420X/diffusion.html at master · alppiskin/420X · GitHub

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<!doctype html>
<html lang='en'>
<head>
  <style>
    body{
      margin:0;
      background:black;
    }
    canvas{
      width:100%; height:100%; position:relative;
    }
  </style>
  <script type="text/javascript" src="misc/dat.gui.js"></script>
</head>

<body>
<canvas></canvas>
</body>
<script id="vshader" type="whatever">
  precision mediump float;
  attribute vec2 a_position;
  void main() {
    gl_Position = vec4( a_position, 0, 1.0);
  }
</script>

<script id="fshader_draw" type="whatever">
  precision mediump float;
  uniform sampler2D state;
  uniform vec2 scale;
  uniform float r;
  uniform float g;
  uniform float b;

  void main() {
    vec4 color = texture2D(state, gl_FragCoord.xy / scale);
    gl_FragColor = vec4( r-color.x, g-color.x, b-color.x, 1. );
  }
</script>

<script id="fshader_render" type="whatever">
  precision mediump float;
  uniform sampler2D state;
  uniform vec2 scale;
  //float f=.0545, k=.062, dA = 1., dB = 0.; // coral preset
  //uniform float f = .0457, k = .0635, dA = 1., dB = .5;
  uniform float f, k, dA, dB;
  uniform float div, time;
  uniform float l1,l2;

  vec2 get(int x, int y) {
    return texture2D( state, ( gl_FragCoord.xy + vec2(x, y) ) / scale ).rg;
  }

  vec2 run() {
    vec2 state = get( 0, 0 );
    float a = state.r;
    float b = state.g;
    float sumA = a * -1.;
    float sumB = b * -1.;

    sumA += get(-1,0).r * .2;
    sumA += get(-1,-1).r * .05;
    sumA += get(0,-1).r * .2;
    sumA += get(1,-1).r * .05;
    sumA += get(1,0).r * .2;
    sumA += get(1,1).r * .05;
    sumA += get(0,1).r * .2;
    sumA += get(-1,1).r * .05;

    sumB += get(-1,0).g * .2;
    sumB += get(-1,-1).g * .05;
    sumB += get(0,-1).g * .2;
    sumB += get(1,-1).g * .05;
    sumB += get(1,0).g * .2;
    sumB += get(1,1).g * .05;
    sumB += get(0,1).g * .2;
    sumB += get(-1,1).g * .05;

    float dF = f + (sin(time / (l1*l2)) / div);

    state.r = a + dA
      * sumA -
      a * b * b +
      f * (1. - a);

    state.g = b + dB *
      sumB +
      a * b * b -
      ((k+dF) * b);

    return state;
  }
  void main() {
    vec2 nextState = run();
    gl_FragColor = vec4( nextState.r, nextState.g, 0., 1. );
  }
</script>
<script>
  window.onload = function() {
    let canvas = document.querySelector( 'canvas' )
    canvas.width = window.innerWidth
    canvas.height = window.innerHeight
    let gl = canvas.getContext( 'webgl' )
    let stateSize = Math.pow( 2, Math.floor(Math.log(canvas.width)/Math.log(2)) )

    let verts = [
      1, 1,
      -1, 1,
      -1,-1,
      1, 1,
      -1, -1,
      1, -1,
    ]

    let vertBuffer = gl.createBuffer()
    gl.bindBuffer( gl.ARRAY_BUFFER, vertBuffer )
    gl.bufferData( gl.ARRAY_BUFFER, new Float32Array(verts), gl.STATIC_DRAW )
    gl.vertexAttribPointer( 0, 2, gl.FLOAT, false, 0, 0 )
    gl.enableVertexAttribArray( 0 )

    let shaderScript = document.getElementById( 'vshader' )
    let shaderSource = shaderScript.text
    const vertexShader = gl.createShader( gl.VERTEX_SHADER )
    gl.shaderSource( vertexShader, shaderSource )
    gl.compileShader( vertexShader )
    console.log( gl.getShaderInfoLog( vertexShader ) ) // create fragment shader to run our simulation

    shaderScript = document.getElementById( 'fshader_render' )
    shaderSource = shaderScript.text
    const fragmentShaderRender = gl.createShader( gl.FRAGMENT_SHADER )
    gl.shaderSource( fragmentShaderRender, shaderSource )
    gl.compileShader( fragmentShaderRender )
    console.log( gl.getShaderInfoLog( fragmentShaderRender ) ) // create shader program const

    programRender = gl.createProgram()
    gl.attachShader( programRender, vertexShader )
    gl.attachShader( programRender, fragmentShaderRender )
    gl.linkProgram( programRender )
    gl.useProgram( programRender )

