OxiPhysics

https://docs.rs/oxiphysics/0.1.2/oxiphysics/
Admin
OxiPhysics is a pure-Rust, modular physics engine that provides unified multi-physics simulation...
Tokens:68,924
Snippets:841
Trust Score:9.1
Update:1 month ago
Show doc for...
Tokens:
Raw
### AnimationPlayer Usage Example

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/animation/struct.AnimationPlayer.html

Demonstrates creating an AnimationPlayer with a clip, starting playback, and updating the player over time.

```rust
use oxiphysics::animation::{Vec3Track, EaseKind, AnimationPlayer, AnimationClip, BodyAnimation};

let mut t = Vec3Track::new(false);
t.push_keyframe(0.0, [0.0, 0.0, 0.0], EaseKind::Linear);
t.push_keyframe(2.0, [10.0, 0.0, 0.0], EaseKind::Linear);

let clip = AnimationClip::new("slide", vec![BodyAnimation::new("box").with_position(t)]);
let mut player = AnimationPlayer::new(clip);
player.play();
player.update(1.0);
assert!(!player.is_finished()); // still playing at t=1
player.update(1.0);
assert!(player.is_finished()); // reached t=2
```

--------------------------------

### SimRecorder::begin_step

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/replay/struct.SimRecorder.html

Marks the start of a new simulation step.

```APIDOC
## pub fn begin_step(&mut self, dt: f64)

### Description
Mark the start of a new step with time step `dt`. Must be followed by zero or more `record_*` calls and then `end_step`.
```

--------------------------------

### Initialize and Apply Buoyancy

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/buoyancy/struct.BuoyancyWorld.html

Example showing how to create a world, add a fluid, define a body, and calculate buoyancy forces.

```rust
use oxiphysics::buoyancy::{BuoyancyWorld, BuoyantBody, BuoyantShape};

let mut world = BuoyancyWorld::new(9.81);
world.add_fluid([-10.0, -5.0, -10.0], [10.0, 0.0, 10.0], 1000.0, 0.0);

let body = BuoyantBody {
    id: 1,
    position: [0.0, -0.5, 0.0],
    velocity: [0.0; 3],
    angular_velocity: [0.0; 3],
    mass: 5.0,
    shape: BuoyantShape::Sphere { radius: 0.5 },
};
let result = world.apply(&[body]);
println!("{result:?}");
```

--------------------------------

### SpatialGrid Usage Example

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/spatial_grid/index.html

Demonstrates initializing a SpatialGrid, inserting entries, and performing a radius query to filter nearby items.

```rust
use oxiphysics::spatial_grid::SpatialGrid;

let mut grid = SpatialGrid::new(5.0); // 5 m cells
grid.insert(0, [1.0, 0.0,  2.0]);
grid.insert(1, [3.0, 0.0, -1.0]);
grid.insert(2, [100.0, 0.0, 100.0]); // far away

let hits = grid.query_radius([0.0, 0.0, 0.0], 5.0);
assert!(hits.contains(&0));
assert!(hits.contains(&1));
assert!(!hits.contains(&2));
```

--------------------------------

### Rope Simulation

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/rope/index.html

Example of initializing a rope with 6 links and performing a simulation step.

```APIDOC
## Rope Simulation Example

### Description
Initializes a rope of 6 links hanging from a fixed world position and iterates the simulation using Verlet integration.

### Usage
```rust
use oxiphysics::rope::{AnchorKind, Rope};

// Rope of 6 links hanging from [0, 5, 0], segment rest-length 1 m.
let mut rope = Rope::new([0.0, 5.0, 0.0], 6, 1.0, 1.0).expect("valid rope");
rope.anchor_head = Some(AnchorKind::World([0.0, 5.0, 0.0]));

let no_bodies = &(|_: u64| -> Option<[f64; 3]> { None });
let dt = 1.0 / 60.0;
for _ in 0..200 {
    rope.step(dt, no_bodies);
}
```
```

--------------------------------

### Folded Stacks Format Example

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/profiler/struct.FrameReport.html

Example output format for the to_folded_stacks method.

```text
root;physics;collision 4200

```

--------------------------------

### FractalNoise Usage Example

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/noise/struct.FractalNoise.html

Demonstrates initializing a FractalNoise instance, configuring its parameters, and sampling a value.

```rust
use oxiphysics::noise::FractalNoise;

let mut n = FractalNoise::new(7, 6);
n.persistence = 0.5;
n.lacunarity  = 2.0;
let v = n.sample(0.5, 1.5, 2.5);
assert!(v >= -1.0 && v <= 1.0);
```

--------------------------------

### Construct Box from raw pointer

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/pipeline/type.StageCallback.html

Examples demonstrating how to recreate a Box from a raw pointer or manually allocate memory for a Box.

```rust
#![feature(allocator_api)]

use std::alloc::System;

let x = Box::new_in(5, System);
let (ptr, alloc) = Box::into_raw_with_allocator(x);
let x = unsafe { Box::from_raw_in(ptr, alloc) };
```

```rust
#![feature(allocator_api, slice_ptr_get)]

use std::alloc::{Allocator, Layout, System};

unsafe {
    let ptr = System.allocate(Layout::new::<i32>())?.as_mut_ptr() as *mut i32;
    // In general .write is required to avoid attempting to destruct
    // the (uninitialized) previous contents of `ptr`, though for this
    // simple example `*ptr = 5` would have worked as well.
    ptr.write(5);
    let x = Box::from_raw_in(ptr, System);
}
```

