Overriding the x getter in Actionscript 3.0 - actionscript-3

I have a class called Element. It is basically my ultra-movieclip, and nearly all classes in the game subclass it. Element extends Movieclip
The code in the game is built around the idea that all Movieclips are registered at the top-left corner. Register it somewhere else, and everything starts to fall apart.
The problem is, sometimes the in the animation and such, the top-left corner moves, but the registration point doesn't, and you end up with a registration point somewhere in the middle of the Movieclip. This causes problems.
So, how do I fix this problem? We can find the true top-left corner of a Movieclip using getBounds (this is the documentation for it), but using getBounds over and over in code would get kinda tedious.
My idea is to override the x getter in the Element class. That way, we can always know where the Element's true top-left corner is, without having to write a bunch of complicated code every time!
And for the sake of argument, let's assume that just making a new getter like "trueX" will open a trapdoor beneath my feet and plunge me into a cage of starving gophers.
I cannot figure out how to override the x getter! How can we do this? Have I missed an incredibly simple solution to the problem that has nothing to do with overriding?
override public function get x():Number {
//I have no idea what I'm doing!
}

This should be all you need to do: (if I understand your question right)
override public function get x():Number {
return super.x + getBounds(this).x;
}

Related

AS3 dress up game drag & drop not working

I'm making a dress up game and ran into the following issue.
I know how to make things drag and drop, however whenever the movieclip is situated in a layer below another, it will not let me drop it / does not register the mouse release.
In this case for example - The very top layer is the doll's hair. Under this layer are articles of clothing, and under that is the doll base. Like so : https://gyazo.com/a0ea8eae2ee5505874f4207a888249bf
I can pick up a top from the inventory but cannot place it on the doll because my cursor is over the hair from the very top layer. In a way, it seems like the hair layer is acting as a barrier between the cursor click and the article of clothing. Is there any way around this?
Here is a link to the game as it is now - i'm sure you will see the issue quickly if you attempt to move things around.GAME LINK
Here is the code for one of the clothing layers, if needed.
tshirt.addEventListener(MouseEvent.MOUSE_DOWN, drag17);
tshirt.addEventListener(MouseEvent.MOUSE_UP, drop17);
function drag17(event:MouseEvent):void
{
event.target.startDrag();
}
function drop17(event:MouseEvent):void
{
event.target.stopDrag();
}
Sorry for the rather crude explanation, and thank you in advance!
the problem
You are exactly right about the hair getting in the way.
method 1
One way to fix that would be (assuming you dropped the hair there):
function drop17(event:MouseEvent):void
{
event.target.stopDrag();
event.target.mouseEnabled = false;
}
In your hair example, the hair needs to have mouseEnabled set to false so that it won't be able to be your target by mistake on a mouse event. If the hair wasn't "dropped" there, set mouseEnabled to false for the hair wherever it makes sense to do so... maybe when it is first constructed or instantiated.
method 2
An alternative method is to force the item that you picked up to come to the front of the z order. Like this:
function drag17(event:MouseEvent):void
{
addChild(event.target); // this doesn't add another Sprite or movie clip, it just moves it to the top of the z order. Trust me.
event.target.startDrag();
}
With your dragging element now at the top, nothing will be "between" it and the mouse. This method probably looks cleaner since the thing you are dragging isn't getting lost behind other things. This will force you to deal with the eventual need to place the item in the correct z-order when you drop it, but that could easily be done by doing addChild to a clothesContainer or something like that. That would be another question though.

Object changing layer when going between frames?

