Z-Feathering and Smoke effects in COD2

Discussion in 'Architecture and Products' started by Matt B, Oct 31, 2005.

  1. Matt B

    Matt B
    Newcomer

    Joined:
    May 24, 2004
    Messages:
    39
    Likes Received:
    0
    Location:
    Sony Cambridge, UK
    Hi guys, I was just wondering if anyone knew much about the implementation of the smoke and particle effects in call of duty 2. This game has to be one of the best looking ones I've ever played and in particularly the smoke effects are phenomenal. It seems that they are just very cleverly used sprites but it's the first time I've seen sprites used which don't "clip" into their surroundings, they seem to really have volume and thin out before clipping through objects.

    I've heard there is a technique called Z-Feathering they've used for this but i haven't been able to find much about it. Does anyone have any info about how it's implemented?
     
    #1 Matt B, Oct 31, 2005
    Last edited by a moderator: Oct 31, 2005
  2. mmp121

    mmp121
    Newcomer

    Joined:
    Apr 23, 2004
    Messages:
    16
    Likes Received:
    0
    Location:
    DC Metro
    I don't know how they do it, but I played the demo and was blown away at how realistic the explosions looked! I kept replaying the start of the demo over and over just cause I couldn't believe the explosions / dust / smoke were being created real-time.
     
    #2 mmp121, Nov 1, 2005
  3. RejZoR

    RejZoR
    Regular

    Joined:
    May 9, 2004
    Messages:
    300
    Likes Received:
    3
    Location:
    Europe\Slovenia\Ljubljana
    I think Quake 4 is using similar technique for smoke. AT least it looked that way on Nexus where you blow up the hangars with jets...
     
    #3 RejZoR, Nov 1, 2005
  4. chrisATI

    chrisATI
    Newcomer

    Joined:
    Feb 28, 2003
    Messages:
    21
    Likes Received:
    6
    Location:
    Boston, MA
    There are a few ways to achieve this effect. One way is with depth sprites, described here:

    http://www.ati.com/developer/samples/DepthExplosion.html

    One other option is to disable depth testing when rendering the sprites then do a depth compare in the pixel shader and alpha blend the sprite based on the depth compare (so that the sprite fades as it intersects the ground, for example).

    --Chris
     
    #4 chrisATI, Nov 1, 2005
  5. Matt B

    Matt B
    Newcomer

    Joined:
    May 24, 2004
    Messages:
    39
    Likes Received:
    0
    Location:
    Sony Cambridge, UK
    Hey chris, thanks for the info, the Z-Depth compare trick seems like a pretty nice and quick solution. However how stable/glitchy are the results? I would have thought it could break down in a complex scene and give odd results where the normal of the tested object is close to perpendicular to the camera.
     
    #5 Matt B, Nov 1, 2005
  6. Hyp-X

    Hyp-X Irregular
    Veteran

    Joined:
    Feb 6, 2002
    Messages:
    1,170
    Likes Received:
    5
    You don't have to disable depth testing, just make sure it only rejects the pixels where the alpha would be 0 anyway.
     
    #6 Hyp-X, Nov 2, 2005
(You must log in or sign up to post here.)
Loading...
Similar Threads - Feathering Smoke effects
  1. Cyan

    Legality of Emus on Consoles *feather split*

    Cyan, Jul 6, 2016, in forum: Console Industry
    Replies:
    123
    Views:
    9,838
    Cyan
    Apr 16, 2017
  2. cubrman

    How would you implement a "dripping smoke" shader like in DOTA 2

    cubrman, Feb 11, 2014, in forum: Rendering Technology and APIs
    Replies:
    10
    Views:
    3,401
    cubrman
    Feb 21, 2014
  3. ECH

    Game Smoke, what's the big deal?

    ECH, Jun 16, 2010, in forum: PC Gaming
    Replies:
    8
    Views:
    1,568
    Simon F
    Jun 18, 2010
  4. _xxx_

    After "green police", we're about to get "smoke police"

    _xxx_, Mar 24, 2010, in forum: Religion, Politics & Socioeconomic Climate
    Replies:
    50
    Views:
    376
    _xxx_
    Apr 8, 2010
  5. CamRaiD

    A burning long unanswered question about smoke effects in games !!!!

    CamRaiD, Mar 9, 2010, in forum: Rendering Technology and APIs
    Replies:
    10
    Views:
    3,372
    tabs
    Mar 13, 2010
  6. g__day

    What's heavier - a pound of feathers or a pound of gold?

    g__day, Jan 3, 2006, in forum: General Discussion
    Replies:
    49
    Views:
    5,831
    Nite_Hawk
    Jan 11, 2006

Share This Page

Toggle Width
Style
Beyond3D

  • About Us

    Beyond3D has been around for over a decade and prides itself on being the best place on the web for in-depth, technically-driven discussion and analysis of 3D graphics hardware. If you love pixels and transistors, you've come to the right place!

    Beyond3D is proudly published by GPU Tools Ltd.

  • Quick Navigation

Loading...