First question. Please be gentle.
I’m making a simple (I'd hoped) keyboard controlled movieclip of a game character. The Movieclip has five frames, each with a simple animation inside for when the player presses the arrow keys, walking up, down, stable etc.
I made a simple prototype in the main application class file and it works PERFECTLY. I also traced currentFrame and totalFrames and that is correct too. When key is pressed it plays correct frame and it says the totalFrames are 5. Great!
However I want to make a multi level game, so have used the application class as a level switcher and each level and object is its own class. During this migration the MovieClip stops working. It is added to the stage fine and can be moved with the arrow keys but the individual animations wont play. It just flickers through each of the five keyframes.
Also when I trace it, it says currentFrame is 0 (?) and totalFrames is 1 (?)
It wont be controlled by .stop or .gotoAndPlay either.
Please help!
Here is the single class version that works fine.
package
{
import flash.display.Sprite;
import flash.display.DisplayObject;
import flash.display.MovieClip;
import flash.events.Event;
import flash.events.KeyboardEvent;
import flash.ui.Keyboard;
[SWF(width="650", height="450",backgroundColor="#FFFFFF", frameRate="60")]
public class CharacterMovieclip extends MovieClip
{
//Create and initialize the vx and vy variables
public var vx:int = 0;
public var vy:int = 0;
[Embed(source="../swfs/characterRes.swf", symbol="Character")]
public var Character:Class;
public var character:MovieClip = new Character();
public function CharacterMovieclip()
{
//Add Character
stage.addChild(character);
character.x = 200;
character.y = 100;
character.gotoAndStop(1);
//Add the event listeners
stage.addEventListener(KeyboardEvent.KEY_DOWN, keyDownHandler);
stage.addEventListener(KeyboardEvent.KEY_UP, keyUpHandler);
stage.addEventListener(Event.ENTER_FRAME, enterFrameHandler);
}
public function keyDownHandler(event:KeyboardEvent):void
{
if (event.keyCode == Keyboard.LEFT)
{
vx = -5;
character.gotoAndStop(4);
}
else if (event.keyCode == Keyboard.RIGHT)
{
vx = 5;
character.gotoAndStop(5);
}
else if (event.keyCode == Keyboard.UP)
{
vy = -5;
character.gotoAndStop(2);
}
else if (event.keyCode == Keyboard.DOWN)
{
vy = 5;
character.gotoAndStop(3);
}
}
public function keyUpHandler(event:KeyboardEvent):void
{
if (event.keyCode == Keyboard.LEFT
|| event.keyCode == Keyboard.RIGHT)
{
vx = 0;
character.gotoAndStop(1);
}
else if (event.keyCode == Keyboard.DOWN
|| event.keyCode == Keyboard.UP)
{
vy = 0;
character.gotoAndStop(1);
}
}
public function enterFrameHandler(event:Event):void
{
//Move the player
character.x += vx
character.y += vy;
trace(character.currentFrame);
trace(character.totalFrames);
trace(character.x);
}
}
}
But that all goes to hell once I try it across a few classes. Here is the character class.
package
{
import flash.display.DisplayObject;
import flash.display.MovieClip;
public class Character extends MovieClip
{
[Embed(source="../swfs/characterRes.swf", symbol="Character")]
private var CharacterImage:Class;
//Private properties
private var _characterImage:DisplayObject = new CharacterImage();
private var _character:MovieClip = new MovieClip();
//Public properties
public var vx:int = 0;
public var vy:int = 0;
public function Character()
{
_character.addChild(_characterImage);
this.addChild(_character);
}
}
}
The character object is then added to the LevelOne class
package
{
import flash.display.Sprite;
import flash.display.DisplayObject;
import flash.display.MovieClip;
import flash.events.Event;
import flash.events.KeyboardEvent;
import flash.ui.Keyboard;
public class LevelOne extends Sprite
{
//Declare the variables to hold
//the game objects
private var _character:Character;
private var _background:Background;
//A variable to store the reference
//to the stage from the application class
private var _stage:Object;
public function LevelOne(stage:Object)
{
_stage = stage;
this.addEventListener(Event.ADDED_TO_STAGE, addedToStageHandler);
}
private function addedToStageHandler(event:Event):void
{
startGame();
this.removeEventListener(Event.ADDED_TO_STAGE, addedToStageHandler);
}
private function startGame():void
{
//Create Game Objects
_character = new Character();
_background = new Background();
//Add them to stage
this.addChild(_background);
_background.x = 0;
_background.y = 0;
this.addChild(_character);
_character.x = 300;
_character.y = 50;
_character.gotoAndStop(1);
//Event listeners
_stage.addEventListener(KeyboardEvent.KEY_DOWN, keyDownHandler);
_stage.addEventListener(KeyboardEvent.KEY_UP, keyUpHandler);
this.addEventListener(Event.ENTER_FRAME, enterFrameHandler);
}
private function enterFrameHandler(event:Event):void
{
//Move the game character and check its stage boundaries
_character.x += _character.vx;
_character.y += _character.vy;
checkStageBoundaries(_character);
trace(_character.currentFrame);
trace(_character.totalFrames);
trace(_character.x);
}
private function checkStageBoundaries(gameObject:MovieClip):void
{
if (gameObject.x < 50)
{
gameObject.x = 50;
}
if (gameObject.y < 50)
{
gameObject.y = 50;
}
if (gameObject.x + gameObject.width > _stage.stageWidth - 50)
{
gameObject.x = _stage.stageWidth - gameObject.width - 50;
}
if (gameObject.y + gameObject.height > _stage.stageHeight - 50)
{
gameObject.y = _stage.stageHeight - gameObject.height - 50;
}
}
private function keyDownHandler(event:KeyboardEvent):void
{
if (event.keyCode == Keyboard.LEFT)
{
_character.vx = -5;
_character.gotoAndStop(4);
}
else if (event.keyCode == Keyboard.RIGHT)
{
_character.vx = 5;
_character.gotoAndStop(5);
}
else if (event.keyCode == Keyboard.UP)
{
_character.vy = -5;
_character.gotoAndStop(2);
}
else if (event.keyCode == Keyboard.DOWN)
{
_character.vy = 5;
_character.gotoAndStop(3);
}
}
private function keyUpHandler(event:KeyboardEvent):void
{
if (event.keyCode == Keyboard.LEFT
|| event.keyCode == Keyboard.RIGHT)
{
_character.vx = 0;
_character.gotoAndStop(1);
}
else if (event.keyCode == Keyboard.DOWN
|| event.keyCode == Keyboard.UP)
{
_character.vy = 0;
_character.gotoAndStop(1);
}
}
}
}
And levelOne is added to the stage by the Main application class.