I have a child of an object that stays on the scene when the frame changes. So I gotoAndStop(2); and the object is still there. However, when I come back to frame one. The object is on the lowest layer, despite the fact that I originally added it using addChildAt(character, 1); I think this adds it to the first layer? Anyone know how I can fix this issue of keeping a movieclip object on the top layer despite changing frames? Thanks.
In AS3/Flash, the bottom most layer is 0. So doing addChildAt(character, 1) would make your character the second to the bottom layer. addChildAt(character, 0) would make it the very bottom/back layer.
If you want to make it the top most layer, you do any one of the following:
addChild(character); //this is the shortest amount of code
addChildAt(character, numChildren-1); //the is exactly the same as above
setChildIndex(character, numChildren-1); //this is also the same but requires the character already be present on the display list
The latter (setChildIndex) may be preferred IF your character originates on the timeline (eg not created through code). The reason being, if you change through code the parentage of something created on the timeline, it will not go away when no longer present on the timeline.
If you want a way to force something to always be on top, you can do something along these lines:
this.addEventListener(Event.ADDED, bringToTop);
function bringToTop(e:Event):void {
setChildIndex(character, numChildren-1);
}
Doing that, makes it so whenever any other object is added as a child of this, it will set the character to the very top most layer/z-index.

nested collision starling as3

I am using starling and tweenMax frameworks in my project.
The trouble I am running into is this:
For the purpose of animating along different paths, I am using tweenmax.
There is one _leaderEnemy that animates along a path and I am pushing several other _shooterEnemy (they are of the same class) into it.
public function createEnemies(enemyNo:int, path:Array, offset:int):void
{
for(var i:uint=1;i<=enemyNo;i++){
if (i==1){
_leaderCount++;
_leaderEnemy = new ShooterEnemy();
_leaderEnemy.x=600;
_leaderEnemy.y=300;
_leaderEnemy.name="_shooterEnemy"+_leaderCount;
this.addChild(_leaderEnemy);
leaderEnemyArray.push(_leaderEnemy);
}
else
{
_leaderCount++;
_shooterEnemy= new ShooterEnemy();
_shooterEnemy.x=0;
_shooterEnemy.y=(offset*(i-1));
_shooterEnemy.name="_shooterEnemy"+_leaderCount;
trace("no: "+_shooterEnemy.name);
leaderEnemyArray.push(_shooterEnemy);
_leaderEnemy.addChild(_shooterEnemy);
}
}
Now I want to check for collision using starling between each of the _leaderEnemy and the _shooterEnemy inside it with _shooterHero.
Running this array successfully checks collision with the whole group i.e. _leaderEnemy but not the individual ones inside it.
Technically, I should be able to do this just by:
var Track:Object;
for(var i:uint=0;i<leaderEnemyArray.length;i++) {
Track=leaderEnemyArray[i];
if (Track.bounds.intersects(_shooterHero.bounds)){
Track.rotation=deg2rad(70);
}
}
It may be something stupid I am doing. But I have not been able to solve this.
Any help on this would be appreciated.
Some other questions I have:
Can I check for collision with _shooterHero from inside the _shooterEnemy's class?
I have tried:
if (this.bounds.intersects(stage.getChildByName("_hero"))){
}
although it did not work.
Can I check for collision of one Enemy with everything on stage, so I can assign individual functions for his each contact?
For example: hit with hero: die; hit with another enemy: turn around
If you need more info, I will be happy to provide it.
Thank You.
Can I check for collision of one Enemy with everything on stage, so I can assign individual functions for his each contact? For example: hit with hero: die; hit with another enemy: turn around
Of course you can. You should! This is approximatively how collision engines works.
Running this array successfully checks collision with the whole group i.e. _leaderEnemy but not the individual ones inside it.
Nope. It won't work. Because the bounds property use the parent coordinates.
Meaning you can intersect each child display (of same container) with each other.
But you shouldn't intersect a child display of A with a child display of B.
Except if you convert every bounds coordinates (which are local) to global.
http://doc.starling-framework.org/core/starling/display/DisplayObject.html#localToGlobal()
Using Track.bounds.intersects is one way of checking collosions. Another would be to use hitTest method of starling.displayDisplayObject
You could also check the distance of your hero and other enemies calculated by a pythagorean theorem type calculation.
Are you checking enemies against each other? If you have many enemies you might want to look into "flocking" algorithms. Keith Petes covers this subject nicely in his book Advanced Actionscript Animation.

Children of Children of MovieClip not showing up when MovieClip is added to stage?

