Add Background Animation

Spinning Block Example

spinningBlock( )

The function below uses p5.js functions to create a spinning block that you can add to your app background.

1 - Add the following function to the bottom of your JavaScript.

JavaScript

function spinningBlock() { 
    background("gray"); 
    translate(width / 2, height / 2); //move to the middle
    rotate(PI / 90 * frameCount); //rotate more with each frame
    rect(-26, -26, 52, 52); //place the rectangle
}

2 - Now you simply need to call this function when you want it to display in the background. In the example below, spinningBlock( ) is called in the draw( ) function when the trivia game state is "welcome" on line 3. If you want, you can choose to call the function at a different point.

JavaScript

//Loops continously for background effects and animations. (p5.js)
function draw() {
  if (trivia.state == "welcome") spinningBlock();
  else if (trivia.state == "question") background("lightblue");
  else if (trivia.state == "correct") background("green");
  else if (trivia.state == "incorrect") background("red");
  else if (trivia.state == "thankyou") background("orange");
}

The spinningBlock is a simple example of adding an animation to your background, but you can come up with your own animation and call it something different than spinningBlock( ). For example, you may choose to create an animation that looks like balloons rising up and call it balloons( ). It may be challenging, but you can use functions from the p5.js (as we did above for the spinning block) to create some really interesting animations.

Other Example Animations

Here are more examples of custom animation functions that could be implemented like the spinningBlock() above.

ballInBox( )

//Just a ball that bounces around on the screen
function ballInBox() {
  background("gray");
  //adjust ball x/y positions based on frameCount
  //and know when to "bounce"
  var x = frameCount%width;
  if (floor(frameCount/width)%2 == 0) x = width - x;
  var y = frameCount*1.3%height;
  if (floor(frameCount*1.3/height)%2 == 0) y = height - y;
  translate(x, y);
  ellipse(0, 0, 3, 3);
}

balloons( )

//balloons rising to the top
function balloons() {
  background("gray");
  var sFrame = floor(frameCount / (4*height))*4*height; //starting frame for looping
  for (var i = 0; i < 30; i++) { //let's do 30 balloons
    randomSeed(10510 * i + 2); //ensures a repeatable random #
    var y = int(random(height*4) - (frameCount - sFrame)/2);
    randomSeed(30260 * i + 1); //ensures another repeatable random #
    var x = int(random(width));
    fill("red");
    line(x, y, x, y + 30);//balloon string
    ellipse(x, y, 10, 15);//balloon
  }
}