mirror of
https://github.com/patriciogonzalezvivo/thebookofshaders
synced 2024-11-03 23:15:23 +00:00
118 lines
3.1 KiB
GLSL
118 lines
3.1 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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// Based on Morgan
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// https://www.shadertoy.com/view/4dS3Wd
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float random (in float x) {
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return fract(sin(x)*1e4);
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}
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float random (in vec2 _st) {
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// return fract(sin(dot(_st.xy ,vec2(12.9898,78.233))) * 43758.5453123);
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return fract( 1e4 * sin(17.0 * _st.x + _st.y * 0.1) * (0.1 + abs(sin(_st.y * 13.0 + _st.x))));
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}
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float noise (in float x) {
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float i = floor(x);
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float f = fract(x);
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float u = f * f * (3.0 - 2.0 * f);
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return mix(random(i), random(i + 1.0), u);
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}
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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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// Simple 2D lerp using smoothstep envelope between the values.
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// return vec3(mix(mix(a, b, smoothstep(0.0, 1.0, f.x)),
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// mix(c, d, smoothstep(0.0, 1.0, f.x)),
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// smoothstep(0.0, 1.0, f.y)));
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// Same code, with the clamps in smoothstep and common subexpressions
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// optimized away.
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vec2 u = f * f * (3.0 - 2.0 * f);
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return mix(a, b, u.x) + (c - a) * u.y * (1.0 - u.x) + (d - b) * u.x * u.y;
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}
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float noise (in vec3 _p) {
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const vec3 step = vec3(110.0, 241.0, 171.0);
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vec3 i = floor(_p);
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vec3 f = fract(_p);
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// For performance, compute the base input to a 1D random from the integer part of the argument and the
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// incremental change to the 1D based on the 3D -> 1D wrapping
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float n = dot(i, step);
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vec3 u = f * f * (3.0 - 2.0 * f);
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return mix(mix(mix( random(n + dot(step, vec3(0, 0, 0))), random(n + dot(step, vec3(1, 0, 0))), u.x),
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mix( random(n + dot(step, vec3(0, 1, 0))), random(n + dot(step, vec3(1, 1, 0))), u.x), u.y),
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mix(mix( random(n + dot(step, vec3(0, 0, 1))), random(n + dot(step, vec3(1, 0, 1))), u.x),
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mix( random(n + dot(step, vec3(0, 1, 1))), random(n + dot(step, vec3(1, 1, 1))), u.x), u.y), u.z);
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}
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#define NUM_OCTAVES 5
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float fbm ( in float x) {
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float v = 0.0;
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float a = 0.5;
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float shift = float(100.0);
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for (int i = 0; i < NUM_OCTAVES; ++i) {
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v += a * noise(x);
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x = x * 2.0 + shift;
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a *= 0.5;
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}
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return v;
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}
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float fbm ( in vec2 _st) {
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float v = 0.0;
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float a = 0.5;
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vec2 shift = vec2(100.0);
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// Rotate to reduce axial bias
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mat2 rot = mat2(cos(0.5), sin(0.5), -sin(0.5), cos(0.50));
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for (int i = 0; i < NUM_OCTAVES; ++i) {
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v += a * noise(_st);
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_st = rot * _st * 2.0 + shift;
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a *= 0.5;
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}
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return v;
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}
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float fbm ( in vec3 _p) {
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float v = 0.0;
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float a = 0.5;
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vec3 shift = vec3(100);
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for (int i = 0; i < NUM_OCTAVES; ++i) {
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v += a * noise(_p);
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_p = _p * 2.0 + shift;
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a *= 0.5;
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}
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return v;
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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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vec3 color = vec3(0.0);
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color = vec3( fbm(vec3(st*10.,u_time*0.1)) );
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gl_FragColor = vec4(color,1.0);
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}
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