我在互联网上找到了这段代码。我粘贴到我的记事本++中，然后更改了这两个文件以匹配我在桌面上创建的文件。
<script src='C:/Users/home-1/Desktop/Box2dWeb-2.1.a.3.js'></script>
<script src='C:/Users/home-1/Desktop/example5.js'></script>
我在 html 文件中有脚本标记，但我已经在代码和文件中尝试过，但它们似乎都不起作用。
由于某种原因，该页面无法正常工作。我想知道这个页面有什么不同以及为什么它不起作用。
Box2dWeb-2.1.a.3.js
然后创建了 example5.js 文件并将它也放在我的桌面上。这应该显示一个画布以及您可以在屏幕上拖放和拖动的几个对象。
<!DOCTYPE HTML>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Mouse Joint</title>
<script src='C:/Users/home-1/Desktop/Box2dWeb-2.1.a.3.js'></script>
<script src='C:/Users/home-1/Desktop/example5.js'></script>
<style>
canvas
{
background-color:black;
}
</style>
</head>
<body>
<canvas id='b2dCanvas' width='1024' height='500'>Broswer does not
support Canvas Tag</canvas>
<script>
(function() {
var b2Vec2 = Box2D.Common.Math.b2Vec2;
var b2BodyDef = Box2D.Dynamics.b2BodyDef;
var b2Body = Box2D.Dynamics.b2Body;
var b2FixtureDef = Box2D.Dynamics.b2FixtureDef;
var b2Fixture = Box2D.Dynamics.b2Fixture;
var b2World = Box2D.Dynamics.b2World;
var b2MassData = Box2D.Collision.Shapes.b2MassData;
var b2PolygonShape = Box2D.Collision.Shapes.b2PolygonShape;
var b2CircleShape = Box2D.Collision.Shapes.b2CircleShape;
var b2DebugDraw = Box2D.Dynamics.b2DebugDraw;
var Physics = window.Physics = function(element,scale) {
var gravity = new b2Vec2(0,9.8);
this.world = new b2World(gravity, true);
this.element = element;
this.context = element.getContext("2d");
this.scale = scale || 20;
this.dtRemaining = 0;
this.stepAmount = 1/60;
};
Physics.prototype.debug = function() {
this.debugDraw = new b2DebugDraw();
this.debugDraw.SetSprite(this.context);
this.debugDraw.SetDrawScale(this.scale);
this.debugDraw.SetFillAlpha(0.3);
this.debugDraw.SetLineThickness(1.0);
this.debugDraw.SetFlags(b2DebugDraw.e_shapeBit | b2DebugDraw.e_jointBit);
this.world.SetDebugDraw(this.debugDraw);
};
Physics.prototype.step = function(dt) {
this.dtRemaining += dt;
while(this.dtRemaining > this.stepAmount) {
this.dtRemaining -= this.stepAmount;
this.world.Step(this.stepAmount,
10, // velocity iterations
10);// position iterations
}
if(this.debugDraw) {
this.world.DrawDebugData();
} else {
var obj = this.world.GetBodyList();
this.context.clearRect(0,0,this.element.width,this.element.height);
this.context.save();
this.context.scale(this.scale,this.scale);
while(obj) {
var body = obj.GetUserData();
if(body)
{
body.draw(this.context);
}
obj = obj.GetNext();
}
this.context.restore();
}
};
Physics.prototype.click = function(callback) {
var self = this;
function handleClick(e) {
e.preventDefault();
var point = {
x: (e.offsetX || e.layerX) / self.scale,
y: (e.offsetY || e.layerY) / self.scale
};
self.world.QueryPoint(function(fixture) {
callback(fixture.GetBody(),
fixture,
point);
},point);
}
this.element.addEventListener("mousedown",handleClick);
this.element.addEventListener("touchstart",handleClick);
};
Physics.prototype.dragNDrop = function() {
var self = this;
var obj = null;
var joint = null;
function calculateWorldPosition(e) {
return point = {
x: (e.offsetX || e.layerX) / self.scale,
y: (e.offsetY || e.layerY) / self.scale
};
}
this.element.addEventListener("mousedown",function(e) {
e.preventDefault();
var point = calculateWorldPosition(e);
self.world.QueryPoint(function(fixture) {
obj = fixture.GetBody().GetUserData();
},point);
});
this.element.addEventListener("mousemove",function(e) {
if(!obj) { return; }
var point = calculateWorldPosition(e);
if(!joint) {
var jointDefinition = new Box2D.Dynamics.Joints.b2MouseJointDef();
jointDefinition.bodyA = self.world.GetGroundBody();
jointDefinition.bodyB = obj.body;
jointDefinition.target.Set(point.x,point.y);
jointDefinition.maxForce = 100000;
jointDefinition.timeStep = self.stepAmount;
joint = self.world.CreateJoint(jointDefinition);
}
joint.SetTarget(new b2Vec2(point.x,point.y));
});
this.element.addEventListener("mouseup",function(e) {
obj = null;
if(joint) {
self.world.DestroyJoint(joint);
joint = null;
}
});
};
Physics.prototype.collision = function() {
this.listener = new Box2D.Dynamics.b2ContactListener();
this.listener.PostSolve = function(contact,impulse) {
var bodyA = contact.GetFixtureA().GetBody().GetUserData(),
bodyB = contact.GetFixtureB().GetBody().GetUserData();
if(bodyA.contact) { bodyA.contact(contact,impulse,true) }
if(bodyB.contact) { bodyB.contact(contact,impulse,false) }
};
this.world.SetContactListener(this.listener);
};
var Body = window.Body = function(physics,details) {
this.details = details = details || {};
// Create the definition
this.definition = new b2BodyDef();
// Set up the definition
for(var k in this.definitionDefaults) {
this.definition[k] = details[k] || this.definitionDefaults[k];
}
this.definition.position = new b2Vec2(details.x || 0, details.y || 0);