package
{
import flash.display.Sprite;
import flash.events.Event;
import flash.display.MovieClip;
[SWF(width="650", height="450",
backgroundColor="#FFFFFF", frameRate="60")]
public class Main extends Sprite
{
private var _levelOne:LevelOne;
public function Main()
{
_levelOne = new LevelOne(stage);
stage.addChild(_levelOne);
}
}
}
Somewhere in all this my MovieClip stops playing the individual animations. Its on the stage, can be moved around with arrow keys, but wont play the keyframe animations. (And trace seems to think its playing frame 0, and it only has 1 frame too.)
Any help would be hugely appreciated. My head hurts.
The problem is in your new Character class.
Let's see on the first class that works perfectly, you embed symbol="Character" from the characterRes.swf file and it's your 5 frame movie clip.
Now see on the second class, that is broken: you do the same embedding and now your 5 frame movie clip is _characterImage rather than Character class, that you create. It's right decision from the OOP point of view to hide implementation (the direct MovieClip from the library or custom class) inside the same API (in both cases Character is outside a simple MovicClip) and there can be two solutions for the problem:
First - try to embed symbol for the hole class and remove your current code it's not needed here:
[Embed(source="../swfs/characterRes.swf", symbol="Character")]
public class Character extends MovieClip
{
//Public properties
public var vx:int = 0;
public var vy:int = 0;
public function Character()
{
}
}
Second: make you Character class wrapper for the Character from swf - pass all MovieClip API from it to the _character MovieClip:
package
{
import flash.display.DisplayObject;
import flash.display.MovieClip;
public class Character extends MovieClip
{
[Embed(source="../swfs/characterRes.swf", symbol="Character")]
private var _characterClass:Class;
//Private properties
private var _character:MovieClip = new _characterClass();
//Public properties
public var vx:int = 0;
public var vy:int = 0;
public function Character()
{
addChild(_character)
}
override public function gotoAndPlay(frame:Object, scene:String=null):void
{
_character.gotoAndPlay(frame, scene);
}
override public function gotoAndStop(frame:Object, scene:String=null):void
{
_character.gotoAndStop(frame, scene);
}
override public function play():void
{
_character.play();
}
override public function stop():void
{
_character.stop();
}
//and other methods and getters for currentFrame, totalFrames
}
}
The first method is more simple, the second one is more flexible, because it's separate graphics and logic - so you in future you will be able for instance pass this link in Character Constructor and load assets dynamically or use Character class as animation controller for the different MovieClips from the loaded swfs.
Related
I'm very new to AS3 and programming in general and I've been developing a space shooter game in AS3 and have run into trouble regarding the enemy shots. The enemies fly vertically down from the top of the screen and should fire two shots (one going left and one going right) once their y coordinates equal that of the player. This works fine, except after anything from 30 seconds to 2 minutes, the following errors occur.
TypeError: Error #1009: Cannot access a property or method of a null object reference.
at EnemyShip2/fireWeapon()[G:\Games Related\1942\src\EnemyShip2.as:78]
at EnemyShip2/loop2()[G:\Games Related\1942\src\EnemyShip2.as:65]
TypeError: Error #1009: Cannot access a property or method of a null object reference.
at EnemyShot/removeSelf()[G:\Games Related\1942\src\EnemyShot.as:43]
at EnemyShot/loop()[G:\Games Related\1942\src\EnemyShot.as:36]
Below is the relevant code, for the enemy ship class as well as the enemy shot class.
Enemy Ship
package
{
import flash.display.Sprite;
import flash.display.Bitmap;
import flash.display.Stage;
import flash.events.Event;
import flash.events.TimerEvent;
import flash.utils.Timer;
/**
* ...
* #author D Nelson
*/
[Embed(source = "../assets/enemyship2.png")]
//This enemy moves relatively slowly and fires horizontal shots
public class EnemyShip2 extends Bitmap
{
private var vy:Number = 3;
//private var ay:Number = .2;
private var target:HeroShip;
private var enemyShip2:EnemyShip2;
private var enemyfireTimer:Timer;
private var enemycanFire:Boolean = true;
public function EnemyShip2(target:HeroShip):void
{
this.target = target;
scaleX = 0.3;
scaleY = 0.3;
x = Math.floor(Math.random() * 550);
y = -105;
addEventListener(Event.ENTER_FRAME, loop2, false, 0, true);
enemyfireTimer = new Timer(1000, 1);
enemyfireTimer.addEventListener(TimerEvent.TIMER, handleenemyfireTimer, false, 0, true);
}
private function handleenemyfireTimer(e:TimerEvent) : void
{
//the timer runs, so a shot can be fired again
enemycanFire = true;
}
private function removeSelf2():void
{
removeEventListener(Event.ENTER_FRAME, loop2);
if (stage.contains(this))
{
stage.removeChild(this);
}
}
private function loop2 (e:Event):void
{
//vy += ay;
y += vy;
if (y > stage.stageHeight)
{
removeSelf2();
}
if (y >= target.y && (enemycanFire))
{
fireWeapon();
enemycanFire = false;
enemyfireTimer.start();
}
if (this.x > 540 || this.x < 10)
{
removeSelf2();
}
}
private function fireWeapon():void
{
stage.addChild(new EnemyShot(target, x, y, -4));
stage.addChild(new EnemyShot(target, x, y, +4));
}
}
}
Enemy Shot
package
{
import flash.display.Sprite;
import flash.display.Bitmap;
import flash.events.Event;
import flash.display.Stage;
/**
* ...
