Optimize viewer shaders and camera controls; sample GPU profiles asynchronously

Amp-Thread-ID: https://ampcode.com/threads/T-01a0b382-1e79-712b-abd1-d29201c9bb5e
Co-authored-by: Heaust Azure <heaust.azure@gmail.com>

core/render_graph/gpu_resource.rs

@@ -1,8 +1,8 @@
 use std::collections::{BTreeMap, HashMap, HashSet};
 use std::num::NonZeroU64;
-use std::sync::atomic::{AtomicU8, Ordering};
 use std::sync::Arc;
 
+use futures_channel::oneshot;
 use serde::de::DeserializeOwned;
 use serde_json::Value;
 
@@ -31,7 +31,7 @@ pub struct GpuProfiler {
 
 pub struct ProfileMap {
     readback: Arc<wgpu::Buffer>,
-    state: Arc<AtomicU8>,
+    completion: oneshot::Receiver<Result<(), wgpu::BufferAsyncError>>,
     labels: Vec<String>,
     timestamp_period: f32,
 }
@@ -417,16 +417,15 @@ impl GpuResources {
 
     pub fn map_profile(&self, timestamp_period: f32) -> Option<ProfileMap> {
         let profiler = self.profiler.as_ref()?;
-        let state = Arc::new(AtomicU8::new(0));
-        let callback = state.clone();
+        let (complete, completion) = oneshot::channel();
         profiler
             .readback
             .map_async(wgpu::MapMode::Read, .., move |result| {
-                callback.store(if result.is_ok() { 1 } else { 2 }, Ordering::Release);
+                let _ = complete.send(result);
             });
         Some(ProfileMap {
             readback: profiler.readback.clone(),
-            state,
+            completion,
             labels: self
                 .passes
                 .iter()
@@ -438,11 +437,8 @@ impl GpuResources {
 }
 
 impl ProfileMap {
-    pub fn state(&self) -> u8 {
-        self.state.load(Ordering::Acquire)
-    }
-
-    pub fn read(self) -> Vec<(String, f64)> {
+    pub async fn read(self) -> Option<Vec<(String, f64)>> {
+        self.completion.await.ok()?.ok()?;
         let bytes = self.readback.get_mapped_range(..);
         let values = bytes
             .chunks_exact(8)
@@ -463,7 +459,7 @@ impl ProfileMap {
             .collect();
         drop(bytes);
         self.readback.unmap();
-        profile
+        Some(profile)
     }
 }