HOW Increasing lightmap quality

(benj) #1

Hi there.

I’d like to increment the global lightmap’s size per face
is there a q3map2 switch to do that?

i don’t see any differences with “samplesize”
“lightmapsize” changes the size of the texture…

can you help please?
thanks

(obsidian) #2

-lightmapsize changes the physical size of the lightmap pages.
-samplesize changes the scale of the lightmap resolution.

Both switches affects your entire map unless otherwise specified.

If you have specific faces of a brush that you would like to alter the lightmap quality on, you need to create a shader with q3map_lightmapSampleSize and/or q3map_lightmapSize

Changing the lightmapSize will only work on certain games that support it, for instance, Enemy Territory. Other games that don’t support it will have no effect, like Quake 3.

(Twisted0n3) #3

You can also change the sample size on a specific chunk of geometry by func_grouping it and setting the key _lightmapscale with a value such as 0.125. (That will octuple the lightmap resolution – similar to lightmapSampleSize 2, in the case of Q3 where the default is 16.) I’m not sure if the same key will work on lightmapped (spawnflags 4) mapmodels, but it works on grouped brushes and patches. Useful on geometry where there are shadows that have stairsteppy edges, or to improve the smoothness appearance of patch geometry.

(obsidian) #4

Additional notes of interest:

Increasing the lightmap resolution works best when you have alphashadow’ed textures or fine brushwork with a strong light passing through it. You need a higher lightmap resolution to capture the fineline detail of the alphashadow or brushwork.

With the problem of jagged shadow edges, the problem is usually better handled with some method of lightmap filtering or penumbra jittering effects, set in either the surface shader, sky shader, light entity, or compile switch. Merely increasing the lightmap resolution to solve jagged shadow edges only creates, well, higher resolution jagged shadow edges. Experiment with a bit of both and you’ll save lightmap memory and have silky smooth shadows.

(benj) #5

thanks.

But i’m using the switch -export and -samplesize 4 (for example) and
i don’t see any differences in the exported lightmaps
(tga files)…

q3map2’s log says:
"…
default lightmap sample size set to 4x4 units
…
"

is the default lightmap sample size overriden somewhere else?

i 'm using gtk-radiant , q3map2 , q3map2 toolz (and q3)

(Kobayashi) #6

Try using -samplesize in the BSP phase if you haven’t already.
Samplesize in the Light phase doesn’t seem to do anything… or am i missing something?

(Q.) #7

Q3map2 reads samplesize from *.srf file which is generated via bsp phase.
So light phase has no effect on it.

@obsidian
Lightfilter’ed texture is also demanding.
For example in case we want to use a n00d pic to get a sexy result.