Workaround for mergeBufferGeometries failure when loading Collada files with inconsistent attributes

src/index.js

@@ -12,6 +12,24 @@ require('ccapture.js');
 // We must implement extension types 0x16 and 0x17. The trick to
 // decoding them is they must be converted from littleEndian.
 const extensionCodec = new msgpack.ExtensionCodec();
+
+// Uint8Array
+extensionCodec.register({
+  type: 0x12,
+  encode: (obj) => {
+    console.error("Uint8Array encode not implemented")
+    return null;
+  },
+  decode: (data) => {
+    const to_return = new Uint8Array(data.byteLength);
+    let dataview = new DataView(data.buffer, data.byteOffset, data.byteLength);
+    for (let i = 0; i < to_return.length; i++) {
+      to_return[i] = dataview.getUint8(i, true);  // true b.c. littleEndian
+    }
+    return to_return
+  },
+});
+
 // Uint32Array
 extensionCodec.register({
   type: 0x16,
@@ -28,7 +46,7 @@ extensionCodec.register({
     return to_return
   },
 });
-   +
+
 // Float32Array
 extensionCodec.register({
   type: 0x17,
@@ -73,7 +91,26 @@ function merge_geometries(object, preserve_materials = false) {
             result.material = materials[0];
         }
     } else if (geometries.length > 1) {
+        // There is a known issue where mergeBufferGeometries fails when some of the geometries do not have UV textures.
+        // A workaround is to delete all UV textures. Rather than failing silently (failing to load by returning null),
+        // we will remove textures when needed.
+        let uses_uv = new Array(geometries.length).fill(false);
+        for (let i = 0; i < geometries.length; ++i) {
+            uses_uv[i] = geometries[i].attributes.hasOwnProperty('uv');
+        }
+        let all_true = uses_uv.every(v => v === true);
+        let all_false = uses_uv.every(v => v === false);
+        let broken_dae = (all_true === all_false);
+        if (broken_dae) {
+            console.warn("Broken DAE: Either all geometries need to contain uv tags or none. To circumvent failure in mergeBufferGeometries, removing all textures");
+            for (let i = 0; i < geometries.length; ++i) {
+                geometries[i].deleteAttribute("uv");
+            }
+        }
         result = mergeBufferGeometries(geometries, true);
+        if (result == null) {
+          console.error("Merging buffer geometries failed:", geometries);
+        }
         if (preserve_materials) {
             result.material = materials;
         }
@@ -133,16 +170,26 @@ function handle_special_geometry(geom) {
             loaded_geom.uuid = geom.uuid;
             return loaded_geom;
         } else if (geom.format == "dae") {
-            let loader = new ColladaLoader();
-            let obj = loader.parse(geom.data);
-            let result = merge_geometries(obj.scene);
-            result.uuid = geom.uuid;
-            return result;
+            try {
+                let loader = new ColladaLoader();
+                let obj = loader.parse(geom.data);
+                let result = merge_geometries(obj.scene);
+                result.uuid = geom.uuid;
+                return result;
+            } catch(e) {
+                console.error("Failure parsing DAE:", e);
+                return null;
+            }
         } else if (geom.format == "stl") {
-            let loader = new STLLoader();
-            let loaded_geom = loader.parse(geom.data.buffer);
-            loaded_geom.uuid = geom.uuid;
-            return loaded_geom;
+            try {
+                let loader = new STLLoader();
+                let loaded_geom = loader.parse(geom.data.buffer);
+                loaded_geom.uuid = geom.uuid;
+                return loaded_geom;
+            } catch (e) {
+                console.error("Failure parsing STL:", e, geom);
+                return null;
+            }
         } else {
             console.error("Unsupported mesh type:", geom);
             return null;