sim_lib_view_device/
adapter.rs

1//! Device-local adapters for already encoded Scenes.
2
3use std::rc::Rc;
4
5use sim_kernel::{Expr, Result};
6
7use crate::DeviceProfile;
8
9/// A content-rate Scene shared across device-rate local adaptations.
10///
11/// The shared pointer is part of the contract: a display-only mirror path can
12/// reuse the exact encoded tree for every device frame without deep-cloning the
13/// Scene.
14#[derive(Clone, Debug, PartialEq)]
15pub struct EncodedScene {
16    scene: Rc<Expr>,
17}
18
19impl EncodedScene {
20    /// Wraps an owned encoded Scene in shared storage.
21    pub fn new(scene: Expr) -> Self {
22        Self {
23            scene: Rc::new(scene),
24        }
25    }
26
27    /// Wraps an already shared encoded Scene.
28    pub fn from_shared(scene: Rc<Expr>) -> Self {
29        Self { scene }
30    }
31
32    /// Borrows the encoded Scene expression.
33    pub fn expr(&self) -> &Expr {
34        &self.scene
35    }
36
37    /// Clones the shared pointer to the encoded Scene.
38    pub fn shared(&self) -> Rc<Expr> {
39        Rc::clone(&self.scene)
40    }
41}
42
43/// The latency-critical, device-local last step of surface projection.
44///
45/// A local adapter is pure: it receives an already encoded Scene, the freshest
46/// device-local state, and the typed device profile. It does not receive a
47/// runtime context, cannot call SIM code, and cannot re-enter the content
48/// encoder.
49pub trait LocalAdapter {
50    /// Device-local state consumed by the adapter.
51    type State;
52
53    /// Adapts an already encoded Scene for one device state sample.
54    fn adapt(
55        &self,
56        scene: &EncodedScene,
57        state: &Self::State,
58        profile: &DeviceProfile,
59    ) -> Result<Rc<Expr>>;
60}
61
62/// Display-only adapter that mirrors the encoded Scene unchanged.
63///
64/// This is the degenerate device case: the same shared Scene pointer is returned
65/// for every frame, so the tree is not cloned per adaptation.
66#[derive(Clone, Copy, Debug, Default, PartialEq, Eq)]
67pub struct MirrorAdapter;
68
69impl LocalAdapter for MirrorAdapter {
70    type State = ();
71
72    fn adapt(
73        &self,
74        scene: &EncodedScene,
75        _state: &Self::State,
76        _profile: &DeviceProfile,
77    ) -> Result<Rc<Expr>> {
78        Ok(scene.shared())
79    }
80}
sim_lib_view_device/adapter.rs

sim_lib_view_device/
adapter.rs
