I am new to as3, I tried to look for an answer to my question already. For a side scrolling game I have enemies set at certain locations, and I need them to spawn, not just show up once at these specific places in the game. These are excerpts from the timeline code concerning the problem.
var enemyList:Array = new Array();
function addEnemiesToLevel1():void
{
addEnemy (700, 125);
addEnemy (1000, 125);
addEnemy(2405, 125);
addEnemy(3300, -155);
}
if (enemyList.length > 0)
{
for (var i:int = 0; i < enemyList.length; i++)
{
function addEnemy(xLocation:int, yLocation:int):void
{
var enemy:Enemy = new Enemy(xLocation, yLocation);
back.addChild(enemy);
enemy.addEventListener(Event.REMOVED, enemyRemoved);
enemyList.push(enemy);
}
The enemy is tied to a class file controlling movement towards player
package {
import flash.display.MovieClip;
import flash.events.Event;
public class Enemy extends MovieClip {
private var xSpeedConst:int = 6;
public function Enemy(xLocation:int, yLocation:int) {
// constructor code
x = xLocation;
y = yLocation;
addEventListener(Event.ENTER_FRAME, loop);
}
public function loop(e:Event):void {
x -= xSpeedConst;
}
public function removeSelf():void {
trace("remove enemy");
removeEventListener(Event.ENTER_FRAME, loop);
this.parent.removeChild(this);
}
}
}
The enemy is also set for collisions so I don't want to change the code too much, since I might spoil something. If I have to add Timer, please tell me where exactly, because I already tried that and failed. Thank you for your help.
Although I recommend not coding in the timeline, a working example timer setup in the timeline would look like this:
var timer:Timer = new Timer(2000,0);
timer.addEventListener(TimerEvent.TIMER, createEnemy);
function createEnemy(e:TimerEvent):void{
//create a new enemy, pass the x and y you want (xPos and yPos here)
//var xPos:int, yPos:int
var enemy:Enemy = new Enemy( xPos, yPos );
back.addChild(enemy);
}
timer.start();
You could also do a similar setup in your class files if you are generating enemies there. Again, doing this in the timeline will much harder to maintain and debug.
Related
So I'm currently attempting to make a prototype for a Bullet Hell game and I've run into a bit of a dead end.
So far I can move my player perfectly, the boss moves back and forth as he is supposed to, however the projectiles have some funny behaviour. Basically, when the boss moves left/right, so do the projectiles as if they are stuck to him. They move on the y as they are supposed to, except they stop just short of the player and move no further, so I'm hoping anyone can take a look at my code and give me a hand with what's going on.
Note: Ignore the rotation stuff, that's for later implementation, I was just laying the ground work.
Projectile.as
package
{
import flash.display.Stage;
import flash.display.MovieClip;
import flash.events.Event;
public class Projectile extends MovieClip
{
private var stageRef:Stage;
private var _xVel:Number = 0;
private var _yVel:Number = 0;
private var rotationInRadians = 0;
private const SPEED:Number = 10;
public function Projectile(stageRef:Stage, x:Number, y:Number, rotationInDegrees:Number)
{
this.stageRef = stageRef;
this.x = x;
this.y = y;
this.rotation = rotationInDegrees;
this.rotationInRadians = rotationInDegrees * Math.PI / 180;
}
public function update():void
{
this.y += SPEED;;
if(x > stageRef.stageWidth || x < 0 || y > stageRef.stageHeight || y < 0)
{
//this.removeChild(this); <- Causing a crash, will fix later
}
}
}
}
Boss.as
package
{
import flash.display.MovieClip;
import flash.display.Stage;
import flash.events.Event;
import flash.utils.Timer;
import flash.events.TimerEvent;
public class Boss extends MovieClip
{
private var stageRef:Stage;
private var _vx:Number = 3;
private var _vy:Number = 3;
private var fireTimer:Timer;
private var canFire:Boolean = true;
private var projectile:Projectile;
public var projectileList:Array = [];
public function Boss(stageRef:Stage, X:int, Y:int)
{
this.stageRef = stageRef;
this.x = X;
this.y = Y;
fireTimer = new Timer(300, 1);
fireTimer.addEventListener(TimerEvent.TIMER, fireTimerHandler, false, 0, true);
}
public function update():void
{
this.x += _vx;
if(this.x <= 100 || this.x >= 700)
{
_vx *= -1;
}
fireProjectile();
projectile.update();
}
public function fireProjectile():void
{
if(canFire)
{
projectile = new Projectile(stageRef, this.x / 200 + this._vx, this.y, 90);
addChild(projectile);
canFire = false;
fireTimer.start();
}
}
private function fireTimerHandler(event:TimerEvent) : void
{
canFire = true;
}
}
}
Edit: Current suggestions have been to do the following:
stage.addChild(projectile); and this.parent.addChild(projectile); both which have the projectile firing from the top left corner (0, 0) and not constantly firing from the current center of the Boss.
