Reuse buffers for render statistics. Now they work similarly to wgpu-…

…profiler (while collecting more data)

crates/bevy_render/src/renderer/graph_runner.rs

@@ -68,14 +68,18 @@ impl RenderGraphRunner {
         Self::run_graph(graph, None, &mut render_context, world, &[], None)?;
         finalizer(render_context.command_encoder());
 
-        {
+        let (render_device, mut statistics_recorder) = {
             #[cfg(feature = "trace")]
             let _span = info_span!("submit_graph_commands").entered();
-            queue.submit(render_context.finish());
-        }
+
+            let (commands, render_device, statistics_recorder) = render_context.finish();
+            queue.submit(commands);
+
+            (render_device, statistics_recorder)
+        };
 
         let render_statistics_mutex = world.resource::<RenderStatisticsMutex>().0.clone();
-        let statistics_recorder = render_context.download_statistics(queue, move |statistics| {
+        statistics_recorder.finish_frame(&render_device, move |statistics| {
             *render_statistics_mutex.lock() = Some(statistics);
         });
 

crates/bevy_render/src/renderer/mod.rs

@@ -356,29 +356,23 @@ impl RenderContext {
     }
 
     /// Finalizes the queue and returns the queue of [`CommandBuffer`]s.
-    pub fn finish(&mut self) -> Vec<CommandBuffer> {
+    ///
+    /// When the render statistics become available, `statistics_callback` will be invoked.
+    pub fn finish(mut self) -> (Vec<CommandBuffer>, RenderDevice, StatisticsRecorder) {
         let command_encoder = self.command_encoder.get_or_insert_with(|| {
             self.render_device
                 .create_command_encoder(&wgpu::CommandEncoderDescriptor::default())
         });
 
-        self.statistics_recorder
-            .resolve(command_encoder, &self.render_device);
+        self.statistics_recorder.resolve(command_encoder);
 
         self.flush_encoder();
-        std::mem::take(&mut self.command_buffers)
-    }
 
-    /// Downloads [`RenderStatistics`] from GPU, asynchronously calling the callback
-    /// when the data is available. Should be caled after `finish`.
-    pub fn download_statistics(
-        mut self,
-        queue: &Queue,
-        callback: impl FnOnce(RenderStatistics) + Send + 'static,
-    ) -> StatisticsRecorder {
-        self.statistics_recorder
-            .download(&self.render_device, queue, callback);
-        self.statistics_recorder
+        (
+            self.command_buffers,
+            self.render_device,
+            self.statistics_recorder,
+        )
     }
 
     fn flush_encoder(&mut self) {