/!\ ALPHA SOFTWARE. CAN BREAK AND CHANGE COMPLETELY OVER TIME /!\

blender-demo-en.webm

Direct Model Importer

This is currently a Proof of Concept of how to regenerate meshes encoded in EXR inside VRChat.

This package actually provide an encoder within Unity, to encode any Mesh as a file.

You'll still have to upload the generated EXR file somewhere (Discord being the easiest solution) and then enter the URL inside the panel within the game.

You can actually test it in the Editor, during 'Play' mode too.

An exporter for Blender is also available here :

https://github.com/vr-voyage/direct-model-exporter-blender

Encoding documentation

The data are supposed to be encoded in RGBA, using 32-bits floating point for each channel.

I have no idea how to only use one channel at the moment, so four channels (RGBA) are used. This actually hinders the decoder implementation, but I have no clear idea how to avoid that, beside using shader tricks that would make the whole thing even more complex.

Version 2

Metadata

The first 64 bytes provide the file metadata

Float 0 == (float) 0x00564f59 (VOY)
Float 1 == (float) 0x00454741 (AGE)
Float 2 == Float.INFINITY (Currently unchecked)
Float 3 == Float.NAN (Currently unchecked)
Float 4 == Version number
Float 8 == Number of vertices stored
Float 9 == Number of normals stored
Float 10 == Number of UVs stored (Only one UV map is stored at the moment)
Float 11 == Number of indices stored

The rest is unused at the moment.

Vertices (from index 64)

Vertices are stored in the RGB channels. Alpha is ignored.

        int metadataSize = 64;
        int nfloatsInColor = 4;
        int cursor = metadataSize / nfloatsInColor;
        for (int v = 0; v < nVertices; v++, cursor++)
        {
            Color currentCol = colors[cursor];
            Vector3 vertex = new Vector3(
                currentCol.r,
                currentCol.g,
                currentCol.b);
            vertices[v] = vertex;
        }

Normals (after the vertices)

Normals are stored in the RGB channels. Alpha is ignored.

        for (int n = 0; n < nNormals; n++, cursor++)
        {
            Color currentCol = colors[cursor];
            Vector3 normal = new Vector3(
                currentCol.r,
                currentCol.g,
                currentCol.b);
            normals[n] = normal;
        }

UVS (after the normals)

UV coordinates are stored in the RG channels. Blue and Alpha are ignored.

        for (int u = 0; u < nUVS; u++)
        {
            Color currentCol = colors[cursor];
            Vector2 uv = new Vector2(
                currentCol.r,
                currentCol.g);
            uvs[u] = uv;
            cursor++;
        }

Indices (after the UV)

Indices are packed. The easiest way is to read 'nIndices / (float values in Color)' values.
Then, at the end, read the remaining parts depending on how much data is left.

    /* This rounds the value to a multiple of 4.
     * There are way smarter ways to do it, I'm just lazy
     */
    int alignedIndices = nIndices / nfloatsInColor * nfloatsInColor;
    int currentIndex = 0;
    for (; currentIndex < alignedIndices; currentIndex += 4, cursor++)
    {

        Color currentCol = colors[cursor];
        /*Debug.Log($"Index : {currentIndex} ({cursor*4}) - Indices : {(int)currentCol.r},{(int)currentCol.g},{(int)currentCol.b},{(int)currentCol.a}");*/
        indices[currentIndex + 0] = (int)currentCol.r;
        indices[currentIndex + 1] = (int)currentCol.g;
        indices[currentIndex + 2] = (int)currentCol.b;
        indices[currentIndex + 3] = (int)currentCol.a;
    }
    /*Debug.Log($"cursor after indices : {cursor - start} ({(cursor - start) * 4})");*/
    int remainingIndices = nIndices - alignedIndices;
    if (remainingIndices > 0)
    {
        Color currentCol = colors[cursor];
        if (remainingIndices >= 1)
        {
            indices[currentIndex] = (int)currentCol.r;
            currentIndex++;
        }
        if (remainingIndices >= 2)
        {
            indices[currentIndex] = (int)currentCol.g;
            currentIndex++;
        }
        if (remainingIndices == 3)
        {
            indices[currentIndex] = (int)currentCol.b;
            currentIndex++;
        }
    }

vr-voyage / direct-model-importer-vrchat