/*
  In this variant on moving_circles, the circle becomes the sun, and
 the color of the sun and the background varies with the height
 of the sun.
 */

color sunHigh = color(245, 234, 12); // yellow
color sunLow = color(234, 148, 7);   // orange

color skyHigh = color(164, 236, 243);
color skyLow = color(211, 136, 165); 

// This function is executed only once, at the very beginning
void setup() {
  size(500, 400);
  noStroke();
}


// This function is repeatedly call in an implicit loop.
// A single call is responsible for drawing a single frame.
void draw() {
  float t = pow(float(mouseY) / height, 4);
  background(red(skyHigh)*(1-t) + red(skyLow)*t, 
             green(skyHigh)*(1-t) + green(skyLow)*t, 
             blue(skyHigh)*(1-t) + blue(skyLow)*t);
  fill(red(sunHigh)*(1-t) + red(sunLow)*t, 
       green(sunHigh)*(1-t) + green(sunLow)*t, 
       blue(sunHigh)*(1-t) + blue(sunLow)*t);
  float r = 50 + t*20;       // gets bigger near bottom
  ellipse(mouseX, mouseY, r, r);
}