소개

precision mediump float;
uniform vec2  m;       // mouse
uniform float t;       // time
uniform vec2  r;       // resolution
uniform sampler2D smp; // prev scene

highp float rand(vec2 co){
   highp float a = 12.9898;
   highp float b = 78.233;
   highp float c = 43758.5453;
   highp float dt= dot(co.xy ,vec2(a,b));
   highp float sn= mod(dt,3.14);
   return fract(sin(sn) * c);
}

void main(void){
    vec2 p = (gl_FragCoord.xy * 2.0 - r) / min(r.x, r.y);
    float d;
    for(int i=0;i<20;i++){
        vec2 q=p;
        float pos = mod(t+float(i)*.3+rand(vec2(float(i),float(i))),2.0);
        q.y+=1.;
        q.y-=pos;
        q.x+=sin(pos*5.+float(i))*.4;
        d+=clamp(.2-length(q),0.,1.);
    }
    gl_FragColor = vec4(vec3(d), 1.0);
 }

파티클에서 변위 맵을 만들어 봅시다.

precision mediump float;
uniform vec2  m;       // mouse
uniform float t;       // time
uniform vec2  r;       // resolution
uniform sampler2D smp; // prev scene

highp float rand(vec2 co){
   highp float a = 12.9898;
   highp float b = 78.233;
   highp float c = 43758.5453;
   highp float dt= dot(co.xy ,vec2(a,b));
   highp float sn= mod(dt,3.14);
   return fract(sin(sn) * c);
}

void main(void){
    vec2 p = (gl_FragCoord.xy * 2.0 - r) / min(r.x, r.y);
    float d;
    for(int i=0;i<20;i++){
        vec2 q=p;
        float pos = mod(t+float(i)*.3+rand(vec2(float(i),float(i))),2.0);
        q.y+=1.;
        q.y-=pos;
        q.x+=sin(pos*5.+float(i))*.4;
        d+=clamp(.2-length(q),0.,1.);
    }
    //gl_FragColor = vec4(vec3(d), 1.0);
    //return;
    p+=d*.1;
    p*=8.;
    float l = mod(floor(p.x)+floor(p.y),2.0);
    gl_FragColor = vec4(vec3(l), 1.0);
}