Loading Meshopt Compressed GLB Files in React Native

The error message "THREE.GLTFLoader: setMeshoptDecoder must be called before loading compressed files" indicates that the MeshoptDecoder isn't being properly initialized before attempting to load the compressed GLB file.

Issue Analysis

Looking at your code, you're importing MeshoptDecoder from three-stdlib and setting it with loader.setMeshoptDecoder(MeshoptDecoder), but the error suggests that the decoder isn't being properly initialized.

When working with Meshopt compression in React Native, there are a few specific considerations:

Solution Approaches

1. Initialize MeshoptDecoder Properly

The MeshoptDecoder needs to be initialized before use. Try this approach:

JAVASCRIPTCopied
import { MeshoptDecoder } from "three-stdlib";

// Initialize the decoder first
MeshoptDecoder.ready
  .then(() => {
    // Set the decoder on the loader
    loader.setMeshoptDecoder(MeshoptDecoder);
  })
  .catch(error => {
    console.error("Error initializing MeshoptDecoder:", error);
  });

2. Use WebAssembly Module Directly

For React Native, you might need to handle the WebAssembly module differently:

JAVASCRIPTCopied
import { GLTFLoader } from "three-stdlib";
import { DRACOLoader } from "three-stdlib";
import { MeshoptDecoder } from "three/examples/jsm/libs/meshopt_decoder.module.js";

const useMeshLoader = () => {
  // ...existing code...
  
  // Initialize MeshoptDecoder before setting it
  useEffect(() => {
    async function initDecoders() {
      await MeshoptDecoder.ready;
      loader.setMeshoptDecoder(MeshoptDecoder);
    }
    
    initDecoders().catch(console.error);
  }, []);
  
  // ...rest of your code...
};

3. Ensure Proper Loading Order

Make sure the decoder is fully initialized before any loading attempts:

JAVASCRIPTCopied
const useMeshLoader = () => {
  // ...existing code...
  
  const [decoderReady, setDecoderReady] = useState(false);
  
  useEffect(() => {
    MeshoptDecoder.ready
      .then(() => {
        loader.setMeshoptDecoder(MeshoptDecoder);
        setDecoderReady(true);
      })
      .catch(error => {
        console.error("Failed to initialize MeshoptDecoder:", error);
      });
  }, []);
  
  const LoadMeshes = useCallback(
    (assetsObject) => {
      // Only proceed if decoder is ready
      if (!decoderReady) {
        console.warn("MeshoptDecoder not ready yet");
        return;
      }
      
      // ...rest of your loading logic...
    },
    [meshes, decoderReady]
  );
  
  // ...rest of your code...
};

Additional Considerations for React Native

1. WebAssembly Support: Ensure your React Native environment properly supports WebAssembly, which is required by MeshoptDecoder.

2. Alternative Approach: If you continue to have issues, consider pre-processing your models to use Draco compression instead of Meshopt, as Draco might have better support in React Native environments.

3. Debug the Decoder: Add logging to verify the decoder initialization:

JAVASCRIPTCopied
console.log("MeshoptDecoder before init:", MeshoptDecoder);
MeshoptDecoder.ready
  .then(() => {
    console.log("MeshoptDecoder initialized successfully");
    loader.setMeshoptDecoder(MeshoptDecoder);
  })
  .catch(error => {
    console.error("MeshoptDecoder initialization failed:", error);
  });

By ensuring proper initialization of the MeshoptDecoder before attempting to load any compressed files, you should be able to resolve this issue.

Loading Meshopt Compressed GLB Files in React Native

The error message "THREE.GLTFLoader: setMeshoptDecoder must be called before loading compressed files" indicates that the MeshoptDecoder isn't being properly initialized before attempting to load the compressed GLB file.

Issue Analysis

Looking at your code, you're importing MeshoptDecoder from three-stdlib and calling loader.setMeshoptDecoder(MeshoptDecoder), which is the correct approach. However, in React Native environments, there are some additional steps needed to properly initialize the MeshoptDecoder.

Solution

The MeshoptDecoder needs to be properly initialized before it can be used. Here's how to fix the issue:

1. First, make sure you're properly initializing the MeshoptDecoder by awaiting its initialization:

JAVASCRIPTCopied
import { MeshoptDecoder } from "three-stdlib";

// Initialize the decoder at the beginning of your component or in a useEffect
const initializeDecoders = async () => {
  // Initialize MeshoptDecoder
  await MeshoptDecoder.ready;
  loader.setMeshoptDecoder(MeshoptDecoder);
};

2. Update your component to use this initialization:

JAVASCRIPTCopied
const useMeshLoader = () => {
  const [meshes, setMeshes] = useState(null);
  const [isLoading, setIsLoading] = useState(false);
  const [isAssetReplacing, setIsAssetReplacing] = useState(false);
  const [decodersReady, setDecodersReady] = useState(false);
  const loader = useRef(new GLTFLoader()).current;
  const dracoLoader = useRef(new DRACOLoader()).current;

  // Initialize decoders
  useEffect(() => {
    const initDecoders = async () => {
      // Set up Draco
      dracoLoader.setDecoderPath(
        "https://www.gstatic.com/draco/versioned/decoders/1.5.7/"
      );
      loader.setDRACOLoader(dracoLoader);
      
      // Set up Meshopt - make sure to await its initialization
      await MeshoptDecoder.ready;
      loader.setMeshoptDecoder(MeshoptDecoder);
      
      setDecodersReady(true);
    };
    
    initDecoders().catch(console.error);
  }, []);

  // Rest of your code...

  const LoadMeshes = useCallback(
    (assetsObject) => {
      // Only proceed if decoders are ready
      if (!decodersReady) {
        console.warn("Decoders not yet initialized");
        return;
      }
      
      // Your existing loadEverything function...
    },
    [meshes, decodersReady]
  );

  // Rest of your code...
};

Alternative Approach

If the above solution doesn't work, you might need to try a more direct approach with the WebAssembly module:

JAVASCRIPTCopied
import { GLTFLoader } from "three-stdlib";
import { DRACOLoader } from "three-stdlib";
import { MeshoptDecoder } from "three/examples/jsm/libs/meshopt_decoder.module.js";

const useMeshLoader = () => {
  // ...existing code

  useEffect(() => {
    const init = async () => {
      dracoLoader.setDecoderPath(
        "https://www.gstatic.com/draco/versioned/decoders/1.5.7/"
      );
      loader.setDRACOLoader(dracoLoader);
      
      // Initialize MeshoptDecoder
      await MeshoptDecoder.ready;
      loader.setMeshoptDecoder(MeshoptDecoder);
      
      setDecodersReady(true);
    };
    
    init();
  }, []);

  // ...rest of your code
};

Additional Considerations for React Native

React Native might have issues with WebAssembly which is required by MeshoptDecoder. You might need to:

1. Make sure you have the appropriate polyfills for WebAssembly in your React Native project
2. Consider using a package like react-native-webassembly if direct WebAssembly support is needed
3. Check if your bundler (Metro) is properly configured to handle WebAssembly files

If you continue to face issues, you might need to consider using non-compressed GLB files for React Native or implementing a custom solution for handling the decompression.