precision highp float;

​

  attribute vec3 aPosition;

​

  void main() {

     vec4 positionVec4 = vec4(aPosition, 1.0);

​

     gl_Position = positionVec4;

}

`;

​

let fs = `

  precision highp float;

​

  uniform vec2 resolution;

    uniform vec2 mouse;

​

  void main() {

    float r = 0.0;

    float g = fract((pow((gl_FragCoord.x-resolution.x)/100.0,2.0)-pow((gl_FragCoord.y-resolution.y)/100.0,2.0))*0.2);

    float b = 0.0;

​

    gl_FragColor = vec4(r, g, b, 1.0);

}

`;

​

let theShader;

​

function setup() {

   createCanvas(500, 500, WEBGL);

​

   theShader = createShader(vs, fs);

   noStroke();

​

​

}

​

function draw(){

  shader(theShader);

   theShader.setUniform('resolution', [width, height]);

        theShader.setUniform('mouse', [mouseX, mouseY]);

  quad(-1, -1, -1, 1, 1, 1, 1, -1);

  resetShader();

​

​

}