bevy_rapier2d/plugin/
configuration.rs

1//! Components used to configure a simulation run by rapier, these are not modified by bevy_rapier.
2
3use bevy::{
4    prelude::{Component, Resource},
5    reflect::Reflect,
6};
7
8use crate::math::{Real, Vect};
9
10#[cfg(doc)]
11use {crate::prelude::TransformInterpolation, rapier::dynamics::IntegrationParameters};
12
13/// The different ways of adjusting the timestep length each frame.
14#[derive(Copy, Clone, Debug, PartialEq, Resource)]
15pub enum TimestepMode {
16    /// Use a fixed timestep: the physics simulation will be advanced by the fixed value
17    /// `dt` seconds at each Bevy tick by performing `substeps` of length `dt / substeps`.
18    Fixed {
19        /// The physics simulation will be advanced by this total amount at each Bevy tick.
20        dt: f32,
21        /// This number of substeps of length `dt / substeps` will be performed at each Bevy tick.
22        substeps: usize,
23    },
24    /// Use a variable timestep: the physics simulation will be advanced by the variable value
25    /// `min(max_dt, Time::delta_seconds() * time_scale)` seconds at each Bevy tick. If
26    /// `time_scale > 1.0` then the simulation will appear to run faster than real-time whereas
27    /// `time_scale < 1.0` makes the simulation run in slow-motion.
28    Variable {
29        /// Maximum amount of time the physics simulation may be advanced at each Bevy tick.
30        max_dt: f32,
31        /// Multiplier controlling if the physics simulation should advance faster (> 1.0),
32        /// at the same speed (= 1.0) or slower (< 1.0) than the real time.
33        time_scale: f32,
34        /// The number of substeps that will be performed at each tick.
35        substeps: usize,
36    },
37    /// Use a fixed timestep equal to `IntegrationParameters::dt`, but don't step if the
38    /// physics simulation advanced by a time greater than the real-world elapsed time multiplied by `time_scale`.
39    /// Rigid-bodies with a component [`TransformInterpolation`] attached will use interpolation to
40    /// estimate the rigid-bodies position in-between steps.
41    Interpolated {
42        /// The physics simulation will be advanced by this total amount at each Bevy tick, unless
43        /// the physics simulation time is ahead of a the real time.
44        dt: f32,
45        /// Multiplier controlling if the physics simulation should advance faster (> 1.0),
46        /// at the same speed (= 1.0) or slower (< 1.0) than the real time.
47        time_scale: f32,
48        /// The number of substeps that will be performed whenever the physics simulation is advanced.
49        substeps: usize,
50    },
51}
52
53impl Default for TimestepMode {
54    fn default() -> Self {
55        TimestepMode::Variable {
56            max_dt: 1.0 / 60.0,
57            time_scale: 1.0,
58            substeps: 1,
59        }
60    }
61}
62
63#[derive(Component, Copy, Clone, Debug, Reflect)]
64/// A component for specifying configuration information for the physics simulation
65pub struct RapierConfiguration {
66    /// Specifying the gravity of the physics simulation.
67    pub gravity: Vect,
68    /// Specifies if the physics simulation is active and update the physics world.
69    pub physics_pipeline_active: bool,
70    /// Specifies the number of subdivisions along each axes a shape should be subdivided
71    /// if its scaled representation cannot be represented with the same shape type.
72    ///
73    /// For example, a ball subject to a non-uniform scaling cannot be represented as a ball
74    /// (it’s an ellipsoid). Thus, in order to be compatible with Rapier, the shape is automatically
75    /// discretized into a convex polyhedron, using `scaled_shape_subdivision` as the number of subdivisions
76    /// along each spherical coordinates angle.
77    pub scaled_shape_subdivision: u32,
78    /// Specifies if backend sync should always accept transform changes, which may be from the writeback stage.
79    pub force_update_from_transform_changes: bool,
80}
81
82impl RapierConfiguration {
83    /// Configures rapier with the specified length unit.
84    ///
85    /// See the documentation of [`IntegrationParameters::length_unit`] for additional details
86    /// on that argument.
87    ///
88    /// The default gravity is automatically scaled by that length unit.
89    pub fn new(length_unit: Real) -> Self {
90        Self {
91            gravity: Vect::Y * -9.81 * length_unit,
92            physics_pipeline_active: true,
93            scaled_shape_subdivision: 10,
94            force_update_from_transform_changes: false,
95        }
96    }
97}
bevy_rapier2d/plugin/configuration.rs

bevy_rapier2d/plugin/
configuration.rs
