Pen Settings

HTML

CSS

CSS Base

Vendor Prefixing

Add External Stylesheets/Pens

Any URL's added here will be added as <link>s in order, and before the CSS in the editor. If you link to another Pen, it will include the CSS from that Pen. If the preprocessor matches, it will attempt to combine them before processing.

+ add another resource

JavaScript

Babel is required to process package imports. If you need a different preprocessor remove all packages first.

Add External Scripts/Pens

Any URL's added here will be added as <script>s in order, and run before the JavaScript in the editor. You can use the URL of any other Pen and it will include the JavaScript from that Pen.

+ add another resource

Behavior

Save Automatically?

If active, Pens will autosave every 30 seconds after being saved once.

Auto-Updating Preview

If enabled, the preview panel updates automatically as you code. If disabled, use the "Run" button to update.

Format on Save

If enabled, your code will be formatted when you actively save your Pen. Note: your code becomes un-folded during formatting.

Editor Settings

Code Indentation

Want to change your Syntax Highlighting theme, Fonts and more?

Visit your global Editor Settings.

HTML

              
                <main>
  <h1>2D Perlin Noise 1</h1>
  <shader-doodle>
    vec3 hsv2rgb(vec3 c) {
      vec4 K = vec4(1.0, 2.0 / 3.0, 1.0 / 3.0, 3.0);
      vec3 p = abs(fract(c.xxx + K.xyz) * 6.0 - K.www);
      return c.z * mix(K.xxx, clamp(p - K.xxx, 0.0, 1.0), c.y);
    }

    vec4 mod289(vec4 x)
    {
      return x - floor(x * (1.0 / 289.0)) * 289.0;
    }

    vec4 permute(vec4 x)
    {
      return mod289(((x*34.0)+1.0)*x);
    }

    vec4 taylorInvSqrt(vec4 r)
    {
      return 1.79284291400159 - 0.85373472095314 * r;
    }

    vec2 fade(vec2 t) {
      return t*t*t*(t*(t*6.0-15.0)+10.0);
    }

    // Classic Perlin noise
    float cnoise(vec2 P)
    {
      vec4 Pi = floor(P.xyxy) + vec4(0.0, 0.0, 1.0, 1.0);
      vec4 Pf = fract(P.xyxy) - vec4(0.0, 0.0, 1.0, 1.0);
      Pi = mod289(Pi); // To avoid truncation effects in permutation
      vec4 ix = Pi.xzxz;
      vec4 iy = Pi.yyww;
      vec4 fx = Pf.xzxz;
      vec4 fy = Pf.yyww;

      vec4 i = permute(permute(ix) + iy);

      vec4 gx = fract(i * (1.0 / 41.0)) * 2.0 - 1.0 ;
      vec4 gy = abs(gx) - 0.5 ;
      vec4 tx = floor(gx + 0.5);
      gx = gx - tx;

      vec2 g00 = vec2(gx.x,gy.x);
      vec2 g10 = vec2(gx.y,gy.y);
      vec2 g01 = vec2(gx.z,gy.z);
      vec2 g11 = vec2(gx.w,gy.w);

      vec4 norm = taylorInvSqrt(vec4(dot(g00, g00), dot(g01, g01), dot(g10, g10), dot(g11, g11)));
      g00 *= norm.x;  
      g01 *= norm.y;  
      g10 *= norm.z;  
      g11 *= norm.w;  

      float n00 = dot(g00, vec2(fx.x, fy.x));
      float n10 = dot(g10, vec2(fx.y, fy.y));
      float n01 = dot(g01, vec2(fx.z, fy.z));
      float n11 = dot(g11, vec2(fx.w, fy.w));

      vec2 fade_xy = fade(Pf.xy);
      vec2 n_x = mix(vec2(n00, n01), vec2(n10, n11), fade_xy.x);
      float n_xy = mix(n_x.x, n_x.y, fade_xy.y);
      return 2.3 * n_xy;
    }

    void main() {
        vec2 uv = gl_FragCoord.xy/u_resolution.xy;
  
        uv.x += sin(u_time * 0.25);
        uv.y += cos(u_time * 0.25);

        float noise = cnoise(uv * 5.);
        noise = noise + sin(u_time * 0.5) * 1.5 + 0.5;
    
        float hue = 1. - noise;
        float sat = 1. - step(0.8, noise);
        float bri = smoothstep(0.7, 0.8, noise);
        float op = 1. - step(0.9, noise);

        vec3 col = hsv2rgb(vec3(hue, sat, bri));
        
        gl_FragColor = vec4(col, op);
    }
  </shader-doodle>
  <p>smoothstep threshold 2D perlin noise</p>
</main>
              
            
!

CSS

              
                shader-doodle {
  background-color: grey;
}
              
            
!

JS

              
                
              
            
!
999px

Console