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View Full Version : game levels are tile based textures still?


yinako
05-25-2003, 06:09 PM
anyone can tell me if most 3d game level developed today still use tilable texture in them? I mean shared UV space for textures.

if so than how is that possible that I see some games use light maps in levels? are they not huge memory hog, i persume they are full textures no tiled light maps.

kleinluka
05-25-2003, 06:31 PM
yeah they do. texture resolution has increased over the past few years though, so textures 1024x1024 are no rarity on modern graphic engines.

what exactly do you mean by 'lightmaps' ?

Ryan-B
05-25-2003, 07:05 PM
The UV coordinates are seperate from the textures applied to them.

Lightmaps are a big memory hog. If you want detailed lightmaps, you have to make them larger, which means even higher memory usage. You will often notice jagged edges on low-resolution lightmapped shadows. Many games try to lower the memory usage of the lightmapped shadows with a resulting decrease in quality.

Lightmaps also take longer to calculate than vertex lighting.

zworp
05-25-2003, 07:56 PM
yinako:
you have separate uv sets.
one uv for the tiled textures
and one non tileing uv for the lightmap.

Jabo
05-25-2003, 09:06 PM
Speaking of the latest Unreal engine build, lighting sucks because it's cheap vertex lighting. The problem is that most shadows are blurry stains on the textures. With the new import feature of 3d-application-based geometry (so-called static meshes) and the new "render-to-texture"-feature of Max5.0, you can "bake" the shadow, light and eben bumpmaps onto one single UV texture, which means you have all the stuff branded on one texture. That's the method Legend Entertainment used to get some sharp shadows into Unreal2. They still look ugly and the effort is big, but it helps... in a way.

zworp
05-25-2003, 09:27 PM
hmm baking both texture and lightmap into one texture does not sound like a good idea, it would recuire extremely large textures for a good result..

BiTMAP
05-25-2003, 09:37 PM
I remeber my old half-life days, we made our lighting part of the texture and used the game lighting to accent it. It took real talented guys to make it work, which is how it SHOULD be... And just a question, what form of lighting is the new HL2 engine useing??

SquirrelyJones
05-25-2003, 11:59 PM
From the video it looks like theyre using lightmaps on some of the stuff (bsp geometry) and vertex lighting on static meshes and models, but it looks like most of the static meshes cast a shadow (not always in the right direction though)

yinako
05-26-2003, 03:26 AM
yes I have seen seperate UV sets used, but have always wondered if many game engines today supports this. As far as I know Its more like a maya feature.

So they export that sort of shading network straight out of maya?

BiTMAP
05-26-2003, 03:43 AM
valve didn't use maya, and I was hearing that they used Pre Calculated Radiostity that even effects moving objects and I'm pretty sure its not lightmaps becuase they use things like bump maps and such and they interact in real time.

Omita
05-26-2003, 04:45 AM
Half Live 2 uses SoftImage and Normal Mapping. Soft has great Normal mapping tools/pipeline and tangent mapping support. To my knowledge they are only using normal mapping, no bump, spec or tangent.

Models around 5000 polys for character. PCGamer has a making of... and if Game Developer is worth anything they should get on the story. I personally think it looks better then Doom3.

-Omita

zworp
05-26-2003, 07:15 AM
most game engines (all ive used) support dual pass textures (lighmaps), and yes you export the shadernetwork from maya for an example.
the modern graphicscards render lightmaps very fast parallel resulting in small or none performance loss.

Marcel
05-26-2003, 11:38 AM
Lightmaps can be (4bit?) grayscale, that makes them much smaller than the other textures.

zworp
05-26-2003, 06:12 PM
yeah, though i prefer 8bit to get the best results.

another thing that most people dont think of is that you kan use colors in the light map, with a little work in photoshop you can make the same texture look quite different by affecting its color.

gaggle
05-27-2003, 01:25 PM
HL2 uses, as far as I've been told, you standard grayscale bumpmapping for the environment, and normal-map controlled bumpmapping on the characters.
Actually hopefully it'll all be controlled by a flexible shader-implementation, so we can do our own shit just the way we want it to. I'm hoping for more or less full access to pixel- and vertex-shaders, so it'll be up to the artists to determine if a character or a wall needs, say, specular and/or selfillumination applied beyond the standard diffuse-, bump-, and opacity-channels. Though I've no idea how exactly the engine will scale down to cards that don't have pixel- and vertex-shaders... hm.

Anyway, lighting looks (very) similar to HL1, with the precalculated radiosity and the vertex-stuff for the characters. Looks like increased resolution in the lightmaps, and dare we hope for a more flexible implementation as well, so we can keep the environment dynamic without ending up with strange lighting-errors.

I'm personally in favor of the precalculated radiosity approch with lightmaps that can take hours to compute, when the alternative would be (God forbid) pure vertex-lighting, or even the still-pretty-crappy approch favored by for instance Quake 3, which is precalculated lightmaps but with an extremly simple lighting-model (just gives off these spheres of light. No bounce-light or anything. Bah). ..well I guess Doom 3 offers a fourth option, but.. that's hardly relevant for quite a while yet.

I'll stop the ranting now :)

BiTMAP
05-28-2003, 12:53 AM
you guys keep saying lightmaps, that was the wonderful think about half-life THEIR ARE NO LIGHTMAPS, as well as after watching some demos from the HAVOK I see that HL Could have dynamic lighting, as in throw something at a hanging lamp and it moves and the light changes in REAL TIME...

