GZDoom Screen Glitch Problem?

[stixc]

So I was playing some of the WADs a lot of people sent in to Vinesauce Joel and I was playing one of them when I noticed the sky looked like this:

Compared to Joel's gameplay of it, it doesn't have this sky issue.

How do I fix this skybox glitch? I'm using GZDoom g4.1.3 64-Bit on Windows 10 Pro.

 

(p.s. the WAD is Spooky Castle by Toxicoow, just to give credit)

[Danfun64]

My first suggestion is to try running that particular wad in OpenGL mode, as your screenshot shows software renderer banding that the Joel screenshot does not and that there are some skyboxes which require OpenGL IIRC

[stixc]

I found the fix! Hopefully this thread gets locked:

 

I changed the render mode in GZDoom from Softpoly Render to Hardware Accelerated!

[Danfun64]

I thought as much... wait, you were using Softpoly and not regular Software? Not that I'd encourage you to fix what isn't broken when you found a solution but... huh.