fix(falukant): use nearest lower age model fallback

frontend/src/components/Character3D.vue

@@ -27,15 +27,12 @@ import { getApiBaseURL } from '@/utils/axios.js';
 /** Backend-Route: GET /api/models/3d/falukant/characters/:filename (Proxy mit Draco-Optimierung) */
 const MODELS_API_PATH = '/api/models/3d/falukant/characters';
 const OPTIMIZED_MODEL_SUFFIX = '_opt.glb';
-// Optional: zusätzliche Namenskonventionen, die vor dem Standardpfad ausprobiert werden.
-// Hier werden mögliche Alternativ-Dateinamen aufgeführt, die für bestimmte Altersstufen
-// (z.B. weibliche Modelle für 1-4 Jahre) existieren könnten. Trage hier die tatsächlichen
-// Dateinamen ein, falls dein Backend solche Varianten enthält.
-const AGE_ALTERNATIVE_SUFFIXES = [
-  '_alt.glb',
-  '_special.glb',
-  '_v2.glb'
-];
+// Only concrete age models are used. If an exact age is not available, choose
+// the nearest lower one instead of the generic gender/age-group fallback.
+const AVAILABLE_MODEL_AGES = Object.freeze({
+  female: Object.freeze([0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 20, 25, 30, 40, 50, 60]),
+  male: Object.freeze([0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 18, 20, 25, 30, 40, 50, 60]),
+});
 
 // Per-age camera offsets applied after auto-fit. Values are additive (meters).
 // Set `y` to raise/lower the camera, `z` to move it closer/further.
@@ -196,18 +193,6 @@ export default {
       if (age <= 17) return 'teen';
       return 'adult';
     },
-    modelPath() {
-      const base = getApiBaseURL();
-      const prefix = base ? `${base}${MODELS_API_PATH}` : MODELS_API_PATH;
-      return `${prefix}/${this.actualGender}_${this.ageGroup}.glb`;
-    },
-    exactAgeModelPath() {
-      // Pfad für genaues Alter (z.B. female_1y.glb für Alter 1)
-      const age = this.actualAge;
-      const base = getApiBaseURL();
-      const prefix = base ? `${base}${MODELS_API_PATH}` : MODELS_API_PATH;
-      return `${prefix}/${this.actualGender}_${age}y.glb`;
-    },
     fallbackImageSrc() {
       return this.actualGender === 'female'
         ? '/images/mascot/mascot_female.png'
@@ -219,7 +204,7 @@ export default {
       if (this.is3DDisabled) return;
       await this.loadModel();
     },
-    async ageGroup() {
+    async actualAge() {
       if (this.is3DDisabled) return;
       await this.loadModel();
     }
@@ -454,35 +439,14 @@ export default {
         const base = getApiBaseURL();
         const prefix = base ? `${base}${MODELS_API_PATH}` : MODELS_API_PATH;
         
-        // Fallback-Hierarchie:
-        // Standard:
-        // 1. Exaktes Altersmodell
-        // 2. Altersbereich
-        // 3. Basis-Modell
-        // Lightweight:
-        // 1. Altersbereich
-        // 2. Basis-Modell
-        const exactAgePath = this.toOptimizedModelPath(this.exactAgeModelPath);
-        const ageGroupPath = this.toOptimizedModelPath(this.modelPath);
-        const fallbackPath = `${prefix}/${this.actualGender}${OPTIMIZED_MODEL_SUFFIX}`;
-
-        // Build a list of candidate paths. For every age and gender we first try
-        // possible alternate filenames for the exact-age model (e.g. female_1y_alt.glb),
-        // then the exact-age file, then the age-group file, and finally the base gender
-        // fallback. This makes the age-specific model the primary source and the
-        // age-group only a later fallback.
-        const candidates = [];
         const modelAge = this.actualAge;
-
-        // Try exact-age variants with configured suffixes first (works for any gender/age)
-        for (const sfx of AGE_ALTERNATIVE_SUFFIXES) {
-          candidates.push(this.toOptimizedModelPath(`${prefix}/${this.actualGender}_${modelAge}y${sfx}`));
-        }
-
-        // Standard preference order: exact age, age group, fallback
-        candidates.push(exactAgePath);
-        candidates.push(ageGroupPath);
-        candidates.push(fallbackPath);
+        const availableAges = AVAILABLE_MODEL_AGES[this.actualGender] || [];
+        const candidateAges = availableAges
+          .filter((age) => age <= modelAge)
+          .sort((left, right) => right - left);
+        const candidates = candidateAges.map((age) =>
+          `${prefix}/${this.actualGender}_${age}y${OPTIMIZED_MODEL_SUFFIX}`
+        );
 
         let gltf;
         try {
@@ -505,10 +469,8 @@ export default {
             // store for debug overlay
             this.debugInfo.modelPath = chosenPath;
             // determine modelType
-            if (chosenPath === exactAgePath) this.debugInfo.modelType = 'exactAge';
-            else if (chosenPath === ageGroupPath) this.debugInfo.modelType = 'ageGroup';
-            else if (chosenPath === fallbackPath) this.debugInfo.modelType = 'fallback';
-            else this.debugInfo.modelType = 'alternate';
+            const chosenAge = candidateAges[candidates.indexOf(chosenPath)];
+            this.debugInfo.modelType = chosenAge === modelAge ? 'exactAge' : 'nearestLowerAge';
         } finally {
           dracoLoader.dispose();
         }