N Gonzalez - Smoke Shader Sketch

mySketch.js
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let myShader;
​
function setup() {
  createCanvas(windowWidth, windowHeight, WEBGL);
  noStroke();
  // Use createShader in setup rather than loadShader in preload because we're
  // using shader programs that are declared in javascript as strings.
  // NOTE: it is important that this come after createCanvas is called.
  myShader = createShader(vert, frag);
}
​
function draw() {
  background(255);
  
  shader(myShader);
​
  // These correspond to the custom uniforms declared in our fragment shader.
  myShader.setUniform("uTime", millis() / 1000.0);
  myShader.setUniform("uResolution", [width, height]);
  
  orbitControl(2, 2, 0.01);
  
  // Draw some geometry to the screen
  sphere(200);
}
​
// *************************************
// *************************************
let vert = `
// geometry vertex position provided by p5js.
attribute vec3 aPosition;
// vertex texture coordinate provided by p5js.
attribute vec2 aTexCoord;
​
// Built in p5.js uniforms
uniform mat4 uModelViewMatrix;
uniform mat4 uProjectionMatrix;
​
// Varying values passed to our fragment shader
varying vec2 vTexCoord;
varying vec3 vVertexPos;
​
void main() {
  vTexCoord = aTexCoord;
  vVertexPos = aPosition;
  
  vec4 pos = vec4(aPosition, 1.0);
  
  // Apply the ModelView and Projection matricies
  gl_Position = uProjectionMatrix * uModelViewMatrix * pos;
}
`;
​
let frag = `
// set the default precision for float variables
precision mediump float;
​
uniform float uTime;
uniform vec2 uResolution;
​
varying vec2 vTexCoord;
varying vec3 vVertexPos;
​
float random(in vec2 _st) {
  return fract(sin(dot(_st.xy, vec2(12.9898, 78.233))) * 43758.5453123);
}
​
float noise(in vec2 _st) {
  vec2 i = floor(_st);
  vec2 f = fract(_st);
​
  // Four corners in 2D of a tile
  float a = random(i);
  float b = random(i + vec2(1.0, 0.0));
  float c = random(i + vec2(0.0, 1.0));
  float d = random(i + vec2(1.0, 1.0));
​
  vec2 u = f * f * (3.0 - 2.0 * f);
​
  return mix(a, b, u.x) +
    (c - a) * u.y * (1.0 - u.x) +
    (d - b) * u.x * u.y;
}
​
#define NUM_OCTAVES 5
​
float fbm(in vec2 _st) {
  float v = 0.0;
  float a = 0.5;
  vec2 shift = vec2(100.0);
  // Rotate to reduce axial bias
  mat2 rot = mat2(cos(0.5), sin(0.5), -sin(0.5), cos(0.50));
  
  // OpenProcessing.org NOTE: Becuase this shader contains a for loop,
  // the Loop Protection feature must be disabled in the sketch editor.
  for (int i = 0; i < NUM_OCTAVES; ++i) {
    v += a * noise(_st);
    _st = rot * _st * 2.0 + shift;
    a *= 0.5;
  }
  return v;
}
​
void main() {
  vec2 st = vVertexPos.xy * 4. + vec2(vVertexPos.z + 1., vVertexPos.z + 1.) * 2.;
​
  vec2 q = vec2(0.0);
  q.x = fbm( st );
  q.y = fbm( st + vec2(1.0) );
​
  vec2 r = vec2(0.);
  r.x = fbm( st + 1.0*q + vec2(1.7,9.2) + 0.15*uTime );
  r.y = fbm( st + 1.0*q + vec2(8.3,2.8) + 0.226*uTime );
​
  float f = fbm(st+r);
​
  vec3 color = mix(
    vec3(0.101961,0.619608,0.666667),
    vec3(0.666667,0.666667,0.498039),
    clamp((f*f)*4.0,0.0,1.0)
  );
​
  color = mix(
    color,
    vec3(0,0,0.164706),
    clamp(length(q),0.0,1.0)
  );
​
  color = mix(
    color,
    vec3(0.666667,1,1),
    clamp(length(r.x),0.0,1.0)
  );
  
  // Specify the color for the current pixel.
  gl_FragColor = vec4((f*f*f + .6*f*f + .5*f) * color, 1.0);
}
`;