There's nothing spectacular or ground-breaking about this game concept, but it's pretty good for teaching some of the techniques needed for games, such as motion based on angle of rotation (using trigonometry) and managing multiple game objects (enemies, bullets, etc.). Also, the idea in my head has a little twist to it that makes things a little more interesting, but I'll get on to that in a future article.

For now, I'll just show you how to get the cannon rotating using the arrow keys. I always find it best to start with something simple so that you can build up some momentum. Let's start by creating some graphics and turning them into movieclip symbols- a base and a barrel for the cannon. Put the registration point of the barrel on the point that you want it to rotate around, then combine the two of them together into a 'cannon' movieclip.

Inside the cannon movieclip, give the base and barrel instance names - 'base' and 'barrel'. We want the instances in the cannon movieclip to be centred on the registration point, so make sure to enter 0 for both the x and y properties of the instances.

Drag an instance of the cannon movieclip onto the stage and give it the instance name 'cannon'. Put it wherever you like, maybe in the centre of the stage. You could also add a tint to it like mine (see below).

That concludes the graphics side of things, next we need to get our hands dirty with the code. Select the first frame of the main timeline and bring up the Actions panel (F9). Here is the code that we will use to get started, just copy and paste it in and I'll explain what's happening:

[sourcecode language='csharp']
var turningCW:Boolean = false;
var turningCCW:Boolean = false;
var turningSpeed:uint = 1;

stage.addEventListener(KeyboardEvent.KEY_DOWN, keyIsDown);
stage.addEventListener(KeyboardEvent.KEY_UP, keyIsUp);
stage.addEventListener(Event.ENTER_FRAME, runGame);

function keyIsDown(event:KeyboardEvent):void
{
if(event.keyCode == Keyboard.LEFT){ turningCCW = true; }
if(event.keyCode == Keyboard.RIGHT){ turningCW = true; }
if(event.keyCode == Keyboard.UP){ turningSpeed = 4; }
}

function keyIsUp(event:KeyboardEvent):void
{
if(event.keyCode == Keyboard.LEFT){ turningCCW = false; }
if(event.keyCode == Keyboard.RIGHT){ turningCW = false; }
if(event.keyCode == Keyboard.UP){ turningSpeed = 1; }
}

function runGame (event:Event):void
{
if(turningCCW) { cannon.barrel.rotation -= turningSpeed; }
if(turningCW) { cannon.barrel.rotation += turningSpeed; }
}
[/sourcecode]

The code is pretty self explanatory. First, we initialise some variables, booleans for applying the rotation clockwise or anti-clockwise and a speed variable to control the rate of the turn. Next we setup our event listeners, to keep track of the keyboard and to update the cannon's rotation every frame.

In the keyIsDown function, called when a key is held down, we change the variables depending on what key is pressed. Effectively, we are activating a set of switches that the main game loop will use to decide how to rotate the cannon barrel. The keyIsUp function basically undoes whatever changes were made to those variables when the keys are released.

Finally, the runGame function gets called every frame and updates the rotation of the cannon barrel. If you are pressing left, it subtracts the speed from the rotation. If you are pressing right, it adds the speed to the rotation. If you are pressing both at the same time they will cancel each other out. Also, the up arrow can be used as a modifier to increase the turning speed.

The code really isn't that complicated, but it achieves the effect we are looking for. You can see my finished example here. Coming up next we'll try some slightly more complex approaches, like applying acceleration and friction to the rotation or rotating based on the mouse position. After that, we'll have a go at firing some bullets and blowing up some enemies.

I hope you've enjoyed this little tutorial and found it useful in some way. Remember, I'm a learner as much as I am a teacher. If you see anything in my tutorials that could be done better, please leave a comment to help me and anyone else reading this.

Este fin de semana me tope con algo aún mejor!... Esa librería de sistema de partículas fue utilizada durante una plática en un congreso en la que Seb Lee-Delisle explicaba desde lo básico hasta lo complejo de cómo hacer partículas en ActionScript3... Y aquí encontré los videos de esa plática!!!...

Y para rematar: Un tutorial (con código fuente incluido) POCA MADRE del mismo autor estrito para la revista Computer Arts.

