mirror of
https://github.com/patriciogonzalezvivo/thebookofshaders
synced 2024-11-09 19:10:24 +00:00
62 lines
1.3 KiB
GLSL
62 lines
1.3 KiB
GLSL
// Author @patriciogv - 2015
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// http://patriciogonzalezvivo.com
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#ifdef GL_ES
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precision mediump float;
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#endif
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uniform vec2 u_resolution;
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uniform vec2 u_mouse;
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uniform float u_time;
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float random (in vec2 st) {
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return fract(sin(dot(st.xy,
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vec2(12.9898,78.233)))*
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43758.5453123);
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}
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// Based on Morgan McGuire @morgan3d
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// https://www.shadertoy.com/view/4dS3Wd
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float noise (in vec2 st) {
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vec2 i = floor(st);
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vec2 f = fract(st);
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// Four corners in 2D of a tile
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float a = random(i);
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float b = random(i + vec2(1.0, 0.0));
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float c = random(i + vec2(0.0, 1.0));
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float d = random(i + vec2(1.0, 1.0));
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vec2 u = f * f * (3.0 - 2.0 * f);
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return mix(a, b, u.x) +
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(c - a)* u.y * (1.0 - u.x) +
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(d - b) * u.x * u.y;
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}
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#define OCTAVES 6
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float fbm (in vec2 st) {
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// Initial values
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float value = 0.0;
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float amplitude = .5;
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float frequency = 0.;
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//
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// Loop of octaves
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for (int i = 0; i < OCTAVES; i++) {
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value += amplitude * noise(st);
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st *= 2.;
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amplitude *= .5;
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}
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return value;
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}
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void main() {
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vec2 st = gl_FragCoord.xy/u_resolution.xy;
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st.x *= u_resolution.x/u_resolution.y;
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vec3 color = vec3(0.0);
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color += fbm(st*3.0);
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gl_FragColor = vec4(color,1.0);
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}
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