[v2.2.15] The Horizon effect is broken for OPENGL and creates visual glitches.
The new SRB2 version seems to break how the horizon effect renders for the OPENGL renderer. Where the software renderer seems to have no issues at all.
So the context behind finding this bug was me converting my 2.2.13 map into 2.2.15. So the map used a combination of horizon effect applied on a thok barrier (just like recommended in the wiki guide), which worked perfectly fine in both renderers in 2.2.13. But when I updated to 2.2.15 this is what I was met with while testing the map in OPENGL renderer:
158370-4b1e39d87eba55866553c13edb804cf7.mp4
For context, the wall on the left has the celling lowered down to create a thok barrier, but that causes the effect to completely disappear. But If I get rid of the thok barrier and get the ceiling to it's regular height the effect works again, yet it causes geometry and other objects to pierce through the walls in a similar way as if there were no textures applied to the wall (Only in OPENGL.)
And here is the bug fully replicated and compared with the way horizon effect works in software.
158372-bb5dc8e3103566b3da95dbbab7f8a892.mp4
And here's how closely the "no textures" pierce-through thingy in OPENGL looks to the horizon effect bug present in 2.2.15.
And here's the setup I used to recreate the bug along with the map available for further testing.
The fact the horizon effect with thok barriers worked perfectly fine in earlier versions until 2.2.15 tells me that this is a bug that shouldn't normally appear. And my idea for why the geometry pierces through horizon effect when applied on walls is because it may be in some way similar to the no-texture bug in a sense that they visually work pretty much the same. (Does that sentence even make sense...?)
And this post is directly copied from the thread I made in bug-reports on SRB2MB. And this is my first time ever using gitlab, so I'm sorry if I made some fumbles with this post.
I hope y'all will take a look at this and hopefully fix it in the next SRB2 version!