thebookofshaders/11/wood.frag
2017-08-23 11:34:44 +02:00

59 lines
1.3 KiB
GLSL

// Author @patriciogv - 2015
// http://patriciogonzalezvivo.com
#ifdef GL_ES
precision mediump float;
#endif
uniform vec2 u_resolution;
uniform vec2 u_mouse;
uniform float u_time;
float random (in vec2 st) {
return fract(sin(dot(st.xy,
vec2(12.9898,78.233)))
* 43758.5453123);
}
// Value noise by Inigo Quilez - iq/2013
// https://www.shadertoy.com/view/lsf3WH
float noise(vec2 st) {
vec2 i = floor(st);
vec2 f = fract(st);
vec2 u = f*f*(3.0-2.0*f);
return mix( mix( random( i + vec2(0.0,0.0) ),
random( i + vec2(1.0,0.0) ), u.x),
mix( random( i + vec2(0.0,1.0) ),
random( i + vec2(1.0,1.0) ), u.x), u.y);
}
mat2 rotate2d(float angle){
return mat2(cos(angle),-sin(angle),
sin(angle),cos(angle));
}
float lines(in vec2 pos, float b){
float scale = 10.0;
pos *= scale;
return smoothstep(0.0,
.5+b*.5,
abs((sin(pos.x*3.1415)+b*2.0))*.5);
}
void main() {
vec2 st = gl_FragCoord.xy/u_resolution.xy;
st.y *= u_resolution.y/u_resolution.x;
vec2 pos = st.yx*vec2(10.,3.);
float pattern = pos.x;
// Add noise
pos = rotate2d( noise(pos) ) * pos;
// Draw lines
pattern = lines(pos,.5);
gl_FragColor = vec4(vec3(pattern),1.0);
}