snaaaaake

Food.pde

class Food {
  PVector location;
  float xrad,yrad;

  Food() {
    xrad = 5;
    yrad = 5;
    location = new PVector(random(xrad,width-xrad), random(yrad,height-yrad));
  }
  void display() {
    ellipseMode(CENTER);
    ellipse(location.x, location.y, 2*xrad, 2*yrad);
  }
}

snaaake.pde

/*
snAaaaaaAAaAaAAke
 */

int W = 300;
int H = 300;
int cx = W/2;
int cy = H/2;
int highScore;
boolean gameOver;
float seconds;
Snake user;
Food f;

void setup() {
  size(W, H);
  background(100);
  startGame();
  highScore = 0;
}

void startGame() {
  gameOver = false;
  user = new Snake();
  f = new Food();
}

void draw() {
  background(100);
  displayScore();
  if (gameOver) {
    text("click to restart", cx/2, cy/2);
  } 
  else {
    if (user.canEat(f)) {
      user.eat();
      f = new Food();
    };
    f.display();
    user.move();
    gameOver = user.isDead();
    user.display();
  }
}

void displayScore() {
  String scoreTxt = "Score: "+user.eaten+"\nHigh Score: "+highScore;
  text(scoreTxt, cx, cy);
}

void mousePressed() {
  highScore = max(highScore,user.eaten);
  startGame();
}

void keyPressed() {
  if (key == CODED) {
    user.changeDirection(keyCode);
  }
}

Snake.pde

class Snake {
  PVector head;
  PVector velocity;
  int r, xside, yside;
  ArrayList<PVector> body;
  int eaten; //num food eaten
  int lastCommand;

  Snake() {
    body = new ArrayList<PVector>();
    head = new PVector(width/2, height/2);
    velocity = new PVector(1.5, 1.5);
    body.add(head);
    r = 5;
    xside = 2*r;
    yside = 2*r;
    eaten = 0;
    lastCommand = UP;
  }

  boolean canEat(Food food) {
    float fx = food.location.x;
    float fy = food.location.y;
    boolean withinX = (head.x+xside >= fx-food.xrad && fx+food.xrad >= head.x);
    boolean withinY = (head.y+yside >= fy-food.yrad && fy+food.yrad >= head.y);
    return (withinX && withinY);
  }

  void eat() {
    println(body);
    eaten++;
    //add new segment
    newSeg(eaten-1);
    PVector accel = new PVector(1.0/(eaten+1), 1.0/(eaten+1));
    velocity.add(accel);
    println("aftereating: "+body);
  }

  boolean isDead() {
    //death by hitting a wall
    return (head.x >= width-xside || head.x <= 0 || head.y >= height-yside || head.y <= 0);
  }

  void move() {
    newSeg(0);
    head = body.get(0);
    println("just added new head"+body);
    body.remove(eaten+1);
  }
  
  void newSeg(int idx) {
    PVector toClone = body.get(idx); //get segment to latch onto
    PVector newPos = new PVector(toClone.x, toClone.y);
    int factor = (idx == 0) ? 1 : -1;
    if (lastCommand == UP) {
      newPos.y-=(velocity.y*factor);
    } 
    else if (lastCommand == DOWN) {
      newPos.y+=(velocity.y*factor);
    } 
    else if (lastCommand == RIGHT) {
      newPos.x+=(velocity.x*factor);
    } 
    else if (lastCommand == LEFT) {
      newPos.x-=(velocity.x*factor);
    } 
    else {
      //do nothing
    }
    body.add(idx, newPos);
  }
  
  void changeDirection(int k) {
    lastCommand = k;
  }

  void display() {
    fill(255);
    stroke(0);
    for (int i = body.size()-1 ; i >= 0; i--) { //draws from tail to head so that head overlaps the following segments
      PVector pv = body.get(i);
      rect(pv.x, pv.y, xside, yside);
    }
  }
}