Wall climbing/Gravity adjustment

[Hornetzero]

Hey everyone,
                      I'm seeking a mod by Cutmanmike that allowed players to climb walls, since its link has been dead for sometime and I can't find mirror for it on the internet.

https://forum.zdoom.org/viewtopic.php?t=11547

What I need it for? I'm trying to implement a wall climbing function similar to the Aliens in Alien vs Predator:

https://www.youtube.com/watch?v=i9vghoMZ80A&ab_channel=Sakuraba1982Gaming

There is the camera trickery required and the manipulation of gravity.

I thought about giving the player the +NOGRAVITY flag, and then adding a velocity on every tick, perpendicular to the "floor" the player's currently on. For floors and ceilings, this is usually straight down/up. I don't know how to find the angle of a slope in the level struct. For walls, it's perpendicular to the Line that represents the wall.

I was hoping Mike's wall climbing example could provide some insight on how one can call that function with the direction of the line as the axis.

Thank you
HZ