Carmack talks Doom 3

Discussion in 'Architecture and Products' started by Doomtrooper, Feb 9, 2002.

  1. Doomtrooper

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  2. Pete

    Pete Moderate Nuisance
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    Yep, also pretty stale. :smile:
     
  3. LeStoffer

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    Damn, I thought that this was a whole new interview...

    Anyway, yes, it was very interesting and I think the Doom III-engine will finally show us what hardware T&L is all about. I'm not really looking that much forward to more polygons - it's nice and all but the whole lightning part of Doom III is going to be awesome. This is were (T&)L will shine IMO. Die lightmaps - die!!!

    REgards, LeStoffer
     
  4. Ozymandis

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    Does the new engine use lightmaps at all? Just curious.
     
  5. bystander

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  6. Humus

    Humus Crazy coder
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    Actually, I don't think it'll use "L" in T&L at all. It's done with DOT3.
     
  7. LeStoffer

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    Humus: Okay, as you can tell I don't know much about how light is "projected" onto a given triangle/texture, but I thought that you either had to use a lightmap (mapped upon a texture) or a lightsource (CPU/software or Hardware L) on a mesh of triangles? Wouldn't DOT3 have to use one of these?

    Hmmm, I guess I have this [odd] understanding from 3Dmax.

    Regards, LeStoffer
     
  8. tEd

    tEd Casual Member
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    That would be vertex lighting (using gpu L), j.c does per pixel lighting with dot3 bumpmapping although i'm not 100% sure.
     
  9. DemoCoder

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    Even with DOT3 you need the vertex shader (e.g. T&L stage) to perform per vertex lighting calculations, for example, if you are using local lights or if you are doing anything more complicated than bog standard diffuse and specular per-pixel calculations.

    But Carmack has said in the past that Doom3 doesn't use a lot of polygons. It uses imposters.

    Per-vertex calculations are very useful when setting up the per-pixel stage.



    <font size=-1>[ This Message was edited by: DemoCoder on 2002-02-09 14:10 ]</font>
     
  10. Xmas

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    Yes, they generate normal maps from high-poly models but use "low-poly" models in the game. The per-pixel dot3 lighting based on these normal maps makes sure the models still look very impressive even with "few" polygons. Of course the silhouettes won't look perfectly smooth.
     
  11. LeStoffer

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    This was what I meant. :oops:

    But in what cases do you not need to use vertex lighting calculations if you discard the use of lightmaps [with DOT3]? I ask because you always will need some kind af lightsource unless a texture is to be absolutely black. Right? Wrong?

    Thank for any clarification. :oops:

    Regards, LeStoffer
     
  12. JF_Aidan_Pryde

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    Imposters?

    Please elaborate :smile:
     
  13. Humus

    Humus Crazy coder
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    Well, there are loads of ways of doing it. You can put the tangent space normal into color and do a dot 3 with the normal map. Another way is to use some texgen and a texture matrix to rotate a 3d vector field texture into the tangent space and DOT with the normal map, which is something I've done in the volumetric demo you can find here. This way you can put attuenation into it without any additional math. You can also replace the 3d texture with a normalizing cubemap and do the attenuation with a 2d and a 1d luminance texture.

    Anyway, when someone says "T&amp;L" the L usually mean traditional vertex lighting, at least that was what it meant when the original GF arrived. But you can maybe include texgen/vertex shaders etc. into the definition of L too.
     
  14. Humus

    Humus Crazy coder
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    Well, you don't need any lights in the traditional glEnable(GL_LIGHT0) sense, but you'll of course need to represent them in your world in way or the other, possibly only storing the position and intensity. What DOT3 does is that make a dot product between the surface normal (stored per pixel in the normal map texture) and the light vector normalized. A dot product between two vectors of size 1 gives you the cosine of the angle between the vectors, which is exactly the factor you want for diffuse lighting. You then modulate this with the base texture. With traditional vertex lighting you'd only dot this at each vertex and interpolate the light color to modulate with the base textures, which give worse quality than using lightmaps. The problem with lightmaps are that they are many and can thus only be small and thus can't give you a expecially good lighting. The other problem is that they are static. Both these can be solved with dot3, but the problem with dot3 bumpmapping is that you don't get any shadows as you could get with lightmaps, thus you need to use shadow volumes or shadow mapping to shadows back.
     
  15. Dave B(TotalVR)

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    Jesus, on offence to the man he is a brilliant programmer, but he sounds like such a nerdy little teenager!

    Doom 3 sounds like its going to be damn good - 5 years after its release coz no cards will run it properly:p

    Dave
     
  16. Doomtrooper

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    I was thinking the same thing about the 'nerd' part :smile:
    Yet he has made some nice engines, as for Quake 3 gameplay..Bleh !
     
  17. Brimstone

    Brimstone B3D Shockwave Rider
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    Am I the only person looking forward to New World Order? The game has all the fancy 3d buzzwords in it (Per Pixel Lighting, Bump Mapping, and so on) and the playable demo is coming out soon.

    The NWO team hasn't released a game, so I guess thats a legitimate reason not to get to excited about the game. But the tech demo showing off the levels look so damn good, I wish more people knew about the game.

    Doom 3 will be an incredible experience though. The Mac World video looked so creepy with the lighting effects, I love it.
     
  18. Richard999

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    I think it's safe to say that I can hardly wait for some form of Doom3 news. Granted, I'd prefer the game out tomorrow, but I'll settle for some nice updates on when the game is supposed to be ready.
     
  19. nooneyouknow

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    NWO is going to look fantastic... They have a press release talking about their ATI support which means Truform, PS 1.4, etc..

    Wonder how the gamplay will be.. No doubt it will look great...
     
  20. Brimstone

    Brimstone B3D Shockwave Rider
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    Wow...it's great to hear that another person thinks NWO has potential. The game doesn't have any problems when it comes to graphics. Doom 3 and Unreal 2 deserve the attention they get, but it would be nice to see NWO get a litte more mainstream coverage besides just Voodoo Extreme.
     
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