--------------------------------

### Sample ValueNoise3D

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/noise/struct.ValueNoise3D.html

Example usage of initializing a new noise instance and sampling a value at specific coordinates.

```rust
use oxiphysics::noise::ValueNoise3D;

let n = ValueNoise3D::new(0);
let v = n.sample(1.5, -2.3, 4.1);
assert!(v >= -1.0 && v <= 1.0);
```

--------------------------------

### Allocating with custom allocators

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/pipeline/type.StageCallback.html

Examples of using new_in and try_new_in to allocate memory using a specific allocator instance.

```rust
#![feature(allocator_api)]

use std::alloc::System;

let five = Box::new_in(5, System);
```

```rust
#![feature(allocator_api)]

use std::alloc::System;
```

--------------------------------

### TriggerWorld Usage Example

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/trigger/struct.TriggerWorld.html

Demonstrates initializing a TriggerWorld, adding an AABB trigger, and processing body updates to detect occupancy events.

```rust
use oxiphysics::trigger::{TriggerWorld, BodyEntry};

let mut world = TriggerWorld::new();
let _id = world.add_aabb([-5.0, -5.0, -5.0], [5.0, 5.0, 5.0], vec![]);

let bodies = vec![BodyEntry { index: 0, position: [0.0, 0.0, 0.0], radius: 0.5, is_sleeping: false }];
let ev = world.update(1, &bodies);
assert_eq!(ev.len(), 1); // Enter
let ev2 = world.update(2, &bodies);
assert!(ev2.is_empty()); // Stay suppressed by default
```

--------------------------------

### NavMesh::find_path

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/navmesh/struct.NavMesh.html

Calculates a path from a start point to a goal point using A* and the Simple Stupid Funnel algorithm.

```APIDOC
## NavMesh::find_path

### Description
Find a path from `start` to `goal`. Uses A* over the triangle graph, then the Simple Stupid Funnel algorithm to smooth the corridor into waypoints. `agent_radius` and `obstacles` are used to mark portals as impassable.

### Signature
`pub fn find_path(&self, start: [f64; 3], goal: [f64; 3], agent_radius: f64, obstacles: &[Circle2D]) -> Result<Path, NavError>`
```

--------------------------------

### Animation System Usage

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/animation/index.html

Example of creating a Vec3Track, grouping it into a BodyAnimation and AnimationClip, and using an AnimationPlayer to sample the state.

```APIDOC
use oxiphysics::animation::{Vec3Track, EaseKind, AnimationPlayer, AnimationClip, BodyAnimation};

let mut pos = Vec3Track::new(false);
pos.push_keyframe(0.0, [0.0, 0.0, 0.0], EaseKind::Linear);
pos.push_keyframe(1.0, [0.0, 5.0, 0.0], EaseKind::Linear);
pos.push_keyframe(2.0, [0.0, 0.0, 0.0], EaseKind::Linear);

let body_anim = BodyAnimation::new("ball").with_position(pos);
let clip = AnimationClip::new("rise_and_fall", vec![body_anim]);
let mut player = AnimationPlayer::new(clip);
player.play();

let states = player.update(0.5);
```

--------------------------------

### Convert Box to raw pointer with allocator

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/pipeline/type.StageCallback.html

Demonstrates consuming a Box into a raw pointer and allocator, with examples for both automatic and manual memory cleanup.

```rust
#![feature(allocator_api)]

use std::alloc::System;

let x = Box::new_in(String::from("Hello"), System);
let (ptr, alloc) = Box::into_raw_with_allocator(x);
let x = unsafe { Box::from_raw_in(ptr, alloc) };
```

```rust
#![feature(allocator_api)]

use std::alloc::{Allocator, Layout, System};
use std::ptr::{self, NonNull};

let x = Box::new_in(String::from("Hello"), System);
let (ptr, alloc) = Box::into_raw_with_allocator(x);
unsafe {
    ptr::drop_in_place(ptr);
    let non_null = NonNull::new_unchecked(ptr);
    alloc.deallocate(non_null.cast(), Layout::new::<String>());
}
```

--------------------------------

### Construct Box from NonNull pointer

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/pipeline/type.StageCallback.html

Examples demonstrating how to recreate a Box from a NonNull pointer or manually allocate memory for a Box using NonNull.

```rust
#![feature(allocator_api)]

use std::alloc::System;

let x = Box::new_in(5, System);
let (non_null, alloc) = Box::into_non_null_with_allocator(x);
let x = unsafe { Box::from_non_null_in(non_null, alloc) };
```

```rust
#![feature(allocator_api)]

use std::alloc::{Allocator, Layout, System};

unsafe {
    let non_null = System.allocate(Layout::new::<i32>())?.cast::<i32>();
    // In general .write is required to avoid attempting to destruct
    // the (uninitialized) previous contents of `non_null`.
    non_null.write(5);
    let x = Box::from_non_null_in(non_null, System);
}
```

