refactor: Simplify texture loading and disposal in draw-relief-icons renderer

src/modules/webgl-layer.ts

@@ -4,7 +4,7 @@ import { byId } from "../utils";
 export interface WebGLLayerConfig {
   id: string;
   setup: (group: Group) => void; // called once after WebGL2 confirmed; add meshes to group
-  render: (group: Group) => void; // called each frame before renderer.render(); update uniforms/geometry
+  render?: (group: Group) => void; // called each frame before renderer.render(); update uniforms/geometry
   dispose: (group: Group) => void; // called on unregister(); dispose all GPU objects in group
 }
 interface RegisteredLayer {
@@ -48,7 +48,7 @@ export class WebGL2LayerClass {
     return true;
   }
 
-  register(config: WebGLLayerConfig): void {
+  register(config: WebGLLayerConfig) {
     if (!this.scene) {
       // init() has not been called yet — queue for processing in init()
       this.pendingConfigs.push(config);
@@ -63,7 +63,7 @@ export class WebGL2LayerClass {
     this.layers.set(config.id, { config, group });
   }
 
-  unregister(id: string): void {
+  unregister(id: string) {
     const layer = this.layers.get(id);
     if (!layer || !this.scene) return;
     const scene = this.scene;
@@ -74,7 +74,7 @@ export class WebGL2LayerClass {
     if (this.canvas && !anyVisible) this.canvas.style.display = "none";
   }
 
-  setVisible(id: string, visible: boolean): void {
+  setVisible(id: string, visible: boolean) {
     const layer = this.layers.get(id);
     if (!layer) return;
     layer.group.visible = visible;
@@ -83,14 +83,14 @@ export class WebGL2LayerClass {
     if (visible) this.requestRender();
   }
 
-  clearLayer(id: string): void {
+  clearLayer(id: string) {
     const layer = this.layers.get(id);
     if (!layer) return;
     layer.group.clear();
     this.requestRender();
   }
 
-  requestRender(): void {
+  requestRender() {
     if (this.rafId !== null) return;
     this.rafId = requestAnimationFrame(() => {
       this.rafId = null;
@@ -98,7 +98,7 @@ export class WebGL2LayerClass {
     });
   }
 
-  syncTransform(): void {
+  private syncTransform() {
     if (!this.camera) return;
     const x = -viewX / scale;
     const y = -viewY / scale;
@@ -112,11 +112,12 @@ export class WebGL2LayerClass {
     this.camera.updateProjectionMatrix();
   }
 
-  private render(): void {
+  private render() {
     if (!this.renderer || !this.scene || !this.camera) return;
     this.syncTransform();
     for (const layer of this.layers.values()) {
-      if (layer.group.visible) layer.config.render(layer.group);
+      if (layer.group.visible && layer.config.render)
+        layer.config.render(layer.group);
     }
     this.renderer.render(this.scene, this.camera);
   }

src/renderers/draw-relief-icons.ts

@@ -25,10 +25,7 @@ WebGLLayer.register({
   id: "terrain",
   setup(group: Group): void {
     terrainGroup = group;
-    preloadTextures();
-  },
-  render(_group: Group): void {
-    // no-op: relief geometry is static between drawRelief() calls
+    for (const set of Object.keys(RELIEF_SYMBOLS)) loadTexture(set);
   },
   dispose(group: Group): void {
     group.traverse((obj) => {
@@ -38,14 +35,11 @@ WebGLLayer.register({
         (obj.material as MeshBasicMaterial).dispose();
       }
     });
-    disposeTextureCache();
+    for (const tex of textureCache.values()) tex?.dispose();
+    textureCache.clear();
   },
 });
 
-function preloadTextures(): void {
-  for (const set of Object.keys(RELIEF_SYMBOLS)) loadTexture(set);
-}
-
 function loadTexture(set: string): Promise<Texture | null> {
   if (textureCache.has(set))
     return Promise.resolve(textureCache.get(set) ?? null);
@@ -147,11 +141,6 @@ function buildSetMesh(
   return new Mesh(geo, mat);
 }
 
-function disposeTextureCache(): void {
-  for (const tex of textureCache.values()) tex?.dispose();
-  textureCache.clear();
-}
-
 function buildReliefScene(icons: ReliefIcon[]): void {
   if (!terrainGroup) return;
   terrainGroup.traverse((obj) => {
@@ -208,14 +197,12 @@ window.drawRelief = (
     drawSvg(icons, parentEl);
   } else {
     const set = parentEl.getAttribute("set") || "simple";
-    loadTexture(set).then(() => {
-      if (icons !== lastBuiltIcons || set !== lastBuiltSet) {
-        buildReliefScene(icons);
-        lastBuiltIcons = icons;
-        lastBuiltSet = set;
-      }
-      WebGLLayer.requestRender();
-    });
+    if (icons !== lastBuiltIcons || set !== lastBuiltSet) {
+      buildReliefScene(icons);
+      lastBuiltIcons = icons;
+      lastBuiltSet = set;
+    }
+    WebGLLayer.requestRender();
   }
 };