Only idea - i have not tried it yet.
Implement it as vertex fog
F(x, y, z) - integrated by z axis fog function,
for each lighted vertex V.color = alpha*V.color +
(1-alpha)*F(x,y,z). You should render background fog
also... may be render F(x,y,z) into billboard
grid vertices ?
volumetric fog (FlyFire)
Author
hmm, i don't know much about this, though i've looked for stuff on it in the past. i guess there
isn't a whole lot out there on the subject. all i can tell you is that i think, if implemented in
realtime, the stencil buffer is used....
isn't a whole lot out there on the subject. all i can tell you is that i think, if implemented in
realtime, the stencil buffer is used....
-Nick
Author
I'll have an article on this topic within a week or
two.
two.
The program will use vertex based multi-pass
blending. (Only one pass for the fog, but it can be
layered on top of other passes). I believe this is
how quake3 does it. It's a good solution for decent
quality, flexibility and speed.
The article will discuss a few other ways of doing it.
particle-based
3d-textures
I hope to expand it to more advanced algorithms,
including animated procedural fog.
I'll post something here when I get it done.
Scott Franke [druid-]
sfranke@usc.edu
druid-'s GLJournal
Author
i'm beginner in this kind of stuff, so i don't know
some of terms. Can you explain what is stencil buffers?
i heard about them, but didn't find any explanation
thanx
some of terms. Can you explain what is stencil buffers?
i heard about them, but didn't find any explanation
thanx
Author
ok, multipass rendering only good for hardware
rendering, but i was talking about software techniques,
like volumetric fog in Unreal.
rendering, but i was talking about software techniques,
like volumetric fog in Unreal.
Author
It's a second pass with gouroud shaded polygons.
Doubling the number of polygons, but it could be worse.
Doubling the number of polygons, but it could be worse.
You'll notice that having fog in scene will slow down
the Unreal engine quite a bit (check the fps on the
opening shot). I'm not sure what technique they used,
but I'm trying to find out.
Nick:
I'm not familiar with any volumetric fog techniques
that use the stencil buffer. Do you have an example
of one?
Author
Another idea - for fog with cylindrical symmetry
u can precalculate a set of map (it will be one -
parametrical) and between the map use linear
blending; the corresponding (to From ->To vectors) map
applied to object either as second texture or as
quad + stencil (here is a stencil buffer)template.
u can precalculate a set of map (it will be one -
parametrical) and between the map use linear
blending; the corresponding (to From ->To vectors) map
applied to object either as second texture or as
quad + stencil (here is a stencil buffer)template.
Author
Hmm, looks like a good article (i didn't read it yet
due a lack of time
)
But anyway, example works veeery slow on my pc (P166MMX
with S3 ViRGE 3D) - only 1-3 frames per second.
due a lack of time
)But anyway, example works veeery slow on my pc (P166MMX
with S3 ViRGE 3D) - only 1-3 frames per second.
This topic is closed to new replies.
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