What obstruction block tracers?

[Lollipop]

I have thought about this, and I want to know more about which structural properties of maps that block sight tracers that return the color value displayed at your screen.

Now, I have found out (thanks Ænima) that null space block these tracers, though I wondered if other things, such as slopes can block these as well, or if only null space does this?

If it is so, then I would like to know what would theoretically be the best way to prevent lag in large areas, as I am playing with some ideas in my head :)

[ZZYZX]

ehh.. AFAIK as ZDoom (and Zandronum) retains ancient pieces of original Doom engine code, it doesn't consider obstructing slopes when calculating whether a subsector is visible. The only things that matter are either solid walls or sectors with zero height (like closed doors).

This approach always leads to certain overhead. The easiest way to observe this is using wallhack on Doom2 MAP01. Newer ZDoom versions stop looking for things in sectors that they consider invisible, thus you can check what things does the engine think to be potentially visible. If I remember correctly, from the spawning point you can see things in at least 3 sectors beyond the one that is actually visible to you (i.e. you can see an imp in the room to your right, even though there are few sectors between green corridor, the sector that you actually see, and the sector the imp is in).

And the most funny thing is what happens to all the things and all the segments (i.e. wall parts) in those sectors that you "can see", but don't actually see.
All things GET CLIPPED AGAINST EVERYTHING THAT OBSTRUCTS THEM[/size] FOR EVERY TEXTURE COLUMN DRAWN[/size].
Not scary? Well, it shouldn't be. Because even while I'm not quite sure about the thing that causes this perfomance drop in detailed maps only on ZDoom 2.x-based engines, I'm pretty sure that it isn't the rendering.

[uggi121]

using wallhack on Doom2 MAP01

Your secret has been revealed. Let's all ban Alien!!!111