The other issue, which has been untouched, is the fast that the projectile stops moving after a certain point and remains on the screen.
Another Edit:
After commenting out the code with the timer I have found that the projectile stops moving entirely. The reason why it was stopping after a certain amount of time was due to the timer, when the timer elapsed the projectile stopped and another would fire.
So now I need the projectile to constantly fire and move until it hits the edge of the screen, any ideas?
The problem is you are 'addChild'ing your projectiles to your Boss as opposed the stage (or the same display level as your Boss). When your Boss moves, your projectiles will move relative to him (ie, when he moves sideways, so will they).
When your boss fires a projectile, use a custom event to trigger a fireProjectile method in the Class that is your Boss' display parent. Instantiate your projectiles there and addChild them to the same object to which you addChild your Boss (possibly the stage?).
Alternatively, if you don't want to use a custom event, in your current fireProjectile method change the addChild line to:
this.parent.addChild(projectile);
This will add projectiles to the parent object of your Boss. Although that line seems, slightly, like cheating to me.
Im making a game as a graduation project and have encountered a little issue. The goal of the game is to maneuver a ship and avoid asteroids as long as possible. I'm almost done but I'm now trying to solve the collision detection.
My problem is how do I reach the enemy in the loop variable so that it can check for collision with it? Here is the code:
package com.asgamer.basics1
{
import flash.display.MovieClip;
import flash.display.Stage;
import flash.events.Event;
public class Engine extends MovieClip
{
private var numStars:int = 80;
private static var enemyList:Array = new Array();
private var ourShip:Ship;
public function Engine() : void
{
ourShip = new Ship(stage);
ourShip.x = stage.stageWidth / 2;
ourShip.y = stage.stageHeight / 2;
stage.addChild(ourShip);
for (var i:int = 0; i < numStars; i++)
{
stage.addChildAt(new Star(stage), 1)
}
addEventListener(Event.ENTER_FRAME, loop, false, 0, true);
stage.addEventListener(Event.ENTER_FRAME, krash);
}
private function krash(e:Event) : void
{
function krash(e:Event):void
{
if (enemy.hitTestObject(ourShip)==true)
{
stage.removeChild(ourShip);
stage.removeEventListener(Event.ENTER_FRAME, krash);
}
}
}
private function loop(e:Event) : void
{
if (Math.floor(Math.random() * 10) == 5)
{
var enemy:Asteroid = new Asteroid(stage);
enemy.addEventListener(Event.REMOVED_FROM_STAGE, removeEnemy, false, 0, true);
enemyList.push(enemy);
stage.addChild(enemy);
}
}
private function removeEnemy(e:Event)
{
enemyList.splice(enemyList.indexOf(e.currentTarget), 1);
}
}
}
As you can see I have a function for making enemies which is called loop, and a function for collision detection called krash. But since enemy is a variable inside loop, how can I check for collision with it in the krash function. (Sort of new to actionscript, so I dont know the terminology all to well)
In krash you will need to check each enemy in enemyList.
example:
private function krash(e:Event) : void
{
function krash(e:Event):void
{
for(var i:int = 0; i < enemyList.length; i++)
{
if (enemyList[i].hitTestObject(ourShip)==true)
{
stage.removeChild(ourShip);
stage.removeEventListener(Event.ENTER_FRAME, krash);
}
}
}
}
Unfortunately, if you have a lot of enemies on the stage the program will lag a bit because you're checking for collisions with all of them every frame.
Also, I'd reccommend you add something to remove you enemies from the screen :P
private function removeEnemy(e:Event)
{
enemyList.splice(enemyList.indexOf(e.currentTarget), 1);
stage.removeChild(enemyList.indexOf(e.currentTarget));
}
Hope this helps.
I'm new to ActionScript 3.0. I tried a tutorial at http://www.senocular.com/flash/tutorials/as3withmxmlc/ . The demo program animates a ball and allows it to be dragged.
There was a problem with the program as written. When you drag the mouse outside the stage and release the mouse button, the ball wouldn't get the MOUSE_UP event. The code, therefore would never call stopDrag(). I searched stackoverflow for suggestions, and one suggestion was to listen to MOUSE_UP with the stage as well as the ball and add some logic for dealing with it.
