bevy_diagnostic/
entity_count_diagnostics_plugin.rs

1use bevy_app::prelude::*;
2use bevy_ecs::entity::Entities;
3
4use crate::{
5    Diagnostic, DiagnosticPath, Diagnostics, RegisterDiagnostic, DEFAULT_MAX_HISTORY_LENGTH,
6};
7
8/// Adds "entity count" diagnostic to an App.
9///
10/// # See also
11///
12/// [`LogDiagnosticsPlugin`](crate::LogDiagnosticsPlugin) to output diagnostics to the console.
13pub struct EntityCountDiagnosticsPlugin {
14    /// The total number of values to keep.
15    pub max_history_length: usize,
16}
17
18impl Default for EntityCountDiagnosticsPlugin {
19    fn default() -> Self {
20        Self::new(DEFAULT_MAX_HISTORY_LENGTH)
21    }
22}
23
24impl EntityCountDiagnosticsPlugin {
25    /// Creates a new `EntityCountDiagnosticsPlugin` with the specified `max_history_length`.
26    pub fn new(max_history_length: usize) -> Self {
27        Self { max_history_length }
28    }
29}
30
31impl Plugin for EntityCountDiagnosticsPlugin {
32    fn build(&self, app: &mut App) {
33        app.register_diagnostic(
34            Diagnostic::new(Self::ENTITY_COUNT).with_max_history_length(self.max_history_length),
35        )
36        .add_systems(Update, Self::diagnostic_system);
37    }
38}
39
40impl EntityCountDiagnosticsPlugin {
41    /// Number of currently allocated entities.
42    pub const ENTITY_COUNT: DiagnosticPath = DiagnosticPath::const_new("entity_count");
43
44    /// Updates entity count measurement.
45    pub fn diagnostic_system(mut diagnostics: Diagnostics, entities: &Entities) {
46        diagnostics.add_measurement(&Self::ENTITY_COUNT, || entities.len() as f64);
47    }
48}
bevy_diagnostic/entity_count_diagnostics_plugin.rs

bevy_diagnostic/
entity_count_diagnostics_plugin.rs
