p2.js物理エンジン関連記事
【p2.js】p2.js 物理エンジンを使用して1000個の玉を描画する方法
【p2.js】クラス分けで拡張性が向上したp2.js物理ボールの生成方法
【p2.js】p2.js 物理エンジンを使用した衝突判定「collisionGroup」「collisionMask」
はじめに
p2.js物理エンジンを使って、ボールとブロックが衝突したときにHPを減らす方法を紹介します。
Unity等のコンポーネント指向でプログラムを組むと、以下のようなことが起きます。
これは、Box ClassのコリジョンイベントにHPを減らす処理を書いてしまったため、後からインスタンス化したBoxのHPだけが減る結果になりました。
以下に失敗したコードも載せておきます。
Main.ts （失敗コード）
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enum GraphicShape{ NONE = Math.pow(2,0), CIECLE = Math.pow(2,1), BOX = Math.pow(2,2), } class Main extends eui.UILayer { static timeStamp : number; public constructor() { super(); this.once(egret.Event.ADDED_TO_STAGE, this.addToStage, this); } private addToStage() { GameObject.initial( this.stage ); CreateGameScene.init(); } } class CreateGameScene{ static width : number; static height: number; static init() { this.width = egret.MainContext.instance.stage.stageWidth; this.height = egret.MainContext.instance.stage.stageHeight; new CreatePhysicsWorld(); new Ball(CreateGameScene.width/2, 0, 20); //------------------------------------------------------------ //Boxを２つインスタンス化すると、1つ目のBoxにボールが当たっても、2つ目のBoxのHPが減る new Box(CreateGameScene.width/2, 500, 100, 30, 10); new Box(CreateGameScene.width/2, 800, 100, 30, 10); //--------------------------------------------------------------- egret.startTick(this.tickLoop, this); } static tickLoop(timeStamp:number = Main.timeStamp):boolean{ GameObject.update(); CreatePhysicsWorld.worldBegin(timeStamp); return false; } } abstract class GameObject { protected shape:egret.Shape = null; public body : p2.Body = null; protected bodyShape : p2.Circle | p2.Box = null; protected world : p2.World = null; static objects: GameObject[]; static display: egret.DisplayObjectContainer; constructor() { GameObject.objects.push(this); } static initial(mainStage: egret.DisplayObjectContainer){ GameObject.objects = []; GameObject.display = mainStage; } abstract updateContent() : void; static update(){ GameObject.objects.forEach(obj => obj.updateContent()); } } class CreatePhysicsWorld extends GameObject{ static world : p2.World = null; constructor(){ super(); this.createWorld(); } createWorld(){ CreatePhysicsWorld.world = new p2.World(); CreatePhysicsWorld.world.sleepMode = p2.World.BODY_SLEEPING; CreatePhysicsWorld.world.gravity = [0, 9.8]; } updateContent(){ } static worldBegin(dt : number) :boolean{ CreatePhysicsWorld.world.step(1/60, dt/1000, 10); return false; } } class Ball extends GameObject{ static I:Ball = null; constructor(x: number, y:number, radius: number){ super(); Ball.I = this; this.setBody(x, y, radius); this.setShape(radius); } setBody(x: number, y:number, radius: number){ Ball.I =this; this.body = new p2.Body({mass : 1, position:[x,y]}); this.bodyShape = new p2.Circle({ radius : radius, collisionGroup: GraphicShape.CIECLE, collisionMask:GraphicShape.BOX , fixedRotation:true }); this.body.addShape(this.bodyShape); CreatePhysicsWorld.world.addBody(this.body); } setShape(radius: number){ this.shape = new egret.Shape(); this.shape.x = this.body.position[0]; this.shape.y = this.body.position[1]; this.shape.graphics.beginFill(0xff0000); this.shape.graphics.drawCircle(0, 0, radius); this.shape.graphics.endFill(); GameObject.display.addChild(this.shape); } updateDrowShape(){ this.shape.x = this.body.position[0]; this.shape.y = this.body.position[1]; GameObject.display.addChild(this.shape); } updateContent(){ this.updateDrowShape(); } } class Box extends GameObject{ private hp :number = null; private hPText : MyText = null; constructor(x: number, y:number, boxWidth: number, boxHeight: number, hp : number){ super(); this.hp = hp; this.setBody(x, y, boxWidth, boxHeight); this.setShape(boxWidth, boxHeight); this.hPText = new MyText(x,y, hp.toString() ,100, 0.5,0xFFFFFF,"Meiryo",0x000000, 0); CreatePhysicsWorld.world.on("beginContact", this.collision, this); } setBody(x: number, y:number, width: number, height : number){ this.body = new p2.Body({mass : 1, position:[x,y], type:p2.Body.STATIC}); this.bodyShape = new p2.Box({ width : width, height : height,collisionGroup: GraphicShape.BOX, collisionMask:GraphicShape.CIECLE, fixedRotation:true }); this.body.addShape(this.bodyShape); CreatePhysicsWorld.world.addBody(this.body); } setShape(width: