I'm building a spritesheet class. Hopefully this will be low hanging fruit to someone, but I'm stumped.
I have a spritesheet (.png) that I've loaded at runtime and placed a section of it on the stage using this code from within the Spritesheet class .as file ouside of the constructor method:
private function onLoad(e:Event):void
{
var loaderBmp:Bitmap = Bitmap(_loader.content);
_bmpData.copyPixels(loaderBmp.bitmapData, new Rectangle(0,0,80,80),new Point(0,0));
}
That works fine. I get my slice of the .png file displaying nicely. In my case, the spritesheet is meant for animating a character, so I need to update the BitmapData and I'm not having any luck. Here is what I'm trying this within my Main class in a function I use to alter the frame of the animation depending on the state of the character:
c._thisSpriteSheet._loader.content.bitmapData.copyPixels(loaderBmp.bitmapData, new Rectangle(0,20,50,30),new Point(0,0));
loaderBmp is a variable who's value is var loaderBmp: Bitmap = Bitmap(_spriteSheet._loader.content);
c is a reference to the Runner object that is the character.
_spriteSheet is a property of the Runner class of type Spritesheet.
_loader is a property of the c._spriteSheet and is the Loader object used when the spritesheet was instantiated.
It doesn't throw an error, but it also doesn't replace the original bitmapData object with the new one. I thought maybe this meant that I need to create a new BitmapData object and use that in the copyPixels method, but that returned the same results (nothing). When I step through the code in debug mode, everything looks like it is working, but my display object does not update with the new bitmapData. What am I tripping on?
Thanks for looking!
Well, probably no one will read this since I'm answering it so quickly, but I literally spent 3 days trying to figure this out. Sometimes trying to ask the question in a concise way helps one answer their own question, and moments later, voila!
So in case anyone has a similar issue, what I was doing wrong was that I was trying to access the BitmapData object via the Loader that originally loaded it. Then it dawned on me that I could simply reference the BitmapData directly via that property of the SpriteSheet class I had made. I think this will be pretty confusing for someone else to follow. If a moderator sees this and thinks it's junk, I don't mind it getting erased, but thought I'd keep it up anyway. The new code looked like this:
c._thisSpriteSheet._bmpDSheet.copyPixels(loaderBmp.bitmapData, new Rectangle(0,20,50,30),new Point(0,0));
and _bmpDSheet is the bitmapdata property of the class.
Related
Complete AS3 noob here - I've tried Googling this, but I can't seem to find what I'm looking for (I stumbled across this, http://ub4.underblob.com/as3-naming-elements-dynamically/, but it doesn't weem to work for me).
I'm trying to dynamically add a Movieclip inside another Movieclip through an external AS3 class
Something like this:
var bullet:Bullet = new Bullet(x, y, "right");
var stageBackground:MovieClip = (stage.getChildByName("back") as MovieClip);
stageBackground.addChild(bullet);
However, while this compiles correctly, at run time, I get error #1009 - Cannot access a property or method of a null object reference.
The debug panel tells me the problem is with this line:
stageBackground.addChild(bullet);
But I can't seem to figure out what's wrong with it. I've tried recasting stageBackground as a Sprite, but that didn't change anything. I know the MovieClip back exists - when I reference it through near identical code in my document class, it works perfectly.
You are accessing stage here to find your container, which is very likely the problem.
You are probably thinking that the stage property refers to "the stage" in Adobe Flash authoring environment.
That's not true.
If you placed a MovieClip on "the stage" in the Flash IDE, it ends up on the main time line, this however, is not the thing the stage property is referencing. stage is the topmost DisplayObjectContainer in the display list. It only exists at runtime. It more or less represents the FlashPlayer window, the runtime environment that executes your .swf file.
In short: you are simply looking for your back MovieClip in the wrong place.
The property of a container that represents the main timeline is root.
Do not use root either.
As you can see, your code becomes dependent on the display list
structure of your application. You are already struggling to find the
container that you are looking for. If you change the structure, your code breaks. Even changing the name of the container (for example to something like "background") will wreak havoc.
Instead, use Events.
You are in another class and you want to fire a bullet.