* #author D Nelson
*/
[Embed(source="../assets/enemyshot.png")]
public class EnemyShot extends Bitmap
{
private var speed:Number;
private var target:HeroShip;
private var vx:Number;
public function EnemyShot(target:HeroShip, x:Number, y:Number, vx:Number)
{
this.target = target;
this.x = x;
this.y = y;
this.vx = vx;
scaleX = 0.3;
scaleY = 0.3;
addEventListener(Event.ENTER_FRAME, loop, false, 0, true);
}
private function loop(e:Event) : void
{
x += vx;
if (x >= 600 || x <= -50)
{
removeSelf();
}
}
private function removeSelf():void
{
removeEventListener(Event.ENTER_FRAME, loop);
if (stage.contains(this))
{
stage.removeChild(this);
}
}
}
}
Also provided is the main class, in case that is of any help.
package
{
import flash.display.Sprite;
import flash.display.MovieClip;
import flash.display.DisplayObject;
import flash.display.Stage;
import flash.events.*;
import flash.events.Event;
import flash.events.EventDispatcher;
import flash.events.KeyboardEvent;
import flash.events.TimerEvent;
import flash.ui.Mouse;
import flash.utils.*;
import flash.utils.ByteArray;
import flash.utils.Timer;
import flash.text.*;
import flash.media.Sound;
import flash.media.SoundChannel;
/**
* ...
* #author D Nelson
*/
public class Main extends MovieClip
{
[Embed(source = "snd/gamemusic2.mp3")]
private var MySound : Class;
private var mainsound : Sound;
private var shootsound: Sound = new ShootSound;
private var sndChannel:SoundChannel = new SoundChannel;
public var heroShip:HeroShip;
public var enemyShip1:EnemyShip1
public var enemyShip2:EnemyShip2
public var enemyShip3:EnemyShip3
public var enemyShip4:EnemyShip4
public var bossShip: BossShip
public var enemyShot: EnemyShot;
public var playerShot: PlayerShot;
private var background1:Background1;
private var background2:Background2;
public static const scrollspeed:Number = 2;
public var playerShotArray:Array = new Array()
public var enemyShotArray:Array = new Array()
public var enemies1Array:Array = new Array()
public var enemies2Array:Array = new Array()
private var fireTimer:Timer; //this creates a delay between each shot
private var canFire:Boolean = true; //this checks if a shot can be fired
public function Main():void
{
if (stage) init();
else addEventListener(Event.ADDED_TO_STAGE, init);
mainsound = (new MySound) as Sound;
shootsound = (new ShootSound) as Sound;
mainsound.play();
background1 = new Background1();
background2 = new Background2();
//setting the backgrounds one below another
background1.y = 0;
background2.y = background1.height;
//add background at the lowest depth level
stage.addChildAt(background1,0);
stage.addChildAt(background2, 0);
//sets up the timer and its listener
fireTimer = new Timer(250, 1);
fireTimer.addEventListener(TimerEvent.TIMER, handlefireTimer, false, 0, true);
stage.addEventListener(KeyboardEvent.KEY_DOWN, handleCharacterShoot);
//background scrolling effect
stage.addEventListener(Event.ENTER_FRAME, backgroundScroll);
//loop for enemy1 variety
stage.addEventListener(Event.ENTER_FRAME, loop1, false, 0, true);
//loop for enemy2 variety
stage.addEventListener(Event.ENTER_FRAME, loop2, false, 0, true);
//speed of player shots
setInterval(playerShootMovement, 10);
}
private function init(e:Event = null):void
{
removeEventListener(Event.ADDED_TO_STAGE, init);
//entry point
heroShip = new HeroShip();
stage.addChild(heroShip);
//test values for enemies
/*enemyShip1 = new EnemyShip1();
stage.addChildAt(enemyShip1, 2);
enemyShip1.y = stage.stageWidth * 0.3;
enemyShip1.x = 300;
enemyShip2 = new EnemyShip2();
stage.addChildAt(enemyShip2, 2);
enemyShip2.y = stage.stageWidth * 0.3;
enemyShip2.x = 200;
enemyShip3 = new EnemyShip3();
stage.addChildAt(enemyShip3, 2);
enemyShip3.y = stage.stageWidth * 0.3;
enemyShip3.x = 100;
enemyShip4 = new EnemyShip4();
stage.addChildAt(enemyShip4, 2);
enemyShip4.y = stage.stageWidth * 0.3;
enemyShip4.x = 400;
bossShip = new BossShip();
stage.addChildAt(bossShip, 1);
bossShip.y = 10;
bossShip.x = 130;*/
Mouse.hide();
}
private function handlefireTimer(e:TimerEvent) : void
{
//the timer runs, so a shot can be fired again
canFire = true;
}
public function playerShoot():void
{
//if canFire is true, allow a shot to be fired, then set canFire to false and start the timer again
//else, do nothing
if (canFire)
{
//Add new line to the array
playerShotArray.push(playerShot = new PlayerShot);
//Spawn missile in ship
playerShot.y = heroShip.y;
playerShot.x = heroShip.x+11;
addChild(playerShot);
canFire = false;
fireTimer.start();
sndChannel = shootsound.play();
}
}
public function playerShootMovement():void
{
//code adapted from the Pie Throw tutorial
for (var i:int = 0; i < playerShotArray.length; i++)
{
playerShotArray[i].y -= 10;
if (playerShotArray[i].y == 850)
{
playerShotArray.shift();
}
}
}
public function handleCharacterShoot(e:KeyboardEvent):void
{
/**
* SpaceBar = 32
*/
if (e.keyCode == 32)
{
playerShoot();
}
}
public function backgroundScroll (evt:Event):void
{
background1.y += scrollspeed;
background2.y += scrollspeed;
if (background1.y >= stage.stageHeight)
{
//the background is below the visible stage area, put it above the other background
background1.y = background2.y - background2.height;
}
else if (background2.y >= stage.stageHeight)
{
background2.y = background1.y - background2.height;
}
}
//EnemyShip 1 spawning
private function loop1(e:Event):void
{
//generates probability for the ship to spawn (lower number to increase odds, decrease it to decrease odds)
if (Math.floor(Math.random() * 55) == 5)
{
var enemyShip1:EnemyShip1 = new EnemyShip1(heroShip);
enemyShip1.addEventListener(Event.REMOVED_FROM_STAGE, removeEnemy1, false, 0, true);
enemies1Array.push(enemyShip1);
stage.addChild(enemyShip1);
}
}
private function removeEnemy1(e:Event):void
{
//removes the enemy that most recently left the screen from the array
enemies1Array.splice(enemies1Array.indexOf(e.currentTarget), 1);
}
//EnemyShip2 spawning
private function loop2(e:Event):void
{
if (Math.floor(Math.random() * 40) == 5)
{
var enemyShip2:EnemyShip2 = new EnemyShip2(heroShip);
enemyShip2.addEventListener(Event.REMOVED_FROM_STAGE, removeEnemy2, false, 0, true);
enemies2Array.push(enemyShip2);
stage.addChild(enemyShip2);
}
}
private function removeEnemy2(e:Event):void
{
enemies2Array.splice(enemies2Array.indexOf(e.currentTarget), 1);
}
}
}
Initially I thought it was to do with enemies firing shots while being too far to either side of the screen, but that doesn't seem to be the case. Any help would be greatly appreciated.
