custom_diagnostic/
custom_diagnostic.rs

1//! This example illustrates how to create a custom diagnostic.
2
3use bevy::{
4    diagnostic::{
5        Diagnostic, DiagnosticPath, Diagnostics, LogDiagnosticsPlugin, RegisterDiagnostic,
6    },
7    prelude::*,
8};
9
10fn main() {
11    App::new()
12        .add_plugins((
13            DefaultPlugins,
14            // The "print diagnostics" plugin is optional.
15            // It just visualizes our diagnostics in the console.
16            LogDiagnosticsPlugin::default(),
17        ))
18        // Diagnostics must be initialized before measurements can be added.
19        .register_diagnostic(Diagnostic::new(SYSTEM_ITERATION_COUNT).with_suffix(" iterations"))
20        .add_systems(Update, my_system)
21        .run();
22}
23
24// All diagnostics should have a unique DiagnosticPath.
25const SYSTEM_ITERATION_COUNT: DiagnosticPath = DiagnosticPath::const_new("system_iteration_count");
26
27fn my_system(mut diagnostics: Diagnostics) {
28    // Add a measurement of 10.0 for our diagnostic each time this system runs.
29    diagnostics.add_measurement(&SYSTEM_ITERATION_COUNT, || 10.0);
30}