--------------------------------

### MaterialTable API Usage

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/material_table/index.html

Examples of how to interact with the MaterialTable to retrieve material IDs, query contact properties, and set pair-specific overrides.

```APIDOC
## MaterialTable API

### Description
The `MaterialTable` struct allows for the management of material definitions and the calculation of contact properties between material pairs.

### Methods
- **id_for_name(name: &str) -> Option<MaterialId>**
  Retrieves the `MaterialId` associated with a given material name.

- **contact_static_friction(a: MaterialId, b: MaterialId) -> f32**
  Calculates the static friction coefficient for a contact pair using the configured `CombineRule`.

- **contact_restitution(a: MaterialId, b: MaterialId) -> f32**
  Calculates the restitution coefficient for a contact pair.

- **set_pair_restitution(a: MaterialId, b: MaterialId, value: f32)**
  Sets a specific override for the restitution coefficient between two materials.

### Example
```rust
use oxiphysics::material_table::{MaterialTable, CombineRule};

let mut table = MaterialTable::new();
let rubber = table.id_for_name("rubber").unwrap();
let concrete = table.id_for_name("concrete").unwrap();

// Query friction
let friction = table.contact_static_friction(rubber, concrete);

// Set override
let ice = table.id_for_name("ice").unwrap();
table.set_pair_restitution(ice, ice, 0.05);
```
```

--------------------------------

### Convert Box to NonNull pointer with allocator

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/pipeline/type.StageCallback.html

Demonstrates consuming a Box into a NonNull pointer and allocator, with examples for both automatic and manual memory cleanup.

```rust
#![feature(allocator_api)]

use std::alloc::System;

let x = Box::new_in(String::from("Hello"), System);
let (non_null, alloc) = Box::into_non_null_with_allocator(x);
let x = unsafe { Box::from_non_null_in(non_null, alloc) };
```

```rust
#![feature(allocator_api)]

use std::alloc::{Allocator, Layout, System};

let x = Box::new_in(String::from("Hello"), System);
let (non_null, alloc) = Box::into_non_null_with_allocator(x);
unsafe {
    non_null.drop_in_place();
    alloc.deallocate(non_null.cast::<u8>(), Layout::new::<String>());
}
```

--------------------------------

### Typical Snapshot Workflow

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/snapshot/index.html

Demonstrates initializing a SnapshotManager and recording a WorldSnapshot after a simulation step.

```rust
use oxiphysics::snapshot::{BodySnapshot, WorldSnapshot, SnapshotManager};

let mut manager = SnapshotManager::new(10);   // keep last 10 snapshots

// After each simulation step…
let snap = WorldSnapshot::new(1, 1.0 / 60.0)
    .add_body(BodySnapshot::at_rest(0, [0.0, 0.0, 0.0]));
manager.push(snap);

assert_eq!(manager.len(), 1);
assert!(manager.latest().is_some());
```

--------------------------------

### Initialize and Configure ForceFieldSystem

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/force_field/struct.ForceFieldSystem.html

Demonstrates creating a system, adding global and bounded force fields, and calculating the resulting force at a specific point in time.

```rust
use oxiphysics::force_field::{ForceFieldKind, ForceFieldSystem, AabbRegion};

let mut sys = ForceFieldSystem::new();

// Gravity (downward uniform field)
sys.add(ForceFieldKind::Uniform { force: [0.0, -9.81, 0.0] });

// An explosion at origin, starting at t=0
sys.add(ForceFieldKind::Explosion {
    center: [0.0, 0.0, 0.0],
    peak_force: 1000.0,
    wave_speed: 50.0,
    thickness: 2.0,
    start_time: 0.0,
});

// Vortex bounded to a region
let id = sys.add_bounded(
    ForceFieldKind::Vortex {
        center: [0.0, 0.0, 0.0],
        axis: [0.0, 1.0, 0.0],
        tangential_strength: 5.0,
        axial_strength: 0.0,
    },
    AabbRegion::new([-5.0; 3], [5.0; 3]),
);

let force = sys.force_at([1.0, 0.0, 0.0], 0.5);
assert!(force.iter().any(|&f| f.abs() > 1e-10));

sys.disable(id);
```

--------------------------------

### BodyTransformLookup Implementation Pattern

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/rope/type.BodyTransformLookup.html

Example syntax for implementing the lookup as a closure.

```rust
&|handle: u64| -> Option<[f64; 3]> { … }
```

--------------------------------

### Initialize and step an XPBD solver

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/xpbd/index.html

Demonstrates creating an XpbdSolver, adding particles with specific masses, defining a distance constraint, and advancing the simulation by one time step.

```rust
use oxiphysics::xpbd::{XpbdConstraint, XpbdSolver};

let mut solver = XpbdSolver::new();
let a = solver.add_particle([0.0, 0.0, 0.0], 0.0); // pinned
let b = solver.add_particle([1.0, 0.0, 0.0], 1.0); // dynamic
solver.add_constraint(XpbdConstraint::Distance {
    a,
    b,
    rest_length: 1.0,
    compliance: 0.0,
});
solver.step(1.0 / 60.0);
```

--------------------------------

### Initialize NavMesh and Find Path

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/navmesh/index.html

Demonstrates creating a NavMesh from vertices and triangles, then calculating a path between two points.

```rust
use oxiphysics::navmesh::{NavMesh, Circle2D};

let verts = vec![
    [0.0, 0.0, 0.0f64],
    [1.0, 0.0, 0.0],
    [0.0, 0.0, 1.0],
    [1.0, 0.0, 1.0],
];
let tris = vec![[0u32, 1, 2], [1, 3, 2]];
let mesh = NavMesh::from_triangles(verts, tris);
let path = mesh.find_path([0.1, 0.0, 0.1], [0.9, 0.0, 0.9], 0.0, &[]);
assert!(path.is_ok());
```

