//i,j,k,m
int dx,dy;
int x,y;
boolean shaking;

void setup() {
  size(300,300);
  background(50,50,50);
  stroke(0,0,0);
  fill(50,50,50);
  x=width/2;
  y=height/2;
  shaking=false;
}

void draw() {
  if (shaking) {
    rect(0,0,width,height);
    //println("SHAKEN");
  }
  if (mousePressed) {
    int x1,y1,xo,yo;
    dx=dy=0;
    xo=mouseX-x;
    yo=mouseY-y;
    if (xo!=0) {
      dx=xo/abs(xo);
      if (yo/xo>2) dx=0;
    }
    if (yo!=0) {
      dy=yo/abs(yo);
      if (xo/yo>2) dy=0;
    }
  }
  line(x,y,x+dx,y+dy);
  x+=dx;
  y+=dy;
  x=x%width;
  if (x<0) x+=width;
  y=y%width;
  if (y<0) y+=height;
}

void keyPressed() { 
  switch (key) {
    case 'm':
     dy=1;
     break;
    case 'i':
      dy=-1;
      break;
    case 'k':
     dx=1;
     break;
    case 'j':
      dx=-1;
      break;
    case 's':
      shaking=true;
      break;
      
  }
}
void keyReleased() { 
  switch (key) {
    case 'i':
    case 'm':
     dy=0;
     break;
    case 'j':
    case 'k':
    dx=0;
     break;
    case 's':
      shaking=false;
      break;
  }
}
void mouseReleased() {
  dx=dy=0;
}