Así que... ¿Qué mas quieres?... Tienes, del mismo autor, la librería de sistemas de partículas, el video que explica cómo hacer partículas, y el pdf que refuerza y documenta la explicación. :-)

AYAN RAY | AS3 / Flash: Introducing the AssetLoader Class

In Actionscript 3, there are many different ways to load external assets from the Internet. Unfortunately, this can become tiresome to find different ways to load each one in it's own individual way. With this problem in mind, I have created the AssetLoader class.

Tink » Blog Archive » Seamless Animated Skins in Flex

In Joey Lotts session on styling Flex at FOTB (where he did a great job), one of the attendees asked about animated skins.

There’s
obviously many ways to approach this but I thought I’d do an example of
how you can have seamless transitions between these states using frame
labels inside the symbol in Flash, and by adding code using
addFrameScript().

Liquid Components for Flash CS3 [ by Didier Brun ] < ByteArray.org

The “Liquid Components” have been created for the Flash people, freelance coders and designers who wish to integrate fully skinnable components in their website, games or little RIA applications.

AS3 - URL Class | Manfred Weber`s Weblog

I could not find it in the net so I hacked something together quickly. A simple URL class that parses an url string.

Problems using navigateToURL - aron / philipp development blog

Hi there... we've been busy these past couple of days so there
wasn't much time for new posts - sorry. But here is a little update.
While developing a flash website (AS3 & SWFObject2.0)
that heavily depended on opening URLs in a new browser window we came
across the popup blocker problem that the use of navigateToURL causes.
When trying to open a new window firefox'/IE's popup blocker will block
the window and display its warning. After googling for some time we
came across some neat workarounds:

1) How to prevent pop-up blocking in Firefox by Sergey Kovalyov

2) The Nightmare that is "_blank": Part II (resolved???) by The Saj

putting these two approaches into one AS3 util-class, this is what we came up with:

An Actionscript 3 library for reading and writing Excel files. Currently reading numbers, text, and formulas from Excel version 2.0-2003 and writing numbers, text, and dates to Excel 2.0 is supported. No server-side help is needed.

<mx:Script>
    <![CDATA[
        import mx.utils.Base64Encoder;
        import mx.controls.Alert;

        private var baseUrl:String = "http://phprestsql.sourceforge.net/tutorial/user";
        private var auth:String = "p126371rw:demo";

        private function init():void{
            var encoder : Base64Encoder = new Base64Encoder();
            encoder.encode(auth);
            userService.headers["Authorization"] = "Basic " + encoder.toString();
            deleteUser();
        }
    ]]>
</mx:Script>

Enjoyyy!!!

Today i bring you two tutorials showing how to export either from Blender or 3D Max Studio, as also a cool place for getting free 3D models which you can use to test your PV3D skills.

Exporting from 3D Max Studio

Read Tutorial

Exporting from Blender 3D

Read Tutorial

Free 3D Models - 3ds, lwo, lightwave, br4, bryce, pz3, poser, md2

Download

Google has been developing a new algorithm for indexing textual content in Flash files of all kinds, from Flash menus, buttons and banners, to self-contained Flash websites. Recently, we've improved the performance of this Flash indexing algorithm by integrating Adobe's Flash Player technology.

In the past, web designers faced challenges if they chose to develop a site in Flash because the content they included was not indexable by search engines. They needed to make extra effort to ensure that their content was also presented in another way that search engines could find.

Now that we've launched our Flash indexing algorithm, web designers can expect improved visibility of their published Flash content, and you can expect to see better search results and snippets. There's more info on the Webmaster Central blog about the Searchable SWF integration.

I imagine that it is still more difficult to index flash content and this opens questions as to what is searched and how as content can be loaded in dynamically and some content might be overly verbose that should not be indexed such as code.  Also, the placement of text matters on a regular website so I imagine that it also matters according to what content is in a flash SWF file.

It will be interesting to hear how this evolves but as of right now it is good news that content in flash is searchable.  The format is now open and this is probably why the capability is now possible as there aren't any fees to using the format.  So expect more accessibiliy from flash as time goes on like this.

Developing Widgets with Flash

Read Tutorial

Yahoo! Maps AS3 Component Flash and Flex Examples

View Examples and source

Skinning in Flex: Beauty is Only Skin Deep

Read Tutorial

Developing with the Display List in ActionScript 3

Read Tutorial

I tried to search everywhere, google, adobe's forum, actionscripts.org, kirupa.com, ... and no solution had been found... just the same old answers : "...it's simple, you uncheck export in first frame for all the linkage items, don't put any stuff on the first keyframe, choose another frame to export class files, and apply these code...". I wanted to shout at them : "It won't work ! I tried, tried a thousand times ! And it doesn't work ! ". I also found a trick from Keith Peter about optimize loading process, using [Frame(factoryClass=.....)], but just for Flex... nothing has ever worked for flash...