--------------------------------

### Initialize and Configure ForceFieldSystem

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/force_field/index.html

Demonstrates creating a ForceFieldSystem and adding multiple force field types such as radial attraction and wind.

```rust
use oxiphysics::force_field::{ForceFieldKind, ForceFieldSystem};

let mut sys = ForceFieldSystem::new();

// Gravity-like field pulling toward origin
sys.add(ForceFieldKind::RadialAttract {
    center: [0.0, 0.0, 0.0],
    strength: 9.81,
    falloff_exp: 2.0,
});

// Wind pushing in +X
sys.add(ForceFieldKind::Wind {
    direction: [1.0, 0.0, 0.0],
    base_speed: 5.0,
});

let f = sys.force_at([1.0, 1.0, 1.0], 0.0);
assert!(f[0].is_finite()); // wind contribution
```

--------------------------------

### Initialize and Configure MaterialTable

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/material_table/index.html

Demonstrates creating a MaterialTable, retrieving material IDs, querying contact friction, and setting a custom pair-wise restitution override.

```rust
use oxiphysics::material_table::{MaterialTable, CombineRule};

let mut table = MaterialTable::new();
let rubber   = table.id_for_name("rubber").unwrap();
let concrete = table.id_for_name("concrete").unwrap();

// Rubber-on-concrete: high friction
let friction = table.contact_static_friction(rubber, concrete);
assert!(friction > 0.5);

// Ice-on-ice: override bounce to a specific value
let ice = table.id_for_name("ice").unwrap();
table.set_pair_restitution(ice, ice, 0.05);
assert!((table.contact_restitution(ice, ice) - 0.05).abs() < 1e-9);
```

--------------------------------

### Initialize and populate SnapshotManager

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/snapshot/struct.SnapshotManager.html

Demonstrates creating a manager with a fixed capacity and pushing snapshots, showing how older snapshots are automatically dropped.

```rust
use oxiphysics::snapshot::{BodySnapshot, WorldSnapshot, SnapshotManager};

let mut manager = SnapshotManager::new(5);
for step in 0..8_u64 {
    let snap = WorldSnapshot::new(step, step as f64 / 60.0)
        .add_body(BodySnapshot::at_rest(0, [0.0, step as f64, 0.0]));
    manager.push(snap);
}
// Only the last 5 are kept
assert_eq!(manager.len(), 5);
assert_eq!(manager.latest().unwrap().step, 7);
```

--------------------------------

### Initialize and Step RollbackWorld

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/rollback/index.html

Demonstrates setting up a RollbackWorld with custom simulation functions and performing a simulation step.

```rust
use oxiphysics::rollback::RollbackWorld;

struct Sim { state: i64 }

fn advance(w: &mut Sim, _dt: f64, cmds: &[i32]) {
    w.state += cmds.iter().map(|c| *c as i64).sum::<i64>();
}
fn snapshot(w: &Sim) -> Vec<u8> { w.state.to_le_bytes().to_vec() }
fn restore(w: &mut Sim, snap: &[u8]) {
    if snap.len() == 8 {
        let arr: [u8; 8] = snap.try_into().unwrap_or([0; 8]);
        w.state = i64::from_le_bytes(arr);
    }
}

let mut rw = RollbackWorld::new(Sim { state: 0 }, 64, advance, snapshot, restore);
rw.step(1.0 / 60.0, &[5_i32]);
assert_eq!(rw.world.state, 5);
```

--------------------------------

### Initialize and Run Physics Scheduler

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/scheduler/index.html

Demonstrates the lifecycle of a Scheduler, including island registration, frame scheduling, and velocity updates for auto-sleeping.

```rust
use oxiphysics::scheduler::{Scheduler, Priority};

let mut sched = Scheduler::new(2, 4); // base = 2, max = 4

let island_a = sched.add_island(Priority::Critical, 10);
let island_b = sched.add_island(Priority::Normal, 50);
let island_c = sched.add_island(Priority::Low, 200);

// Simulate a few frames
for _ in 0..60 {
    let frame = sched.schedule(1.0 / 60.0);
    for alloc in &frame.allocations {
        // run `alloc.substeps` sub-steps of dt = `alloc.dt_per_substep`
        let _ = alloc.substeps;
        let _ = alloc.dt_per_substep;
    }
    // update velocity hints so the scheduler can auto-sleep idle islands
    sched.update_velocity(island_b, 0.001);
    sched.update_velocity(island_c, 0.0);
    sched.auto_sleep_step();
}
```

--------------------------------

### Initialize and update LodSystem

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/lod/index.html

Demonstrates configuring the LOD system with distance thresholds and substep counts, adding bodies, and processing tier transitions.

```rust
use oxiphysics::lod::{LodSystem, LodConfig, LodTier};

let config = LodConfig {
    full_radius:    50.0,
    reduced_radius: 150.0,
    minimal_radius: 300.0,
    substeps_full:    4,
    substeps_reduced: 2,
    substeps_minimal: 1,
};
let mut lod = LodSystem::new(config, [0.0; 3]);

let near_body = lod.add_body([10.0, 0.0, 0.0], 0.0);
let far_body  = lod.add_body([500.0, 0.0, 0.0], 0.0);

let transitions = lod.update();
assert_eq!(lod.tier(near_body), Some(LodTier::Full));
assert_eq!(lod.tier(far_body), Some(LodTier::Frozen));
assert!(!transitions.is_empty());
```

