JavaScript-mechanics-box2D
Материал из Department of Theoretical and Applied Mechanics
Кафедра ТМ > Программирование > Интернет > JavaScript > Механика Box2D
Текст программы на языке JavaScript, использованы библиотека Box2DJS, а также исходный код с сайта библиотеки. Для простоты js-скрипт интегрирован прямо в html файл:
Файл "box2D_example.html"
1 <html>
2 <head>
3 <title>Box2dWeb example</title>
4 </head>
5 <body onload="init();">
6 <canvas id="canvas" width="600" height="400"></canvas>
7 </body>
8 <script type="text/javascript" src="Box2dWeb-2.1.a.3.min.js"></script>
9 <script type="text/javascript">
10 var world;
11
12 function init() {
13 var b2Vec2 = Box2D.Common.Math.b2Vec2
14 , b2BodyDef = Box2D.Dynamics.b2BodyDef
15 , b2Body = Box2D.Dynamics.b2Body
16 , b2FixtureDef = Box2D.Dynamics.b2FixtureDef
17 , b2Fixture = Box2D.Dynamics.b2Fixture
18 , b2World = Box2D.Dynamics.b2World
19 , b2MassData = Box2D.Collision.Shapes.b2MassData
20 , b2PolygonShape = Box2D.Collision.Shapes.b2PolygonShape
21 , b2CircleShape = Box2D.Collision.Shapes.b2CircleShape
22 , b2DebugDraw = Box2D.Dynamics.b2DebugDraw
23 ;
24
25 world = new b2World(
26 new b2Vec2(0, 10) //gravity
27 , true //allow sleep
28 );
29
30 var fixDef = new b2FixtureDef;
31 fixDef.density = 1.0;
32 fixDef.friction = 0.5;
33 fixDef.restitution = 0.2;
34
35 var bodyDef = new b2BodyDef;
36
37 //create ground
38 bodyDef.type = b2Body.b2_staticBody;
39 bodyDef.position.x = 10;
40 bodyDef.position.y = 13;
41 fixDef.shape = new b2PolygonShape;
42 fixDef.shape.SetAsBox(10, 0.01);
43 world.CreateBody(bodyDef).CreateFixture(fixDef);
44
45
46 //create some objects
47 bodyDef.type = b2Body.b2_dynamicBody;
48
49 fixDef.shape = new b2PolygonShape; // добавим прямоугольник
50 fixDef.shape.SetAsBox(0.5, 2); // размеры прямоугольника
51 bodyDef.position.x = 10;
52 bodyDef.position.y = 10;
53 world.CreateBody(bodyDef).CreateFixture(fixDef);
54
55 fixDef.shape = new b2PolygonShape;
56 fixDef.shape.SetAsBox(2, 0.5);
57 bodyDef.position.x = 10;
58 bodyDef.position.y = 8;
59 world.CreateBody(bodyDef).CreateFixture(fixDef);
60
61 fixDef.shape = new b2CircleShape(2); // добавим круг
62 bodyDef.position.x = 13;
63 bodyDef.position.y = 3;
64 world.CreateBody(bodyDef).CreateFixture(fixDef);
65
66
67 //setup debug draw
68 var debugDraw = new b2DebugDraw();
69 debugDraw.SetSprite(document.getElementById("canvas").getContext("2d"));
70 debugDraw.SetDrawScale(30.0);
71 debugDraw.SetFillAlpha(0.3);
72 debugDraw.SetLineThickness(1.0);
73 debugDraw.SetFlags(b2DebugDraw.e_shapeBit | b2DebugDraw.e_jointBit);
74 world.SetDebugDraw(debugDraw);
75
76 window.setInterval(update, 1000 / 60);
77 };
78
79 function update() {
80 world.Step(
81 1 / 60 //frame-rate
82 , 10 //velocity iterations
83 , 10 //position iterations
84 );
85 world.DrawDebugData();
86 world.ClearForces();
87 };
88
89 </script>
90 </html>
