Description

gltfio is a loader library that consumes gltf or glb content and produces Filament objects. For usage details, see the docstring for AssetLoader.

gltfio has two plug-in interfaces, TextureProvider and MaterialProvider. Filament ships with several ready-to-go implementations described below.

• MaterialProvider creates Filament materials in response to certain glTF requirements.
  • UbershaderProvider loads pre-built materials.
  • JitShaderProvider builds materials at run time using the filamat library.
• TextureProvider creates and populates Filament Texture objects.
  • StbProvider uses the STB library to read PNG and JPEG files.
  • Ktx2Provider uses the BasisU library to read KTX2 files.

UbershaderProvider

UbershaderProvider is a ready-to-go implementation of the MaterialProvider interface that should be used in applications that need fast startup times. There is no material compilation that occurs at run time, but the shaders might be relatively large and complex.

At load time, the ubershader loader consumes an ubershader archive which is a precompiled set of materials bundled with formal descriptions of the glTF features that they support.

The uberz command line tool consumes a list of .spec and .filamat files and produces a single .uberz file. For details on these two file formats, see the README in libs/uberz.