--------------------------------

### Leaking Box memory

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/pipeline/type.StageCallback.html

Examples of consuming a Box to return a static mutable reference, applicable to both simple types and unsized slices.

```rust
let x = Box::new(41);
let static_ref: &'static mut usize = Box::leak(x);
*static_ref += 1;
assert_eq!(*static_ref, 42);
```

```rust
let x = vec![1, 2, 3].into_boxed_slice();
let static_ref = Box::leak(x);
static_ref[0] = 4;
assert_eq!(*static_ref, [4, 2, 3]);
```

--------------------------------

### Record and Replay Simulation Inputs in Rust

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/replay/index.html

Demonstrates the full lifecycle of recording simulation steps with SimRecorder and replaying them using SimReplayer.

```rust
use oxiphysics::replay::{SimRecorder, SimReplayer, ReplayCommand};

let mut rec = SimRecorder::new(42);

// Simulate 3 steps, recording the inputs
for step in 0..3 {
    rec.begin_step(1.0 / 60.0);
    rec.record_force(0, [0.0, 100.0, 0.0]);
    rec.record_impulse(1, [1.0, 0.0, 0.0]);
    rec.end_step();
}
let record = rec.finish();
assert_eq!(record.step_count(), 3);

// Replay
let mut replayer = SimReplayer::new(record);
while let Some(step) = replayer.advance() {
    for cmd in &step.commands {
        let _ = cmd; // re-apply each command to the simulation
    }
}
assert!(replayer.is_done());
```

--------------------------------

### SnapshotManager Usage

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/snapshot/index.html

Demonstrates the typical workflow for initializing a SnapshotManager and pushing a new WorldSnapshot after a simulation step.

```APIDOC
## SnapshotManager Workflow

### Description
This example shows how to initialize a `SnapshotManager` with a fixed capacity and record a `WorldSnapshot` containing body states.

### Code Example
```rust
use oxiphysics::snapshot::{BodySnapshot, WorldSnapshot, SnapshotManager};

let mut manager = SnapshotManager::new(10);   // keep last 10 snapshots

// After each simulation step…
let snap = WorldSnapshot::new(1, 1.0 / 60.0)
    .add_body(BodySnapshot::at_rest(0, [0.0, 0.0, 0.0]));
manager.push(snap);

assert_eq!(manager.len(), 1);
assert!(manager.latest().is_some());
```
```

--------------------------------

### Initialize Transform and Vector

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/index.html

Demonstrates basic usage of the core math and transform modules to perform a point transformation.

```rust
use oxiphysics::core::math::Vec3;
use oxiphysics::core::Transform;

let t = Transform::default();
let v = Vec3::new(1.0, 2.0, 3.0);
let _transformed = t.transform_point(&v);
```

--------------------------------

### Constructing a PhysicsConfig

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/pipeline/struct.PipelineConfigBuilder.html

Demonstrates the fluent API usage to initialize and configure a new physics pipeline configuration.

```rust
let config = PipelineConfigBuilder::new()
    .gravity(Vec3::new(0.0, -9.81, 0.0))
    .solver_iterations(10)
    .ccd_enabled(true)
    .build();
```

--------------------------------

### Construct a PhysicsPipeline

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/pipeline/struct.PipelineBuilder.html

Demonstrates the fluent builder pattern to configure and finalize a PhysicsPipeline instance.

```rust
let pipeline = PhysicsPipeline::builder()
    .gravity(Vec3::new(0.0, -9.81, 0.0))
    .ccd_enabled(true)
    .profiling(true)
    .finish();
```

--------------------------------

### EventBus Usage

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/event_bus/index.html

Demonstrates how to initialize an EventBus, subscribe to events, publish events, and process the event queue.

```APIDOC
## EventBus

### Description
A lightweight publish/subscribe event bus for physics events.

### Methods
- **new()**: Creates a new EventBus instance.
- **subscribe(listener: Fn(PhysicsEvent)) -> ListenerId**: Registers a listener function to be called when events are flushed.
- **unsubscribe(id: ListenerId)**: Removes a previously registered listener.
- **publish(event: PhysicsEvent)**: Queues a physics event to be dispatched.
- **flush()**: Dispatches all queued events to registered listeners.
- **drain() -> Vec<PhysicsEvent>**: Drains the event queue and returns the events as a vector without dispatching to listeners.
```

--------------------------------

### Using ProfilerSession for hierarchical timing

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/profiler/index.html

Demonstrates initializing a session, creating nested scopes with RAII guards, and generating reports in CSV, JSON, and folded stack formats.

```rust
use oxiphysics::profiler::ProfilerSession;

let mut session = ProfilerSession::new();
session.begin_frame();

{
    let _a = session.scope("physics");
    {
        let _b = session.scope("collision");
        // inner work
    } // _b drops here — records "collision"
}   // _a drops here — records "physics"

let report = session.end_frame();
println!("frame ns: {}", report.frame_ns);
println!("csv:\n{}", report.to_csv());
println!("json:\n{}", report.to_json());
println!("folded:\n{}", report.to_folded_stacks());
```

--------------------------------

### Using DebugDrawSession for Simulation Steps

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/debug_draw/struct.DebugDrawSession.html

