[SOLVED] LOD Fading feature cost?

Unity Engine
1

Background
A client has requested that we add Unity’s dithered LOD Crossfade feature to all our shaders for flexibility. However, I have reservations about this since Unity doesn’t use it on any of their shaders besides the SpeedTree shader.

Questions

  • Is there a default increase in cost from simply supporting the feature on my shaders, even when the effect isn’t executing?
  • I noticed that the SpeedTree shader has a flag to disable batching when using LOD Fading. Can I assume that normal batching behavior applies when it isn’t fading?

Thanks for any help you can provide.

2

No, there is no additional cost if you do it right. Put your implementation behind preprocessor (LOD_FADE_CROSSFADE or LOD_FADE_PERCENTAGE or both). Unity will enable those keywords only when the transition is happening. Your shader will be unchanged otherwise.

The cost of the transition depends on your implementation. I guess that is one of the reasons why Unity doesn’t use it in built-in shaders. There are several ways how to implement it and different platforms work best with different methods.

1 Like
3

@Michal_1
Okay. I kinda figured that was the case, but I thought I’d ask since you can never be sure with Unity. And yeah, I planned to use the same setup as the SpeedTree shaders since it looked like that would prevent any extra cost when not using the feature.

Thanks for the help.