + 1) & mask];
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// Create and evaluate a polynomial with given derivatives
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return (d1 * (1.f - fracCoord) - d2 * fracCoord) * fracCoord * (1.f - fracCoord);
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}
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}
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}
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