Add shared KTX2 loader management utilities

src/assets/ktx2-texture-support.ts

@@ -0,0 +1,64 @@
+import { WebGLRenderer, type WebGLRendererParameters } from "three";
+import { KTX2Loader } from "three/examples/jsm/loaders/KTX2Loader.js";
+
+const KTX2_TRANSCODER_PATH = "/basis/";
+
+let sharedKtx2Loader: KTX2Loader | null = null;
+let sharedKtx2LoaderInitialized = false;
+let fallbackRenderer: WebGLRenderer | null = null;
+
+function getErrorDetail(error: unknown): string {
+  if (error instanceof Error && error.message.trim().length > 0) {
+    return error.message.trim();
+  }
+
+  return "Unknown error.";
+}
+
+function createSharedKtx2Loader(): KTX2Loader {
+  const loader = new KTX2Loader();
+  loader.setTranscoderPath(KTX2_TRANSCODER_PATH);
+  return loader;
+}
+
+export function getSharedKtx2LoaderIfInitialized(): KTX2Loader | null {
+  return sharedKtx2LoaderInitialized ? sharedKtx2Loader : null;
+}
+
+export function initializeSharedKtx2Loader(renderer: WebGLRenderer): KTX2Loader {
+  if (sharedKtx2Loader === null) {
+    sharedKtx2Loader = createSharedKtx2Loader();
+  }
+
+  sharedKtx2Loader.detectSupport(renderer);
+  sharedKtx2LoaderInitialized = true;
+  return sharedKtx2Loader;
+}
+
+function createFallbackRenderer(): WebGLRenderer {
+  const parameters: WebGLRendererParameters = {
+    antialias: false,
+    alpha: false,
+    powerPreference: "low-power"
+  };
+
+  return new WebGLRenderer(parameters);
+}
+
+export function ensureSharedKtx2LoaderInitialized(): KTX2Loader {
+  if (sharedKtx2LoaderInitialized && sharedKtx2Loader !== null) {
+    return sharedKtx2Loader;
+  }
+
+  try {
+    if (fallbackRenderer === null) {
+      fallbackRenderer = createFallbackRenderer();
+    }
+
+    return initializeSharedKtx2Loader(fallbackRenderer);
+  } catch (error) {
+    throw new Error(
+      `KTX2 texture support could not be initialized. WebGL compressed texture support is required to load KTX2 model textures. ${getErrorDetail(error)}`
+    );
+  }
+}