1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
//! `Nav` and `NavCell` structs for navigation and movement cost data.
use bevy::math::UVec3;
use crate::{prelude::ORDINAL_3D_OFFSETS, MovementCost};
/// Navigation state for a cell (position) in the `Grid`.
#[derive(Clone, Copy, Debug)]
pub enum Nav {
/// Agents can move this cell with a defined movement cost.
Passable(MovementCost),
/// Agents cannot move through this cell ever, it is solid.
Impassable,
/// Agents can use this cell to transition to a different height level,
/// such as a ramp/slope/staircase, with a defined movement cost.
Ramp(MovementCost),
}
/// [`NavCell`] represents the navigation data for a position in the grid.
/// Normal use shouldn't require direct interaction with this struct,
#[derive(Debug, Clone)]
pub struct NavCell {
/// Whether the cell is walkable, solid, or a ramp and its associated movement cost.
pub(crate) nav: Nav,
// Internal storage for fast lookup
pub(crate) cost: MovementCost,
// Cached neighbors for this cell.
pub(crate) neighbor_bits: u32,
}
impl NavCell {
/// Creates a new `NavCell` with the given `Nav` state.
pub fn new(nav: Nav) -> Self {
Self {
nav,
cost: match nav {
Nav::Passable(cost) => cost,
Nav::Ramp(cost) => cost,
Nav::Impassable => 0,
},
neighbor_bits: 0,
}
}
/// Is this cell passable?
pub fn is_passable(&self) -> bool {
matches!(self.nav, Nav::Passable { .. } | Nav::Ramp { .. })
}
/// Is this cell impassable?
pub fn is_impassable(&self) -> bool {
matches!(self.nav, Nav::Impassable)
}
/// Is this cell a ramp?
pub fn is_ramp(&self) -> bool {
matches!(self.nav, Nav::Ramp { .. })
}
/// Returns the `Nav` state associated with this cell.
pub fn nav(&self) -> Nav {
self.nav
}
/// Returns an iterator over the neighboring positions that are passable.
pub fn neighbor_iter(&self, pos: UVec3) -> impl Iterator<Item = UVec3> + '_ {
let origin = pos.as_ivec3();
ORDINAL_3D_OFFSETS
.iter()
.enumerate()
.filter_map(move |(i, offset)| {
if (self.neighbor_bits >> i) & 1 != 0 {
Some((origin + *offset).as_uvec3())
} else {
None
}
})
}
}
impl Default for NavCell {
fn default() -> Self {
Self {
nav: Nav::Passable(1),
cost: 1,
neighbor_bits: 0,
}
}
}