gistfile1.java

import java.util.Random;

class Walker {
  int[] xYPosition = new int[2];
  int[] prevXYPosition = new int[2];
  Random generator;

  Walker() {
    generator = new Random();

    xYPosition[0] = width  / 2;
    xYPosition[1] = height / 2;
    
    // Assignment in java, as you'll probably recognize
    // from other OO languages, just assigns a reference.
    // So, previously, because you pointed them both at
    // the same area in memory, editing one edited the other,
    // hence the gaps :)
//    prevXYPosition = xYPosition;
    prevXYPosition = xYPosition.clone();
  }

  void display() {
    stroke (0);
    line (prevXYPosition[0], prevXYPosition[1], xYPosition[0], xYPosition[1]);
  }
  
  int gaussianDistance() {
    int num = (int) generator.nextGaussian();
    int standardDeviation = 2;
    
    return max(standardDeviation * ((int) num), 1); 
  }
  
  int[] gaussianVector(int[] vector) {
    int distance = gaussianDistance();
    vector[0] *= distance;
    vector[1] *= distance;
    println(distance);
    return vector;
  }

  int[] directionTowardsMousePosition() {
    int[] mouseXYPosition = { mouseX, mouseY };
    int[] direction = { 0, 0 };

    for (int axisIndex = 0; axisIndex < xYPosition.length; axisIndex ++) {
      if (mouseXYPosition[axisIndex] < xYPosition[axisIndex]) { 
        direction[axisIndex] = -1;
      }
      else if (mouseXYPosition[axisIndex] > xYPosition[axisIndex]) { 
        direction[axisIndex] =  1;
      }
      else { 
        direction[axisIndex] =  0;
      }
    }

    return direction;
  }

  void walk(int[] vector) {
//    prevXYPosition = xYPosition;
    prevXYPosition = xYPosition.clone();
    
    xYPosition[0] += vector[0];
    xYPosition[1] += vector[1];
  }

  int[] randomDirection() {    
    int[] direction = { 0, 0 };
    direction[0] += random(3) - 2;
    direction[1] += random(3) - 2;
    return direction;
  }

  void step() {
    float randomNumber = random(1);
    float chance = 1;
    int[] direction = { 0, 0 };

    if (randomNumber < chance) { 
      direction = directionTowardsMousePosition();
    }
    else { 
      direction = randomDirection();
    }
    
    int[] vector = gaussianVector(direction);
    
    walk(vector);
  }
}

Walker w;

void setup() {
  size (640, 360);
  w = new Walker();
  background (255);
}

void draw() {
  w.step();
  w.display();
}