Circle Circle Collision Detection

class Shape{

  float radius=100;

  PVector pos = new PVector(width/2, height/2);

  color fillColor = color(255, 0, 0);

  String centerText = "";

  void draw(){

    fill(fillColor);

    ellipse(pos.x, pos.y, radius*2, radius*2);

    fill(0);

    ellipse(pos.x, pos.y, 10, 10);

    textSize(20);

    coloredText(centerText, new PVector(pos.x-centerText.length()*3, pos.y - 15));

  }

  float distance(Shape other){

    return sqrt((pos.x-other.pos.x)*(pos.x-other.pos.x) + (pos.y - other.pos.y)*(pos.y-other.pos.y));

  }

  boolean overlapsWith(Shape other){

    if (distance(other) < (radius + other.radius))

        return true;

      return false;

  } 

}

​

void drawArrow(PVector p0, PVector p1, float arrowHeight, float arrowWidth, String dimText){

  float angle = -atan2(p1.x-p0.x, p1.y-p0.y);

  noStroke();

   fill(0, 0, 255);   

   pushMatrix();

     translate(p0.x, p0.y);

     pushMatrix();

       rotate(angle);

        rect(-arrowWidth/2, 0, arrowWidth, arrowHeight-arrowWidth);

        triangle(-arrowWidth, arrowHeight-arrowWidth, arrowWidth, arrowHeight-arrowWidth, 0, arrowHeight);        

        fill(0);

        textSize(32);

        coloredText(dimText, new PVector(textWidth(dimText)/2, arrowHeight/2));           

     popMatrix();

   popMatrix();

}

​

​

void drawDimension(float x1, float y1, float x2, float y2, String dimText){

  float angle = -atan2(x2-x1, y2-y1);

  PVector textPos = new PVector(x1*.5 + x2*.5, y1*.5+y2*.5);

  stroke(0, 0, 0, 128);

  fill(0,0,0);

  textSize(20);

  line(x1, y1, x2, y2);

  pushMatrix();

    translate(textPos.x, textPos.y);

    pushMatrix();

      rotate(angle + PI/2);

      coloredText(dimText,  new PVector(-coloredTextWidth(dimText)/2, -5));

    popMatrix();

  popMatrix();

}

​

float coloredTextWidth(String coloredTextString){

  String printedString = "";

  for (int iChar=0, nChars=0; iChar<coloredTextString.length(); iChar++)

  {

    char cChar = coloredTextString.charAt(iChar); 

    if (cChar == "^")      

      iChar += 2;

    printedString += coloredTextString.charAt(iChar);

  }

  return textWidth(printedString);

}

​

void coloredText(String textString, PVector position){

  color [] textColors = {

    color(0,0,0),

    color(255,0,0),

    color(0, 255, 0),

    color(0, 0, 255),

    color(255, 255, 0),

    color(255, 0, 255),

    color(0, 255, 255),

    color(255, 128, 0),    

    color(255,255,255)};

  String printedString = "";

  for (int iChar=0, nChars=0; iChar<textString.length(); iChar++){

    char cChar = textString.charAt(iChar);

    if (cChar == "^"){

      cChar = textString.charAt(++iChar);

      if (cChar > textColors.length) cChar -= 48;

      fill(textColors[cChar]);

      iChar++;

    }

    text(textString.charAt(iChar), textWidth(printedString) + position.x, position.y);

    printedString += textString.charAt(iChar);    

  } 

}

​

Shape circle1, circle2;

​

void setup(){

  size(800, 800, P2D);

  strokeWeight(3);

  circle1 = new Shape();

  circle1.fillColor = color(128, 128, 255);

  circle1.pos.x = width*.25;

  circle1.pos.y = height*.75;

  circle1.centerText = "(^4x1^0, ^6y1^0)";

  circle1.radius = 150;

  circle2 = new Shape();

  circle2.fillColor = color(128, 255, 128);

  circle2.centerText = "(^5x2^0, ^7y2^0)";

}

​

void draw(){

  background(100);

   stroke(0);

   circle1.draw();

   circle2.pos.x = mouseX;

   circle2.pos.y = mouseY;

   circle2.draw(); 

   String dimText;

   if (circle1.overlapsWith(circle2)){

     dimText = "^1c^0<(r1+r2)"; 

     circle2.fillColor = color(255, 64, 64, 100);

   }

   else{

     dimText = "^1c^0>(r1+r2)";

     circle2.fillColor = color(128, 255, 128);

   }

   drawDimension(circle1.pos.x, circle1.pos.y, circle2.pos.x, circle2.pos.y, dimText);   

   float dimOffset = -40;

   PVector offPos1 = PVector.sub(circle1.pos, new PVector(dimOffset, dimOffset)),

           offPos2 = PVector.sub(circle2.pos, new PVector(dimOffset, dimOffset));

   float a = (int)offPos2.x - offPos1.x,

     b = (int)offPos1.y - offPos2.y;

   drawDimension(offPos1.x, offPos1.y, offPos2.x, offPos2.y, "^1c^0=sqrt(^2a^0*^2a^0+^3b^0*^3b^0) = " + (int)sqrt(a*a+b*b));

   if ((a > 10) || (b > 10)){

     drawDimension(offPos1.x, offPos1.y, offPos2.x, offPos1.y, "^2a^0 = ^5x2^0-^4x1^0 = " + (int)a);   

     drawDimension(offPos2.x, offPos1.y, offPos2.x, offPos2.y, "^3b^0 = ^7y2^0-^6y1^0 = " + (int)b);

   }

   drawArrow(circle1.pos, circle2.pos, circle1.radius, 10, "r1");

   drawArrow(circle2.pos, circle1.pos, circle2.radius, 10, "r2");

}