Fix Draco compression: dedup transform + clean NodeIO writer

- Import dedup from @gltf-transform/functions
- Apply dedup() BEFORE weld() to materialize Draco data
- Use clean NodeIO (without Draco encoder) for writing
- Add accessor buffer assignment for bufferView fix
- This prevents Draco re-encoding and fixes accessor=-1 issue

services/processor/index.ts

@@ -3,6 +3,7 @@ import path from 'path';
 import fs from 'fs';
 import { NodeIO } from '@gltf-transform/core';
 import { ALL_EXTENSIONS } from '@gltf-transform/extensions';
+import { weld, dedup } from '@gltf-transform/functions';
 import draco3d from 'draco3dgltf';
 import sharp from 'sharp';
 
@@ -79,17 +80,48 @@ export async function convertGlbToSkp(inputPath: string, outputPath: string, opt
         console.log(`[DEBUG] Draco extension detected: ${dracoFound}. Converted ${sparseConverted} sparse accessors to dense.`);
 
         // 2. Remove problematic extensions (Draco, WebP)
+        // CRITICAL: Must remove these BEFORE writing or they'll be re-encoded
         const extensions = root.listExtensions();
+        console.log(`[DEBUG] Extensions found: ${extensions.map(e => e.extensionName).join(', ') || 'none'}`);
+
         for (const ext of extensions) {
-            const extName = ext.getName();
+            const extName = ext.extensionName; // Use extensionName, not getName()
             // Remove Draco, WebP, and other non-standard extensions
-            if (extName.includes('draco') || extName.includes('Draco') ||
-                extName.includes('webp') || extName.includes('EXT_texture_webp')) {
+            if (extName.toLowerCase().includes('draco') ||
+                extName.includes('webp') ||
+                extName === 'EXT_texture_webp' ||
+                extName === 'KHR_draco_mesh_compression') {
                 console.log(`    Disposing extension: ${extName}`);
                 ext.dispose();
             }
         }
 
+        // ======= CRITICAL FIX FOR DRACO: Force accessor buffer assignment =======
+        // When Draco is decoded, accessors may still have bufferView = -1 
+        // We MUST assign each accessor to a valid buffer so gltf-transform writes proper
+        // bufferView references when serializing. This is the KEY fix for accessor=-1.
+        const buffers = root.listBuffers();
+        let buffer = buffers.length > 0 ? buffers[0] : document.createBuffer();
+        let accessorsFixed = 0;
+
+        for (const acc of root.listAccessors()) {
+            // Force the accessor to use our buffer - this makes gltf-transform 
+            // generate proper bufferView references when writing
+            acc.setBuffer(buffer);
+            accessorsFixed++;
+        }
+        console.log(`[DEBUG] Assigned ${accessorsFixed} accessors to buffer`);
+
+        // 4. Apply dedup() FIRST - this forces accessor data to be materialized into buffers
+        // This is CRITICAL: dedup() breaks the Draco "lazy" reference and creates real buffer data
+        await document.transform(dedup());
+        console.log(`[DEBUG] Applied dedup() transform`);
+
+        // 5. Apply weld() transform - consolidates vertices and generates proper index buffer
+        // This is important for Draco-decoded data to work properly in SketchUp
+        await document.transform(weld());
+        console.log(`[DEBUG] Applied weld() transform`);
+
         // Optional: Remove Skins/Animations
         for (const skin of root.listSkins()) skin.dispose();
         for (const anim of root.listAnimations()) anim.dispose();
@@ -152,8 +184,12 @@ export async function convertGlbToSkp(inputPath: string, outputPath: string, opt
             console.log('  - No textures to process');
         }
 
-        // Write processed GLB
-        await io.write(processedGlbPath, document);
+        // Write processed GLB using a CLEAN NodeIO (without Draco encoder)
+        // CRITICAL: If we use the same 'io' that has ALL_EXTENSIONS registered,
+        // gltf-transform will RE-ENCODE the mesh with Draco during write!
+        const cleanIO = new NodeIO(); // No extensions registered = no Draco re-encoding
+        await cleanIO.write(processedGlbPath, document);
+        console.log(`[DEBUG] Written with CLEAN NodeIO (no Draco encoder)`);
 
         const stats = fs.statSync(processedGlbPath);
         console.log(`[DEBUG] Processed GLB saved to ${processedGlbPath} (Size: ${stats.size} bytes)`);