geng_rodio/source/
spatial.rs

1use std::time::Duration;
2
3use crate::source::ChannelVolume;
4use crate::{Sample, Source};
5
6/// Combines channels in input into a single mono source, then plays that mono sound
7/// to each channel at the volume given for that channel.
8#[derive(Clone)]
9pub struct Spatial<I>
10where
11    I: Source,
12    I::Item: Sample,
13{
14    input: ChannelVolume<I>,
15}
16
17fn dist_sq(a: [f32; 3], b: [f32; 3]) -> f32 {
18    a.iter()
19        .zip(b.iter())
20        .map(|(a, b)| (a - b) * (a - b))
21        .sum::<f32>()
22}
23
24impl<I> Spatial<I>
25where
26    I: Source,
27    I::Item: Sample,
28{
29    pub fn new(
30        input: I,
31        emitter_position: [f32; 3],
32        left_ear: [f32; 3],
33        right_ear: [f32; 3],
34    ) -> Spatial<I>
35    where
36        I: Source,
37        I::Item: Sample,
38    {
39        let mut ret = Spatial {
40            input: ChannelVolume::new(input, vec![0.0, 0.0]),
41        };
42        ret.set_positions(emitter_position, left_ear, right_ear);
43        ret
44    }
45
46    /// Sets the position of the emitter and ears in the 3D world.
47    pub fn set_positions(
48        &mut self,
49        emitter_pos: [f32; 3],
50        left_ear: [f32; 3],
51        right_ear: [f32; 3],
52    ) {
53        debug_assert!(left_ear != right_ear);
54        let left_dist_sq = dist_sq(left_ear, emitter_pos);
55        let right_dist_sq = dist_sq(right_ear, emitter_pos);
56        let max_diff = dist_sq(left_ear, right_ear).sqrt();
57        let left_dist = left_dist_sq.sqrt();
58        let right_dist = right_dist_sq.sqrt();
59        let left_diff_modifier = (((left_dist - right_dist) / max_diff + 1.0) / 4.0 + 0.5).min(1.0);
60        let right_diff_modifier =
61            (((right_dist - left_dist) / max_diff + 1.0) / 4.0 + 0.5).min(1.0);
62        let left_dist_modifier = (1.0 / left_dist_sq).min(1.0);
63        let right_dist_modifier = (1.0 / right_dist_sq).min(1.0);
64        self.input
65            .set_volume(0, left_diff_modifier * left_dist_modifier);
66        self.input
67            .set_volume(1, right_diff_modifier * right_dist_modifier);
68    }
69}
70
71impl<I> Iterator for Spatial<I>
72where
73    I: Source,
74    I::Item: Sample,
75{
76    type Item = I::Item;
77
78    #[inline]
79    fn next(&mut self) -> Option<I::Item> {
80        self.input.next()
81    }
82
83    #[inline]
84    fn size_hint(&self) -> (usize, Option<usize>) {
85        self.input.size_hint()
86    }
87}
88
89impl<I> ExactSizeIterator for Spatial<I>
90where
91    I: Source + ExactSizeIterator,
92    I::Item: Sample,
93{
94}
95
96impl<I> Source for Spatial<I>
97where
98    I: Source,
99    I::Item: Sample,
100{
101    #[inline]
102    fn current_frame_len(&self) -> Option<usize> {
103        self.input.current_frame_len()
104    }
105
106    #[inline]
107    fn channels(&self) -> u16 {
108        self.input.channels()
109    }
110
111    #[inline]
112    fn sample_rate(&self) -> u32 {
113        self.input.sample_rate()
114    }
115
116    #[inline]
117    fn total_duration(&self) -> Option<Duration> {
118        self.input.total_duration()
119    }
120}
geng_rodio/source/spatial.rs

geng_rodio/source/
spatial.rs
