Homer Simpson
9eead719b0
Full project snapshot migrated to new Gitea remote without history: engine, editor, physics, script, examples, tests, docs, and assets. Relicensed from GPLv3 to MIT and updated repo URLs. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
102 lines
3.8 KiB
Rust
102 lines
3.8 KiB
Rust
//! The [`CharacterController`] component — a kinematic capsule character.
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//!
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//! A character controller is *not* a rigid body: it never reacts to forces.
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//! Instead the game asks it to move by some desired translation each frame and
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//! the controller resolves that against the world's colliders — sliding along
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//! walls, stepping up small ledges, sticking to the ground on slopes, and
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//! refusing to climb anything too steep — then reports whether the character
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//! ended up grounded. It is the basis for player/NPC movement and is reused by
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//! the Stage-15 prototyping kit.
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//!
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//! The character is a **capsule** (radius + cylindrical half-height along `+Y`).
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//! An entity with this component is moved through
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//! [`PhysicsWorld::move_character`](crate::PhysicsWorld::move_character); it does
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//! **not** carry a [`RigidBody`](crate::RigidBody)/[`Collider`](crate::Collider)
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//! (it isn't simulated), so it never appears in the body set and never
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//! self-collides.
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use oxide_engine::math::Vec3;
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use oxide_engine::reflect::Reflect;
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use serde::{Deserialize, Serialize};
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/// Component: a kinematic capsule character moved by move-and-slide.
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///
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/// Tune the capsule shape (`radius`/`half_height`) and the movement rules
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/// (`max_slope_degrees`, `step_offset`, `snap_to_ground`, `skin_width`). Pass an
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/// entity carrying this to
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/// [`PhysicsWorld::move_character`](crate::PhysicsWorld::move_character).
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#[derive(Debug, Clone, Copy, PartialEq, Serialize, Deserialize, Reflect)]
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pub struct CharacterController {
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/// Capsule radius.
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pub radius: f32,
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/// Capsule cylindrical half-height (the straight segment between the two
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/// hemispherical caps), along local `+Y`.
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pub half_height: f32,
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/// Steepest ground slope (degrees from horizontal) the character will walk
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/// up; steeper surfaces are treated as walls.
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pub max_slope_degrees: f32,
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/// Tallest step/ledge the character will automatically climb. `0` disables
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/// auto-stepping.
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pub step_offset: f32,
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/// Distance below the feet within which the character snaps down to stay
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/// grounded (prevents bouncing down stairs/slopes). `0` disables snapping.
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pub snap_to_ground: f32,
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/// A small collision-detection margin kept around the capsule.
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pub skin_width: f32,
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}
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impl Default for CharacterController {
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fn default() -> Self {
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Self {
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radius: 0.3,
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half_height: 0.6,
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max_slope_degrees: 45.0,
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step_offset: 0.3,
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snap_to_ground: 0.2,
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skin_width: 0.01,
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}
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}
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}
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impl CharacterController {
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/// The total half-height of the capsule (cylinder half-height + one radius),
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/// i.e. the distance from the capsule center to either tip.
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pub fn total_half_height(&self) -> f32 {
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self.half_height + self.radius
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}
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/// The local-space offset from the capsule center down to the feet (the
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/// bottom tip), useful for placing/grounding the character.
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pub fn foot_offset(&self) -> Vec3 {
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Vec3::new(0.0, -self.total_half_height(), 0.0)
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}
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn default_is_a_reasonable_humanoid_capsule() {
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let c = CharacterController::default();
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assert_eq!(c.radius, 0.3);
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assert!((c.total_half_height() - 0.9).abs() < 1e-6);
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assert!((c.foot_offset() - Vec3::new(0.0, -0.9, 0.0)).length() < 1e-6);
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}
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#[test]
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fn round_trips_through_ron() {
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let c = CharacterController {
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radius: 0.4,
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half_height: 1.0,
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max_slope_degrees: 50.0,
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step_offset: 0.0,
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snap_to_ground: 0.0,
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skin_width: 0.02,
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};
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let ron = ron::to_string(&c).unwrap();
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let back: CharacterController = ron::from_str(&ron).unwrap();
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assert_eq!(c, back);
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}
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}
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