this.definition.linearVelocity = new b2Vec2(details.vx || 0, details.vy || 0);
this.definition.userData = this;
this.definition.type = details.type == "static" ? b2Body.b2_staticBody :
b2Body.b2_dynamicBody;
// Create the Body
this.body = physics.world.CreateBody(this.definition);
// Create the fixture
this.fixtureDef = new b2FixtureDef();
for(var l in this.fixtureDefaults) {
this.fixtureDef[l] = details[l] || this.fixtureDefaults[l];
}
details.shape = details.shape || this.defaults.shape;
switch(details.shape) {
case "circle":
details.radius = details.radius || this.defaults.radius;
this.fixtureDef.shape = new b2CircleShape(details.radius);
break;
case "polygon":
this.fixtureDef.shape = new b2PolygonShape();
this.fixtureDef.shape.SetAsArray(details.points,details.points.length);
break;
case "block":
default:
details.width = details.width || this.defaults.width;
details.height = details.height || this.defaults.height;
this.fixtureDef.shape = new b2PolygonShape();
this.fixtureDef.shape.SetAsBox(details.width/2,
details.height/2);
break;
}
this.body.CreateFixture(this.fixtureDef);
};
Body.prototype.defaults = {
shape: "block",
width: 4,
height: 4,
radius: 1
};
Body.prototype.fixtureDefaults = {
density: 2,
friction: 1,
restitution: 0.2
};
Body.prototype.definitionDefaults = {
active: true,
allowSleep: true,
angle: 0,
angularVelocity: 0,
awake: true,
bullet: false,
fixedRotation: false
};
Body.prototype.draw = function(context) {
var pos = this.body.GetPosition(),
angle = this.body.GetAngle();
context.save();
context.translate(pos.x,pos.y);
context.rotate(angle);
if(this.details.color) {
context.fillStyle = this.details.color;
switch(this.details.shape) {
case "circle":
context.beginPath();
context.arc(0,0,this.details.radius,0,Math.PI*2);
context.fill();
break;
case "polygon":
var points = this.details.points;
context.beginPath();
context.moveTo(points[0].x,points[0].y);
for(var i=1;i<points.length;i++) {
context.lineTo(points[i].x,points[i].y);
}
context.fill();
break;
case "block":
context.fillRect(-this.details.width/2,
-this.details.height/2,
this.details.width,
this.details.height);
default:
break;
}
}
if(this.details.image) {
context.drawImage(this.details.image,
-this.details.width/2,
-this.details.height/2,
this.details.width,
this.details.height);
}
context.restore();
}
var physics,
lastFrame = new Date().getTime();
window.gameLoop = function() {
var tm = new Date().getTime();
requestAnimationFrame(gameLoop);
var dt = (tm - lastFrame) / 1000;
if(dt > 1/15) { dt = 1/15; }
physics.step(dt);
lastFrame = tm;
};
function init() {
var img = new Image();
// Wait for the image to load
img.addEventListener("load", function() {
physics = window.physics = new Physics(document.getElementById("b2dCanvas"));
physics.collision();
// Create some walls
new Body(physics, { color: "red", type: "static", x: 0, y: 0, height: 50, width: 0.5 });
new Body(physics, { color: "red", type: "static", x:51, y: 0, height: 50, width: 0.5});
new Body(physics, { color: "red", type: "static", x: 0, y: 0, height: 0.5, width: 120 });
new Body(physics, { color: "red", type: "static", x: 0, y:25, height: 0.5, width: 120 });
new Body(physics, { image: img, x: 5, y: 8 });
new Body(physics, { image: img, x: 13, y: 8 });
new Body(physics, { color: "blue", x: 8, y: 3 });
new Body(physics, { color: "gray", shape: "circle", radius: 4, x: 5, y: 20 });
new Body(physics, { color: "pink", shape: "polygon",
points: [ { x: 0, y: 0 }, { x: 0, y: 4 },{ x: -10, y: 0 } ],
x: 20, y: 5 });
physics.dragNDrop();
requestAnimationFrame(gameLoop);
});
img.src = "images/bricks.jpg";
}
window.addEventListener("load",init);
}());
// Lastly, add in the `requestAnimationFrame` shim, if necessary. Does nothing
// if `requestAnimationFrame` is already on the `window` object.
(function() {
var lastTime = 0;
var vendors = ['ms', 'moz', 'webkit', 'o'];
for(var x = 0; x < vendors.length && !window.requestAnimationFrame; ++x) {
window.requestAnimationFrame = window[vendors[x]+'RequestAnimationFrame'];
window.cancelAnimationFrame =
window[vendors[x]+'CancelAnimationFrame'] || window[vendors[x]+'CancelRequestAnimationFrame'];
}
if (!window.requestAnimationFrame) {
window.requestAnimationFrame = function(callback, element) {
var currTime = new Date().getTime();
var timeToCall = Math.max(0, 16 - (currTime - lastTime));
var id = window.setTimeout(function() { callback(currTime + timeToCall); },
timeToCall);
lastTime = currTime + timeToCall;
return id;
};
}
if (!window.cancelAnimationFrame) {
window.cancelAnimationFrame = function(id) {
clearTimeout(id);
};
}
}());
</script>
</body>
</html>
下面是代码应该在屏幕上产生的内容。我想以这个为例，但无法让它工作。
这就是我目前拥有文件的方式：
<script src='Box2dWeb-2.1.a.3.js'></script>
<script src='example5.js'></script>