This problem seems very simple to me, but I've been unable to fix it, or find an answer anywhere.
This is in a class constructor for a class called block, block_maker is the object that called the constructor, an instance of level.
this.bitmap = new Bitmap(this.bitmap_data);
this.addChild(this.bitmap);
this.block_maker.stage_foreground.addChild(this);
In level, stage_foreground is added to the stage, but nothing appears. trace(stage_foreground.numChildren); shows the correct count of children, and var temp = (this.stage_foreground.getChildAt(0)); trace(temp.numChildren); correctly but the children OF the children don't actually show up, the stage just stays blank.
When I change the above code to
this.bitmap = new Bitmap(this.bitmap_data);
this.block_maker.stage_foreground.addChild(this.bitmap);
the blocks appear on the stage, as children of level_instance.stage_foreground, but with this method, the bitmaps aren't appropriately positioned, as they have no position data. I can simply give this.bitmap x and y positions, and it works, but I am curious as to why it won't work when just adding the bitmap as a child to the block and then adding that as a child to stage_foreground.
I've tried replacing this.bitmap with a number of other object classes, such as a temporary MovieClip I made, or a Shape, but nothing shows up, so I know it has nothing to do with it being a Bitmap.
As you stated
This is in a class constructor for a class called block, block_maker
is the object that called the constructor, an instance of level.
this.bitmap = new Bitmap(this.bitmap_data);
this.addChild(this.bitmap);
this.block_maker.stage_foreground.addChild(this);
The level class needs to to extend a display object for it to show up.
In other words
"this"
has to be a display object or extend it in some form.
The reason this doesn't work.
this.block_maker.stage_foreground.addChild(this);
and this does
this.block_maker.stage_foreground.addChild(this.bitmap);
Is because "this" is not a display object but "this.bitmap" is.
The DisplayObject class is the base class for all objects that can be placed on the display list.
First of all, even though it's not neccesary, I'd suggest to make a classname start with a capital letter, and vars always start with a lower-case letter. It's a common 'rule' in AS3 that's mainly to avoid confusion.
The problem most likely lies within you use of this; what you're doing is adding this into this. It seems to me it's not a proper way of coding.
Also, since all of the other attempts didn't work; have you tried to make the var you want ot add a public static var?

Movieclip stacking in Actionscript

I'm building a game of which the interface is one of the first items to load on screen. Sound button, pause and all the bits -
During the game - all manor of things are dynamically added and removed to the stage. Therefore my interface goes behind my game scene.
How do I ensure the movieclip always stays on top?
Can I override the addChild of my Document Class and every time a new child is added, I restack the interface to the top?
You can use setChildIndex to rearrange objects that are already contained within a MovieClip or Sprite. For example, if you have an object called container, which contains a redBall, blueBall and many other ball objects, you can use the following to make sure redBall is behind everything else:
container.setChildIndex(redBall, 0);
Equally you can make sure that blueBall will be displayed infront of everything else using:
container.setChildIndex(blueBall, container.numChildren-1);
addChildAt will sort you out for adding children straight into their correct position, and setChildIndex will allow you to re-position objects already placed. Hope that helps.
debu
Look into addChildAt, it allows you to specify the index that the new object should be added too.
http://livedocs.adobe.com/flash/9.0/ActionScriptLangRefV3/flash/display/DisplayObjectContainer.html#addChildAt%28%29
A good strategy is to keep all interface elements in one parent Sprite/MovieClip, and all game assets in another. (With the interface one on top)
With your guys suggestion I made this, apparently, if you addChild an object already on the screen, it's simply reindex'd to the top. Does this look ok?
private var topLevelChildrenArray:Array = [];
public function addTopLevelChild(child:DisplayObject):DisplayObject
{
topLevelChildrenArray.push(child)
return this.addChildAt( child, this.numChildren - 1 );
}
override public function addChild(child:DisplayObject):DisplayObject
{
this.addChildAt(child, this.numChildren);
for each(var topChild:DisplayObject in topLevelChildrenArray)
{
super.addChild(topChild);
}
return child
}