You need to make sure you remove the ENTER_FRAME listeners whenever you remove the object.
Actually, my advise is to not add ENTER_FRAME handlers throughout your game objects. This gets hard to manage and leads to bugs like you've encountered. Instead, add a single ENTER_FRAME as your core game loop, and update objects by calling an update() function on a list of game objects you maintain in your main game class. When you remove an object you simply won't call update() anymore. It also becomes easy to pause the game by just removing the ENTER_FRAME handler.
For example, here's a pattern I like to use for simple games:
interface IGameObject {
update():void;
}
class Enemy extends Sprite implements IGameObject {
public update():void {
// move, fire, etc
}
}
class Player extends Sprite implements IGameObject {
public update():void {
// move, fire, etc
}
}
class Bullet extends Bitmap implements IGameObject {
public update():void {
// move, collide, etc
}
}
class Main extends Sprite {
private objects:Vector.<IGameObject> = new <IGameObject>[];
public start():void {
addEventListener(Event.ENTER_FRAME, update);
}
public stopGame():void {
removeEventListener(Event.ENTER_FRAME, update);
}
private function update(e:Event):void {
for each (var object:IGameObject in objects) {
object.update();
}
}
public addObject(object:IGameObject):void {
objects.push(object);
addChild(object as DisplayObject);
}
public removeObject(object:IGameObject):void {
objects.splice(objects.indexOf(object), 1);
removeChild(object as DisplayObject);
}
}
Add and remove objects using addObject and removeObject. You can invoke them through a reference to Main or through event handlers you dispatch from your objects.
I'm trying to create a button that when you click on it, the ship fires a laser, but the button isn't working. I mean I didn't get any error when debugging, however it won't allow me to click on the button, but instead it allows me to click on my ship to fire. Any help is greatly appreciated, thanks!
My Fire.as
package control {
import flash.events.Event;
import flash.display.Stage;
import flash.display.MovieClip;
import flash.events.MouseEvent;
import flash.geom.Rectangle;
import flash.events.Event;
import objects.Ship;
public class Fire extends MovieClip {
private var my_x: Number;
private var my_y: Number;
private var ourShip: Ship;
var mouseDown: Boolean;
public function Fire(margin_left: Number, margin_bottom: Number, ourShip_mc: Ship) {
my_x = margin_left;
my_y = margin_bottom;
ourShip = ourShip_mc;
if (stage) {
init();
} else {
addEventListener(Event.ADDED_TO_STAGE, init);
}
}
private function init(e: Event = null): void {
if (hasEventListener(Event.ADDED_TO_STAGE)) {
removeEventListener(Event.ADDED_TO_STAGE, init);
}
this.x = my_x + this.width / 2;
this.y = stage.stageHeight - my_y - this.height / 2;
this.addEventListener(MouseEvent.CLICK, onClick);
}
private function onClick(event: MouseEvent): void {
//EVENT DISPATCHER
dispatchEvent(new Event("eventshoot", true));
trace("Fire clicked");
}
}
}
My Ship.as
package objects {
import flash.display.MovieClip;
import flash.display.Stage;
import flash.ui.Keyboard;
import flash.ui.Mouse;
import flash.utils.Timer;
import flash.display.JointStyle;
import control.Controller;
import control.Joystick;
import control.Fire;
public class Ship extends MovieClip {
var mouseDown: Boolean;
private var stageRef: Stage;
private var key: Controller;
private var speed: Number = 2.5;
private var vx: Number = 0;
private var vy: Number = 0;
private var friction: Number = 0.93;
private var maxspeed: Number = 8;
//fire related variables
private var fireTimer: Timer; //causes delay between fires
private var canFire: Boolean = true; //can you fire a laser
public var move_left: Boolean = false;
public var move_up: Boolean = false;
public var move_right: Boolean = false;
public var move_down: Boolean = false;
public function Ship(stageRef: Stage): void {
this.stageRef = stageRef;
key = new Controller(stageRef);
this.addEventListener(Event.ENTER_FRAME, ShipMove);
stage.addEventListener("eventshoot", firenow);
//setup your fireTimer and attach a listener to it.
fireTimer = new Timer(250, 1);
fireTimer.addEventListener(TimerEvent.TIMER, fireTimerHandler, false, 0, true);
addEventListener(Event.ENTER_FRAME, loop, false, 0, true);
}
private function ShipMove(event: Event): void {
if (move_left)
vx -= speed;
else if (move_right)
vx += speed;
else
vx *= friction;
if (move_up)
vy -= speed;
else if (move_down)
vy += speed;
else
vy *= friction;
}
public function firenow(event: Event) {
fireLaser();
}
public function loop(e: Event): void {
//update position
x += vx;
y += vy;
//speed adjustment
if (vx > maxspeed)
vx = maxspeed;
else if (vx < -maxspeed)
vx = -maxspeed;
if (vy > maxspeed)
vy = maxspeed;
else if (vy < -maxspeed)
vy = -maxspeed;
//ship appearance
rotation = vx;
scaleX = (maxspeed - Math.abs(vx)) / (maxspeed * 4) + 0.75;
//stay inside screen
if (x > stageRef.stageWidth - 30) {
x = stageRef.stageWidth - 30;
vx = -vx;
} else if (x < 30) {
x = 30;
vx = -vx;
}
if (y > stageRef.stageHeight) {
y = stageRef.stageHeight;
vy = -vy;
} else if (y < 0) {
y = 0;
vy = -vy;
}
}
private function fireLaser(): void {
//if canFire is true, fire a laser
//set canFire to false and start our timer
//else do nothing.