Demonstrates initializing a session, beginning a step, adding a sphere command, and finalizing the frame.

```rust
use oxiphysics::debug_draw::{DebugDrawSession, DrawDuration};

let mut session = DebugDrawSession::new();
session.begin_step(42);
session.sphere([0.0, 1.0, 0.0], 0.5, [1.0, 0.0, 0.0, 1.0]);
let frame = session.end_step();
assert_eq!(frame.step, 42);
assert_eq!(frame.commands.len(), 1);
```

--------------------------------

### Initialize and move a CharacterController

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/character/index.html

Demonstrates setting up a character controller with a capsule shape and performing a movement operation using a custom sweep callback.

```rust
use oxiphysics::character::{CharacterController, CharacterConfig, CharacterShape, SweepHit};

let shape = CharacterShape { radius: 0.4, half_height: 0.9 };
let config = CharacterConfig::default();

let mut controller = CharacterController::new([0.0, 1.0, 0.0], shape, config);

// Move down by 1 unit; caller-provided sweep returns no hit.
let result = controller.move_and_slide([0.0, -1.0, 0.0], |_origin, _dir| None);
let _ = result.translation;
```

--------------------------------

### Calculate Aerodynamic Forces with AeroSystem

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/aero/index.html

Demonstrates setting up an AeroEntry with a bluff-body and a wing surface, then calculating the resulting forces using AeroSystem.

```rust
use oxiphysics::aero::{
    AeroBody, AeroEntry, AeroSystem,
    DragCurve, LiftCurve, WingSurface,
};

// Identity rotation (body axes aligned with world axes)
let identity = [[1.0, 0.0, 0.0], [0.0, 1.0, 0.0], [0.0, 0.0, 1.0]];

// A flat plate moving at 20 m/s into the wind
let entry = AeroEntry {
    position: [0.0, 0.0, 0.0],
    rotation: identity,
    velocity: [20.0, 0.0, 0.0],
    drag_body: Some(AeroBody {
        drag_coeff: 1.28,
        cross_section: 0.05,
        air_density: 1.225,
    }),
    wings: vec![WingSurface {
        center_local: [0.0, 0.0, 0.0],
        normal_local: [0.0, 1.0, 0.0],
        chord: 0.3,
        span: 1.2,
        lift_curve: LiftCurve::Linear { cl0: 0.0, slope: 5.73 },
        drag_curve: DragCurve::Constant(0.02),
        air_density: 1.225,
    }],
};

let system = AeroSystem { entries: vec![entry], wind: [0.0; 3] };
let forces = system.apply();
assert_eq!(forces.len(), 1);
assert!(forces[0].force[0] < 0.0, "drag opposes +X motion");
```

--------------------------------

### Perform a Raycast Query in Rust

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/query/index.html

Demonstrates initializing a QueryWorld, adding spheres, and performing a raycast to find the first intersection.

```rust
use oxiphysics::query::{QueryWorld, Ray, QueryFilter};

let mut world = QueryWorld::new();
world.add_sphere(0, [0.0, 0.0, 0.0], 1.0, false);
world.add_sphere(1, [3.0, 0.0, 0.0], 1.0, false);

let ray = Ray::new([-5.0, 0.0, 0.0], [1.0, 0.0, 0.0]);
let hit = world.raycast(&ray, &QueryFilter::default());
assert!(hit.is_some());
assert_eq!(hit.unwrap().body_index, 0);
```

--------------------------------

### Using the EventBus for Physics Events

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/event_bus/index.html

Demonstrates how to subscribe to events, publish them, and manage the event queue using flush or drain.

```rust
use oxiphysics::event_bus::{EventBus, PhysicsEvent};

let mut bus = EventBus::new();

// Register a listener that counts collisions
let id = bus.subscribe(|ev| {
    if matches!(ev, PhysicsEvent::CollisionBegin { .. }) {
        // handle collision
    }
});

// Emit some events (normally done by the pipeline)
bus.publish(PhysicsEvent::CollisionBegin {
    body_a: 0, body_b: 1,
    contact_normal: [0.0, 1.0, 0.0],
    penetration_depth: 0.01,
});
bus.publish(PhysicsEvent::StepCompleted { step: 1, sim_time: 1.0 / 60.0, dt: 1.0 / 60.0 });

// Flush: deliver all queued events to listeners
bus.flush();

// Or drain: take ownership without calling listeners
let events = bus.drain();
assert!(events.is_empty()); // already flushed above

bus.unsubscribe(id);
```

--------------------------------

### Scheduler::new

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/scheduler/struct.Scheduler.html

Creates a new instance of the Scheduler with specified substep configurations.

```APIDOC
## pub fn new(base_substeps: u32, max_substeps: u32) -> Self

### Description
Creates a new scheduler instance. The base_substeps parameter is clamped to >= 1, and max_substeps is clamped to >= base_substeps.

### Parameters
- **base_substeps** (u32) - Required - Substeps for Normal islands.
- **max_substeps** (u32) - Required - Substeps for High/Critical islands.
```

--------------------------------

### Initialize CouplingRuntime

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/struct.CouplingRuntime.html

