Cocos2d Box2D之简介

 1 /// The body type.
 2 /// static: zero mass, zero velocity, may be manually moved
 3 /// kinematic: zero mass, non-zero velocity set by user, moved by solver
 4 /// dynamic: positive mass, non-zero velocity determined by forces, moved by solver
 5 enum b2BodyType
 6 {
 7         b2_staticBody = 0,    //静止Body
 8         b2_kinematicBody,     //浮动Body
 9         b2_dynamicBody        //动态Body
10         // TODO_ERIN
11         //b2_bulletBody,
12 };
13 
14 /// A body definition holds all the data needed to construct a rigid body.
15 /// You can safely re-use body definitions. Shapes are added to a body after construction.
16 struct b2BodyDef
17 {
18         /// This constructor sets the body definition default values.
19         b2BodyDef()
20         {
21                userData = NULL;
22                position.Set(0.0f, 0.0f);          //位置
23                angle = 0.0f;                      //弧度
24                linearVelocity.Set(0.0f, 0.0f);    //直线速度设置
25                angularVelocity = 0.0f;
26                linearDamping = 0.0f;              //直线阻尼
27                angularDamping = 0.0f;
28                allowSleep = true;
29                awake = true;
30                fixedRotation = false;             //角度
31                bullet = false;
32                type = b2_staticBody;
33                active = true;
34                gravityScale = 1.0f;          
35         }
36 
37         /// The body type: static, kinematic, or dynamic.
38         /// Note: if a dynamic body would have zero mass, the mass is set to one.
39 
40     ///如果一个动态的身体将有零质量，质量被设置为一。
41         b2BodyType type;
42 
43         /// The world position of the body. Avoid creating bodies at the origin
44         /// since this can lead to many overlapping shapes.
45 
46     /// 刚体在物理世界中的位置
47         b2Vec2 position;
48 
49         /// The world angle of the body in radians.
50         float32 angle;
51 
52         /// The linear velocity of the body‘s origin in world co-ordinates.
53         b2Vec2 linearVelocity;
54 
55         /// The angular velocity of the body.
56         float32 angularVelocity;
57 
58         /// Linear damping is use to reduce the linear velocity. The damping parameter
59         /// can be larger than 1.0f but the damping effect becomes sensitive to the
60         /// time step when the damping parameter is large.
61         float32 linearDamping;
62 
63         /// Angular damping is use to reduce the angular velocity. The damping parameter
64         /// can be larger than 1.0f but the damping effect becomes sensitive to the
65         /// time step when the damping parameter is large.
66         float32 angularDamping;
67 
68         /// Set this flag to false if this body should never fall asleep. Note that
69         /// this increases CPU usage.
70         bool allowSleep;
71 
72         /// Is this body initially awake or sleeping?
73         bool awake;
74 
75         /// Should this body be prevented from rotating? Useful for characters.
76         bool fixedRotation;
77 
78         /// Is this a fast moving body that should be prevented from tunneling through
79         /// other moving bodies? Note that all bodies are prevented from tunneling through
80         /// kinematic and static bodies. This setting is only considered on dynamic bodies.
81         /// @warning You should use this flag sparingly since it increases processing time.
82         bool bullet;
83 
84         /// Does this body start out active?
85         bool active;
86 
87         /// Use this to store application specific body data.
88         void* userData;
89 
90         /// Scale the gravity applied to this body.
91         float32 gravityScale;
92 };