bevy_app: add tracing event with tracy.frame_mark (#4320)

Currently `tracy` interprets the entire trace as one frame because the marker for frames isn't being recorded.

~~When an event with `tracy.trace_marker=true` is recorded, `tracing-tracy` will mark the frame as finished:
<https://github.com/nagisa/rust_tracy_client/blob/aa0b96b2ae2aee6f3831994f9a3a8c29bcc85fae/tracing-tracy/src/lib.rs#L240>~~

~~Unfortunately this leads to~~
```rs
INFO bevy_app:frame: bevy_app::app: finished frame tracy.frame_mark=true
```
~~being printed every frame (we can't use DEBUG because bevy_log sets `max_release_level_info`.~~

Instead of emitting an event that gets logged every frame, we can depend on tracy-client itself and call `finish_continuous_frame!();`

crates/bevy_internal/Cargo.toml

@@ -12,7 +12,7 @@ categories = ["game-engines", "graphics", "gui", "rendering"]
 [features]
 trace = [ "bevy_app/trace", "bevy_ecs/trace", "bevy_log/trace", "bevy_render/trace", "bevy_core_pipeline/trace" ]
 trace_chrome = [ "bevy_log/tracing-chrome" ]
-trace_tracy = [ "bevy_log/tracing-tracy" ]
+trace_tracy = ["bevy_render/tracing-tracy", "bevy_log/tracing-tracy" ]
 wgpu_trace = ["bevy_render/wgpu_trace"]
 debug_asset_server = ["bevy_asset/debug_asset_server"]
 

crates/bevy_log/src/lib.rs

@@ -159,6 +159,11 @@ impl Plugin for LogPlugin {
             let tracy_layer = tracing_tracy::TracyLayer::new();
 
             let fmt_layer = tracing_subscriber::fmt::Layer::default();
+            #[cfg(feature = "tracing-tracy")]
+            let fmt_layer = fmt_layer.with_filter(
+                tracing_subscriber::filter::Targets::new().with_target("tracy", Level::ERROR),
+            );
+
             let subscriber = subscriber.with(fmt_layer);
 
             #[cfg(feature = "tracing-chrome")]

crates/bevy_render/Cargo.toml

@@ -21,6 +21,7 @@ zlib = ["flate2"]
 zstd = ["ruzstd"]
 
 trace = []
+tracing-tracy = []
 wgpu_trace = ["wgpu/trace"]
 ci_limits = []
 webgl = ["wgpu/webgl"]

crates/bevy_render/src/renderer/mod.rs

@@ -63,6 +63,13 @@ pub fn render_system(world: &mut World) {
                 if let Some(surface_texture) = texture_view.take_surface_texture() {
                     surface_texture.present();
                 }
+
+                #[cfg(feature = "tracing-tracy")]
+                bevy_utils::tracing::event!(
+                    bevy_utils::tracing::Level::INFO,
+                    message = "finished frame",
+                    tracy.frame_mark = true
+                );
             }
         }
     }