Create a new, empty instance of the runtime.

```rust
pub fn new() -> Self
```

--------------------------------

### IkChain::new

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/ik/struct.IkChain.html

Creates a new IkChain instance from a root position and a list of segment definitions.

```APIDOC
## pub fn new(root_world: [f64; 3], segments: &[(f64, f64, f64)]) -> Self

### Description
Builds a new kinematic chain starting at the specified root world position. The segments parameter accepts a list of tuples containing (segment_length, cone_limit_rad, twist_limit_rad).

### Parameters
- **root_world** ([f64; 3]) - The world-space position of the root joint base.
- **segments** (&[(f64, f64, f64)]) - A slice of tuples defining segment length, cone limit in radians, and twist limit in radians.
```

--------------------------------

### Initialize and update ContactCache

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/contact_cache/index.html

Demonstrates the basic lifecycle of a ContactCache, including initialization, updating a contact pair, and retrieving cached data.

```rust
use oxiphysics::contact_cache::{ContactCache, ContactPoint};

let mut cache = ContactCache::new(3);

cache.begin_step();
let pt = ContactPoint {
    pos_a: [0.0, 1.0, 0.0],
    pos_b: [0.0, 0.9, 0.0],
    normal: [0.0, 1.0, 0.0],
    depth: 0.1,
};
cache.update_pair(0, 1, vec![pt]);
cache.evict_stale();

let entry = cache.lookup(0, 1).unwrap();
assert_eq!(entry.points.len(), 1);
```

--------------------------------

### BenchmarkBaseline::new

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/perf_regression/struct.BenchmarkBaseline.html

Creates a new empty BenchmarkBaseline instance.

```APIDOC
## pub fn new(commit_hash: &str, date: &str) -> Self

### Description
Creates a new empty baseline with the specified commit hash and date.

### Parameters
- **commit_hash** (&str) - Required - Git commit hash or identifier.
- **date** (&str) - Required - Human-readable date string.
```

--------------------------------

### CouplingRuntime::new

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/struct.CouplingRuntime.html

Creates a new, empty CouplingRuntime instance.

```APIDOC
## pub fn new() -> Self

### Description
Create an empty runtime with no domains or couplers.
```

--------------------------------

### Solve an IK chain using FABRIK

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/ik/index.html

Demonstrates initializing an IkChain with three segments and solving for a target position using the FABRIK solver.

```rust
use oxiphysics::ik::{IkChain, IkSolver};

// Three 1-metre segments hanging downward from origin
let mut chain = IkChain::new([0.0, 0.0, 0.0], &[
    (1.0, std::f64::consts::PI, 0.0),
    (1.0, std::f64::consts::PI, 0.0),
    (1.0, std::f64::consts::PI, 0.0),
]);

let solver = IkSolver::Fabrik { max_iterations: 30, tolerance: 1e-6 };
let report = solver.solve(&mut chain, [0.0, 3.0, 0.0]);
assert!(report.converged);
```

--------------------------------

### Construct a scene using SceneBuilder

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/scene/struct.SceneBuilder.html

Demonstrates the fluent builder pattern to define a scene with gravity, a sphere, and a static box.

```rust
use oxiphysics::scene::SceneBuilder;

let scene = SceneBuilder::new("demo")
    .with_gravity([0.0, -9.81, 0.0])
    .add_sphere("ball", [0.0, 5.0, 0.0], 0.5, false)
    .add_static_box("floor", [0.0, 0.0, 0.0], [10.0, 0.1, 10.0])
    .build();

assert_eq!(scene.body_count(), 2);
```

--------------------------------

### Constructing a PhysicsPipeline with the Builder

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/pipeline/struct.PhysicsPipeline.html

Use the builder pattern to initialize a pipeline with specific gravity and CCD settings.

```rust
let pipeline = PhysicsPipeline::builder()
    .gravity(Vec3::new(0.0, -9.81, 0.0))
    .ccd_enabled(true)
    .finish();
```

--------------------------------

### CharacterController Methods

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/character/struct.CharacterController.html

Methods for initializing the controller, handling movement with collision, jumping, and applying gravity.

```rust
pub fn new( position: [f64; 3], shape: CharacterShape, config: CharacterConfig, ) -> Self
```

```rust
pub fn move_and_slide<F>( &mut self, desired_delta: [f64; 3], sweep: F, ) -> CharacterMove
where F: Fn([f64; 3], [f64; 3]) -> Option<SweepHit>,
```

```rust
pub fn jump(&mut self, speed: f64)
```

```rust
pub fn apply_gravity(&mut self, gravity_accel: f64, dt: f64)
```

--------------------------------

### Factory Methods

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/scene/struct.SceneMaterial.html

Convenience methods to create pre-configured SceneMaterial instances.

```APIDOC
## Factory Methods

### static_surface()
Returns a material for static surfaces (high friction, no bounce).

### rubber()
Returns a rubber-like material (high restitution, high friction).

### metal()
Returns a metal-like material (low restitution, moderate friction).

### ice()
Returns an ice-like material (very low friction).
```

--------------------------------

### Clone Box from Reference

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/pipeline/type.StageCallback.html

Demonstrates cloning a Box from a reference using a specific allocator.

```rust
let hello: Box<str, System> = Box::try_clone_from_ref_in("hello", System)?;
```

--------------------------------

### RollbackWorld::new

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/rollback/struct.RollbackWorld.html

