veloren_rtsim/ai/
predicate.rs

1use rand::Rng;
2
3use super::NpcCtx;
4
5pub trait Predicate: Sized + Clone {
6    fn should(&mut self, ctx: &mut NpcCtx) -> bool;
7
8    fn chance(self, chance: f32) -> Chance<Self> {
9        Chance {
10            predicate: self,
11            chance,
12        }
13    }
14
15    /// Hint for when this will be true.
16    fn time_hint(&self) -> Option<f32> { None }
17}
18
19#[derive(Clone, Copy)]
20pub struct Yes;
21
22impl Predicate for Yes {
23    fn should(&mut self, _ctx: &mut NpcCtx) -> bool { true }
24
25    fn time_hint(&self) -> Option<f32> { Some(0.0) }
26}
27
28#[derive(Clone)]
29pub struct EveryRange {
30    next: Option<f32>,
31    sample: std::ops::Range<f32>,
32}
33
34pub fn every_range(r: std::ops::Range<f32>) -> EveryRange {
35    EveryRange {
36        next: None,
37        sample: r,
38    }
39}
40
41impl Predicate for EveryRange {
42    fn should(&mut self, ctx: &mut NpcCtx) -> bool {
43        if let Some(ref mut next) = self.next {
44            *next -= ctx.dt;
45            if *next <= 0.0 {
46                *next += ctx.rng.gen_range(self.sample.clone());
47                true
48            } else {
49                false
50            }
51        } else {
52            self.next = Some(ctx.rng.gen_range(self.sample.clone()));
53            false
54        }
55    }
56
57    fn time_hint(&self) -> Option<f32> { self.next }
58}
59
60#[derive(Clone, Copy)]
61pub struct Chance<P> {
62    predicate: P,
63    chance: f32,
64}
65
66impl<P: Predicate> Predicate for Chance<P> {
67    fn should(&mut self, ctx: &mut NpcCtx) -> bool {
68        self.predicate.should(ctx) && ctx.rng.gen_bool(self.chance as f64)
69    }
70
71    fn time_hint(&self) -> Option<f32> { self.predicate.time_hint() }
72}
73
74impl<F: Fn(&mut NpcCtx) -> bool + Clone> Predicate for F {
75    fn should(&mut self, ctx: &mut NpcCtx) -> bool { self(ctx) }
76}
77
78// Seconds
79pub fn timeout(time: f64) -> Timeout { Timeout { seconds_left: time } }
80
81#[derive(Clone, Copy)]
82pub struct Timeout {
83    seconds_left: f64,
84}
85
86impl Predicate for Timeout {
87    fn should(&mut self, ctx: &mut NpcCtx) -> bool {
88        self.seconds_left -= ctx.dt as f64;
89        self.seconds_left <= 0.0
90    }
91
92    fn time_hint(&self) -> Option<f32> { Some(self.seconds_left.max(0.0) as f32) }
93}
veloren_rtsim/ai/predicate.rs

veloren_rtsim/ai/
predicate.rs
