// VARIABLES
float x = 100;
float y = 100;
float angleDog = 0.0;
float angleTail1 = 0.0;
float angleTail2 = 0.0; 
float dogLength = 160;
float tailLength = -10;

// SETUP 
void setup() {
  size(500, 400);
  smooth();
}

// DRAW USING FOLLOW1 EXAMPLE
void draw() {
  background(#017E11); // grass green
  
  float dx = mouseX - x;
  float dy = mouseY - y;
  angleDog = atan2(dy, dx);  
  x = mouseX - (cos(angleDog) * dogLength);
  y = mouseY - (sin(angleDog) * dogLength);
   
  // BONE follows mouse but doesn't rotate
  float boneEnd = 20;
  stroke (255);
  strokeWeight (10);
  line (mouseX, mouseY+20, mouseX, mouseY-20); // middle
  noStroke ();
  fill (255);
  ellipseMode (CENTER);
  ellipse (mouseX+10, mouseY+25, boneEnd, boneEnd); // bottom right
  ellipse (mouseX-10, mouseY+25, boneEnd, boneEnd); // bottom left
  ellipse (mouseX+10, mouseY-25, boneEnd, boneEnd); // top left
  ellipse (mouseX-10, mouseY-25, boneEnd, boneEnd); // top right
  
  dog (x, y, angleDog); // dog follow mouse/bone and rotates
}

// WAGGING TAIL USING ARM EXAMPLE
void tail (float x, float y, float a) {
  translate(x, y);
  rotate(a);
  line(0, 0, tailLength, 0) ;
}

// DOG FUNCTION
void dog (float x, float y, float a) {
  pushMatrix();
  translate(x, y);
  rotate(a);
  // FEET
  fill (#762C00);
  ellipse (110, 20, 25, 25); // front left
  ellipse (110, -20, 25, 25); // front right
  ellipse (60, 20, 25, 25); // back left
  ellipse (60, -20, 25, 25); // back right 
  // BODY
  fill (#893200);
  ellipse (80, 0, 100, 60);
  // TAIL 
  stroke (#893200);
  strokeWeight (14);
  angleTail1 = (mouseX/float(width) - 0.5) * -PI;
  angleTail2 = (mouseY/float(height) - 0.5) * PI;
  pushMatrix();
    translate (30, 0); 
    tail (0, 0, angleTail1); 
    tail (tailLength, 0, angleTail2);
    tail (tailLength, 0, angleTail1);
    tail (tailLength, 0, angleTail2);
    tail (tailLength, 0, angleTail1);
  popMatrix ();
  noStroke (); 
  // HEAD
  fill (#983800);
  ellipse (135, 0, 50, 30);
  ellipse (120, 0, 40, 40);
  // NOSE
  fill (0);
  ellipse (160, 0, 15, 15);
  // EYES
  ellipse (130, 10, 8, 8);
  ellipse (130, -10, 8, 8);
  fill (255, 100);
  ellipse (132, 8, 3, 3);
  ellipse (132, -8, 3, 3);
  // EARS
  fill (#B74300);
  ellipse (120, 20, 30, 10); 
  ellipse (120, -20, 30, 10);
  popMatrix();
}