henad_core/
model.rs

1//! The [`SimState`] interface the runner drives.
2
3use crate::params::ParamValue;
4use crate::send_sync::WasmNotSend;
5use crate::view::{EdgeView, GridView, PointView, StatEntry};
6
7/// A running simulation, as the runner drives it.
8///
9/// The trait is object-safe, and a model entry type-erases every model behind it. A model implements
10/// one of the authoring traits, and the engine implements this trait.
11pub trait SimState: WasmNotSend + 'static {
12    /// Advances the state by one tick.
13    fn step(&mut self);
14    /// Number of ticks stepped so far.
15    fn tick(&self) -> u64;
16    /// Returns the grid layer to draw, if the state has one.
17    ///
18    /// A state can return both a grid and agents from [`SimState::point_view`], and the agents are then drawn
19    /// over the field.
20    fn grid_view(&self) -> Option<GridView<'_>> {
21        None
22    }
23    /// Returns the agents to draw, if the state has any.
24    fn point_view(&self) -> Option<PointView<'_>> {
25        None
26    }
27    /// Returns the edges to draw between the positions from [`SimState::point_view`].
28    fn edge_view(&self) -> Option<EdgeView<'_>> {
29        None
30    }
31    /// Prepares the views before a snapshot is built.
32    ///
33    /// A model turns its state into something drawable here, without paying for it every tick.
34    fn prepare_view(&mut self) {}
35    /// Returns the current statistics, one entry per declared series.
36    fn stats(&self) -> Vec<StatEntry>;
37    /// Sets parameter `index` to `value`, and returns whether the state accepted the edit.
38    ///
39    /// A state rejects an edit to a parameter declared [`ParamApply::OnReload`].
40    ///
41    /// [`ParamApply::OnReload`]: crate::params::ParamApply::OnReload
42    fn set_param(&mut self, index: usize, value: &ParamValue) -> bool;
43    /// Runs the model's action at `index`, between ticks, and returns whether it ran.
44    ///
45    /// It returns false when the model declares no such action.
46    fn act(&mut self, _index: usize) -> bool {
47        false
48    }
49    /// Turns the layout on or off, with a time budget per publish in milliseconds.
50    ///
51    /// Returns false if the state has no layout.
52    fn set_layout(&mut self, _on: bool, _budget_ms: f32) -> bool {
53        false
54    }
55    /// Runs the layout for one time budget, if it is on.
56    ///
57    /// The runner decides which publishes call this.
58    fn relax_layout(&mut self) {}
59    /// Size of the population: its cells, its agents or its live nodes.
60    fn population(&self) -> u64;
61    /// Approximate size in bytes of the memory this state owns, on the host for a CPU state and on the device
62    /// for a GPU state.
63    fn heap_bytes(&self) -> usize;
64    /// Number of jobs that one step splits into. `None` if a backend has no such split.
65    fn parallel_jobs(&self) -> Option<usize> {
66        None
67    }
68}
henad_core/model.rs

henad_core/
model.rs
