thebookofshaders/06/gradient.frag
2015-03-15 11:35:14 -04:00

37 lines
875 B
GLSL

#ifdef GL_ES
precision mediump float;
#endif
#define PI 3.14159265359
uniform vec2 u_resolution;
uniform vec2 u_mouse;
uniform float u_time;
vec3 colorA = vec3(0.149,0.141,0.912);
vec3 colorB = vec3(1.000,0.833,0.224);
float plot (vec2 _st, float _pct){
return smoothstep( _pct-0.01, _pct, _st.y) -
smoothstep( _pct, _pct+0.01, _st.y);
}
void main() {
vec2 st = gl_FragCoord.xy/u_resolution.xy;
vec3 color = vec3(0.0);
vec3 pct = vec3(st.x);
// pct.r = smoothstep(0.0,1.0, st.x);
// pct.g = sin(st.x*PI);
// pct.b = pow(st.x,0.5);
color = mix(colorA, colorB, pct);
// Plot transition lines for each channel
color = mix(color,vec3(1.0,0.0,0.0),plot(st,pct.r));
color = mix(color,vec3(0.0,1.0,0.0),plot(st,pct.g));
color = mix(color,vec3(0.0,0.0,1.0),plot(st,pct.b));
gl_FragColor = vec4(color,1.0);
}