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Javascript 如何解决弹性碰撞?_Javascript_Typescript_Game Physics - Fatal编程技术网

Javascript 如何解决弹性碰撞?

Javascript 如何解决弹性碰撞?,javascript,typescript,game-physics,Javascript,Typescript,Game Physics,我一直在做一个弹性碰撞演示,但似乎不能完全正确。circle1对象似乎从曲面的一侧正确碰撞 circle2对象,但如果它们从另一侧碰撞,则会穿过circle2 如何修改此弹性碰撞以使其更精确 这里有一个链接,链接到一个实时演示 main.ts class DemoCanvas { canvasWidth: number = 500; canvasHeight: number = 500; canvas: HTMLCanvasElement = document.creat

我一直在做一个弹性碰撞演示,但似乎不能完全正确。circle1对象似乎从曲面的一侧正确碰撞 circle2对象,但如果它们从另一侧碰撞,则会穿过circle2

如何修改此弹性碰撞以使其更精确

这里有一个链接,链接到一个实时演示

main.ts

class DemoCanvas {
    canvasWidth: number = 500;
    canvasHeight: number = 500;
    canvas: HTMLCanvasElement = document.createElement('canvas');
    constructor() {
        this.canvas.width = this.canvasWidth;
        this.canvas.height = this.canvasHeight;
        this.canvas.style.border = '1px solid black';
        this.canvas.style.position = 'absolute';
        this.canvas.style.left = '50%';
        this.canvas.style.top = '50%';
        this.canvas.style.transform = 'translate(-50%, -50%)';
        document.body.appendChild(this.canvas);
    }

    clear() {
        this.canvas.getContext('2d').clearRect(0, 0, this.canvas.width, this.canvas.height);
    }

    getContext(): CanvasRenderingContext2D {
        return this.canvas.getContext('2d');
    }

    getWidth(): number {
        return this.canvasWidth;
    }

    getHeight(): number {
        return this.canvasHeight;
    }

    getTop(): number {
        return this.canvas.getBoundingClientRect().top;
    }

    getRight(): number {
        return this.canvas.getBoundingClientRect().right;
    }

    getBottom(): number {
        return this.canvas.getBoundingClientRect().bottom;
    }    

    getLeft(): number {
        return this.canvas.getBoundingClientRect().left;
    }
}

class Circle {
    x: number;
    y: number;
    dx: number;
    dy: number;
    xVelocity: number;
    yVelocity: number;
    radius: number;
    color: string;
    canvas: DemoCanvas;
    context: CanvasRenderingContext2D;

    constructor(x: number, y: number, xVelocity: number, yVelocity: number, color: string, gameCanvas: DemoCanvas) {
        this.radius = 20;
        this.x = x;
        this.y = y;
        this.xVelocity = xVelocity;
        this.yVelocity = yVelocity;
        this.color = color;
        this.canvas = gameCanvas;
        this.context = this.canvas.getContext();
    }

    public draw(): void {
        this.context.fillStyle = this.color;
        this.context.beginPath();
        this.context.arc(this.x, this.y, this.radius, 0, 2 * Math.PI);
        this.context.fill();
    }

    public move(): void {
        this.x += this.xVelocity;
        this.y += this.yVelocity;
    }

    checkWallCollision(gameCanvas: DemoCanvas): void {
        let top = 0;
        let right = 500;
        let bottom = 500;
        let left = 0;

        if(this.y < top + this.radius) {
            this.y = top + this.radius;
            this.yVelocity *= -1;
        }

        if(this.x > right - this.radius) {
            this.x = right - this.radius;
            this.xVelocity *= -1;
        }

        if(this.y > bottom - this.radius) {
            this.y = bottom - this.radius;
            this.yVelocity *= -1;
        }

        if(this.x < left + this.radius) {
            this.x = left + this.radius;
            this.xVelocity *= -1;
        }
    }
}

let demoCanvas = new DemoCanvas();
let circle1: Circle = new Circle(250, 250, 5, 5, "#F77", demoCanvas);
let circle2: Circle = new Circle(250, 540, 5, 5, "#7FF", demoCanvas);


function detectCollisions():void {

    if (circle1.x + circle1.radius + circle2.radius > circle2.x 
        && circle1.x < circle2.x + circle1.radius + circle2.radius
        && circle1.y + circle1.radius + circle2.radius > circle2.y 
        && circle1.y < circle2.y + circle1.radius + circle2.radius) {
            if (distanceTo() < circle1.radius + circle2.radius) {
                calculateNewVelocities();
            }
    }
}

function distanceTo():Number {
    var distance = Math.sqrt(((circle1.x - circle2.x) * (circle1.x - circle2.x)) + ((circle1.y - circle2.y) * (circle1.y - circle2.y)));
    if (distance < 0) { 
        distance = distance * -1; 
    }
    return distance;
}

function calculateNewVelocities():void {
    var mass1 = circle1.radius;
    var mass2 = circle2.radius;
    var velX1 = circle1.xVelocity;
    var velX2 = circle2.xVelocity;
    var velY1 = circle1.yVelocity;
    var velY2 = circle2.yVelocity;

