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81 lines
3.0 KiB
C
81 lines
3.0 KiB
C
const char *noise_fragment_shader =
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//
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// Description : Array and textureless GLSL 2D simplex noise function.
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// Author : Ian McEwan, Ashima Arts.
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// Maintainer : ijm
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// Lastmod : 20110822 (ijm)
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// License : Copyright (C) 2011 Ashima Arts. 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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//
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"vec3 mod289(vec3 x) { \n"
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" return x - floor(x * (1.0 / 289.0)) * 289.0; \n"
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"} \n"
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" \n"
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"vec2 mod289(vec2 x) { \n"
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" return x - floor(x * (1.0 / 289.0)) * 289.0; \n"
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"} \n"
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" \n"
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"vec3 permute(vec3 x) { \n"
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" return mod289(((x*34.0)+1.0)*x); \n"
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"} \n"
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" \n"
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"float snoise(vec2 v) \n"
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" { \n"
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" const vec4 C = vec4(0.211324865405187, // (3.0-sqrt(3.0))/6.0 \n"
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" 0.366025403784439, // 0.5*(sqrt(3.0)-1.0) \n"
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" -0.577350269189626, // -1.0 + 2.0 * C.x \n"
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" 0.024390243902439); // 1.0 / 41.0 \n"
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// First corner
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" vec2 i = floor(v + dot(v, C.yy) ); \n"
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" vec2 x0 = v - i + dot(i, C.xx); \n"
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" \n"
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// Other corners
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" vec2 i1 = (x0.x > x0.y) ? vec2(1.0, 0.0) : vec2(0.0, 1.0); \n"
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" vec4 x12 = x0.xyxy + C.xxzz; \n"
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" x12.xy -= i1; \n"
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" \n"
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// Permutations
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" i = mod289(i); // Avoid truncation effects in permutation \n"
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" vec3 p = permute( permute( i.y + vec3(0.0, i1.y, 1.0 )) \n"
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" + i.x + vec3(0.0, i1.x, 1.0 )); \n"
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" \n"
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" vec3 m = max(0.5 - vec3(dot(x0,x0), dot(x12.xy,x12.xy), dot(x12.zw,x12.zw)), 0.0);\n"
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" m = m*m ; \n"
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" m = m*m ; \n"
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" \n"
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// Gradients: 41 points uniformly over a line, mapped onto a diamond.
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// The ring size 17*17 = 289 is close to a multiple of 41 (41*7 = 287)
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" \n"
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" vec3 x = 2.0 * fract(p * C.www) - 1.0; \n"
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" vec3 h = abs(x) - 0.5; \n"
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" vec3 ox = floor(x + 0.5); \n"
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" vec3 a0 = x - ox; \n"
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" \n"
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// Normalise gradients implicitly by scaling m
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// Approximation of: m *= inversesqrt( a0*a0 + h*h );
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" m *= 1.79284291400159 - 0.85373472095314 * ( a0*a0 + h*h ); \n"
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" \n"
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// Compute final noise value at P
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" vec3 g; \n"
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" g.x = a0.x * x0.x + h.x * x0.y; \n"
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" g.yz = a0.yz * x12.xz + h.yz * x12.yw; \n"
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" return 130.0 * dot(m, g); \n"
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"} \n"
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" \n"
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/*
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"varying vec2 v_texCoord2D; \n"
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"void main( void ) \n"
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"{ \n"
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" float n = snoise(v_texCoord2D); \n"
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" \n"
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" gl_FragColor = vec4(0.5 + 0.5 * vec3(n, n, n), 1.0); \n"
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//" vec4 color = vec4(vec3(gl_Color) + 0.5 * vec3(n, n, n), 1.0); \n"
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//" gl_FragColor = gl_Color*color; \n"
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//" gl_FragColor = color; \n"
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"} \n"
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*/
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;
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