Simple Feedback

A simple feedback effect that is achieved by using two WebGL graphics buffers. This effect works by drawing the previous frame to a second createGraphics() buffer, which can be blended with the current frame. This takes advantage of texture mapping in WebGL.
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let pg, swap;
function setup() {
  createCanvas(710, 400);
  // this will hold the previous frame
  pg = createGraphics(710, 400, WEBGL);
  // this will hold our main graphic
  swap = createGraphics(710, 400, WEBGL);
  describe(
    'a slowly oscillating, radiating white sphere that fades into a dark gray background through a feedback visual effect'
  );
}
function draw() {
  // clears and resets the p5.Graphics so that 3D objects draw correctly
  pg.reset();
  // draw the previous frame
  pg.texture(swap);
  pg.noStroke();
  pg.plane(width, height);
  // draw our sphere on top
  pg.push();
  // slowly move the sphere in a circle
  pg.translate(sin(millis() / 200) * 5, cos(millis() / 200) * 5, 0);
  pg.fill(255);
  pg.sphere(90);
  pg.pop();
  // draw a slightly scaled up copy of the texture
  swap.push();
  swap.scale(1.1, 1.1);
  swap.texture(pg);
  swap.noStroke();
  swap.plane(width, height);
  swap.pop();
  // an opaque rectangle is drawn over top to control the feedback decay
  swap.fill(0, 50);
  swap.rect(-width / 2, -height / 2, width, height);
  // draw the output to the screen
  image(swap, 0, 0);
}
 
 
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Language Settings

Simple Feedback
