Pen Settings

HTML

CSS

CSS Base

Vendor Prefixing

Add External Stylesheets/Pens

Any URLs added here will be added as <link>s in order, and before the CSS in the editor. You can use the CSS from another Pen by using its URL and the proper URL extension.

+ add another resource

JavaScript

Babel includes JSX processing.

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

Packages

Add Packages

Search for and use JavaScript packages from npm here. By selecting a package, an import statement will be added to the top of the JavaScript editor for this package.

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

              
                
              
            
!

CSS

              
                
              
            
!

JS

              
                const DURATION = 6; // Loop 3 sec

// Size of render target
const WIDTH = 512;
const HEIGHT = 512;

const fragmentShader = `
precision mediump float;
uniform float iSampleRate;
uniform float iBlockOffset;

float tri(in float freq, in float time) {
    return -abs(1. - mod(freq * time * 2., 2.));
}

vec2 mainSound( float time )
{
    float freq = 440.;
    freq *= pow(1.06 * 1.06, floor(mod(time, 6.)));
    return vec2( 
        tri(freq, time) * sin(time * 3.141592),
        tri(freq * 1.5, time) * sin(time * 3.141592)
    );
}	

void main() {
  float t = iBlockOffset + ((gl_FragCoord.x-0.5) + (gl_FragCoord.y-0.5)*512.0) / iSampleRate;
  vec2 y = mainSound(t);
  vec2 v  = floor((0.5+0.5*y)*65536.0);
  vec2 vl = mod(v,256.0)/255.0;
  vec2 vh = floor(v/256.0)/255.0;
  gl_FragColor = vec4(vl.x,vh.x,vl.y,vh.y);
}`;

// Create audio context
const ctx = new window.AudioContext();
const node = ctx.createBufferSource();
node.connect(ctx.destination);
node.loop = true;
const audioBuffer = ctx.createBuffer(2, ctx.sampleRate * DURATION, ctx.sampleRate);

// Create canvas
const canvas = document.createElement('canvas');
canvas.width = WIDTH;
canvas.height = HEIGHT;
const renderer = new THREE.WebGLRenderer({ canvas, alpha: true });
const wctx = renderer.getContext();

// Create scenes
const uniforms = {
  iBlockOffset: { type: 'f', value: 0.0 },
  iSampleRate: { type: 'f', value: ctx.sampleRate },
};
const geometry = new THREE.PlaneGeometry(2, 2);
const material = new THREE.ShaderMaterial({ uniforms, fragmentShader });
const plane = new THREE.Mesh(geometry, material);
const scene = new THREE.Scene();
const camera = new THREE.OrthographicCamera(-1, 1, 1, -1, 0.1, 10);
camera.position.set(0, 0, 1);
camera.lookAt(scene.position);
scene.add(plane);
const target = new THREE.WebGLRenderTarget(WIDTH, HEIGHT);

// Render
const samples = WIDTH * HEIGHT;
const numBlocks = (ctx.sampleRate * DURATION) / samples;
for (let i = 0; i < numBlocks; i++) {
  // Update uniform & Render
  uniforms.iBlockOffset.value = i * samples / ctx.sampleRate;
  renderer.render(scene, camera, target, true);

  // Read pixels
  const pixels = new Uint8Array(WIDTH * HEIGHT * 4);
  wctx.readPixels(0, 0, WIDTH, HEIGHT, wctx.RGBA, wctx.UNSIGNED_BYTE, pixels);

  // Convert pixels to samples
  const outputDataL = audioBuffer.getChannelData(0);
  const outputDataR = audioBuffer.getChannelData(1);
  for (let j = 0; j < samples; j++) {
    outputDataL[i * samples + j] = (pixels[j * 4 + 0] + 256 * pixels[j * 4 + 1]) / 65535 * 2 - 1;
    outputDataR[i * samples + j] = (pixels[j * 4 + 2] + 256 * pixels[j * 4 + 3]) / 65535 * 2 - 1;
  }
}

// Play
node.buffer = audioBuffer;
node.start(0);

              
            
!
999px

Console