View Full Version : a few questions
08-14-2003, 01:03 AM
my last time hiere was a long time ago,
There is a question I have never asked but always wanted to have the answer.
-Maybe i'm wrong, but I believe that Q3A do not use detail texturing, why? I love this effect when yo go close to the wall and the texture is great. Is it a technical issue ?
- what are currently the best method to have no owerdrawn? I mean : is there something else than bsp and octree now?
08-14-2003, 01:28 AM
1) Q3 used the texture units for lightmaps and multitexturing. Now when we have better gfx cards with more texture units I suppose it would be easy to add detail texturing, but I guess Doom3 is more important.
2) You may use whatever tree you want/need. Often a combination of trees should be preferred. Some trees:
BSP tree - good for indoor environments, but the old algos that tough every triangle is outdated.
Quad tree - nice for terrain. Like an octree with no height.
Octree - should be average on most environments.
KD tree - a bsp tree with axis aligned planes. Very high performance tree for most environments.
Scene tree - Uses objects as nodes. Good as a higher level tree.
Nodes can be of different shapes in all trees, often spheres are the best option for speed.
No overdraw? That isn't important anymore. It might be good with some rough occlusion culling though. This is an area without any really good solutions IMHO. You should check out portals and PVS for simple solutions. There's a pile of other solutions as well, just search.
Oh, and I might be wrong in more than one statement above...
08-14-2003, 05:22 AM
As far as I remember, unreal tournament 1 was out approximatively in the same period than quake 3, but Ut use detail texturing.
It's the first time that I heard something about KD tree and Scene tree, isn't it something like some algorithms that are under license ? Or everyone can use them freely with sources and so on.
It seems that the BSP hegemonia is finished http://www.opengl.org/discussion_boards/ubb/smile.gif
08-14-2003, 05:39 AM
UT probably prioritized detail textures over something else..
Licensing trees? Sounds strange, kind of like licensing data types. http://www.opengl.org/discussion_boards/ubb/wink.gif
Binary space partitioning will most likely be around for quite some time (forever?). It still has lot's of uses...
Loose octree - like octrees but dynamic.
AABB tree - axis aligned bounding box trees. Great for animated objects, but less fit for large scale scenes.
Beam tree - Should be ok for occlusion culling. Don't know these too well...
I suggest you try out a loose binary axis aligned sphere tree.. http://www.opengl.org/discussion_boards/ubb/biggrin.gif
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