16-bit vs. 32-bit vs. 32-bit 2X Lightmaps - by LarryG
Angs on 28/9/2012 at 10:09
Quote Posted by blaydes99
Angs, from what I can tell in your examples, 2X seems to put a kind of HDR-style overbrightening effect instead of an increase in resolution (this goes with what you are saying LarryG). Seems to make the lights more "potent".
Yes, it seems you are right. Maybe the 2X means twice as bright? I made some comparisons of 32-bit vs 32-bit 2X too:
Inline Image:
http://i.imgur.com/UoGt3.jpg Inline Image:
http://i.imgur.com/BV0sj.jpgI'd say 2X takes better advantage of the increased number of shades (Regular Thief lamps are probably so dark because if a 16-bit lightmap was that bright, the banding would be disturbingly visible). It looks nice, too.
I think the snow white background brings out the worst of 2X. On any other background it looks more natural in my opinion. 16-bit and regular 32-bit lights have these almost uniformly lighted disks around them, which looks as if the brightness hit the maximum value and the peak values near the lamp were cut off.
Weasel on 28/9/2012 at 16:19
I think this is the best way to describe the difference between regular 32-bit and 32-bit 2x lighting:
With Regular 32-bit (or 16-bit) lighting, it doesn't matter how bright the lights are, the brightness you'll get is dependent on the texture being lit. Essentially, you can get the "fullbright" version of that texture. The lightmap will vary the brightness in a scale that goes from fullbright texture to black.
With 2x lighting, the lightmap can actually make things brighter than the texture, or "wash out" the texture.
The lightmap will vary the brightness in a scale that goes from white to black (with the fullbright texture falling somewhere in the middle of that scale.)
For a texture of average brightness, the scale with 2x will be twice as wide. I think that's what the name is referring to.
Schwaa2 on 28/9/2012 at 19:25
Having no idea I would assume that 2x would mean twice as large.
Why would any authors want to increase the light amount by 2? That would require readjusting all the original lights in the hiearchy so they were half as bright to get the results everyone is used to.
And the screen shots don't show that.
But if it makes the lightmaps 2x resolution you will get smoother shadows. If you look at the stair support shadow on the ceiling in Angs screenshot it looks softer.
Lightmaps work on texels. So if you bump a texture up to 3-4 times regular size and render it the shadows on it will look pixelated because you have increased the texel size to 3-4 times the size.
At 2x the resolution the texels would be half the size, thus 'anti-aliasing' them. If you use textures at regular size or smaller you might barely notice the difference (shadows were never that jaggy in T anyway). But when you make a texture larger is when you would notice it the most.
epithumia on 28/9/2012 at 19:30
From new_config_vars.txt:
enable_32bit_lightmaps [<1 , 2>]
(DromEd only) when defined DromEd will defaults to 32-bit lightmaps instead of the normal 16-bit lightmaps
for new map. Setting a value of 2 will default to 32-bit 2X modulate mode. 2X mode allows for overbrightening
at the expense of reducing precision to 1/128 (from 1/256), which is still 4 times better than 16-bit maps.
Overbrightening gives lights a little more "oomph!", a cheap man's HDR-like effect on lightmaps.
When loading an existing map the editor sets the current setting to match that, so re-lighting/re-portalizing
will generate the same type of lightmaps as the mission already had.
The active mode can be changed with the "set_lighting_depth" command. Preferably the "Tools" menu should have
commands to switch mode (see reference MENUS.CFG), but for manual use the command takes following values:
16: original 16-bit lightmaps
32: 32-bit lightmaps
64: 32-bit lightmaps in 2X mode
LarryG on 28/9/2012 at 20:20
Ah! Brilliant and wise epithumia! I missed that in my document perusals. Well found!
I wonder if 2X combined with lower, and more granular ambient lighting might be the ticket for a really gloomy look ... hmmm
ZylonBane on 28/9/2012 at 20:28
Quote Posted by LarryG
I wonder if 2X combined with lower, and more granular ambient lighting might be the ticket for a really gloomy look ... hmmm
Ambient light is just about the
least granular thing Dark does.
LarryG on 28/9/2012 at 20:33
It just got more granular though. See Yandros' earlier post about what he discovered (wherever it is)
Yandros on 28/9/2012 at 23:46
Good find, Jason, now we can stop wondering about 2X lighting.
Quote Posted by LarryG
I wonder if 2X combined with lower, and more granular ambient lighting might be the ticket for a really gloomy look ... hmmm
I can say yes. In the creepiest area of Codex I've done just this, 32bit 2X lighting and low ambient light, and the atmosphere is striking - gloomy, desolate and pretty damn terrifying. Part of it is the novelty, I'm just not used to seeing that kind of contrast in any T2 map.
epithumia on 29/9/2012 at 00:12
Dudes need to learn grep. I just did "grep -ri 2x ." in the doc directory and looked at what came up. Grepping for "lightmap" turns up useful stuff, too.
