cl_visedicts: are duplicate entries OK/expected?

[Johnny Law]

As a learning experience (and out of curiosity) I've been looking into some of the known issues of the reQuiem engine. Some I can track down just from general C debugging, but in other cases I need to pick up more understanding of the Quake data structures and how they're used.

In one case, I see a linked list that is getting corrupted because it is processing cl_visedicts without taking into account that there could be multiple elements of that array that point to the same object. What I don't yet know is whether:

a) it is bad/unexpected for cl_visedicts to have duplicate entries

or

b) duplicates are OK and the linked-list manipulation code should take that possibility into account.


Can someone give me a push in the right direction?

(If you want to climb further back along my debugging logic, it's this issue: https://github.com/SpiritQuaddicted/reQuiem/issues/9 )

[Spike]

however you look at it, dupes are pointless and inefficient. the only way that it might actually do anything is if .alpha isn't 1, but there's better ways to handle that.
if you have multiple scenes being drawn (ie: recursing through water leafs) then you should probably remove any entities already on the list just so you don't draw them twice or whatever.

I can't think of any specific places where dupes would actually be crashy, but then its been a long time since I seriously looked at NQ code. QW generates the data in-place, instead of using pointers to some other random bits of memory, its cleaner that way.

[Johnny Law]

The crashing part is the linked list (skychain), which is something new in reQuiem.

reQuiem's handling of cl_visedicts (which allows/causes duplicate entries) doesn't seem to be notably different from other NQ engines, although of course I could be missing something.

[Baker]

[Baker]

Ran Requiem (I compiled it and ran debug version). game czg07 + map czg07 + kill = crash.

So I started up FitzQuake085.exe as a dedicated server as such:
c:\quake\fitzquake085.exe -game czg07 +map czg07 -dedicated 1 -window

In FitzQuake085.exe, I typed "status" which showed me my ip address of "192.168.1.4"

I started Requiem and change the gamedir to czg07. I typed "connect 192.168.1.4" to connect to FitzQuake running in a different window.

I type "kill" and Requiem crashed. But the music kept playing. I set a breakpoint in Visual Studio in the beginning of _Host_Frame. Nothing happened [it didn't hit the breakpoint] (which means the _Host_Frame which runs 200 frames per second +/- was no longer happening). So despite still having music playing and a non-responsive client and Visual Studio did not catch an error or hit a breakpoint. FMOD plays the music and was still running.

Now ...

I did this.

c:\quake\fitzquake085.exe -game czg07 +coop 1 +map czg07 -dedicated 1 -window

When I changed the gamedir in Requiem and connected, I could kill myself as many times as I wanted!!!!! No crashes or anything.

Why would coop 1 make a difference? Maybe Requiem does something special when you die? Does it auto-record demos? Do they save on death? Does it zip them up?

Or maybe something in Requiem only executes when a single player game is running locally?

Do you have a particular reason you suspect visedicts is the problem?

[Spirit]

[Spike]

[Johnny Law]

[Johnny Law]

[ericw]

just came across this comment from mh which sounds related:
viewtopic.php?f=3&t=5131&p=48507#p48507

[Johnny Law]

Welp! That's confirmation, thanks.

Guess the most prudent fix for reQuiem would be to change the skychain management so that it doesn't implode when there are duplicate cl_visedicts elements.

[Baker]

[Baker]

[Johnny Law]

[Baker]