So you create that bullet same as you do now:
var bullet:Bullet = new Bullet(x, y, "right");
Next, dispatch an Event to notify the rest of your code that a bullet was created and it should be placed in the appropriate container:
dispatchEvent(new BulletEvent(BulletEvent.CREATED, bullet));
(Create a custom event class BulletEvent that extends Event, with the apropriate setter and getter for a Bullet object)
Register a listener on the object of your class that creates the bullets, you will catch this event and place the bullet in the container:
var object:YourClass = new YourClass();
object.addEventListener(BulletEvent.CREATED, addBulletToContainer);
function addBulletToContainer(e:BulletEvent):void
{
// adding the bullet to the container
back.addChild(e.bullet);
}
This code would be placed in the parent of your back MovieClip.
The Flash IDE automatically creates variables behind the scenes that have the same names as the instance names. That's why the variable back is available here.
Using events here allows you to literally fire the bullet into your code with somebody else taking care of it, where it's easy to figure out the container it belongs into.
I'm used to seeing the Loader class used like this:
var loader:Loader = new Loader();
loader.loadBytes(myByteArray);
addChild(loader);
But then I came across some code where it's all done on one line:
Loader(addChild(new Loader())).loadBytes(myByteArray);
What's the difference between the two? Is one way better than the other? Can someone explain what exactly is going on in the second version?
There is barely any difference, and the first version is "better" because it's actually readable.
To break it down:
Loader(addChild(new Loader())).loadBytes(myByteArray);
We cast something as an Object of the type Loader : Loader(...)
Then we add a DisplayObject to the current displaylist with addChild, which will return the DisplayObject we have added (so that we actually have something that we can cast to something else).
The DisplayObject in question is a Loader Object, and we create a new one for this.
So, Loader(addChild(new Loader())) creates a new Loader object and adds it to the displaylist. But this is still kind of useless, because a Loader needs to, well, load something, right? This is the reason why we cast the whole DisplayObject into a Loader in the first place, so that we can use its methods, such as loadBytes(bytearray). If you wouldn't put the whole thing into a Loader(...) cast, you wouldn't have access to these methods, because addChild will only return an object of the DisplayObject type, and not Loader.
To sum it up, this has no effect on performance whatsoever, it's just a shorter writing style for the same goal. If you're the only one who will see this code in your projects, it's fine. If not, consider that other people should be able to read the code as well, without having to break it down step for step.
Thanks partly to info from people here, I'm getting more comfortable with Actionscript 3, but I've got a problem that is very puzzling.
The program (done entirely in AS3, no Flash) has several different screens. One does music and it's working very well. Another does video. Obviously when somebody goes from music to video we need to make sure the music is turned off. There is a Main screen that handles going from one to the other.
I started out doing it this way, and the reason I got "Call to a possibly undefined method" is obvious. The following is in the Main class, with the "private var" part inside the class but external to the functions and the "music = new MusicPanel" part in one of the functions:
private var music:MusicPanel;
music = new MusicPanel(trackNames.songNames, trackNames.numSongs);
When switching to the video panel, I added a public function in MusicPanel called StopMusic and called it when the user went to the video panel:
if(music != null)
music.StopMusic();
That got the error:
Call to a possibly undefined method StopMusic
I was checking to make sure music was not null, but that error didn't seem like a bad thing. So I changed the code to:
private var music:MusicPanel = new MusicPanel();
and added a function that would get the song names and number of songs to the music class. That did not help- I got the same error, and in fact the function that tried to put the song names and number of songs got the error also.
At the same time, the Video panel does not give me that error, even though I have laid it out in exactly the same way.
private var video:VideoPanel = new VideoPanel;
video.PlayVideo();
I do a fair amount of setup on the music screen when it gets called as a new class, I do less setup for the video screen. I'm not sure if that makes a difference.
Clearly there is something I don't understand here. Anybody got any idea what's going on? I've looked at a number of questions about this, but have not found an answer. I think I'm doing this right, but the compiler thinks I'm doing it wrong, so I must be doing it wrong.
Later Note: One answer mentioned the difference between Sprite and MovieClip. I gave that a try, changing to MovieClip does not help, and the VideoPanel, which works, extends Sprite.
