Certain thought on the basis of game graphics.......

Discussion in 'Console Gaming' started by Mobius1aic, Feb 10, 2009.

  1. Mobius1aic

    Mobius1aic Quo vadis?
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    How come at least heavy smoke in games isn't given some sort of shadow map on the ground? I understand the problem with shadow mapping soft particles, but at least with heavy smoke couldn't the effect be approximated reasonably? It's something I've noticed alot lately. If their is dense smoke between me and the sun, I'd expect to be covered in darkness. I also understand the implications of creating this effect as smoke is created and diffuses into the "virtual air" where the shadow must soften up most considerably yet smoothly, however I'd like to hear from more experienced people on this subject. I'd greatly appreciate any feed back.
     
  2. catisfit

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    I believe Stalker does shadowing of partially translucent objects/effects (figure 9-3). Is this what you mean?
     
  3. homerdog

    homerdog donator of the year
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    I recall sebbbi posting on this topic. IIRC his particle system allowed shadows from smoke onto other objects, but not smoke onto smoke.

    There are definitely games out there with great looking shadow casting smoke, STALKER and WiC (see below) being just two examples. Perhaps you're looking in the wrong places.. (
    you know what I mean :yes:
    )

    [​IMG]
     
    #3 homerdog, Feb 10, 2009
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  4. Mobius1aic

    Mobius1aic Quo vadis?
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    Hmm, I guess I never really noticed STALKER and WiC having smoke shadows, as I've beaten STALKER and played through most of WiC, both at max specs too of course.
     
  5. Mobius1aic

    Mobius1aic Quo vadis?
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    Sorry for the double post....but is that entire book on the Nvidia website ?! I've considered purchasing it or GPU Gems 3. I wonder when 4 will be out?
     
  6. Neb

    Neb Iron "BEAST" Man
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    It is subtle. Hard defined black shadows would be very unrealistic in plain daylight or such since light still comes in from all other directions and smoke/effects often are semi-translucent. Sun light occluded with tick volume effects is also in Crysis games making spot ~behind/under/around darker with god-rays puring through holes in the volume effect. For example smoke grenade. Very visible though is the shadows projected onto soft particles. Dunno if the realtime SSAO applied could help or does help to since it applies to bascially everything on the fly.

    Very nice in Crysis Wars. :D
     
    #6 Neb, Feb 11, 2009
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  7. Mobius1aic

    Mobius1aic Quo vadis?
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    Well I understand the need for the shadows to be very very soft, almost an ambient occlusion look to them (well it should be technically part of the process too) and that was what I was wondering in the nature of shadows having to build themselves off of such soft particles. Programming a "defining edge" to build off of would be difficult I would think as the shadow like I had mentioned would need to take into account smoke mixing with air in the virtual world, possibly creating a very difficult artifacting situation or just looking out of place. I haven't played Crysis Wars yet, but I've beaten Crysis. Is it available only at max settings in DX10 mode, or is the smoke shadowing available in DX9 mode at high settings?
     
  8. _phil_

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    MGS4 had shadows on particles (shadow receiving ) ,too.
     
  9. homerdog

    homerdog donator of the year
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    I think the effect is only present at very high/enthusiast settings. Battle dust in think it's called. It's hard to describe, but it looks very real. And I don't mean that in an 'OMG that looks sooo real!!1' way, I mean it looks _real_ . Wish I could find a screenie of it Nebula. :lol:
     
    #9 homerdog, Feb 11, 2009
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  10. _phil_

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    Particles are 2d quads allways facing the camera ,so casting shadows with that will look wrong most of the time.
     
  11. Mobius1aic

    Mobius1aic Quo vadis?
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    I thought about that, and obviously that's near impossible to build an accurate shadow off of. However, doesn't Crysis use volumetric smoke for higher settings? Even in high DX9 mode, the smoke grenades seem to release 3D smoke.
     
  12. zed

    zed
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    u billboard WRT the lights position
    eg its what Im doing here with the 2d leaves etc (u need a slight z offset though cause of the differing z values)
    http://www.flipcode.com/archives/02-27-2005_veg.shtml

    FWIW my engine has handled smoke shadow recieving/casting for at least 5 years its not that difficult
     
  13. Neb

    Neb Iron "BEAST" Man
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    The engine allows and the games uses both 2D and 3D particles by use of geometry IIRC. As far as smoke nade, panning around and over it looks like one single volume without particles facing your camera POV. God rays piercing the more translucent parts also shows it off. :smile:

    In the particle editor you can select to force 'recieve shadows' and 'cast shadows' for particle effects. Have not looked much into this. Though 'receive shadows' is forced on by default as a cvar setting. Dont know to what extent 'cast shadows' is used.

    EDIT: Well smoke grenade uses 'face camera' particles , alpha based blending, soft particles, diffuse lighting and high amount of particles and emitters. Non checked 'cast sahdows' box but I think they utilise another separate method to shade occluded area. :)

    maybe it is the amount of particles making it that way. here is a screenshot of the smoke nade. Looks same in any part but front (sun light is ~high up at middle-top and out of sight). Dont mind the jpg artifact rainbow colors. Sorry Homerdog I forgot to capture the battledust!

    http://img502.imageshack.us/img502/9519/smokegn9.jpg

    Code:
    From particles section:
    
    Receive Shadows 
    
    When turned on, Shadows will be cast on current item. 
    
    Cast Shadows 
    
    Current item will cast shadows. 
    
     
    #13 Neb, Feb 12, 2009
    Last edited by a moderator: Feb 12, 2009
  14. homerdog

    homerdog donator of the year
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    Whoa that's a lot of smoke.
     
  15. Neb

    Neb Iron "BEAST" Man
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    No safety regulations here, smoke away! :wink:

    anyways it probably be rare in games. I remember though an old game which had it or it could be enabled. To bad it looked bad becouse the shadow was hard edged and pitch black and didn't follow the smoke contours in a right way. Shadows on smoke I've seen in several games. For example ArmA has it when shadow setting is set to highest and FC had it to IIRC amongst other games.

    EDIT: BTW battledust screenshot I don't have but video I uploaded some weeks ago has battledust. Just wait for it to build up SD/HD! :D

     
    #15 Neb, Feb 13, 2009
    Last edited by a moderator: Feb 16, 2009
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