And i got to have a conlusion that there're no way to have a preloader in AS3 in the same fla file. Maybe using another .swf file to load the main movie in is the only workaround....

Sadly, most of my work was code-based, so export in first frame for library items wouldn't help much. All my external classes was all exported into first frame even though i tried to export it in frame 2, 3... or any other frame. I even tried to make a different scene (which is not recommended), and changed the loading order top down/bottom up... and nothing works too...

So, what's next? (sight...)

ActionScript has its own rules of grammar and punctuation that determine which characters and words are used to create meaning and in which order they can be written. For example, in English, a period ends a sentence; in ActionScript, a semicolon ends a statement.

var name:String = "Jhon";

The above statement is a variable declaration of string data type.

ActionScript has syntax rules that you must follow to create scripts that can compile and run correctly.

ActionScript 2.0 is case sensitive, so the variables "name" and "Name" are different.

In ActionScript, dot syntax is used ( .) to access properties or methods belonging to an object or movie clip. It is also used to identify the target path to a movie clip, variable, function, or object.

trace( rectangle_mc._width);

The above statement traces the width of the movieclip "rectangle_mc" where "rectangle_mc" is the instance name of the Movieclip.

Note: trace statement is used to output data in the output panel, mainly used for debugging purposes and these statements only execute during authoring.

ActionScript event handlers, class definitions, and functions are grouped together into blocks with curly braces ( {}).

Ex: // Class Form.as

class Form() {

}

// onRelease Event handler for button

go_btn.onRelease = function() {

};

// Function

function getData(name:String):Void {

}

Comments:

There are two ways you can write comments in ActionScript,
single line and multi-line comments.

Ex:

// This is a single line comment

/*

This is a multi-line comment with two lines...

second line goes here...

*/

Constants:

ActionScript contains predefined constants.

For example, the constants ENTER, BACKSPACE,SPACE, and TAB are properties of the Key object and refer to keyboard keys. To test whether the user is pressing the Enter key, you could use the following statement:

if(Key.getCode() == Key.ENTER) {

}

Flash does not enforce constants; that is, you can't define your own constants.

ActionScript has the following basic data types that you use frequently in your programs:

String: A string is a sequence of characters such as letters, numbers, and punctuation marks. You enter strings in an ActionScript statement by enclosing them in single (') or double (") quotation marks.

Ex: var name:String = "Steve";

Number: The number data type is a double-precision floating-point number. The minimum value of a number object is approximately 5e-324. The maximum is approximately 1.79E+308.

Ex: var age:Number = 24;

Boolean: A Boolean value is one that is either true or false. ActionScript also converts the values true and false to 1 and 0 when appropriate. Boolean values are most often used with logical operators in ActionScript statements that make comparisons to control the flow of a script.

Ex: var smoking:Boolean = false;

Object: An object is a collection of properties. Each property has a name and a value. The value of a property can be any Flash data type - even the object data type. This lets you arrange objects inside each other, or nest them. To specify objects and their properties, you use the dot ( .) operator.

Ex:

var user:Object = new Object();

user.name = "Steve";

user.age = 24;

user.sex = "male"

MovieClip: Movie clips are symbols that can play animation in a Flash application. They are the only data type that refers to a graphic element. The MovieClip data type lets you control movie clip symbols using the methods of the MovieClip class.

You do not use a constructor to call the methods of the MovieClip class. You can create a movie clip instance on the Stage or create an instance dynamically. Then you simply call the methods of the MovieClip class using the dot ( .) operator.

Null: The null data type has only one value, null. This value means no value - that is, a lack of data. You can assign the null value in a variety of situations to indicate that a property or variable does not yet have a value assigned to it.

Undefined: The undefined data type has one value, undefined, and is automatically assigned to a variable to which a value hasn't been assigned, either by your code or user interaction.

The value undefined is automatically assigned; unlike null, you don't assign undefined to a variable or property. You use the undefined data type to check if a variable is set or defined.