    var newVelX1 = (velX1 * (mass1 - mass2) + (2 * mass2 * velX2)) / (mass1 + mass2);
    var newVelY1 = (velY1 * (mass1 - mass2) + (2 * mass2 * velY2)) / (mass1 + mass2);

    circle1.xVelocity = newVelX1;
    circle1.yVelocity = newVelY1;

    circle1.x = circle1.x + newVelX1;
    circle1.y = circle1.y + newVelY1;
}

addEventListener('mousemove', function(e) {
    let mouseX = e.clientX - demoCanvas.getLeft();
    let mouseY = e.clientY - demoCanvas.getTop();
    circle2.x = mouseX;
    circle2.y = mouseY;
});

function loop() {
    demoCanvas.clear();
    circle1.draw();
    circle2.draw();
    circle1.move();
    circle1.checkWallCollision(demoCanvas);
    circle2.checkWallCollision(demoCanvas);
    detectCollisions();
    requestAnimationFrame(loop);
}
requestAnimationFrame(loop);
classdemocanvas{
画布宽度:编号=500;
画布高度:编号=500;
canvas:htmlcanvaseElement=document.createElement('canvas');
构造函数(){
this.canvas.width=this.canvasWidth;
this.canvas.height=this.canvasHeight;
this.canvas.style.border='1px纯黑';
this.canvas.style.position='absolute';
this.canvas.style.left='50%';
this.canvas.style.top='50%';
this.canvas.style.transform='translate(-50%,-50%);
document.body.appendChild(this.canvas);
}
清除(){
this.canvas.getContext('2d').clearRect(0,0,this.canvas.width,this.canvas.height);
}
getContext():CanvasRenderingContext2D{
返回此.canvas.getContext('2d');
}
getWidth():数字{
返回此参数。画布宽度;
}
getHeight():编号{
返回此参数。画布高度;
}
getTop():编号{
返回此.canvas.getBoundingClientRect().top;
}
getRight():数字{
返回此.canvas.getBoundingClientRect().right;
}
getBottom():数字{
返回此.canvas.getBoundingClientRect().bottom;
}    
getLeft():数字{
返回此.canvas.getBoundingClientRect().left;
}
}
班级圈子{
x:数字;
y:数字;
dx:数字;
dy:数字;
xVelocity:数字;
yVelocity:数字;
半径:数字;
颜色:字符串;
画布:演示画布;
上下文:CanvasRenderingContext2D;
构造函数(x:number,y:number,xVelocity:number,yVelocity:number,color:string,gameCanvas:DemoCanvas){
这个半径=20;
这个.x=x;
这个。y=y;
这个.xVelocity=xVelocity;
this.yVelocity=yVelocity;
这个颜色=颜色;
this.canvas=gameCanvas;
this.context=this.canvas.getContext();
}
公开提款():无效{
this.context.fillStyle=this.color;
this.context.beginPath();
this.context.arc(this.x,this.y,this.radius,0,2*Math.PI);
this.context.fill();
}
公共移动():无效{
这个.x+=这个.x速度;
this.y+=this.yVelocity;
}
checkWallCollision(游戏画布:DemoCanvas):无效{
设top=0;
设右=500;
设底部=500;
设左=0;
if(此.yright-this.radius){
this.x=右-this.radius;
这是0.xVelocity*=-1;
}
if(this.y>底部-this.radius){
this.y=底部-this.radius;
这个。yVelocity*=-1;
}
if(此.x<左+此半径){
此.x=左+此.radius;
这是0.xVelocity*=-1;
}
}
}
让demoCanvas=新建demoCanvas();
设圆1:圆=新圆(250,250,5,5,“#F77”,demoCanvas);
设圆圈2:圆圈=新圆圈(250、540、5、5、“#7FF”,demoCanvas);
函数detectCollisions():void{
如果(圈1.x+圈1.radius+圈2.radius>圈2.x
&&圆1.x<圆2.x+圆1.radius+圆2.radius
&&圆1.y+圆1.radius+圆2.radius>圆2.y
&&圆1.y<圆2.y+圆1.radius+圆2.radius){
if(distanceTo()
嗯,我不确定你是从哪里得到的公式来更新
圆圈1
圆圈2
碰撞时的速度,但这取决于两个圆圈的相对位置(不仅是它们之间的距离,还有接触角)

如果我们假设
circle2
是静止的(或如此巨大以至于
circle1
不会影响它的运动),那么
calculatenewvelociations()
中的代码应该是这样的:

  var xd = circle1.x - circle2.x; // x displacement between circles
  var yd = circle1.y - circle2.y; // y displacement between circles
  var dsq = xd*xd + yd*yd; // square of distance between circles

  var DV = 2*(velX1*xd + velY1*yd)/dsq; // velocity change factor
  // EDIT
  // fix to prevent orbiting... if circle1 is already rebounding, 
  // leave it alone
  if (DV > 0) {
    DV=0;
  }

  // velocity change is in the opposite direction of 
  // the displacement between circles
  var newVelX1 = velX1 - DV * xd; 
  var newVelY1 = velY1 - DV * yd;
当碰撞来自外部时,这会给你一些模糊合理的解释。如果你发现圆圈重叠,这可能会导致
circle1
环绕
circle2
或类似的疯狂行为,因此你可能想调整它以防止此类事情发生