What is the base class of MusicPanel, Sprite or MovieClip? If Sprite, change to MovieClip and see what that does. In AS3 Sprites are not dynamic, so can't take properties that are not inherent in the class.
It appears that the problem is coming either from Actionscript 3 or from FlashDevelop. I built a new module (SongsPanel) which is very close to the same as the original MusicPanel. It works. If I add a public function in MusicPanel the compiler comes back with the same error. If I add a public function in SongsPanel everything works.
Does FlashDevelop keep track of errors in some hidden file? I'm guessing that's what's going on, and that there is a bug in the way that is done.
PITA!- but at least it now works.
I´m making a level creator for my platformer game on AS3. I´m looking for a way of getting a graphical representation of a library object on my .fla, so the user can insert that object on the world on the desired coordinate. What I mean with this is that I just want a picture of the first frame of the mc, without taking its properties and methods (without the need to make a .jpg containing that image), because that´s when problems begin to appear, and I just want the object functionality on play mode, not the level creator.
Let´s say, for example, a ball that bounces all the time by updating its location every frame. On the level creator I just want to get the ball picture to insert it on the desired location. If I take the whole ball object to the level creator it won´t stop bouncing and it will mess things up.
I hope I´m clear... I just want to know if there is a practical solution to this; if not then I´ll make a class where all the world objects would extend to, that has a init() function that initializes all the object functionality, so it´s called only on play mode and not on level creator. Thanks for reading anyway.
What you're doing wrong is adding functionality directly to the MovieClip.
Please read one of my previous answers that covers this concept in more depth.
MovieClips should be used for the display only, representing the graphics of an actual game class, for example:
public class Player
{
// Graphics that represent the Player.
protected var display:MovieClip;
// Constructor.
public function Player()
{
display = new PlayerMovieClip();
}
}
Anyways, once you fix that you can take a Bitmap sample of MovieClips using BitmapData and its draw():
// Assume that 'mc' is your MovieClip.
var sample:BitmapData = new BitmapData(mc.width, mc.height, true, 0);
sample.draw(mc);
// This is your image.
var texture:Bitmap = new Bitmap(sample);
I got the following problem:
I have an object called tempScore for my game.
This object is blitted to the canvas by a renderer via the copyPixels method. The object is NOT a display object. It's a Score-object (self made). The Score-object extends an object called BasicBlitArrayObject. The BasicBlitArrayObject extends an EventDispatcher (therefore no display object).
I tried to apply several different TweenLite-plugins to my tempScore-object (i.e. TransformAroundCenter, colorMatrixFilter, etc.). But nothing happens. Absolutely nothing.
Sometimes I get error messages (when a plugin requires a display object and my object is NOT a display object). So far so good.
According to Greensock (maker of Tweenlite) his engine can tween ANY numeric property of ANY object. So when a plugin like TransformAroundCenter requires a display object for tweening I have to modify the plugin to get it working for my non-display object (tempScore). Currently I can't do that because it's way too hard for me.
My game rests upon this code:
http://www.8bitrocket.com/book/ch11_blastermines.zip
Try to apply TweenLite with an object called tempMine inside the game class BlasterMines. It won't work. Any help, please?
Greensock's claim is correct, in it's exactness. You can tween any numeric property of any object. This statement does not include the application of plugin features.
The reason that the TransformAroundCenter and ColorMatrixFilter plugins don't work for you is that they each utilise some property or method of DisplayObject. In the case of transformAroundCenter that's DisplayObject.localToGlobal() and for ColorMatrixFiler it's DisplayObject.filters.
I have to ask why you're applying these plugins to something that is not a display object? In blitting (as it applies to AS3), the basic idea is that you read an area from a sprite sheet to a BitmapData object, which in turn you write to a Bitmap object on the stage. Both BitmapData and Bitmap extend DisplayObject, which is what you need. For higher compatibility you should target the Bitmap object that is actually on the stage, TransformAroundCenter will not work correctly with an object that is not on the stage.
For a better answer you will have to post some code, and possibly a screenshot from a debugger like Monster Debugger 3 which shows your expanded display tree.