Recitation 6: Processing Animation

What I have made in recitation 5 is difficult to be animated, so I decided to make something new. When it comes to animation, I think of light and stars shining in the dark sky. So I decided to draw some rotating stars controlled by the keyboard and a light beam moving as the mouse.

Video:

Code:

color a =0;
float b=0;
float c=0;

void setup(){
size(600,600);
background(30);
}

void draw(){

  background(30);
  
    //star
  fill(255, 204, 0);
  pushMatrix();
  translate(width*0.2, height*0.5);
  if (keyPressed == true){
  rotate(frameCount / -100.0);
  }
  star(30,30,15,35,5);
  star(-200,-300,15,35,5);
  star(300,50,15,35,5);
  star(250,200,30,70,5);
  star(-300,-350,15,35,5);
  star(-50,-250,15,35,5);
  popMatrix();
  
  
  strokeWeight(8);
  stroke(random(100,255),random(0,255),random(0,255));
  line(pmouseX, pmouseY, 300, 300);
  
  b=random(0,100);
  c=random(0,100);
  fill(random(100,255),random(0,255),random(0,255));
  noStroke();
  ellipse(pmouseX,pmouseY,b,c);
  
  
  
}

//star function
void star(float x, float y, float radius1, float radius2, int npoints) {
  float angle = TWO_PI / npoints;
  float halfAngle = angle/2.0;
  beginShape();
  for (float a = 0; a < TWO_PI; a += angle) {
    float sx = x + cos(a) * radius2;
    float sy = y + sin(a) * radius2;
    vertex(sx, sy);
    sx = x + cos(a+halfAngle) * radius1;
    sy = y + sin(a+halfAngle) * radius1;
    vertex(sx, sy);
  }
  endShape(CLOSE);
  }

Interesting functions:

star()

I find it hard to draw a star with simple and basic shape functions in Processing. So, I searched for a sample code on the references of Processing and fortunately found one. I used it to create several yellow stars.

rotate()

This function enables those yellow stars to rotate around a certain point, which makes the whole animation looks like a starry night.

keyPressed()

The keyPressed() function is called once every time a key is pressed. It gives users the experience of interaction, which makes the animation funnier.