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/worker.js

@@ -1,7 +1,8 @@
 import initWasm, { Core } from "./pkg/yawn_core.js";
+import { SharedProfile } from "./profile.js";
 
 let core;
-let profileTimer;
+let profile;
 // While a relocation is staged, every request except its commit waits here.
 let awaitingCommit = false;
 const queue = [];
@@ -15,6 +16,8 @@ async function handle(message) {
       if (core || !(message.canvas instanceof OffscreenCanvas)) fail("INIT");
       const wasm = await initWasm();
       core = new Core(message.arenaBytes);
+      profile = new SharedProfile(message.profileBuffer);
+      core.on_profile(json => profile.write(json));
       await core.initialize(message.canvas);
       const buffer = wasm.memory.buffer;
       if (!(buffer instanceof SharedArrayBuffer)) fail("WASM_MEMORY_NOT_SHARED");
@@ -70,11 +73,7 @@ async function handle(message) {
           break;
         case "set-profiler":
           result = core.set_profiler(Boolean(message.enabled));
-          clearInterval(profileTimer);
-          profileTimer = result && message.enabled ? setInterval(() => {
-            const stats = core.take_profile();
-            if (stats) postMessage({ type: "profile", stats: JSON.parse(stats) });
-          }, 250) : undefined;
+          profile.clear();
           break;
         default:
           fail("MESSAGE");