Creates a new instance of RollbackWorld, initializing the simulation world and required callback functions.

```APIDOC
## pub fn new(world: World, capacity: usize, advance_fn: fn(&mut World, f64, &[Cmd]), snapshot_fn: fn(&World) -> Vec<u8>, restore_fn: fn(&mut World, &[u8])) -> Self

### Description
Initializes a new RollbackWorld. An initial frame at tick 0 is captured immediately to ensure state restoration is possible.

### Parameters
- **world** (World) - The initial simulation world.
- **capacity** (usize) - The capacity of the rollback buffer.
- **advance_fn** (fn) - Function to advance the simulation state.
- **snapshot_fn** (fn) - Function to serialize the world state.
- **restore_fn** (fn) - Function to restore the world state from a snapshot.
```

--------------------------------

### CloneToUninit Implementation

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/character/struct.CharacterConfig.html

Experimental nightly-only API for performing copy-assignment to uninitialized memory.

```rust
unsafe fn clone_to_uninit(&self, dest: *mut u8)
```

--------------------------------

### Create a new FluidVolume

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/buoyancy/struct.FluidVolume.html

Constructor for creating a fluid volume with default drag coefficients.

```rust
pub fn new(min: [f64; 3], max: [f64; 3], density: f64) -> Self
```

--------------------------------

### Register domains and couplers

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/struct.CouplingRuntime.html

Methods to add simulation domains and couplers to the runtime, returning their respective indices.

```rust
pub fn add_domain(&mut self, domain: Box<dyn CouplingDomain>) -> usize
```

```rust
pub fn add_coupler(&mut self, coupler: Box<dyn DomainCoupler>) -> usize
```

--------------------------------

### BuoyancyWorld Methods

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/buoyancy/struct.BuoyancyWorld.html

Methods for initializing the buoyancy world, managing fluid volumes, and calculating forces on bodies.

```APIDOC
## pub fn new(gravity: f64) -> Self

### Description
Creates a new BuoyancyWorld instance with the specified gravitational acceleration.

## pub fn add_fluid(&mut self, min: [f64; 3], max: [f64; 3], density: f64, surface_y: f64) -> u32

### Description
Registers a new fluid volume defined by an AABB (min/max coordinates), density, and surface level. Returns a unique ID for the fluid.

## pub fn add_fluid_with_drag(&mut self, min: [f64; 3], max: [f64; 3], density: f64, surface_y: f64, linear_drag: f64, angular_drag: f64) -> u32

### Description
Registers a fluid volume with explicit linear and angular drag coefficients.

## pub fn remove_fluid(&mut self, id: u32)

### Description
Removes a fluid volume from the world by its ID.

## pub fn apply(&self, bodies: &[BuoyantBody]) -> Vec<(u32, BuoyancyForce)>

### Description
Calculates the combined buoyancy and drag forces for a slice of bodies against all overlapping fluid volumes.

## pub fn apply_single(&self, body: &BuoyantBody) -> Option<BuoyancyForce>

### Description
Calculates the buoyancy force for a single body, returning None if the body does not overlap any fluid.

## pub fn is_floating(&self, body: &BuoyantBody, threshold: f64) -> bool

### Description
Estimates if a body is floating at the surface based on a submerged fraction threshold.
```

--------------------------------

### AnimationClip::new

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/animation/struct.AnimationClip.html

Creates a new instance of an AnimationClip.

```APIDOC
## pub fn new(name: impl Into<String>, body_animations: Vec<BodyAnimation>) -> Self

### Description
Creates a new AnimationClip with the specified name and a collection of body animations.

### Parameters
- **name** (impl Into<String>) - The human-readable name of the clip.
- **body_animations** (Vec<BodyAnimation>) - The list of body animation tracks to include.
```

--------------------------------

### Try to create a new Box

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/pipeline/type.StageCallback.html

Experimental API that returns an error if heap allocation fails.

```rust
#![feature(allocator_api)]

let five = Box::try_new(5)?;
```

--------------------------------

### MaterialTable::new

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/material_table/struct.MaterialTable.html

Creates a new MaterialTable instance pre-populated with built-in surface presets.

```APIDOC
## pub fn new() -> Self

### Description
Creates a table pre-populated with six built-in surface presets: concrete, rubber, metal, ice, wood, and glass.
```

--------------------------------

### CouplingRuntime Methods

Source: https://docs.rs/oxiphysics/0.1.2/oxiphysics/coupling/struct.CouplingRuntime.html

Methods for managing domains, couplers, and simulation steps within the CouplingRuntime.

```APIDOC
## pub fn new() -> Self

### Description
Create an empty runtime with no domains or couplers.

## pub fn add_domain(&mut self, domain: Box<dyn CouplingDomain>) -> usize

### Description
Register a domain and return its index.

## pub fn add_coupler(&mut self, coupler: Box<dyn DomainCoupler>) -> usize

### Description
Register a coupler and return its index.

## pub fn schedule_pair(&mut self, coupler_idx: usize, domain_a_idx: usize, domain_b_idx: usize)

### Description
Schedule a coupling step between two domains via an existing coupler. The triple is appended to the schedule in the order it was registered.

## pub fn step(&mut self, dt: f64) -> Vec<CouplingReport>

### Description
Advance all scheduled couplers by one time step of duration `dt`. Returns a `Vec<CouplingReport>` with one entry per scheduled pair, in schedule order.

## pub fn domain_count(&self) -> usize

### Description
Return the number of registered domains.

## pub fn coupler_count(&self) -> usize

### Description
Return the number of registered couplers.

## pub fn schedule_len(&self) -> usize

### Description
Return the number of scheduled pairs.
```
Tokens:
Raw