Omita
05-28-2003, 01:01 AM
Well... no matter what technologies are used, it looks like content will get cut in half again to keep quality high.

A couple companies I know are scanning objects and actors again. To eliminate the need for high poly modelers, or at least minimize the amount of high poly modelers. Even though the scans have ugly mesh's for animations it doesn't matter because all the hi-poly mesh is used for is backing Normal map data.

[/me] thinks he might have wasted a little too much time learning how to paint shadows for Quake 3 based games.

-Omita

zworp
05-28-2003, 04:49 AM
erh., well look closely on the hl2 videos, hl2 definetly use lightmaps for static shadows (from buildings etc) combined with the dynamic lightning.

BiTMAP
05-28-2003, 05:04 AM
HOW can you say that? HL2 has NEVER used lightmaps, Its not even near to how the HL2 engine works! It projects lights and the lights cuase shadows by real world objects blocking light!

That was the most wonderful thing about Half-life, the prerenderd lighting that didn't need any light maps, and that left you time to make the actual map and gemoetry, and to have constantly changeing lighting setups, Trust me i've been mapping in half-life for 4 years.

suck
05-28-2003, 06:15 AM
bitmap,

are you maybe thinking of something else when you are talking about lightmaps? as far as I know, they are the 2nd pass textures that are generated by halflife (1) 's radiosity lighting routine. might you be thinking lightmaps are something different, like that they have to be manually painted into the textures possibly?

zworp
05-28-2003, 08:18 AM
bitmap,
check this screenshot, the shadow from the house is lightmapped.

and about hl1. its lightmaps, however the engine creates the lightmaps itself when you compile your level.

gaggle
05-28-2003, 11:06 AM
Originally posted by BiTMAP
i've been mapping in half-life for 4 years. What hlrad.exe does for all those hours of compiling is generating the lightmaps :p

LAn
05-28-2003, 04:07 PM
i think hl2 use a combinition of lightmaps and dynamic-lighting. It don't look like realtime-lighting.


Lightmaps are nothing special, most games use them.

And one correction about the new Unrealengine:
The engine use lightmaps, but only on bsp, other things does have vertexlighting. Also lightmaps on terrain.
It's only very boring to see much maps, where mappers used only Staticmeshes, but more or less no bsp (especially new mappers, which model their meshes by themself, but which don't create the basics as bsp). There does exist some UT2003-maps with very nice lighting (and gameplay...), they are very rare, but they exist.
good old UT1-time, all things does have a lightmap and you don't see much things with vertex-lighting.

Dai
05-28-2003, 07:47 PM
Originally posted by BiTMAP
you guys keep saying lightmaps, that was the wonderful think about half-life THEIR ARE NO LIGHTMAPS, as well as after watching some demos from the HAVOK I see that HL Could have dynamic lighting, as in throw something at a hanging lamp and it moves and the light changes in REAL TIME...

It's not unified like Doom 3, if that's what you think.

There are loads of static light maps in HL2, and they're as easy to spot as an eye-sore. I don't know how you missed them.

Bilbo_Baggins
05-28-2003, 07:58 PM
I don't know exactly how different types of lighting works, but I noticed than in the HL2 video certain objects cast shadows and others don't. Like if you look at the poles on the concrete and some of the streetlights in this pic (http://www.newtechnix.com/Webmasters/supertony/Images/News_PC_Half-Life_2_3.jpg), they don't cast shadows.

AndreKling
05-29-2003, 01:07 AM
Wow this discussion is very interesting, but i get lost, whats the difference for vertex lighting and light maps, what the advantage in using then? Where can i learn about all those lighting stuff? Someone told they bake a high poly object, is it like the troll in LOTR? if so have any tutorial about this process?
If somenoe answer something i will be extremly thankfull

Thanks
Andre Kling David

chk
05-29-2003, 05:56 AM
Andre, you should take a look at the link I posted at the end of your thread here:

link to a link of a tutorial (http://www.cgtalk.com/showthread.php?s=&postid=609677#post609677)

you run through that tutorial and you will definitely come through with a better understanding of lightmaps.

but in brief:

lightmaps (as used in halflife, quake and its descendants, or almost and current implementation) are grayscale textures created to represent the shadows cast by the static lights in an environment. In most situations, these are mapped to surfaces with a set of UV coordinates separate from those used to map the color channel of a polygon, normally a texture.

vertex lighting is what you see in your perspective view in Maya in textured and shaded mode. It works by looking at the values of any given light and its distance from an arbitrary vertex. That vertex is given a brightness value. These brightness values are interpolated between all the verts of any given polygon, which creates the ramps between light and dark. Vertex lighting by itself isn't affected by occlusion, meaning it does not give you any cast shadows.

AndreKling
05-29-2003, 07:19 AM
Hey Thanks chk, i did took a look at the tutorial and i couldnt quite get the difference bettwen one and other. So lightmap is a channel and not something u burn to the texture right? Is like a bump map but for lights. Is this what ppl are using in the market right now?
Andre Kling David

zworp
05-30-2003, 12:20 PM
AndreKling
yeah, you could say that its like a bump map, its a seperate texture that you blend over the normal texture. and it usually has its own uv set.
this is often called a dualpass texture.

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