glTFNet.Extensions.Khronos 0.1.0-prerelease

glTFNet

A fast and modern glTF reader.

This library can read binary and JSON-based glTF 2.0 files.

Generator

This project contains a C# code generator to convert the schema definition provided by Khronos to model classes.

Usage

This library provides a wrapper struct GltfRef<T> with extension methods for easy access to the glFT models.

var inputFile = "Examples/glTF-Binary/Avocado.glb";

// Loading the glTF data
await using var file = new GltfFile();
var gltf = await file.Open(inputFile);

if (!gltf.HasScene(out var scene)) return;

foreach (var node in scene.Nodes())
{
    if (!node.HasMesh(out var mesh)) continue;

    foreach (var meshPrimitive in mesh.Primitives())
    {
        if (!meshPrimitive.HasIndices(out var indicesAccessor)) continue;
        if (!meshPrimitive.HasAttributes("POSITION", out var positionAccessor)) continue;
        
        // Lazy-loading the data from the gbl file
        var indices = await indicesAccessor.Read();
        var positions = await positionAccessor.Read();
        
        // ...
    }
}

External resources in glTF (like textures or mesh data) are linked via an URI. A FileResolver for the parent directory is automatically added as IResourceResolver, if the GltfFile is loaded by from a filename. Custom resolvers can implement the IResourceResolver interface and overwrite the GltfFile.ResourceResolver property:

await using var file = new GltfFile();
file.ResourceResolver = new MyCustomResourceResolver();

Extensions

The glTF extension can be used by importing the additional extension packages: glTFNet.Extensions.Khronos, glTFNet.Extensions.Vendor or glTFNet.Extensions.Archived.

Make sure to register the extension in the GltfFile before using them:

await using var file = new GltfFile();

// Register the extension set
file.UseKhronosExtensions();

var gltf = await file.Open(inputFile);

Extension data cam be read with TryGetExtension:

var material = gltf.Materials()[0];

// Accessing the extension data
if (material.TryGetExtension("KHR_materials_ior", out MaterialKHRMaterialsIor extension))
{
    var ior = extension.Ior;
    
    // ...
}

When adding custom extension, make sure to create a JSON serializer context and add to the GltfFile:

// For example: Create an extension method for your extension
public static void UseMyCustomExtension(this GltfSerializer serializer)
{
    serializer.AddSerializerContext(MyCustomExtensionSerializerContext.Default);
}

// Register your extension when reading the file
await using var file = new GltfFile();
file.UseMyCustomExtension();