// code by Chris Orban

float I = 0; // initial value
float deltaI = 0;

float Vind;
float L = 20;

float Vbatt = 10; // Volts

float R = 3; //Ohms

float dt = 0.1;

boolean battery_is_connected = false;

DPGraph graph1 = new DPGraph();

PImage imgConnected;
PImage imgDisconnected;

void setup() {
  size(750,500);
  
  I = 0; // initial value
  
  graph1.colorFunction = color(255,177,100); //orange
  graph1.xTitle = "time";

  imgDisconnected = loadImage("http://www.physics.ohio-state.edu/~orban/physics1251lab_2016/RLdisconnected_v2.png");
  imgConnected = loadImage("http://www.physics.ohio-state.edu/~orban/physics1251lab_2016/RLconnected_v2.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() {
  
  if (keyPressed) {
   if (key == 'c') battery_is_connected = true;
   if (key == 'd') battery_is_connected = false;
  }
  
  if ( battery_is_connected == true) {
    Vind = Vbatt - I*R;
    deltaI = Vind/L*dt;
    I += deltaI;
} else {  // battery is not connected
    Vind = I*R;
    deltaI = Vind/L*dt;
    I -= deltaI;
  }
  
  // This will clear the screen and re-draw it
  display();

  graph1.addPoint(I);
  graph1.display();
  //println("I = ",I); // Uncomment if curious about precise value of I

} // end draw()