// By Chris Orban for Physics 1251 at OSU Marion

float x;
float y;

float vx=50.0;
float vy;

float deltaVx;
float deltaVy;

float mass = 1.0; // Atomic mass unit
float dt = 0.05;

float x_target = 500;
float y_target;

float q = 1; // elementary charge
float E; // Natural units

float qtarget = 1; // elementary charge (atomic number)

float k = 100000; // for simplicity, real experiments would use 9e9

float rmin = 10000; //some large number
float ri;

boolean firsttime = true;

//For drawing the image of the proton
PImage img;

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

  x = 0.05*width;
  y = height/2;
  y_target = y;
  img = loadImage("http://www.physics.ohio-state.edu/~orban/physics1251lab/proton.png");
}

// 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;

  // Update location
  x += vx*dt;

  // Set deltaV to zero 
  deltaVx = 0;

  //float r = ???; // fix this!!

  if (x < x_target) 
  {
    E = 0; // fix this!!
  } else if (x > x_target) {
    E = 0; // fix this!!
  }

  deltaVx = (q*E/mass)*dt;

  // Draw ship and other stuff
  display();

  drawText("Minimum distance = ",width/2-125,height/2-100);
  if (rmin > r) rmin = r;
  drawText(rmin,width/2+100,height/2-100);

  drawText("Initial distance = ",width/2-125,height/2-150);
  if (firsttime) {
  ri = r;
  firsttime = false;
  }
  drawText(ri,width/2+100,height/2-150);

  if ((x > width) | (x < 0) ) {
  noLoop();
  }


} // end draw()