game_toolkit_platformer/sim/
surface.rs

1//! [`Surface`]: what kind of ground or wall the character touches: ice, a conveyor belt, a
2//! wall too smooth to climb, a bouncy pad. A [`Terrain`](super::Terrain) answers it in
3//! [`Terrain::surface`](super::Terrain::surface); by default everything is
4//! [`Surface::DEFAULT`] and the [`Tuning`](super::Tuning) alone sets the feel.
5//!
6//! `docs/surfaces.md` has the recipe.
7
8/// The kind of a surface. Each field's default leaves the tuning's feel as it is.
9#[derive(Clone, Copy, Debug, PartialEq)]
10pub struct Surface {
11    /// Scales running's acceleration, braking and turning on this ground: `1.0` as tuned,
12    /// below for ice (`0.1` slides a long way), above for sticky ground.
13    pub friction: f32,
14    /// Whether the character may grab and climb this wall. Wall slides and wall jumps
15    /// still work on a wall that isn't climbable.
16    pub climbable: bool,
17    /// A conveyor belt: carries what stands on it sideways at this speed, units/s
18    /// (positive right). A jump off it keeps the speed, as off moving ground.
19    pub belt: f32,
20    /// Bounciness: a landing faster than [`Surface::BOUNCE_MIN`] bounces back up at this
21    /// share of its downward speed (`0.0`: none, `1.0`: as fast as it came down).
22    pub bounce: f32,
23}
24
25impl Surface {
26    /// Plain ground: the tuning's feel, climbable, still, not bouncy.
27    pub const DEFAULT: Surface = Surface {
28        friction: 1.0,
29        climbable: true,
30        belt: 0.0,
31        bounce: 0.0,
32    };
33
34    /// The slowest landing (units/s down) a bouncy surface bounces back.
35    pub const BOUNCE_MIN: f32 = 40.0;
36}
37
38impl Default for Surface {
39    fn default() -> Self {
40        Self::DEFAULT
41    }
42}
game_toolkit_platformer/sim/surface.rs

game_toolkit_platformer/sim/
surface.rs