I added some code to do this. I also refactored the program as written because it was pretty disorganized. Here's what I have now:
package {
import flash.display.Sprite;
import flash.events.Event;
import flash.events.MouseEvent;
import flash.geom.Point;
import flash.geom.Rectangle;
public class BallToss extends Sprite {
private var ball:TossableBall;
// mouse position at last call to trackMouseMvt()
private var lastMousePos:Point = new Point();
// delta mouse movement from frame L-1 to frame L, where L is last frame
private var lastDeltaMouse:Point = new Point();
public function BallToss() {
var stageBounds:Rectangle = new Rectangle(0, 0, stage.stageWidth,
stage.stageHeight);
ball = new TossableBall(50, stageBounds);
ball.x = stageBounds.width/2;
ball.y = stageBounds.height/2;
addChild(ball);
ball.addEventListener(MouseEvent.MOUSE_DOWN, grabBall);
// however I order the next two calls to addEventListener(), it seems
// that the ball's MOUSE_UP gets handled before the stage's MOUSE_UP
stage.addEventListener(MouseEvent.MOUSE_UP, handleStageMouseUp);
ball.addEventListener(MouseEvent.MOUSE_UP, releaseBall);
// initialize 'lastMousePos' and set up 'trackMouseMvt' to be called on
// every frame
lastMousePos = new Point(mouseX, mouseY);
ball.addEventListener(Event.ENTER_FRAME, trackMouseMvt);
}
private function grabBall(evt:MouseEvent):void {
trace("in grabBall");
// set ball 'glideVector' to (0,0) so it will stop moving
ball.setGlideVector(new Point(0,0));
ball.startDrag();
}
private function releaseBall(evt:MouseEvent):void {
trace("in releaseBall");
ball.stopDrag();
// set up the ball to glide at the rate of 'lastDeltaMouse'
ball.setGlideVector(lastDeltaMouse);
}
private function trackMouseMvt(evt:Event):void {
var currMouse:Point = new Point(mouseX, mouseY);
lastDeltaMouse = currMouse.subtract(lastMousePos);
lastMousePos = currMouse;
}
private function handleStageMouseUp(evt:Event):void {
trace("in handleStageMouseUp");
ball.stopDrag();
var stageBounds:Rectangle = new Rectangle(0, 0, stage.stageWidth,
stage.stageHeight);
if (ball.x > stageBounds.right - 0.5)
ball.x = stageBounds.right - 0.5;
else if (ball.x < 0)
ball.x = 0;
if (ball.y > stageBounds.bottom - 0.5)
ball.y = stageBounds.bottom - 0.5;
else if (ball.y < 0)
ball.y = 0;
}
}
}
import flash.display.Sprite;
import flash.events.Event;
import flash.geom.Point;
import flash.geom.Rectangle;
class TossableBall extends Sprite {
private var stageBounds:Rectangle;
private var glideVector:Point = new Point();
private var friction:Number = .95;
public function TossableBall(size:Number, stageBoundsIn:Rectangle) {
stageBounds = stageBoundsIn;
graphics.lineStyle(1);
graphics.beginFill(0xFF8000);
graphics.drawCircle(0, 0, size/2);
addEventListener(Event.ENTER_FRAME, glide);
}
public function setGlideVector(glideVectorIn:Point):void {
glideVector = glideVectorIn;
}
private function glide(evt:Event):void {
x += glideVector.x;
y += glideVector.y;
var shapeBounds:Rectangle = getBounds(parent);
if (shapeBounds.left < stageBounds.left) {
glideVector.x = Math.abs(glideVector.x);
} else if (shapeBounds.right > stageBounds.right) {
glideVector.x = -Math.abs(glideVector.x);
}
if (shapeBounds.top < stageBounds.top) {
glideVector.y = Math.abs(glideVector.y);
} else if (shapeBounds.bottom > stageBounds.bottom) {
glideVector.y = -Math.abs(glideVector.y);
}
glideVector.x *= friction;
glideVector.y *= friction;
}
}
I don't like this code very much. The problem comes down to not being able to detect all the cases in one place. I would like to write something like this:
if (..ball and stage both got MOUSE_UP..) {
..handle it..;
else if (..only stage got MOUSE_UP..) {
..handle it..;
}
This logic would let me write more foolproof, simpler case handling and clearer logic. As things stand, there is a lot of complex behavior that emerges from this way of organizing the code.
The event listening model doesn't seem to make this possible. The response to events must happen individually, or must it? Is there a way to detect events that are "in the queue"?