Void : The void data type has one value, void, and is used in a function definition to indicate that the function does not return a value, as shown in the following example:

Ex:

//Function with a return type Void

function setItem(url:String):Void {

}

A variable is a container that holds information. The container itself is always the same, but the contents can change. By changing the value of a variable as the SWF file plays, you can record and save information about what the user has done, record values that change as the SWF file plays, or evaluate whether a condition is true or false.

New features and changes in ActionScript language elements

There are many changes and new elements were added in ActionScript 2.0. If you intend to use any of the following elements you need to target your applications to flash player 7 and later.

MovieClipLoader class: Very useful class which lets you monitor the progress of files (SWF or JPEG) as they are loaded into movie clips. The methods and properties available with this class let you monitor the progress of loading files and perform various tasks based on the loading information.

NetConnection class and NetStream class: These classes let you stream local Flash Video (FLV) files and control them.

Sound.onID3 and Sound.id3: Event handler and property to provide access to ID3 data associated with a Sound object that contains in an MP3 file.

Array.sort() and Array.sortOn(): These new methods let you perform additional sorting options, such as ascending and descending sorting, whether to consider case-sensitivity when sorting, and so forth.

System class: This class has several new objects and methods, and the System.capabilities object has several new properties.

TextField.condenseWhite: This property can be used to remove extra white space from HTML text.

TextField.mouseWheelEnabled: This property can be used to specify whether a text field's contents should scroll when the mouse pointer is positioned over a text field and the user rolls the mouse wheel.

TextField.StyleSheet class: This Class lets you create a style sheet object that contains text formatting rules such as font size, color, and other formatting styles.

TextField.styleSheet: This property lets you attach a style sheet object to a text field.

TextFormat.getTextExtent(): This method accepts a new parameter, and the object it returns contains a new member.

XML.addRequestHeader(): This method lets you add or change HTTP request headers sent with POST actions.

Mouse.onMouseWheel: This event listener will be generated when the user scrolls using the mouse wheel.

MovieClip.getNextHighestDepth(): This method lets you create MovieClip instances at runtime and be guaranteed that their objects render in front of the other objects in a parent movie clip's z-order space.

MovieClip.getInstanceAtDepth(): This method lets you access dynamically created MovieClip instances using the depth as a search index.

MovieClip.getSWFVersion(): This method lets you determine which version of Flash Player is supported by a loaded SWF file.

MovieClip.getTextSnapshot(): This method and the "TextSnapshot object" let you work with text that is in static text fields in a movie clip.

MovieClip._lockroot: This property lets you specify that a movie clip will act as _root for any movie clips loaded into it or that the meaning of _root in a movie clip won't change if that movie clip is loaded into another movie clip.

This section describes changes that improve your ability to debug your ActionScript programs.

Output window changed to Output panel You can now move and dock the Output panel in the same way as any other panel in Flash. It shows error messages (including some runtime errors) and lists of variables and objects

Improved error reporting at compile time In addition to providing more robust exception handling, ActionScript 2.0 provides several new compile-time errors.

Improved exception handling The Error class and the throw and try..catch..finally statements let you test and respond to runtime errors from within your script so that you can implement more robust exception handling.

Changes compared to ActionScript 1.0

The following are the major changes that you will find in ActionScript 2.0 when compared with 1.0.
Case Sensitivity: Case sensitivity is the new feature introduced in ActionScript 2.0, and whenever you publish your movie in Flash Player 7 or later it will be applied to your code. That means variable names that differ only in case (depth and Depth) are considered different from each other. This applies to keywords, class names, variables, method names, and so on.

This change also affects external variables loaded with LoadVars.load() or loadvariables().

Case-sensitivity is implemented in external scripts such as class files, scripts that you import using the #include command, and scripts that you write in your flash movie.
Strict Data Typing: This is another useful feature that allows you to type cast your variables to their appropriate data types, so that you can restrict variables to accept only specified data type values.

When creating a variable with ActionScript 2.0, use the following syntax not only to create the variable, but also to assign its data type at the same time:

var a:String = "Hello World";

The above line says that "a" is a variable of string data type. If you assign any other data type value to "a" (Example: a = 20) it throws a "Type mismatch" error when compiled. Strict data typing also applies to classes, functions to type cast function parameters, return types, and so forth. Example:

var my_array:Array = new Array(); var my_lv:LoadVars = new LoadVars(); function myFunction(name:String, age:Number):Void { }

It is recommended to type cast all variables, classes, functions, and so forth that you use in your script; it proves to be a good programming practice.