if (canFire) {
stageRef.addChild(new LaserGreen(stageRef, x + vx, y - 10));
canFire = false;
fireTimer.start();
}
}
//HANDLERS
private function fireTimerHandler(e: TimerEvent): void {
//Timer ran, fire again.
canFire = true;
}
public function takeHit(): void {
dispatchEvent(new Event("hit"));
}
}
}
Updated, here's the Engine.as, sorry for not replying it to your comment below, the structure is messed up if I do so.
package objects {
import flash.display.MovieClip;
import flash.display.Sprite;
import flash.events.Event;
import flash.display.StageScaleMode;
import flash.display.StageAlign;
import control.Joystick;
import control.Fire;
public class Engine extends MovieClip {
private var preloader: ThePreloader;
public function Engine() {
preloader = new ThePreloader(474, this.loaderInfo);
stage.addChild(preloader);
preloader.addEventListener("loadComplete", loadAssets);
preloader.addEventListener("preloaderFinished", showSponsors);
stage.addEventListener("gameSTART", fGameStart);
}
private function loadAssets(e: Event): void {
this.play();
}
private function showSponsors(e: Event): void {
stage.removeChild(preloader);
var ps: PrerollSponsors = new PrerollSponsors(stage);
ps.addEventListener("prerollComplete", showMenu);
ps.preroll();
}
private function showMenu(e: Event): void {
new MainMenu(stage).load();
}
public static var enemyList: Array = new Array();
private var ourShip: Ship;
private var joystick: Joystick;
private var fire: Fire;
private var scoreHUD: ScoreHUD;
public function fGameStart(evt: Event): void {
ourShip = new Ship(stage);
ourShip.x = stage.stageWidth / 2;
ourShip.y = stage.stageHeight / 2;
ourShip.addEventListener("hit", shipHit, false, 0, true);
stage.addChild(ourShip);
joystick = new Joystick(120, 70, ourShip);
addChild(joystick);
fire = new Fire(420, 70, ourShip);
addChild(fire);
scoreHUD = new ScoreHUD(stage);
stage.addChild(scoreHUD);
addEventListener(Event.ENTER_FRAME, loop, false, 0, true);
}
private function loop(e: Event): void {
if (Math.floor(Math.random() * 20) == 5) {
var enemy: E1 = new E1(stage, ourShip);
enemy.addEventListener(Event.REMOVED_FROM_STAGE, removeEnemy, false, 0, true);
enemy.addEventListener("killed", enemyKilled, false, 0, true);
enemyList.push(enemy);
stage.addChild(enemy);
} else if (Math.floor(Math.random() * 80) == 5) {
var enemy2: E2 = new E2(stage, ourShip);
enemy2.addEventListener(Event.REMOVED_FROM_STAGE, removeEnemy, false, 0, true);
enemy2.addEventListener("killed", enemyKilled, false, 0, true);
enemyList.push(enemy2);
stage.addChild(enemy2);
}
}
private function enemyKilled(e: Event) {
scoreHUD.updateKills(1);
scoreHUD.updateScore(e.currentTarget.points);
}
private function removeEnemy(e: Event) {
enemyList.splice(enemyList.indexOf(e.currentTarget), 1);
}
private function shipHit(e: Event) {
scoreHUD.updateHits(1);
}
}
}
So every time the fire button (Fire.as) is clicked, it dispatched an event "eventshoot", and the ship (Ship.as) pick it up. And when the ship receive it, the ship itself fires a laser, that's the idea. But since there are prerolls, menus...stuff like that will loaded before starting the game, I can't just simply drag the fire button to the stage. The engine will load the ship, fire button, enemy, score... to the stage when game started. And I got a error 1009 when debugging "TypeError: Error #1009: Cannot access a property or method of a null object reference.", it is from:
stage.addEventListener("eventshoot", fire now);
in Ship.as
I understand that I'm getting this error because there is no fire button on stage, so my ship can't pickup the "eventshoot" event, is there a way I can make the ship only pickup that event after making sure the button is loaded to the stage to avoid the error?
While you certainly can create a class for your button, the functionality to make the ship object fire a laser should not be in the button.
Given a Ship class that looks like this:
package
{
import flash.display.MovieClip;
public class Ship extends MovieClip
{
public function fireLaser():void
{
trace("pew pew");
}
}
}
You can instantiate this class and add it to your main timeline with this code:
var ship:Ship = new Ship();
addChild(ship);
If you placed the symbol by hand you do not need to do this and instead only need to give it an instance name of ship.
To make something clickable, add an event listener to it. For example, to make the ship itself clickable:
var ship:Ship = new Ship();
addChild(ship);
ship.addEventListener(MouseEvent.MOUSE_DOWN, onMouseDown);
function onMouseDown(event:MouseEvent):void
{
trace("ship clicked");
}
If you have a button on the main time line with an instance name of fire, you can as easily add the listener to that button:
var ship:Ship = new Ship();
addChild(ship);
// v---this changed
fire.addEventListener(MouseEvent.MOUSE_DOWN, onMouseDown);
function onMouseDown(event:MouseEvent):void
{
trace("fire button clicked");
}
Last but not least, if you want to call a method on an object instead of using trace(), you can do that, too:
var ship:Ship = new Ship();
addChild(ship);
fire.addEventListener(MouseEvent.MOUSE_DOWN, onMouseDown);
function onMouseDown(event:MouseEvent):void
{
ship.fireLaser(); // this changed, laser fired "pew pew"
}
tl, dr;
The button itself shouldn't do anything. If the button did anything with the ship directly, it would have to know the ship. The button shouldn't know the ship. All the button does is say "I got clicked" by dispatching an event, everything else should be handled outside.