    // create pointer to vertex array and uniform sharing simulation size
    const position = gl.getAttribLocation( programRender, 'a_position' )
    gl.enableVertexAttribArray( position )
    gl.vertexAttribPointer( position, 2, gl.FLOAT, false, 0,0 )
    let scale = gl.getUniformLocation( programRender, 'scale' )
    gl.uniform2f( scale, stateSize, stateSize )

    // create shader program to draw our simulation to the screen
    shaderScript = document.getElementById( 'fshader_draw' )
    shaderSource = shaderScript.text
    fragmentShaderDraw = gl.createShader( gl.FRAGMENT_SHADER )
    gl.shaderSource( fragmentShaderDraw, shaderSource )
    gl.compileShader( fragmentShaderDraw )
    console.log( gl.getShaderInfoLog( fragmentShaderDraw ) )

    let params = function() {
      this.f = 0.07;
      this.k = 0.06;
      this.dA = 1.0;
      this.dB = 0.5;
      this.R = 1.0;
      this.G = 1.0;
      this.B = 1.0;
      this.dividend = 148.;
      this.L1 = 4.9;
      this.L2 = 4.8;
    };
    modifiers = new params();
    gui = new dat.GUI();
    gui.add(modifiers, 'f', .02, .07);
    gui.add(modifiers, 'k', .02, .065);
    gui.add(modifiers, 'dA', .5, 1.);
    gui.add(modifiers, 'dB', .25, .68);
    gui.add(modifiers, 'R', 0., 1.);
    gui.add(modifiers, 'G', 0., 1.);
    gui.add(modifiers, 'B', 0., 1.);
    gui.add(modifiers, 'dividend', 120., 200.);
    gui.add(modifiers, 'L1', 4., 5.);
    gui.add(modifiers, 'L2', 4., 5.);


    // create shader program
    programDraw = gl.createProgram()
    gl.attachShader( programDraw, vertexShader )
    gl.attachShader( programDraw, fragmentShaderDraw )
    gl.linkProgram( programDraw )
    gl.useProgram( programDraw )

    scale = gl.getUniformLocation( programDraw, 'scale' )
    gl.uniform2f( scale, canvas.width,canvas.height )
    const position2 = gl.getAttribLocation( programDraw, 'a_position' )
    gl.enableVertexAttribArray( position2 )
    gl.vertexAttribPointer( position2, 2, gl.FLOAT, false, 0,0 )

    // enable floating point textures in the browser
    gl.getExtension('OES_texture_float');

    let texFront = gl.createTexture()
    gl.bindTexture( gl.TEXTURE_2D, texFront )
    gl.texParameteri( gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.REPEAT )
    gl.texParameteri( gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.REPEAT )
    gl.texParameteri( gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST )
    gl.texParameteri( gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST )
    gl.texImage2D( gl.TEXTURE_2D, 0, gl.RGBA, stateSize, stateSize, 0, gl.RGBA, gl.FLOAT, null )

    let texBack = gl.createTexture()
    gl.bindTexture( gl.TEXTURE_2D, texBack )
    gl.texParameteri( gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.REPEAT )
    gl.texParameteri( gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.REPEAT )
    gl.texParameteri( gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST )
    gl.texParameteri( gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST )
    gl.texImage2D( gl.TEXTURE_2D, 0, gl.RGBA, stateSize, stateSize, 0, gl.RGBA, gl.FLOAT, null )

    r = gl.getUniformLocation( programDraw, 'r' )
    g = gl.getUniformLocation( programDraw, 'g' )
    b = gl.getUniformLocation( programDraw, 'b' )

