Simon Schneegans
84 lines
3.0 KiB
JavaScript
84 lines
3.0 KiB
JavaScript
//////////////////////////////////////////////////////////////////////////////////////////
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// ) ( //
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// ( /( ( ( ) ( ( ( ( )\ ) ( ( //
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// )\()) ))\ )( ( ( )\ ) )\))( )\ ( (()/( ( )\))( ( //
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// ((_)\ /((_|()\ )\ ) )\ '(()/( ((_)()((_) )\ ) ((_)))\((_)()\ )\ //
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// | |(_|_))( ((_)_(_/( _((_)) )(_)) _(()((_|_)_(_/( _| |((_)(()((_|(_) //
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// | '_ \ || | '_| ' \)) | ' \()| || | \ V V / | ' \)) _` / _ \ V V (_-< //
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// |_.__/\_,_|_| |_||_| |_|_|_| \_, | \_/\_/|_|_||_|\__,_\___/\_/\_//__/ //
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// |__/ //
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// Copyright (c) 2021 Simon Schneegans //
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// Released under the GPLv3 or later. See LICENSE file for details. //
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//////////////////////////////////////////////////////////////////////////////////////////
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'use strict';
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//////////////////////////////////////////////////////////////////////////////////////////
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// These functions return strings which can be injected to GLSL shader code. //
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//////////////////////////////////////////////////////////////////////////////////////////
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// These should be included in every shader.
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// uTexture: Contains the texture of the window.
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// uProgress: A value which transitions from 0 to 1 during the entire animation.
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// uTime: A steadily increasing value in seconds.
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// uSizeX: The horizontal size of uTexture in pixels.
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// uSizeY: The vertical size of uTexture in pixels.
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function standardUniforms() {
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return `
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uniform sampler2D uTexture;
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uniform float uProgress;
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uniform float uTime;
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uniform int uSizeX;
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uniform int uSizeY;
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`;
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}
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// The noise implementation is from https://www.shadertoy.com/view/3tcBzH (CC-BY-NC-SA).
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function noise() {
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return `
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float rand(vec2 co) {
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return fract(sin(dot(co.xy, vec2(12.9898,78.233))) * 43758.5453);
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}
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vec2 rand2(vec2 co) {
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return vec2(rand(co), rand(co + vec2(12.9898,78.233)));
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}
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float hermite(float t) {
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return t * t * (3.0 - 2.0 * t);
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}
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float noiseImpl(vec2 co, float frequency) {
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vec2 v = vec2(co.x * frequency, co.y * frequency);
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float ix1 = floor(v.x);
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float iy1 = floor(v.y);
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float ix2 = floor(v.x + 1.0);
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float iy2 = floor(v.y + 1.0);
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float fx = hermite(fract(v.x));
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float fy = hermite(fract(v.y));
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float fade1 = mix(rand(vec2(ix1, iy1)), rand(vec2(ix2, iy1)), fx);
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float fade2 = mix(rand(vec2(ix1, iy2)), rand(vec2(ix2, iy2)), fx);
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return mix(fade1, fade2, fy);
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}
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float perlinNoise(vec2 co, float freq, int steps, float persistence) {
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float value = 0.0;
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float ampl = 1.0;
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float sum = 0.0;
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for(int i=0 ; i<steps ; i++) {
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sum += ampl;
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value += noiseImpl(co, freq) * ampl;
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freq *= 2.0;
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ampl *= persistence;
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}
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return value / sum;
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}
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`;
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}
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