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Quellcode

int planeX, planeY;
int radius;
 
void setup() {
  size(640, 400);
 
  planeX = 500;
  planeY = 200;
 
  radius = 100;
}
 
void draw() {
  background(150, 150, 220);
 
  noFill();
 
  rectMode(CENTER);
 
  //Kreis um mouse und plane berechnen
  int kreisRadius = getDistance(mouseX, mouseY, planeX, planeY) / 2;
  int kreisMitteX = (mouseX + planeX) / 2;
  int kreisMitteY = (mouseY + planeY) / 2;  
 
  ellipse(kreisMitteX, kreisMitteY, kreisRadius * 2, kreisRadius * 2);
 
  ellipse(mouseX, mouseY, radius * 2, radius * 2);
 
  //Punkte z1 und z2 berechnen
  //http://stackoverflow.com/questions/3349125/circle-circle-intersection-points
  int d = getDistance(kreisMitteX, kreisMitteY, mouseX, mouseY);
  int a = (pow(radius, 2) - pow(kreisRadius, 2) + pow(d, 2)) / (2 * d);
 
  int p2x = mouseX + a * (kreisMitteX - mouseX) / d;
  int p2y = mouseY + a * (kreisMitteY - mouseY) / d;
  
  ellipse(p2x, p2y, 10, 10);
 
  int h = sqrt(pow(radius, 2) - pow(a, 2));
 
  int z1x = p2x + h * (mouseY - kreisMitteY) / d;
  int z1y = p2y - h * (mouseX - kreisMitteX) / d;
 
  int z2x = p2x - h * (mouseY - kreisMitteY) / d;
  int z2y = p2y + h * (mouseX - kreisMitteX) / d;
 
  ellipse(z1x, z1y, 10, 10);
 
  ellipse(z2x, z2y, 10, 10);
 
  fill(255, 255, 255);
 
  ellipse(mouseX, mouseY, 20, 20);
 
  rect(planeX,  planeY,  20,  20);
}
 
int getDistance(int x1, int y1, int x2, int y2) {
  return sqrt(pow(x1 - x2, 2) + pow(y1 - y2, 2));
}