Bug #252

invisible monsters on clientside

Added by brodell almost 17 years ago. Updated almost 10 years ago.

Target version:
Start date:
% Done:



Occasionally monsters are completely invisible on the
client side of a multiplayer game. These monsters
can be killed if I know where to aim, and blood shows
momentarily from the impact. The problem does not
seem to happen on the server. The problem does
seem to happen whether or not I am using sprites or
MD2 models, and whether I am using jDoom or jHeretic.
Sometimes gameplay is frustrating on clientside when I
get killed by a monster that I can't see or hear, and my
partener on the server says "Didin't you see the Spectre
there killing you?". The monsters that I've noticed are
more prone to this are the Spectre on jDoom (and
possible the Demon) and the Gargoyle on jHeretic. It is
possible that I only notice these monsters do this more
because they never give away their position by shooting
a fireball at me, and they all have relatively powerful
close range attacks, and that it may happen with other
types of monsters.

Labels: Multiplayer


#1 Updated by danij almost 17 years ago

Logged In: YES

I've not noticed this myself. Do you have any suggestions on
how I might repeat this bug?

#2 Updated by brodell almost 17 years ago

Logged In: YES

To reproduce the bug, I simply start a two player cooperative
game on my network. The monsters disapperaing seems to
be random as far as the specific monster, doesn't happen
with extreme frequency, and the game will sometimes go for
two or more levels without me noticing anything. I ran an
experiment, creating a small level with each of the monster
types, arranged in a grid. On the other axis of the grid, I
marked the attributes from back to front as: 45, 345, 12345,
12345 deaf, and 12345 multiplayer. Two of the times I started
the level, none of the monsters disappered on the client. The
other two times, however a mancubus with the 12345
attributes was invisible on the client, but not the server. It
was the exact same monster both times. This confirmed my
suspicion that the invisible monsters probably started out that
way at the level start, and don't change afterwards. It was
strange, I thought, that the disappering monster was a
mancubus, and not a spectre or a demon. If you want, I can
send you log files from each computer (just tell me what ones
are relevant) and my test .WAD file. Thank you for your
speedy response.

#3 Updated by skyjake almost 16 years ago

Logged In: YES

This should be fixed in 1.9.0-beta5. The problem was that some mobj deltas
could get lost, and if those deltas contained the Mobj Create information, the
mobj never became visible on the clientside. Beta5 uses a more robust method
which shows the mobjs on clientside as soon as enough information is known
about them (state + position).

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