box2d_rust/types/
body.rs

1// Body creation types and default from types.h / types.c.
2// SPDX-FileCopyrightText: 2023 Erin Catto
3// SPDX-License-Identifier: MIT
4
5use crate::core::{get_length_units_per_meter, SECRET_COOKIE};
6use crate::math_functions::{Pos, Rot, Vec2, POS_ZERO, ROT_IDENTITY, VEC2_ZERO};
7
8/// The body simulation type. Each body is one of these three types.
9/// (b2BodyType)
10#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
11pub enum BodyType {
12    /// zero mass, zero velocity, may be manually moved
13    #[default]
14    Static = 0,
15    /// zero mass, velocity set by user, moved by solver
16    Kinematic = 1,
17    /// positive mass, velocity determined by forces, moved by solver
18    Dynamic = 2,
19}
20
21/// Number of body types. (b2_bodyTypeCount)
22pub const BODY_TYPE_COUNT: usize = 3;
23
24/// Motion locks to restrict the body movement. (b2MotionLocks)
25#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
26pub struct MotionLocks {
27    /// Prevent translation along the x-axis
28    pub linear_x: bool,
29    /// Prevent translation along the y-axis
30    pub linear_y: bool,
31    /// Prevent rotation around the z-axis
32    pub angular_z: bool,
33}
34
35/// A body definition holds all the data needed to construct a rigid body. Must
36/// be initialized using [`default_body_def`]. (b2BodyDef)
37#[derive(Debug, Clone, PartialEq)]
38pub struct BodyDef {
39    /// The body type: static, kinematic, or dynamic.
40    pub type_: BodyType,
41    /// The initial world position of the body.
42    pub position: Pos,
43    /// The initial world rotation of the body.
44    pub rotation: Rot,
45    /// The initial linear velocity of the body's origin, usually m/s.
46    pub linear_velocity: Vec2,
47    /// The initial angular velocity of the body, radians per second.
48    pub angular_velocity: f32,
49    /// Linear damping used to reduce the linear velocity.
50    pub linear_damping: f32,
51    /// Angular damping used to reduce the angular velocity.
52    pub angular_damping: f32,
53    /// Scale the gravity applied to this body. Non-dimensional.
54    pub gravity_scale: f32,
55    /// Sleep speed threshold, default is 0.05 meters per second.
56    pub sleep_threshold: f32,
57    /// Optional body name for debugging. Up to [`NAME_LENGTH`] characters.
58    ///
59    /// [`NAME_LENGTH`]: crate::constants::NAME_LENGTH
60    pub name: String,
61    /// Application specific body data.
62    pub user_data: u64,
63    /// Motion locks to restrict linear and angular movement.
64    pub motion_locks: MotionLocks,
65    /// Set to false if this body should never fall asleep.
66    pub enable_sleep: bool,
67    /// Is this body initially awake or sleeping?
68    pub is_awake: bool,
69    /// Treat this body as a high speed object for continuous collision.
70    pub is_bullet: bool,
71    /// Used to disable a body. A disabled body does not move or collide.
72    pub is_enabled: bool,
73    /// Allow this body to bypass rotational speed limits.
74    pub allow_fast_rotation: bool,
75    /// Enable contact recycling. True by default.
76    pub enable_contact_recycling: bool,
77    /// Used internally to detect a valid definition. DO NOT SET.
78    pub internal_value: i32,
79}
80
81/// Initialize a body definition with the default values. (b2DefaultBodyDef)
82pub fn default_body_def() -> BodyDef {
83    BodyDef {
84        type_: BodyType::Static,
85        position: POS_ZERO,
86        rotation: ROT_IDENTITY,
87        linear_velocity: VEC2_ZERO,
88        angular_velocity: 0.0,
89        linear_damping: 0.0,
90        angular_damping: 0.0,
91        gravity_scale: 1.0,
92        sleep_threshold: 0.05 * get_length_units_per_meter(),
93        name: String::new(),
94        user_data: 0,
95        motion_locks: MotionLocks::default(),
96        enable_sleep: true,
97        is_awake: true,
98        is_bullet: false,
99        is_enabled: true,
100        allow_fast_rotation: false,
101        enable_contact_recycling: true,
102        internal_value: SECRET_COOKIE,
103    }
104}
105
106impl Default for BodyDef {
107    fn default() -> Self {
108        default_body_def()
109    }
110}
box2d_rust/types/body.rs

box2d_rust/types/
body.rs