Alternatively, I could avoid using startDrag(), i.e. avoid making the ball Sprite draggable, and have only the stage listen to MOUSE_UP, then handle all the drag logic myself. That would also let me better handle questions like where I want the ball to be positioned when the user drags outside the stage. I wonder if that is better overall.
To track object being dragged this works good for me:
ball.addEventListener(MouseEvent.MOUSE_DOWN, onBallMouseDown)
var _stage:Stage;
private function onBallMouseDown(e:MouseEvent):void
{
_stage = stage;
stage.addEventListener(MouseEvent.MOUSE_UP, onStageMouseUp)
stage.addEventListener(MouseEvent.MOUSE_MOVE, onStageMouseMove)
ball.startDrag();
}
private function onStageMouseMove(e:MouseEvent):void
{
// track ball coordinates
}
private function onStageMouseUp(e:MouseEvent):void
{
ball.stopDrag();
_stage.removeEventListener(MouseEvent.MOUSE_UP, onStageMouseUp)
_stage.removeEventListener(MouseEvent.MOUSE_MOVE, onStageMouseMove)
}
What about that, after years of Flash programming only now have I discovered the joys of MouseEvent.RELEASE_OUTSIDE. No more ugly hacks needed.
Ok, so I've been stuck on this for about three hours now and I finally feel like asking for help.
Basically, I am trying to remove all instances of an enemy object from the screen when my player ship makes contact with one of them, as he then loses a life and is put back into a safe position on the screen.
EDIT: This is all the code from my Enemy Dude .as file, a bit overboard maybe but nonetheless.
package
{
import flash.display.MovieClip;
import flash.events.*;
import flash.media.Sound;
import flash.media.SoundChannel;
public class Enemydude extends MovieClip
{
private var _root:Object;
private var speed:int = 6;
private var shipps = this
public function Enemydude()
{
addEventListener(Event.ADDED, beginclass);
addEventListener(Event.ENTER_FRAME, entFrame);
}
private function beginclass(event:Event):void
{
_root = MovieClip(root);
}
private function entFrame(event:Event):void
{
x -= speed;
if(this.x < -64)
{
removeEventListener(Event.ENTER_FRAME, entFrame);
_root.removeChild(this)
}
if(_root.gameover)
{
x = -700
removeEventListener(Event.ENTER_FRAME, entFrame);
removeEventListener(Event.ADDED, beginclass);
}
for (var i:int = 0; i<_root.playerBulletContainer.numChildren; i++)
{
var bulletTarget:MovieClip = _root.playerBulletContainer.getChildAt(i)
if (hitTestObject(bulletTarget))
{
removeEventListener(Event.ENTER_FRAME, entFrame);
_root.removeChild(this);
_root.playerBulletContainer.removeChild(bulletTarget);
bulletTarget.removeListeners();
_root.Score += 10
makeExplosion();
}
}
if(hitTestObject(_root.mcship))
{
makeExplosion();
shipPos();
removethis();
}
}
private function makeExplosion()
{
var sndExplode:snd_explosion1;
var sndExplodeChannel:SoundChannel;
sndExplode=new snd_explosion1();
sndExplodeChannel=sndExplode.play();
var newExplosion01:explosionEffect=new explosionEffect ;
newExplosion01.x=this.x;
newExplosion01.y=this.y;
_root.explosionContainer.addChild(newExplosion01);
}
private function shipPos()
{
_root.lives -= 1;
_root.mcship.x = 80;
_root.mcship.y = 225;
for each(var i:Enemydude in _root.enemies)
{
removethis();
}
_root.enemies.length = 0;
}
public function removethis():void
{
if(parent) parent.removeChild(this)
removeEventListener(Event.ENTER_FRAME, entFrame);
}
}
}
EDIT: And this is the code I now have that relates to the Enemydude in my main timeline, quite sorry about all this.
var enemies:Array = [];
var Shipheight:Number = 300;
var Enemytime:int = 0;
var Enemylimit:int = 16;
if (Enemytime<Enemylimit)
{
Enemytime ++;
}
else
{
var newEnemy01 = new Enemydude();
newEnemy01.y = Shipheight;
newEnemy01.x = stage.stageWidth + 64;
addChild(newEnemy01);
enemies.push(newEnemy01);
Enemytime = 0
function shipY(event:Event):void
{
Shipheight = Math.ceil(Math.random()* 250) + 80;
}
Thank you for your help in advance, any advice is appreciated.
I suggest storing your enemies in an Array.