You know, just like when you wrote your question here, it's not the entire internet (including me) sitting in the keyboard buttons of your computer listening to your input. All your keyboard buttons did was saying "I got clicked". Everything else got handled outside, by your operating system, browser, etc.
i'm trying to make a top down shooter game, and have been following tutorials here: http://gamedev.michaeljameswilliams.com/2008/09/17/avoider-game-tutorial-1/
and here: as3gametuts.com/2013/07/10/top-down-rpg-shooter-4-shooting/
i've managed to get shooting and movement, but i need to get a hit test object to register when the bullet (defined in its own seperate as class file) and the enemy (also defined in seperate file) come into contact. code below:
Enemy code:
package
{
import flash.display.MovieClip;
public class Enemy extends MovieClip
{
public function Enemy()
{
x = 100;
y = -15;
}
public function moveDownABit():void
{
y = y + 3;
}
}
}
Bullet code:
package
{
import flash.display.Stage;
import flash.display.MovieClip;
import flash.events.Event;
import flash.utils.Timer;
import flash.events.TimerEvent;
public class Bullet extends MovieClip
{
private var stageRef:Stage;
private var speed:Number = 10;
private var xVel:Number = 0;
private var yVel:Number = 0;
private var rotationInRadians = 0;
public var enemy:Enemy;
public function Bullet(stageRef:Stage, X:int, Y:int, rotationInDegrees:Number):void
{
this.stageRef = stageRef;
this.x = X;
this.y = Y;
this.rotation = rotationInDegrees;
this.rotationInRadians = rotationInDegrees * Math.PI / 180;
}
public function bullethit():void{
if (Bullet.hitTestObject(enemy)){
gameTimer.stop();
}
}
public function loop():void
{
xVel = Math.cos(rotationInRadians) * speed;
yVel = Math.sin(rotationInRadians) * speed;
x += xVel;
y += yVel;
if(x > stageRef.stageWidth || x < 0 || y > stageRef.stageHeight || y < 0)
{
this.parent.removeChild(this);
}
}
}
}
Main.as document class code:
package
{
import flash.display.Stage;
import flash.display.MovieClip;
import flash.events.Event;
import flash.events.MouseEvent;
import flash.utils.Timer;
import flash.events.TimerEvent;
public class Main extends MovieClip
{
public var player:Player;
public var bulletList:Array = []; //new array for the bullets
public var enemy:Enemy;
public var gameTimer:Timer;
public function Main():void
{
player = new Player(stage, 320, 240);
stage.addChild(player);
enemy = new Enemy();
addChild( enemy );
gameTimer = new Timer( 25 );
gameTimer.addEventListener( TimerEvent.TIMER, moveEnemy );
gameTimer.start();
stage.addEventListener(MouseEvent.CLICK, shootBullet, false, 0, true);
stage.addEventListener(Event.ENTER_FRAME, loop, false, 0, true); //add an EventListener for the loop
}
public function moveEnemy( timerEvent:TimerEvent ):void
{
enemy.moveDownABit();
}
public function loop(e:Event):void //create the loop function
{
if(bulletList.length > 0) //if there are any bullets in the bullet list
{
for(var i:int = bulletList.length-1; i >= 0; i--) //for each one
{
bulletList[i].loop(); //call its loop() function
}
}
}
public function shootBullet(e:MouseEvent):void
{
var bullet:Bullet = new Bullet(stage, player.x, player.y, player.rotation);
bullet.addEventListener(Event.REMOVED_FROM_STAGE, bulletRemoved, false, 0, true); //triggers the "bulletRemoved()" function whenever this bullet is removed from the stage
bulletList.push(bullet); //add this bullet to the bulletList array
stage.addChild(bullet);
}
public function bulletRemoved(e:Event):void
{
e.currentTarget.removeEventListener(Event.REMOVED_FROM_STAGE, bulletRemoved); //remove the event listener so we don't get any errors
bulletList.splice(bulletList.indexOf(e.currentTarget),1); //remove this bullet from the bulletList array
}
}
}
As Vesper said, you'll want to do your checks in the Main class. You've already got a game loop set up, so you can just add the check in there:
public function loop(e:Event):void //create the loop function
{
if(bulletList.length > 0) //if there are any bullets in the bullet list
{
for(var i:int = bulletList.length-1; i >= 0; i--) //for each one
{
bulletList[i].loop(); //call its loop() function
// check to see if the enemy has been hit
if(enemy.hitTestObject(bulletList[i]))
{
// the enemy has been hit by the bullet at index i
}
}
}
}
Since you currently only have a single enemy, you're just testing each bullet against that one enemy. If you had more enemies, you'd want to keep an array of references to those enemies and do a nested loop, checking to see if any of the enemies were hit by any of the bullets.
I have a problem. I am trying to make a copter game in Adobe Flash with ActionScript 3.0, but now the game works, but the obstacles can't be removed from stage. The obstacles are still going miles out of the stage. How can I remove the obstacles?? and same problem if you are game over, if you are game over the event end, but the last spawned obstacles you see still and aren't removed. And how can I make the obstacles go faster after a period of time??
There are standing some dutch words in it, such as 'hoeSpelen' that is for instructions text en 'af' is for the gameover text and 'tijd' = time and 'balkje' = obstacles.
