Start from October 2022, I will get more busier than before and don't have enough time to keep the development and modder support for MCglTF. So I've decideded to hand over the maintainment of MCglTF to Protoxy22, who known for his ModularWarfare Mod. Please visit his GitHub repository and Discord server for contiuous support.
A 3D model loader library which load glTF format file and prepare the required techniques to render the model for Minecraft Modding enviroment. Various features from glTF spec are available but still remain a good compatibility and performance.
The example codes for rendering Block, Item, and Entity
Despite Iris Shaders is built upon in OptiFine specification about shader pack for Minecraft, there are a lots of internal implementation differences between two.
For example, you cannot get current GL program that is proper for Item/Entity/BlockEntity renderer like what OptiFine did. Instead, they switch their GL program during GlStateManager#_drawArrays(), which making it hard to deal with glTF model rendering code.
Aside from that, Iris Shaders does not fully support every features from shaderpack. And you can still using OptiFine in Fabric with OptiFabric installed.
So it is most likely that MCglTF will still not support Iris Shaders in the future.