​

function preload() {

  // vertex, fragment

  shader1 = loadShader("assets/shader1.vert", "assets/shader1.frag");

}

​

function setup() {

  createCanvas(w=windowWidth, h=windowHeight, WEBGL);

}

​

function draw() {

  background(220);

  // fill(0,0,255);

  // ellipse(0.5*w, 0.5*w, 0.25*w, 0.25*h);

  shader(shader1);

  b = mouseX/ w;

  shader1.setUniform("opacity",b);

  shader1.setUniform("iResolution", [width, height]);

  rect(0, 0, width, height);

 //fill("red");

 // ellipse(mouseX,mouseY,0.1*w,0.1*h)

}

​