How Many Layered Transparencies

moultano · May 2003

<div class="IPBDescription">can I expect a low end comp to render</div> My current project, ns_Shiva has a coolant processing room where coolant has leaked out forming a layer of mist settling on the floor. I'm creating this effect with layered func_illusionarys. The more layers I use, the more volumetric it will look, but I'm wondering about performance hits for older comps (especially since its a hive room). Anyone have a good estimate on what would be reasonable?

Second question: Is env_fog going to be functional in the future? I've had a hard time finding information on it. And it doesn't seem to work the way it is described.

taleden · May 2003

pretty sure env_fog just doesn't work in NS, and at any rate behaves strangely - you don't see fog unless you're standing inside the env_fog, and then you see it all around you; its not like a defined cloud of fog. you might want to look into using a particle system instead of layering transperencies.

moultano · May 2003

I was going to use a particle system for the coolant spraying out of the pipe, but there isnt any way to get the rest of the effect I'm looking for with it. I was hoping to fill the area under the transparencies with an env_fog. The problem with layering transparencies is that skulks and crouched marines see perfectly well horizontally along the layers of fog. The env_fog would have prevent that by making people within the fog see everything foggy. Anyone know if env_fog will work in the future?

crode · May 2003

i played around with env_fog and found out the same thing, it doesnt work. I accidentally loaded up a test map with the NSTR2 and it worked fine. So yes its busted.

You can achieve the same effects as your illusionaries with particles. Just find a big sprite and scale it up really big. In fact it would be better than illusionaries since you can make them move, fade in and out, etc

moultano · May 2003

</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td><b>QUOTE</b> (crode @ May 11 2003, 12:42 AM)</td></tr><tr><td id='QUOTE'> You can achieve the same effects as your illusionaries with particles. Just find a big sprite and scale it up really big. In fact it would be better than illusionaries since you can make them move, fade in and out, etc  </td></tr></table><span class='postcolor'> 
Alright, time to go read a particle tutorial. <img src='http://www.unknownworlds.com/forums/html/emoticons/biggrin.gif' border='0' style='vertical-align:middle' alt='biggrin.gif'>

NecromanZer · May 2003

or you could add another lot of func_illusionaries vertical up to the height of the first ones, in a cross underneath them,so that no matter where you crouch in the fog u have to see thru more fog... although might look weird from above

moultano · May 2003

I was thinking about that, but it does look pretty wierd from above. One thing I'm considering is having a particle effect produce fog sprite to provide the horizontal occlusion and keeping a single func_illusionary for the smooth top of it.

venomus · May 2003

Using particles for the fog would look more realistic than func_illusionaries (it could move around and not be perfectly flat) and also you would not be able to see horizontally through it. On the other hand it may have a bigger impact on framerate, especially if the fogged area is quite large. Spend some time tweaking the settings on the env_custom_particles until you find a good balance between looks and performance.

As for the env_fog, even when it was functional, it was global fog not volumetric (this is the only type of fog the HL engine can currently support). So you can forget about "elite" Q3/Serious Sam style fog layers.

NerdIII · May 2003

The game Age Of Mythology uses transparent layers for fog. From above it really looks good! Maybe it would be ok to add vertical brushes with the texture of a streched cloud? So there are no visible borders on the top and bottom of the brush.

Btw. what about my latest mist <img src='http://www.unknownworlds.com/forums/html/emoticons/smile.gif' border='0' style='vertical-align:middle' alt='smile.gif'> :
<img src='http://nsworld.ns-central.co.uk/pictures/Uploaded/622/fullsize.GIF' border='0' alt='user posted image'>

Ollj · May 2003

you know how much smoke grenades (5+ large sprites rendered over each other) affect a 200mhz computers fps?

moultano · May 2003

Here are too shots of the effect currently. This room is still heavily under construction, particularly the lighting.

The effect doesn't look great in this shot, but its close enough to what Im looking for. Not that bad for halflife.
<img src='http://www.andrew.cmu.edu/user/rmoulton/ns_shiva0000.jpg' border='0' alt='user posted image'>

This shot is the real problem, and what I was hoping to use the env_fog to correct.
<img src='http://www.andrew.cmu.edu/user/rmoulton/ns_shiva0001.jpg' border='0' alt='user posted image'>

Ollj · May 2003

The public enemy HL beta mod uses this effect a lot.
It uses 3-4 layers and uses it only in areas that you cant reach alife and that are at least 10 meters away from you.
4 layers should be fine for any HL PC, your entity count is a bigger problem.
The PE mod uses TONS of entities, wich NS never could, it needs the entities for all buildable structures.

moultano · May 2003

So long as none of the fog layers overlap I can make them all one entity without causing any wierdness, so I'm not to worried about that.

Ollj · May 2003

the fog is not volumetric when you are inside of it.

You could just use water (no breathe in the dust) or how about this?
(red = NULL-texture)

moultano · May 2003

nice idea, but it still doesnt work for any models in the fog. (not to mention that it would be an absolute pain in the **** to construct with the pipes I've got going in and out of the fog.)

I may end up just lowering it so that the skulk pov is just above the top level of the fog.

Yamazaki · May 2003

I've done the same effect using non-solid func_conveyors with additive rendermode. I made a scrolling vapour texture and had 3 layers, each one travelling in a different direction, and placed the layers 1 unit on top of the other. The result was very convincing, and with some slight adjustments to the texture it looked like water.

I might re-use this effect in the future, but one problem you have is entity size. Always try to keep your entities under 512x512x512, and using 384x384x384 might be safer. Otherwise VIS gets confused and HL starts rendering the entities no matter where you are. So filling up a 768x768 room with 3 layers of fog would make for 3 x 4 = 12 seperate entities.

Using particle systems is even more problematic, since you have fill-rate issues. Really large sprites result in a dramatic slowdown on even top end machines. Half-Life was never really meant to display huge transparent sprites. The other option is to use lots of little sprites, but then you run into problems with having too many overlapping each other, causing another dramatic drop in framerate from all the transparent rendering.

NerdIII · May 2003

@Ollj... smoke grenades on a 200 Mhz PC? hmm.... some years ago I had such a machine, but I would not attempt to play NS on it. But hey! I only use that many sprites in small rooms anyway. It's kinda cool to be in a small room and not to be able to clearly see the other end.

@Yamazaki: <img src='http://www.unknownworlds.com/forums/html/emoticons/biggrin.gif' border='0' style='vertical-align:middle' alt='biggrin.gif'> That goes into the top ten Half-Life rendering techniques!

Supernorn · May 2003

it'll probably be fixed in 1.1 so work on some other parts of your map and then do the fog last. <img src='http://www.unknownworlds.com/forums/html/emoticons/smile.gif' border='0' style='vertical-align:middle' alt='smile.gif'>

amckern · May 2003

for fps issies, get a program called slow down - and set it to the speed of the cpu u want to test it at

i use this for commander keen - as a amd athlon 1400, is to fast for a game made for a 80386

NerdIII · July 2003

I know this program. I also used it years ago <img src='http://www.unknownworlds.com/forums/html/emoticons/wink.gif' border='0' style='vertical-align:middle' alt='wink.gif'> But I wasn't aware they added an option to set the exact Mhz you want to have. This could come in very handy to test NS maps. Also software mode might be an option <img src='http://www.unknownworlds.com/forums/html/emoticons/smile.gif' border='0' style='vertical-align:middle' alt='smile.gif'>

How Many Layered Transparencies

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