number, height : number){ this.shape = new egret.Shape(); this.shape.anchorOffsetX += width/2;//p2とEgretは座標軸とアンカー位置が違うので調整 this.shape.anchorOffsetY += height/2; this.shape.x = this.body.position[0] /*+ width*/; this.shape.y = this.body.position[1] /*- height/2*/; this.shape.graphics.beginFill(0xff0000); this.shape.graphics.drawRect(0, 0, width , height); this.shape.graphics.endFill(); GameObject.display.addChild(this.shape); } setHpText(x:number, y:number, text:string, size:number, ratio:number, color:number, font:string, stColor:number, stSize:number){ new MyText(x,y,text,100, 0.5,0xFFFFFF,"Meiryo",0x000000, 0); } updateContent(){ } //---------------------------------------------------- //コリジョンイベント collision(evt){ const bodyA: p2.Body = evt.bodyA; const shapeA = evt.shapeA; Ball.I.body.applyForceLocal([0,-10000],[0,0]); this.hp -= 1; this.hPText.updateText(this.hp.toString()); } //------------------------------------------------------ } class MyText extends GameObject{ public myTextField : egret.TextField | null = null; public myText : string | null = null; public x : number|null = 0; public y : number|null = 0; public size : number|null = 1; public ratio : number|null = 1; public color : number|null = 0x000000; public stColor : number|null =0x0000000; public stSize : number|null = 0; public font : string|null = "Meiryo"; public text : string|null = ""; public constructor(x:number, y:number, text:string, size:number, ratio:number, color:number, font:string, stColor:number, stSize:number){ super(); this.newText(x, y, text, size, ratio, color, font, stColor, stSize); this.x = x; this.y = y; this.text = text; this.size = size; this.ratio = ratio; this.color= color; this.font = font; this.stColor = stColor; this.stSize = stSize; } protected newText(x:number, y:number, text:string, size:number, ratio:number, color:number, font:string, stColor:number, stSize:number): void { this.myTextField = new egret.TextField(); this.myTextField.x = x || 0; this.myTextField.y = y || 0; this.myTextField.scaleX = ratio || 1; this.myTextField.scaleY = ratio || 1; this.myTextField.textFlow = <Array<egret.ITextElement>>[ {text: text, style: { "textColor": color || 0x000000, "size": size ||1, "fontFamily": font ||"Meiryo", "strokeColor": stColor || 0x000000, "stroke": stSize || 0, } } ]; GameObject.display.addChild(this.myTextField); } public updateText(text:string): void{ this.myTextField.textFlow = <Array<egret.ITextElement>>[ {text: text, style: { "textColor": this.color || 0x000000, "size": this.size ||1, "fontFamily": this.font ||"Meiryo", "strokeColor": this.stColor || 0x000000, "stroke": this.stSize || 0, } } ]; GameObject.display.addChild(this.myTextField); } updateContent(){ } } |
【p2.js】衝突したオブジェクトのHPを減らす方法
Main.ts
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enum GraphicShape{ NONE = Math.pow(2,0), CIECLE = Math.pow(2,1), BOX = Math.pow(2,2), } class Main extends eui.UILayer { static timeStamp : number; public constructor() { super(); this.once(egret.Event.ADDED_TO_STAGE, this.addToStage, this); } private addToStage() { GameObject.initial( this.stage ); CreateGameScene.init(); } } class CreateGameScene{ static width : number; static height: number; static box:Box[] = []; static init() { this.width = egret.MainContext.instance.stage.stageWidth; this.height = egret.MainContext.instance.stage.stageHeight; new CreatePhysicsWorld(); new Ball(CreateGameScene.width/2, 0, 20); //------------------------------------------------------------ //Boxを２つインスタンス化すると、1つ目のBoxにボールが当たっても、2つ目のBoxのHPが減る let a = new Box(CreateGameScene.width/2, 500, 100, 30, 10); let b = new Box(CreateGameScene.width/2, 800, 100, 30, 10); CreateGameScene.box.push(a); CreateGameScene.box.push(b); //--------------------------------------------------------------- egret.startTick(this.tickLoop, this); } static tickLoop(timeStamp:number = Main.timeStamp):boolean{ GameObject.update(); CreatePhysicsWorld.worldBegin(timeStamp); return false; } } abstract class GameObject { public shape:egret.Shape = null; public body : p2.Body = null; protected bodyShape : p2.Circle | p2.Box = null; protected world : p2.World = null; static