oxideav_scene/
duration.rs

1//! Scene-time primitives.
2//!
3//! Every timestamp in this crate is an `i64` in the scene's own
4//! [`TimeBase`](oxideav_core::TimeBase). Use `scene.time_base` to
5//! convert to/from seconds.
6
7/// A timestamp in scene time units (the scene's `time_base` tick
8/// granularity).
9pub type TimeStamp = i64;
10
11/// How long a scene lasts on its own clock.
12#[non_exhaustive]
13#[derive(Clone, Copy, Debug, PartialEq, Eq)]
14pub enum SceneDuration {
15    /// Fixed-length scene. Rendered linearly start→end; finishes at
16    /// `end` and emits no further frames.
17    Finite(TimeStamp),
18
19    /// Streaming / open-ended. The scene runs forever until an
20    /// operation explicitly ends it. Used by the RTMP compositor.
21    /// Seek / rewind are not supported; content is driven forward
22    /// by wall-clock time + control-plane operations.
23    Indefinite,
24}
25
26impl SceneDuration {
27    /// Return `Some(end)` for finite scenes, `None` for streaming.
28    pub fn end(&self) -> Option<TimeStamp> {
29        match self {
30            SceneDuration::Finite(t) => Some(*t),
31            SceneDuration::Indefinite => None,
32        }
33    }
34
35    /// Whether a given timestamp is inside the scene.
36    pub fn contains(&self, t: TimeStamp) -> bool {
37        t >= 0
38            && match self {
39                SceneDuration::Finite(end) => t < *end,
40                SceneDuration::Indefinite => true,
41            }
42    }
43}
44
45/// Per-object on-screen lifetime. `start <= t < end` — objects
46/// outside this half-open interval are not rendered. `end == None`
47/// means "until scene end" (works for both finite and indefinite
48/// scenes).
49#[derive(Clone, Copy, Debug, Default, PartialEq, Eq)]
50pub struct Lifetime {
51    pub start: TimeStamp,
52    pub end: Option<TimeStamp>,
53}
54
55impl Lifetime {
56    /// Whether the object should be drawn at time `t`.
57    pub fn is_live_at(&self, t: TimeStamp) -> bool {
58        t >= self.start && self.end.map_or(true, |end| t < end)
59    }
60}
61
62#[cfg(test)]
63mod tests {
64    use super::*;
65
66    #[test]
67    fn finite_scene_bounds() {
68        let d = SceneDuration::Finite(100);
69        assert!(d.contains(0));
70        assert!(d.contains(99));
71        assert!(!d.contains(100));
72        assert!(!d.contains(-1));
73        assert_eq!(d.end(), Some(100));
74    }
75
76    #[test]
77    fn indefinite_scene_forever() {
78        let d = SceneDuration::Indefinite;
79        assert!(d.contains(0));
80        assert!(d.contains(i64::MAX));
81        assert_eq!(d.end(), None);
82    }
83
84    #[test]
85    fn lifetime_default_is_always_live_after_zero() {
86        let lt = Lifetime::default();
87        assert!(lt.is_live_at(0));
88        assert!(lt.is_live_at(i64::MAX));
89        assert!(!lt.is_live_at(-1));
90    }
91
92    #[test]
93    fn lifetime_finite_range() {
94        let lt = Lifetime {
95            start: 10,
96            end: Some(20),
97        };
98        assert!(!lt.is_live_at(9));
99        assert!(lt.is_live_at(10));
100        assert!(lt.is_live_at(19));
101        assert!(!lt.is_live_at(20));
102    }
103}
oxideav_scene/duration.rs

oxideav_scene/
duration.rs
