67 lines
2.0 KiB
HLSL
67 lines
2.0 KiB
HLSL
//
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// GLSL textureless classic 2D noise "cnoise",
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// with an RSL-style periodic variant "pnoise".
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// Author: Stefan Gustavson (stefan.gustavson@liu.se)
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// Version: 2011-08-22
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//
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// Many thanks to Ian McEwan of Ashima Arts for the
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// ideas for permutation and gradient selection.
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//
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// Copyright (c) 2011 Stefan Gustavson. All rights reserved.
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// Distributed under the MIT license. See LICENSE file.
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// https://github.com/ashima/webgl-noise
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//
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#ifndef _INCLUDE_JP_KEIJIRO_NOISESHADER_CLASSIC_NOISE_2D_HLSL_
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#define _INCLUDE_JP_KEIJIRO_NOISESHADER_CLASSIC_NOISE_2D_HLSL_
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#include "Common.hlsl"
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float ClassicNoise_impl(float2 pi0, float2 pf0, float2 pi1, float2 pf1)
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{
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pi0 = wglnoise_mod289(pi0); // To avoid truncation effects in permutation
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pi1 = wglnoise_mod289(pi1);
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float4 ix = float2(pi0.x, pi1.x).xyxy;
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float4 iy = float2(pi0.y, pi1.y).xxyy;
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float4 fx = float2(pf0.x, pf1.x).xyxy;
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float4 fy = float2(pf0.y, pf1.y).xxyy;
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float4 i = wglnoise_permute(wglnoise_permute(ix) + iy);
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float4 phi = i / 41 * 3.14159265359 * 2;
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float2 g00 = float2(cos(phi.x), sin(phi.x));
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float2 g10 = float2(cos(phi.y), sin(phi.y));
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float2 g01 = float2(cos(phi.z), sin(phi.z));
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float2 g11 = float2(cos(phi.w), sin(phi.w));
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float n00 = dot(g00, float2(fx.x, fy.x));
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float n10 = dot(g10, float2(fx.y, fy.y));
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float n01 = dot(g01, float2(fx.z, fy.z));
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float n11 = dot(g11, float2(fx.w, fy.w));
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float2 fade_xy = wglnoise_fade(pf0);
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float2 n_x = lerp(float2(n00, n01), float2(n10, n11), fade_xy.x);
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float n_xy = lerp(n_x.x, n_x.y, fade_xy.y);
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return 1.44 * n_xy;
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}
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// Classic Perlin noise
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float ClassicNoise(float2 p)
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{
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float2 i = floor(p);
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float2 f = frac(p);
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return ClassicNoise_impl(i, f, i + 1, f - 1);
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}
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// Classic Perlin noise, periodic variant
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float PeriodicNoise(float2 p, float2 rep)
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{
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float2 i0 = wglnoise_mod(floor(p), rep);
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float2 i1 = wglnoise_mod(i0 + 1, rep);
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float2 f = frac(p);
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return ClassicNoise_impl(i0, f, i1, f - 1);
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}
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#endif
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