But I want to write about this little game I found: The binding of Isaac. I am pretty sure it was made in Flash and a demo of it can be found on Newgrounds. It’s a pretty well done game and it reminds me of the dungeons in Zelda and Kid Icarus. It’s got that same feeling, with upgraded graphics. The lore is also pretty funny, it’s got a really skewed sense of humor but everything fits and I find it very funny. Now the concept is really simple, but because they created so many power ups (each with their own hilarious visual) it makes it so that every run of the dungeon is different and it adds a lot of replayability.  Anyway, that is the kinda game I aspire to make. I advise you to go buy it on Steam, it’s only 5$.

Building games is not building websites

It is quite different to be franc, mostly because the challenges are different and because of that I haven’t found much topics to write for this blog. I think it is my fault a bit, I chose to do a game that is very close to an application and doesn’t rely so much on the graphics. I thought this would be a better idea, because I could save a lot of time by doing so. The good thing also is that it is based on a lot of interfaces (visual, not code) and I website building made me very good at making interfaces. The challenge that I face is more about where to put the logic and how to organise my code.

Finding how to make it work (or make me work)

My trick right now is to go to a coffee place and work from there. That has been working quite well for now, but starting Tuesday I will have an office space and I really look forward to it. Working from home is just not doing it for me, I watch TV or do some other random stuff that I won’t do if I am in a working place. Now all I have to figure out is how to wake up earlier in the morning.

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Mouse.hide();
gravity = 2;
attachMovie("crosshair", "crosshair", 1);
attachMovie("tank", "tank", 2, {_x:230, _y:350});
crosshair.onEnterFrame = function() {
  this._x = _xmouse;
  this._y = _ymouse;
};
tank.onEnterFrame = function() {
  mousex = _xmouse-this._x;
  mousey = (_ymouse-this._y)*-1;
  angle = Math.atan(mousey/mousex)/(Math.PI/180);
  if (mousex<0) {
    angle += 180;
  }
  if (mousex>=0 && mousey>0) {
    angle += 360;
  }
  if (angle<160) {
    angle = 160;
  }
  if (angle<20) {
    angle = 20;
  }
  firepower = Math.sqrt(mousex*mousex+mousey*mousey);
  if (firepower>200) {
    firepower = 200;
  }
  this.cannon._rotation = angle*-1;
};
function onMouseDown() {
  angle = tank.cannon._rotation-1;
  start_ball_x = tank._x+48*Math.cos(angle*Math.PI/180);
  start_ball_y = tank._y+48*Math.sin(angle*Math.PI/180);
  cannonball_fired = attachMovie("cannonball", "cannonball_"+_root.getNextHighestDepth(), _root.getNextHighestDepth(), {_x:start_ball_x, _y:start_ball_y});
  cannonball_fired.dirx = Math.cos(angle*Math.PI/180)*firepower;
  cannonball_fired.diry = Math.sin(angle*Math.PI/180)*firepower;
  cannonball_fired.onEnterFrame = function() {
    this.diry += gravity;
    this._x += this.dirx/50;
    this._y += this.diry/50;
    if (this._y+this._height/2>350) {
      this._y = 350-this._height/2;
      this.diry = -this.diry*.3;
    }
  };
}

This code is on the first frame of the fla file. To transfer this in ActionScript 3 and in an object oriented way (I am just starting to learn object oriented programming so if you see way I could improve the code just tell me so). In order to do so I divided his code into 4 classes. One class for the document class, one class for the crosshair (I don’t think I needed to make this as a class but it seemed like a good way to divide things), one class for the tank and one class for the cannonball. Here is the code for the document class saved in a file called artillery9AS3.as since my fla is named artillery9AS3.fla:

