I'm updating a gigantic mod of mine to the latest version, I have just a few questions to start:

 

1. To my understanding the preInit and and initialization events were removed. As an example, in 1.12 I registered my entities' renderer in the preinitialization event, where would this go in 1.16?

 

2. I use GLStateManager calls throughout the mod to make changes to UI, first person item rendering, and the like. But is there a new way of doing this?

 

3. Did entity AI/pathfinding change in any significant way? 

24 minutes ago, Turtledove said:

To my understanding the preInit and and initialization events were removed. As an example, in 1.12 I registered my entities' renderer in the preinitialization event, where would this go in 1.16?

https://mcforge.readthedocs.io/en/latest/conventions/loadstages/

25 minutes ago, Turtledove said:

I use GLStateManager calls throughout the mod to make changes to UI, first person item rendering, and the like. But is there a new way of doing this?

This is either handled through a IRenderTypeBuffer with RenderTypes combined with MatrixStacks or RenderSystem depending on the situation. OpenGL has been isolated as much as possible.

26 minutes ago, Turtledove said:

Did entity AI/pathfinding change in any significant way?

Not really afaik, they just have a brain now allowing for more complex AI tasks and behaviors.