// Bellicose Birds code by Chris Orban

float x;
float y;

float vx;
float vy;

float deltaVx;
float deltaVy;

float theta = 0;

float Fthrust = 30.0;
float mass = 3.0;
float dt = 0.1;

boolean firsttime = true;

float g = 0;

float vinit = 50;

PImage img;
DPGraph graph1 = new DPGraph();
DPGraph graph2 = new DPGraph();
DPGraph graph3 = new DPGraph();

void setup() {
  size(750,500);
  smooth();

  x = 0.25*width;
  y = 0.05*height;
  img = loadImage("http://www.physics.ohio-state.edu/~orban/processing_2015/rougebird.jpg");

  graph1.colorFunction = color(255,177,100); //orange
  graph1.xTitle = "time";

  graph2.colorFunction = color(0,191,191); //aqua

  graph3.colorFunction = color(0); //black

}

// For people with C and C++ experience, draw() is
// very similar to main(), except that draw() 
// is run over and over again 
void draw() {
  
  // Update velocities
  vx += deltaVx;
  vy += deltaVy;

  // Update location
  x += vx*dt;
  y += vy*dt;

  // Set deltaV to zero (thrust off unless user turns it on)
  deltaVx = 0;
  deltaVy = 0;

  // Turn or thrust the ship depending on what key is pressed
  if (keyPressed) {
    if (key == CODED && keyCode == LEFT) {
      theta += 0.05;
    } else if (key == CODED && keyCode == RIGHT) {
      theta += -0.05;
    } else if (key == CODED &&  keyCode == UP ) {
      // Rockets on!
      float accelx = Fthrust*cos(theta)/mass;
      deltaVx = accelx*dt;
      float accely = Fthrust*sin(theta)/mass;
      deltaVy = accely*dt;
    } else if ((key == ' ') && firsttime) { // spacebar is pressed
      g = 9.8;
      vx = vinit*cos(theta);
      vy = vinit*sin(theta);
      firsttime = false;
    } 
  }

  // Add gravity, note that down is positive
  deltaVy += -g*dt;

  // Draw ship and other stuff
  // This will clear the screen and re-draw it
  display();

  drawLine(0,0,width,0);

  float x0 = 0.25*width;
  float y0 = 0.05*height;

  int Npoints=1000;
  for(int i=1;i<=Npoints;i+=1)
  {
  float t = (i-1)*dt;
  float xdraw = x0 + vinit*cos(theta)*t;
  float ydraw = y0 + vinit*sin(theta)*t - 0.5*9.8*t*t;
  drawPoint(xdraw,ydraw);
  }  

  if (y < 0) {
  drawText(theta*180/3.14,width/2,height/2 + 40);
  drawText(x,width/2,height/2 + 20);
  drawText("Game Over!",width/2,height/2);
  noLoop();
  } 

  float KE = 0.5*mass*(vx*vx+vy*vy);
  graph1.addPoint(KE);
  graph1.display(); //orange
  
  float PE = mass*g*y;
  graph2.addPoint(PE);
  graph2.display(); //aqua

  graph3.addPoint(KE+PE);
  graph3.display(); //black


} // end draw()