iD News and Blog

Video Tutorial: Creating a Defender Flash Game

I’ve created a video tutorial breaking down in 10 minutes how to make a Flash defender game. If you’d like to check out the game and source, they are also available.

Play the game: http://forum.internaldrive.com/files/vlog/Yadder.swf
Download the source: http://forum.internaldrive.com/files/vlog/VLog1Yadder_src.zip

 

Tags: Actionscript, defender, Flash, game, tutorial, video
Posted in iD Tech Bloggers | 2 Comments »

 

 

The Ternary Operator in Flash (if-else shorthand)

Most people fluent in Flash Actionscript are familiar with unary and binary operators, but there is also a ternary operator that can be quite useful. First, a refresh on operators:

Unary: count++;

Binary: count = count * 2;

Ternary: var result:String = (count == 0) ? “Empty” : “Not Empty”);

So what does this mean? You can use the ternary form of the if statement as a shorthand. Let’s look at the equivalent full if-else statement:

var result:String;
if (count == 0) result = “Empty”;
else result = “Not Empty”;

Of course, using the ternary operator cuts down on code readability, but three lines can effectively be cut down to one. Remember, the form is this:

(condition) ? ifTrueDoThis : ifFalseDoThis;

 

Tags: Actionscript, code, conditionals, CS4, Flash, programming, ternary operations
Posted in iD Tech Bloggers | No Comments »

 

 

Properly Referencing Your Main Class in Flash Actionscript

For those of you moving from Actionscript 2 to 3 (with a heavier focus on proper object-oriented principles), you may find that accessing your Main class and Stage isn’t as straight-forward. In this post we’ll highlight organizing your classes to properly reference your main class. First, let’s take a look at our Main class:

package {

    import flash.display.Stage;

    import flash.display.MovieClip;

    public class Main extends MovieClip {

        private static var _instance:Main = null;

        public function Main() {

            _instance = this;

        }

        public static function getInstance():Main { return _instance; }

        public static function getStage():Stage { return getInstance().stage; }

    }

}

First we define a static variable, _instance, to hold a static reference to Main. We are assuming throughout this that we will use Main statically. In other words, there will only be a single instance of our Main class. Next, in our constructor, we use the line _instance = this; to set our static version of Main to the one that is created when the constructor is called.

We will use two methods to get access to Main and the main stage. First, getInstace() is a static function that always returns a copy of _instance. If you want the stage instead, use getStage(). All getStage() does differently from getInstance() is return the stage property of _instance rather than the object itself. Using this format simplifies your code in other classes.

Now let’s say you want to use these functions in other classes to add something to the stage. Let’s pretend we have a Tree class that needs to add itself to the main stage when it is created. You could use this code:

package {
    import flash.display.Sprite;</code>

    public class Tree extends Sprite {
        Main.getStage().addChild(this);

        x = Math.random() * Main.getStage().stageWidth;
        y = Math.random() * Main.getStage().stageWidth;
    }
}

You can see that we can easily get properties of the stage (stageWidth and stageHeight) simply by statically referencing Main. Note that we could have used the following lines instead:

x = Math.random() * Main.getInstance().stage.stageWidth;
y = Math.random() * Main.getInstance().stage.stageWidth;

It really just depends on which example you find more elegant. One additional benefit of using the techniques described here is that you can use the getInstance() to determine if Main has loaded. Simply do:

if (Main.getInstance() != null) { /* some function */ }

Hope that gives you an easy framework for accessing your stage and Main class in AS3!

 

Tags: Actionscript, AS3, Classes, Flash, Objects, Stage
Posted in iD Tech Bloggers | 4 Comments »