I hope you can help me.
package
{
import flash.display.MovieClip;
import flash.events.MouseEvent;
import flash.utils.getTimer;
import flash.events.Event;
public class iCopter extends MovieClip
{
private var copter : Copter = null;
private var gameover : GameOver = null;
private var balkje : Balkje = null;
private var tijd : int
var score = 0;
var highscore = 0;
public function onStartButton(event:MouseEvent)
{
startiCopter()
}
public function iCopter()
{
startButton.addEventListener(MouseEvent.CLICK, onStartButton);
af.visible = false
output.visible = false
hscore.visible = false
}
public function startiCopter()
{
removeChild(startButton);
removeChild(hoeSpelen);
removeChild(af);
score = 0
icopterlogo.visible = false
output.visible = true
hscore.visible = true
copter = new Copter();
copter.x = 100;
copter.y = 200;
addChild(copter);
tijd = getTimer();
addEventListener(Event.ENTER_FRAME, onEnterFrame);
}
public function onEnterFrame(event:Event)
{
var now:int = getTimer();
if (now - tijd > 1250)
{
var balkje = new Balkje();
balkje.x = 350;
balkje.y = Math.random() * 150;
addChild (balkje);
tijd = now
score = score + 10;
output.text = "score: "+score;
if (balkje.x <= -10) //don't work.
{ //don't work.
removeChild (balkje); //don't work.
} //don't work.
}
addEventListener(Event.ENTER_FRAME, botsing);
}
function botsing (event:Event)
{
for (var i = 0; i < numChildren; i++)
{
if (getChildAt(i) is Balkje || getChildAt(i) is Vloer)
{
var b = getChildAt(i) as MovieClip;
if (b.hitTestObject(copter))
{
removeChild (copter);
removeEventListener(Event.ENTER_FRAME, onEnterFrame);
var gameover = new GameOver();
addChild(af);
af.visible = true
addChild(hoeSpelen);
addChild(startButton);
if (score > highscore)
{
highscore = score
hscore.text = "highscore: "+highscore;
}
}
}
}
}
}
}
Here are the scripts for the copter and obstacle
copter:
muisKlik = mouseClick
muisDruk = mousePush
muisOmhoog = mouseUp
package
{
import flash.display.MovieClip;
import flash.events.MouseEvent;
import flash.events.Event;
public class Copter extends MovieClip
{
var vy : Number = 0;
var muisKlik : Boolean = false;
public function Copter()
{
vy = 5;
addEventListener(Event.ENTER_FRAME, onEnterFrame);
addEventListener(Event.ADDED_TO_STAGE, init);
}
private function init(event:Event)
{
stage.addEventListener(MouseEvent.MOUSE_DOWN, muisDruk);
stage.addEventListener(MouseEvent.MOUSE_UP, muisOmhoog);
}
public function onEnterFrame(event:Event)
{
if (muisKlik == true)
{
y -= vy;
}
else
{
y += vy;
}
}
public function muisDruk (event:MouseEvent)
{
muisKlik = true
}
public function muisOmhoog (event:MouseEvent)
{
muisKlik = false
}
}
}
obstacle:
package
{
import flash.display.MovieClip;
import flash.events.Event;
public class Balkje extends MovieClip
{
var vx : Number = 1;
public function Balkje()
{
vx = 5;
addEventListener( Event.ENTER_FRAME, onEnterFrame );
}
public function onEnterFrame( event:Event )
{
x -= vx;
}
}
}
Not tested - probably full of errors, and I haven't done AS3 in a while:
When you initialize obstacles, pass in the stage object (not sure if this is the best practice)
package {
import flash.display.MovieClip;
import flash.events.Event;
public class Balkje extends MovieClip
{
var vx : Number = 1;
public function Balkje()
{
vx = 5;
if(!stage){
//if stage isn't populated yet, wait for it
this.addEventListner(Event.ADDED_TO_STAGE,addedToStage);
}else{
init();
}
}
private function addedToStage(e:Event):void {
this.removeEventListener(Event.ADDED_TO_STAGE,addedToStage);
init();
}
protected function init():void {
this.addEventListener(Event.ENTER_FRAME, onEnterFrame);
}
public function onEnterFrame( event:Event )
{
x -= vx;
//check x
if(this.x + this.width <= 0 || this.x >= stage.stageWidth) {
if(this.parent) this.parent.remmoveChild(this);
removeEventListener( Event.ENTER_FRAME, onEnterFrame );
}
}
}
}
Again, not tested (is stage.stageWidth correct to get the stage width?) but you get the idea. Check the x of the object, if it is outside the visible stage remove it from its parent (I just put this.parent because you didn't add the obstacle to the stage).
Also, why do you add event listener to ENTER_FRAME in a function called by ENTER_FRAME?
I am making a platformer game. But I am having issue because whenever I pressed the spacebar to jump, the character will stuck in the mid-air. However, I can resolved the problem by holding spacebar and the character will land.
The issue is at mainJump() located inside Boy class.
I seen many people solved the problem by using action timeline, but my main problem is, are there anyway I can solve the problem by using an external class?
