Have you ever get a problem like this?

Blitz3D Forums/Blitz3D Programming/Have you ever get a problem like this?

Paolo(Posted 2005) [#1]
I certainly don't know where to start looking for... it's so strange...

...sometimes, when I'm running around, I noticed the level begin
to flicker, then I found exactly the point where the problem happens.

If I stand at this place the flicker happens very fast and I took screenshots
to show how it looks.... it seems a lot of polys get missed by some reason ...

Any idea of what could cause this?




GfK(Posted 2005) [#2]
Um, why have you uploaded a JPG image as a text file?

[edit] oh, you sorted it.

RossC's had a very similar problem recently, iirc. It was something to do with multitexturing I think...


Paolo(Posted 2005) [#3]
... hmmmm, multitexturing ...? I will have a look


Ross C(Posted 2005) [#4]
Too many textures on a mesh cause the rendering order to get really buggered up. I had 6 on a mesh, reduced it to 4 surfaces, and it seems fine.


markcw(Posted 2005) [#5]
yes, it is the "alpha demon!" :)

this dreaded demon likes to strike
just the way you described.
the intermittent clipping of faces and
the habit of occuring only at certain
places are its hallmarks! :)

don't know how 2 fix it really but
i have a suggestion.

are your grid walkways alphamapped?
if so, you could try using masked textures for
those instead and see if that fixes it.

i've never found any precise info regarding this,
but i like to think there is a limit to the amount
of alpha filtering that can be handled in dx.

its a depth (z) buffer issue i think. heres a link to
a tutorial that may be of help.

http://www.computersciencelab.com/Direct3DTut1.htm


Paolo(Posted 2005) [#6]
Ok, I will have a look at that link...

I don't think I will be able to correct this... it is
so strage because it also happens with non-alpha meshes (?)

Anyway... I think is actually really difficult to
find some of these "flickers-points" so the end user will
have to live with it (if he ever suffers it :)

Paolo.


markcw(Posted 2005) [#7]
if it happens with non-alpha meshes then
maybe the non-alpha mesh is being
obscured by an alpha mesh or, if that
is not likely, then the engine "thinks"
that the non-alpha is an alpha mesh.

maybe because an alpha mesh is
setting a non-alpha mesh to alpha.

btw, could you do us a favor and see if the
"flicker-points" are still there in the other
blitz versions from 1.86 to 1.90?

that is, if you don't mind. thx.


jfk EO-11110(Posted 2005) [#8]
And don't forget, if you load the Mesh as a .B3D, the File settings will override all manual setting. If there is something Alpha in one of the brushes or textures settings, or even the Vertex Alpha Data, you simply cannot deactivate it by setting non-alpha parameters after loading (EG EntityAlpha won't work with a B3D File that has an 1.0 Alpha Setting inside the File)
I remember I had to replace certain brushes of B3D Meshes when I wanted to change their Alpha behaviour.


Paolo(Posted 2005) [#9]
Well, I found the problem although it is not mine.

I had to format my hard drive and then I installed an
older version of my video card drivers (by mistake)
I ran the game and I got impressed because all the
problems were gone, then I installed the lastest
drivers and the problems pop up again ... and I also
noticed a framerate loss of about 8-10 frames...

This is in XP, but then, I ran the game over win98
with the >lastest driver< and all seemed perfect again ... :(

So, the problem is drivers over win XP..

I'm with a GeForce2 mx 200, and the lastes drivers for
XP are the 71.89.
I have installed Directx 9.0 b , I will see if upgrading to 9.0 c
fix the problem but I don't think so ...

By the way, thanks for those inputs...


markcw(Posted 2005) [#10]
glad you found the problem.

also glad it isnt the "alpha demon"! :)

it did look like an alpha problem, but with
the benefit of hindsight i can see that the
face clipping is far too irregular to be an
alpha issue.

you might also want to try downgrading to dx 8.1,
this being a dx 8 engine... em, i think.


Paolo(Posted 2005) [#11]
yep,
I just hope the Blit3D engine continue being as much
stable as it seems to be these days... the software (drivers and directx)
keep being updated and updated and it is obvious there will
be more bugs coming in the future but anyway ... :)


Ross C(Posted 2005) [#12]
You running an NVidia card by any chance?