objects: GameObject[]; static display: egret.DisplayObjectContainer; constructor() { GameObject.objects.push(this); } static initial(mainStage: egret.DisplayObjectContainer){ GameObject.objects = []; GameObject.display = mainStage; } abstract updateContent() : void; static update(){ GameObject.objects.forEach(obj => obj.updateContent()); } } class CreatePhysicsWorld extends GameObject{ static world : p2.World = null; constructor(){ super(); this.createWorld(); } createWorld(){ CreatePhysicsWorld.world = new p2.World(); CreatePhysicsWorld.world.sleepMode = p2.World.BODY_SLEEPING; CreatePhysicsWorld.world.gravity = [0, 9.8]; } updateContent(){ } static worldBegin(dt : number) :boolean{ CreatePhysicsWorld.world.step(1/60, dt/1000, 10); return false; } } class Ball extends GameObject{ static I:Ball = null; constructor(x: number, y:number, radius: number){ super(); Ball.I = this; this.setBody(x, y, radius); this.setShape(radius); CreatePhysicsWorld.world.on("beginContact", this.collision, this); } setBody(x: number, y:number, radius: number){ Ball.I =this; this.body = new p2.Body({mass : 1, position:[x,y]}); this.bodyShape = new p2.Circle({ radius : radius, collisionGroup: GraphicShape.CIECLE, collisionMask:GraphicShape.BOX , fixedRotation:true }); this.body.addShape(this.bodyShape); CreatePhysicsWorld.world.addBody(this.body); } setShape(radius: number){ this.shape = new egret.Shape(); this.shape.x = this.body.position[0]; this.shape.y = this.body.position[1]; this.shape.graphics.beginFill(0xff0000); this.shape.graphics.drawCircle(0, 0, radius); this.shape.graphics.endFill(); GameObject.display.addChild(this.shape); } updateDrowShape(){ this.shape.x = this.body.position[0]; this.shape.y = this.body.position[1]; GameObject.display.addChild(this.shape); } updateContent(){ this.updateDrowShape(); } //---------------------------------------------------- //コリジョンイベント collision(evt){ const bodyA: p2.Body = evt.bodyA; const shapeA = evt.shapeA; this.body.applyForceLocal([0,-10000],[0,0]); CreateGameScene.box.forEach(obj =>{ //このifが無いと、すべてのboxのhpが減る if(obj.body == bodyA){ obj.hp -= 1; obj.hPText.updateText(obj.hp.toString()); } }); } //------------------------------------------------------ } class Box extends GameObject{ public hp :number = null; public hPText : MyText = null; constructor(x: number, y:number, boxWidth: number, boxHeight: number, hp : number){ super(); this.hp = hp; this.setBody(x, y, boxWidth, boxHeight); this.setShape(boxWidth, boxHeight); this.hPText = new MyText(x,y, hp.toString() ,100, 0.5,0xFFFFFF,"Meiryo",0x000000, 0); } setBody(x: number, y:number, width: number, height : number){ this.body = new p2.Body({mass : 1, position:[x,y], type:p2.Body.STATIC}); this.bodyShape = new p2.Box({ width : width, height : height,collisionGroup: GraphicShape.BOX, collisionMask:GraphicShape.CIECLE, fixedRotation:true }); this.body.addShape(this.bodyShape); CreatePhysicsWorld.world.addBody(this.body); } setShape(width: number, height : number){ this.shape = new egret.Shape(); this.shape.anchorOffsetX += width/2;//p2とEgretは座標軸とアンカー位置が違うので調整 this.shape.anchorOffsetY += height/2; this.shape.x = this.body.position[0] /*+ width*/; this.shape.y = this.body.position[1] /*- height/2*/; this.shape.graphics.beginFill(0xff0000); this.shape.graphics.drawRect(0, 0, width , height); this.shape.graphics.endFill(); GameObject.display.addChild(this.shape); } setHpText(x:number, y:number, text:string, size:number, ratio:number, color:number, font:string, stColor:number, stSize:number){ new MyText(x,y,text,100, 0.5,0xFFFFFF,"Meiryo",0x000000, 0); } updateContent(){ } } class MyText extends GameObject{ public myTextField : egret.TextField | null = null; public myText : string | null = null; public x : number|null = 0; public y : number|null = 0; public size : number|null = 1; public ratio : number|null = 1; public color : number|null = 0x000000; public stColor : number|null =0x0000000; public stSize : number|null = 0; public font : string|null = "Meiryo"; public text : string|null = ""; public constructor(x:number, y:number, text:string, size:number, ratio:number, color:number, font:string, stColor:number, stSize:number){ super(); this.newText(x, y, text, size, ratio, color, font, stColor, stSize); this.x = x; this.y = y; this.text = text; this.size = size; this.ratio = ratio; this.color= color; this.font = font; this.stColor = stColor; this.stSize = stSize; } protected newText(x:number, y:number, text:string, size:number, ratio:number, color:number, font:string, stColor:number, stSize:number): void { this.myTextField = new egret.TextField(); this.myTextField.x = x || 0; this.myTextField.y = y || 0; this.myTextField.scaleX = ratio || 1; this.myTextField.scaleY = ratio || 1; this.myTextField.textFlow = <Array<egret.ITextElement>>[ {text: text, style: { "textColor": color || 0x000000, "size": size ||1, "fontFamily": font ||"Meiryo", "strokeColor": stColor || 0x000000, "stroke": stSize || 0, } } ]; GameObject.display.addChild(this.myTextField); } public updateText(text:string): void{ this.myTextField.textFlow = <Array<egret.ITextElement>>[ {text: text, style: { "textColor": this.color || 0x000000, "size": this.size ||1, "fontFamily": this.font ||"Meiryo", "strokeColor": this.stColor || 0x000000, "stroke": this.stSize || 0, } } ]; GameObject.display.addChild(this.myTextField); } updateContent(){ } } |
CreateGameSceneにboxの配列を追加
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class CreateGameScene{ static width : number; static height: number; static box:Box[] = []; static init() { this.width = egret.MainContext.instance.stage.stageWidth; this.height = egret.MainContext.instance.stage.stageHeight; new CreatePhysicsWorld(); new Ball(CreateGameScene.width/2, 0, 20); //------------------------------------------------------------ //Boxを２つインスタンス化すると、1つ目のBoxにボールが当たっても、2つ目のBoxのHPが減る let a = new Box(CreateGameScene.width/2, 500, 100, 30, 10); let b = new Box(CreateGameScene.width/2, 800, 100, 30, 10); CreateGameScene.box.push(a); CreateGameScene.box.push(b); //--------------------------------------------------------------- egret.startTick(this.tickLoop, this); } static tickLoop(timeStamp:number = Main.timeStamp):boolean{ GameObject.update(); CreatePhysicsWorld.worldBegin(timeStamp); return false; } } |
インスタンス化したBoxをstatic box の配列内にpush（配列に格納する） します。これで、別のクラスでもBoxを利用できます。
Ball.ts
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class Ball extends GameObject{ static I:Ball = null; constructor(x: number, y:number, radius: number){ super(); Ball.I = this; this.setBody(x, y, radius); this.setShape(radius); CreatePhysicsWorld.world.on("beginContact", this.collision, this); } setBody(x: number, y:number, radius: number){ Ball.I =this; this.body = new p2.Body({mass : 1, position:[x,y]}); this.bodyShape = new p2.Circle({ radius : radius, collisionGroup: GraphicShape.CIECLE, collisionMask:GraphicShape.BOX , fixedRotation:true }); this.body.addShape(this.bodyShape); CreatePhysicsWorld.world.addBody(this.body); } setShape(radius: number){ this.shape = new egret.Shape(); this.shape.x = this.body.position[0]; this.shape.y = this.body.position[1]; this.shape.graphics.beginFill(0xff0000); this.shape.graphics.drawCircle(0, 0, radius); this.shape.graphics.endFill(); GameObject.display.addChild(this.shape); } updateDrowShape(){ this.shape.x = this.body.position[0]; this.shape.y = this.body.position[1]; GameObject.display.addChild(this.shape); } updateContent(){ this.updateDrowShape(); } //---------------------------------------------------- //コリジョンイベント collision(evt){ const bodyA: p2.Body = evt.bodyA; const shapeA = evt.shapeA; this.body.applyForceLocal([0,-10000],[0,0]); CreateGameScene.box.forEach(obj =>{ //このifが無いと、すべてのboxのhpが減る if(obj.body == bodyA){ obj.hp -= 1; obj.hPText.updateText(obj.hp.toString()); } }); } //------------------------------------------------------ } |
Boxに記述していたコリジョンイベントをBallへ移しました。コリジョンイベントはどこに書いてもいいのですが、今回はボールが能動的に動くので、ここに入れました。
コリジョンイベントの中でboxの配列をforEachで取得します。forEachを使用しないと、hpやhpTextをstaticにする必要があります。しかし、staticにすると、個別にhpを設定することはできません。
また、forEachは全てのBoxを参照してしまうので、if(obj.body == bodyA)で衝突したboxのbodyと一致したときのみhpを減らすようにしました。
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CreateGameScene.box.forEach(obj =>{ //このifが無いと、すべてのboxのhpが減る if(obj.body == bodyA){ obj.hp -= 1; obj.hPText.updateText(obj.hp.toString()); } }); |
if(obj.body == bodyA)がないと、以下のようになります。