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package{
  import flash.display.Sprite;
  import flash.ui.Mouse;
  import flash.events.*;
  import artillery.*;
  public class artillery9AS3 extends Sprite{
    private var gravity:int;
    private var firepower:Number;
    var crosshair:Crosshair;
    var tank:Tank;
    public function artillery9AS3(){
      Mouse.hide();
      gravity = 2;
      crosshair = new Crosshair();
      addChild(crosshair);
      tank = new Tank(230, 350);
      addChild (tank);
      stage.addEventListener(Event.ENTER_FRAME, doEnterFrame);
      stage.addEventListener(MouseEvent.MOUSE_DOWN, doMouseDown);
    }
    private function doEnterFrame(e:Event){
      crosshair.setPos(mouseX, mouseY);
      var newMousex:Number = mouseX-tank.x;
      var newMousey:Number = (mouseY-tank.y)*-1;
      var newAngle:Number = Math.atan(newMousey/newMousex)/(Math.PI/180);
      if (newMousex<0) {
         newAngle += 180;
      }
      if (newMousex>=0 && newMousey>0) {
        newAngle += 360;
      }
      if (newAngle>160) {
         newAngle = 160;
      }
      if (newAngle<20) {
        newAngle = 20;
      }
      tank.setAngle(newAngle);
      firepower = Math.sqrt(newMousex*newMousex+newMousey*newMousey);
      if (firepower>200) {
        firepower = 200;
      }
    }
    private function doMouseDown(e:MouseEvent){
      var angle:Number = tank.getAngle() - 1;
      var start_ball_x:Number = tank.x + 48*Math.cos(angle*Math.PI/180);
      var start_ball_y:Number = tank.y + 48*Math.sin(angle*Math.PI/180);
      var dirX:Number = Math.cos(angle*Math.PI/180)*firepower;
      var dirY:Number = Math.sin(angle*Math.PI/180)*firepower;
      addChild(new Cannonball(start_ball_x, start_ball_y, dirX, dirY, gravity));
    }
  }
}

Mostly what I am doing here is three things, I create the tank and the crosshair, I add the ENTER_FRAME and the MOUSE_DOWN listeners and I handle these events. In the ENTER_FRAME handler I give the new position to the crosshair, and the new angle to the tank. In the MOUSE_DOWN handler, I create a new cannonball and I give it its parameters so that it can update itself alone.

The code for the crosshair and the tank is pretty straight forward so I won’t paste it here, but download the zip file if you want to see it.

Here is the code for the cannonball

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package artillery{
  import flash.display.Sprite;
  import flash.events.*;
  public class Cannonball extends Sprite{
  private var dirX:Number;
  private var dirY:Number;
  private var gravity:Number;
  public function Cannonball(xpos:Number, ypos:Number, newDirX:Number, newDirY:Number, newGravity:Number){
    x = xpos;
    y = ypos;
    dirX = newDirX;
    dirY = newDirY;
    gravity = newGravity;
    addEventListener(Event.ENTER_FRAME, doEnterFrame);
  }
  private function doEnterFrame(e:Event):void{
    dirY += gravity;
    x += dirX/50;
    y += dirY/50;
    if (y+ height/2 >350) {
      y = 350- height/2;
      dirY = - dirY * .3;
    }
    if (x < 0)
    {
       removeEventListener(Event.ENTER_FRAME, doEnterFrame);
       this.parent.removeChild(this);
    }
    }
  }
}

This code is saved in a file named Cannonball.as in the folder artillery. Basically it updates its position based on the direction it had was it was created. I modified one thing in this code. When the cannonball x position is less than, I remove the ENTER_FRAME listener and I remove this cannonball from the display list. I do this because, for one the cannonball is not visible anymore so we should not calculate its position. Also, with the previous code, all the cannonballs that you had shot would continue to use up memory, so if you played for a long time, you would eventually run out of memory. By removing the listener and the display object, the garbage collector will remove the unused cannonballs thereby freeing memory.

Also, I mostly used Sprites since there was no timelines involved (the cannon is still a MovieClip, I didn’t take the time to convert it). This is good for the crosshair and the tank, but I think the cannonballs should have stayed a MovieClips since eventually you will want these cannonballs to explode and use a timeline in order to animate the explosions.

Well that is about it for now, feel free to download the files to look at the source code.

Source of the artillery game