For example, create the array enemies:
var enemies:Array = [];
And then amend your code to:
else
{
var newEnemy01 = new Enemydude();
newEnemy01.y = Shipheight;
newEnemy01.x = stage.stageWidth + 64;
addChild(newEnemy01);
enemies.push(newEnemy01);
Enemytime = 0;
}
That way you can remove all of the enemies using this new array:
for each(var i:Enemydude in enemies)
{
i.remove(); // Or whatever function Enemydude has to remove itself.
}
// Empty the enemies Array.
enemies.length = 0;
Here's the .remove() method you could make for Enemydude:
public function remove():void
{
if(parent) parent.removeChild(this);
// Remove any event listeners etc from this object.
}
A common and easy way of doing this is to create a subcontainer to hold the objects and destroy this object instead. It makes easy for some collision checks too, since you can use the holder object to make one check against the player.
If you don't want to create this, you can use an array or a vector to store references to this objects, what makes easy to traverse the list.
I persoally recommend the vector aprouch:
var enemyList:Vector.<Enemy> = new Vector.<Enemy>();
Then you can loop almost like an array (as Marty Wallace showed on his answer):
for each(var e:Enemy in enemyList) {
container.removeChild(e);
}
enemyList.length = 0; // empty vector
Vectors are a bit slower than normal arrays, but are type safe. The difference in performance is almost negligible in most cases.
I'm using Flash Professional CS5.5 and I need to make an app where there is a ball (symbol) that moves using the accelerometer and I want that, when the ball coordinates A reach this coordinates B it goes to frame 2 (gotoAndPlay(2)). I have to find the ball coord first, right? How do I make this?
Here is the code I've now
c_ball.addEventListener(MouseEvent.MOUSE_DOWN, fl_ClickToDrag);
function fl_ClickToDrag(event:MouseEvent):void{
c_ball.startDrag();}
stage.addEventListener(MouseEvent.MOUSE_UP, fl_ReleaseToDrop);
function fl_ReleaseToDrop(event:MouseEvent):void{
c_ball.stopDrag();}
would it work if, after retriving the coordinates?
function f_level (e) if (c_ball.x==100 && c_ball.y==100) {
gotoAndStop(2);}
MOUSE_UP and MOUSE_DOWN are not what you need if you're looking for Accelerometer data. You want the Accelerometer class and associated events.
Try something like this:
import flash.sensors.Accelerometer;
import flash.events.AccelerometerEvent;
var accel:Accelerometer = new Accelerometer();
accel.addEventListener(AccelerometerEvent.UPDATE, handleAccelUpdate);
Update handler:
function handleAccelUpdate(e:AccelerometerEvent):void{
//inside this function you now have access to acceleration x/y/z data
trace("x: " + e.accelerationX);
trace("y: " + e.accelerationY);
trace("z: " + e.accelerationZ);
//using this you can move your MC in the correct direction
c_ball.x -= (e.accelerationX * 10); //using 10 as a speed multiplier, play around with this number for different rates of speed
c_ball.y += (e.accelerationY * 10); //same idea here but note the += instead of -=
//you can now check the x/y of your c_ball mc
if(c_ball.x == 100 && c_ball.y == 100){
trace("you win!"); //fires when c_ball is at 100, 100
}
}
Now this will let you "roll" your MC off the screen so you're probably going to want to add some kind of bounds checking.
Check out this great writeup for more info:
http://www.republicofcode.com/tutorials/flash/as3accelerometer/
An easy and save way is to use colission detection, instead of testing for exectly one position ( what is hard to meet for users) you go for a target area :
package
{
import flash.display.Sprite;
import flash.events.Event;
import flash.events.MouseEvent;
public class Hittester extends Sprite
{
var ball:Sprite = new Sprite();
var testarea:Sprite = new Sprite();
public function Hittester()
{
super();
ball.graphics.beginFill(0xff0000);
ball.graphics.drawCircle(0,0,10);
testarea.graphics.beginFill(0x00ff00);
testarea.graphics.drawRect(0,0,50,50);
testarea.x = 100;
testarea.y = 100;
// if testarea should be invisble
/*testarea.alpha = 0;
testarea.mouseEnabled = false;
*/
ball.addEventListener(MouseEvent.MOUSE_DOWN, startDragging);
addChild(testarea);
addChild(ball);
}
private function startDragging( E:Event = null):void{
ball.startDrag();
stage.addEventListener(MouseEvent.MOUSE_UP, stopDragging);
}
private function stopDragging( E:Event = null):void{
stage.removeEventListener(MouseEvent.MOUSE_UP, stopDragging);
ball.stopDrag();
test();
}
private function test():void{
if( ! ball.hitTestObject(testarea) ){
ball.x = 10;
ball.y = 10;
}
else{
// here goes next frame command ;)
}
}
}
}