    f = gl.getUniformLocation( programRender, 'f' )
    k = gl.getUniformLocation( programRender, 'k' )
    dA = gl.getUniformLocation( programRender, 'dA' )
    dB = gl.getUniformLocation( programRender, 'dB' )
    t = gl.getUniformLocation( programRender, 'time' )
    d = gl.getUniformLocation( programRender, 'div' )
    l1 = gl.getUniformLocation( programRender, 'l1' )
    l2 = gl.getUniformLocation( programRender, 'l2' )

    const pixelSize = 4
    const feedSize = 48
    const initState = new Float32Array( stateSize * stateSize * pixelSize )
    const reset = function() {
      for( let i = 0; i < stateSize; i++ ) {
        for( let j = 0; j < stateSize * pixelSize; j+= pixelSize ) {
          // this will be our 'a' value in the simulation
          initState[ i * stateSize * pixelSize + j ] = 1
          // selectively add 'b' value to middle of screen
          if( i > stateSize / 2 - stateSize / feedSize  && i < stateSize / 2 + stateSize / feedSize ) {
            const xmin = j > (stateSize*pixelSize) / 2 - stateSize / feedSize
            const xmax = j < (stateSize*pixelSize) / 2 + (stateSize*pixelSize) / feedSize
            if( xmin && xmax ) {
              initState[ i * stateSize * pixelSize + j + 1 ] = 1
            }
          }
        }
      }

      gl.texSubImage2D(
              gl.TEXTURE_2D, 0, 0, 0, stateSize, stateSize, gl.RGBA, gl.FLOAT, initState, 0
      )
    }

    reset()

    const fb = gl.createFramebuffer()
    const fb2 = gl.createFramebuffer()

    const pingpong = function() {
      gl.bindFramebuffer( gl.FRAMEBUFFER, fb )
      // use the framebuffer to write to our texFront texture
      gl.framebufferTexture2D( gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, texFront, 0 )
      // set viewport to be the size of our state (reaction diffusion simulation)
      // here, this represents the size that will be drawn onto our texture
      gl.viewport(0, 0, stateSize, stateSize )
      // in our shaders, read from texBack, which is where we poked to
      gl.bindTexture( gl.TEXTURE_2D, texBack ) // run shader
      gl.drawArrays( gl.TRIANGLES, 0, 6 )

      gl.bindFramebuffer( gl.FRAMEBUFFER, fb2 )
      gl.framebufferTexture2D( gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, texBack, 0 )
      // set our viewport to be the size of our canvas
      // so that it will fill it entirely
      gl.viewport(0, 0, canvas.width, canvas.height )
      // select the texture we would like to draw the the screen.
      // note that webgl does not allow you to write to / read from the
      // same texture in a single render pass. Because of the swap, we're
      // displaying the state of our simulation ****before**** this render pass (frame)
      gl.bindTexture( gl.TEXTURE_2D, texFront )
      // put simulation on screen
      gl.drawArrays( gl.TRIANGLES, 0, 6 )
    }

    let time = 0;

    const draw = function() {
      gl.useProgram( programRender )

      time++

      gl.uniform1f(f, modifiers.f)
      gl.uniform1f(k, modifiers.k)
      gl.uniform1f(dA, modifiers.dA)
      gl.uniform1f(dB, modifiers.dB)
      gl.uniform1f(t, time);
      gl.uniform1f(d, modifiers.dividend)
      gl.uniform1f(l1, modifiers.L1)
      gl.uniform1f(l2, modifiers.L2)

      for( let i = 0; i < 12; i++ ) pingpong()

      // use the default framebuffer object by passing null
      gl.bindFramebuffer( gl.FRAMEBUFFER, null )
      // set our viewport to be the size of our canvas
      // so that it will fill it entirely
      gl.viewport(0, 0, canvas.width, canvas.height )
      // select the texture we would like to draw the the screen.
      gl.bindTexture( gl.TEXTURE_2D, texBack )
      // use our drawing (copy) shader
      gl.useProgram( programDraw )

      gl.uniform1f(r, modifiers.R)
      gl.uniform1f(g, modifiers.G)
      gl.uniform1f(b, modifiers.B)

      // put simulation on screen
      gl.drawArrays( gl.TRIANGLES, 0, 6 )

      window.requestAnimationFrame( draw )
    }

    draw()
  }

</script>
</html>