Main class
package
{
import flash.display.*;
import flash.text.*;
import flash.events.*;
import flash.utils.Timer;
import flash.text.*;
public class experimentingMain extends MovieClip
{
var count:Number = 0;
var myTimer:Timer = new Timer(10,count);
var classBoy:Boy;
//var activateGravity:gravity = new gravity();
var leftKey, rightKey, spaceKey, stopAnimation:Boolean;
public function experimentingMain()
{
myTimer.addEventListener(TimerEvent.TIMER, scoreUp);
myTimer.start();
classBoy = new Boy();
addChild(classBoy);
stage.addEventListener(KeyboardEvent.KEY_DOWN, pressTheDamnKey);
stage.addEventListener(KeyboardEvent.KEY_UP, liftTheDamnKey);
}
public function pressTheDamnKey(event:KeyboardEvent):void
{
if (event.keyCode == 37)
{
leftKey = true;
stopAnimation = false;
}
if (event.keyCode == 39)
{
rightKey = true;
stopAnimation = false;
}
if (event.keyCode == 32)
{
spaceKey = true;
stopAnimation = true;
}
}
public function liftTheDamnKey(event:KeyboardEvent):void
{
if (event.keyCode == 37)
{
leftKey = false;
stopAnimation = true;
}
if (event.keyCode == 39)
{
rightKey = false;
stopAnimation = true;
}
if (event.keyCode == 32)
{
spaceKey = false;
stopAnimation = true;
}
}
public function scoreUp(event:TimerEvent):void
{
scoreSystem.text = String("Score : "+myTimer.currentCount);
}
}
}
Boy class
package
{
import flash.display.*;
import flash.events.*;
public class Boy extends MovieClip
{
var leftKeyDown:Boolean = false;
var upKeyDown:Boolean = false;
var rightKeyDown:Boolean = false;
var downKeyDown:Boolean = false;
//the main character's speed
var mainSpeed:Number = 5;
//whether or not the main guy is jumping
var mainJumping:Boolean = false;
//how quickly should the jump start off
var jumpSpeedLimit:int = 40;
//the current speed of the jump;
var jumpSpeed:Number = 0;
var theCharacter:MovieClip;
var currentX,currentY:int;
public function Boy()
{
this.x = 600;
this.y = 540;
addEventListener(Event.ENTER_FRAME, boyMove);
}
public function boyMove(event:Event):void
{
currentX = this.x;
currentY = this.y;
if (MovieClip(parent).leftKey)
{
currentX += mainSpeed;
MovieClip(this).scaleX = 1;
}
if (MovieClip(parent).rightKey)
{
currentX -= mainSpeed;
MovieClip(this).scaleX = -1;
}
if (MovieClip(parent).spaceKey)
{
mainJump();
}
this.x = currentX;
this.y = currentY;
}
public function mainJump():void
{
currentY = this.y;
if (! mainJumping)
{
mainJumping = true;
jumpSpeed = jumpSpeedLimit * -1;
currentY += jumpSpeed;
}
else
{
if (jumpSpeed < 0)
{
jumpSpeed *= 1 - jumpSpeedLimit / 250;
if (jumpSpeed > -jumpSpeedLimit/12)
{
jumpSpeed *= -2;
}
}
}
if (jumpSpeed > 0 && jumpSpeed <= jumpSpeedLimit)
{
jumpSpeed *= 1 + jumpSpeedLimit / 120;
}
currentY += jumpSpeed;
if (currentY >= stage.stageHeight - MovieClip(this).height)
{
mainJumping = false;
currentY = stage.stageHeight - MovieClip(this).height;
}
}
}
}
First of all, formalize your code, eliminating sassy things like 'pressTheDamnKey,' which doesn't even describe the function very well because a function cannot press a key. That is an event handler and should be named either keyDownHandler or onKeyDown, nothing else.
Secondly, you rarely want to do any actual work in event handlers beyond the immediate concerns of the event data. Instead call out to the function which does the actual work. A handler handles the event, then calls the code which does the work. This separates out concerns nicely for when you want something else to be able to also make the little boy animate besides the enterFrameHandler, like perhaps a mouse.
I can imagine your trace log is getting filled up pretty quickly with "Score" lines since your timer is firing 100 times a second (10 milliseconds per). I would change that to not fire on a timer, but to be refreshed when the score actually changes.
The problem with the jumping, aside from spaghetti code, is that you are basing his movements upon whether the key is pressed or not by saving the state of the key press in a variable and having him continually inspect it. This is bad for a couple of reasons: 1. he should not need to reach out to his environment for information, it should be given to him by whatever object owns him or by objects that are responsible for telling him and 2. It requires you to continually hold down the spacebar or he will stop moving, since he checks to see if it is being held down (see problem 1).
I will address all these issues below, leaving out the scoring, which is another matter altogether.
package
{
import flash.display.*;
import flash.events.*;
import flash.text.*;
import flash.utils.*;
// Sprite is preferred if you are not using the timeline
public class Application extends Sprite
{
private var boy:Boy;
public function Application()
{
boy = new Boy();
addChild(boy);
boy.x = 600; // set these here, not in the boy
boy.y = 540;
stage.addEventListener(KeyboardEvent.KEY_DOWN, keyDownHandler);
stage.addEventListener(KeyboardEvent.KEY_UP, keyUpHandler );
}
public function keyDownHandler(event:KeyboardEvent):void
{
switch(event.keyCode)
{
case 32: boy.jump();
break;
case 37: boy.moveLeft();
break;
case 39: boy.moveRight();
break;
default:
// ignored
break;
}
}
public function keyUpHandler(event:KeyboardEvent):void
{
switch(event.keyCode)
{
// ignored for jumping (32)
case 37: // fall through
case 39: boy.stop();
break;
default:
// ignored
break;
}
}
}//class
}//package
package
{
import flash.display.*;
import flash.events.*;
// It is assumed that there is an asset in the library
// that is typed to a Boy, thus it will be loaded onto
// the stage by the owner
public class Boy extends Sprite
{
private var horzSpeed :Number = 0;
private var vertSpeed :Number = 0;
private var floorHeight :Number;
private var jumpHeight :Number;
private var amJumping :Boolean = false;
public function Boy()
{
addEventListener(Event.ENTER_FRAME, enterFrameHandler);
}
public function moveLeft():void
{
horzSpeed = -1;
}
public function moveRight():void
{
horzSpeed = 1;
}
public function stop():void
{
horzSpeed = 0;
}
public function jump():void
{
if (amJumping) return;
floorHeight = y;
jumpHeight = floorHeight + 20;
vertSpeed = 2;
amJumping = true;
animateJump();
}
private function enterFrameHandler(event:Event):void
{
animate();
}
private function animate():void
{
x += horzSpeed;
if( amJumping )
{
animateJump();
}
}
// Doing a simple version for this example.
// If you want an easier task of jumping with gravity,
// I recommend you employ Greensock's superb
// TweenLite tweening library.
private function animateJump():void
{
y += vertSpeed;
if( y >= jumpHeight )
{
y = jumpHeight;
vertSpeed = -2;
}
else if( y <= floorHeight )
{
y = floorHeight;
amJumping = false;
}
}
}//class
}//package
Another way to approach this, and probably the better way long-term, is for the boy to not even be responsible for moving himself. Instead, you would handle that in the parent, his owner or some special Animator class that is responsible for animating things on schedule. In this even more encapsulated paradigm, the boy is only responsible for updating his own internal look based upon the outside world telling him what is happening to him. He would no longer handle jumping internally, but instead would be responsible for doing things like animating things he owns, like his arms and legs.
You've got a mainJumping variable that is only true while the jump is running. Why not just use that?
if (MovieClip(parent).spaceKey || mainJumping)
{
mainJump();
}