// Program draws a black square in the middle of the screen. 
// It reacts to multiple key-presses, growing.

// Constants

int MININTERVAL = 100;
float MULTIPLIER = 0.00004;
float MINSIZE = 100.;
float MAXSIZE = 640.;
int XSIZE = 640;
int YSIZE = 800;
int CONTRACTPERIOD = 1;

int INCREMENT=10;

// Program Variables

int hits = 0;
int i=0;
int timelasthit = -2000;
int hitinterval = 2000;
float cursize = 100.;
float lastsize = 100.;

// Program

void setup() 
{ 
//  size(200, 200); 
  size(XSIZE, YSIZE);
//  rectMode(CENTER_DIAMETER);
  noStroke();
  fill(0);
  background(255);
} 
 
void loop() 
{ 
  i++;
  if (i > CONTRACTPERIOD)
  {
    i=0;
    background(255);
    
    //cursize = max(MINSIZE, float(Logarithmic_model(hitinterval)));
    hitinterval+=INCREMENT;
//    cursize = max(MINSIZE, cursize-(cursize*cursize*MULTIPLIER));//INCREMENT);//float(Logarithmic_model(hitinterval)));
//    cursize = max(MINSIZE, cursize-float(Reciprocal_Logarithmic_model(cursize)));//INCREMENT);//float(Logarithmic_model(hitinterval)));
    cursize = constrain(cursize-Reciprocal_Logarithmic_model(cursize), MINSIZE, MAXSIZE);

  }

  rect(XSIZE/2, YSIZE/2, cursize, cursize);
} 
 
float Logarithmic_model(float x_in)
{
  //log model from zunzun.com
  //fit to data points
  //  100, 40
  //  2000, 1
   
  double temp;
  temp = 0.0;
  
  // coefficients
  float a = 9.9952499373538743E+01;
  float b = -1.3018519827118025E+01;

  temp = a + b*Math.log(x_in);
  return (float)temp;
}

float Reciprocal_Logarithmic_model(float x_in)
{
  //reciprocal log model from zunzun.com
  //fit to data points
  //  100, 0
  //  640, 40

  float temp;
  temp = 0.0;

  // coefficients
  float a = 3.4188147348130071E+00;
  float b = -5.2523894603906762E-01;

  temp = (float)(1.0 /(a + b*Math.log(x_in)));
  return temp;
}

void mousePressed() 
{
  hits++;
  int timenow = millis();
  hitinterval = (timenow-timelasthit);
  print(hitinterval + " - ");
  timelasthit = timenow;

  lastsize = cursize;
  cursize = constrain(cursize + (float)Logarithmic_model(hitinterval), MINSIZE, MAXSIZE);

  println(cursize);
}