Results 1 to 6 of 6

Thread: Just what is "analog sprite scaling" ?

  1. #1
    Red (Level 21) Jorpho's Avatar
    Join Date
    Jul 2002
    Location
    We're all mad here
    Posts
    13,541
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    1
    Thanked in
    1 Post

    Default Just what is "analog sprite scaling" ?

    There's probably a better board out there for asking this question, but maybe someone here knows:

    Part of the reason that Buck Rogers was a relative latecomer to MAME was that it had "analog sprite scaling circuitry", and that was a difficult thing to emulate.

    It occurs to me I have no idea as to what this actually means, and I'm kind of curious about the details. How exactly could you use analog circuitry to scale a sprite? It doesn't quite make sense.
    "There is much pleasure to be gained from useless knowledge." --Bertrand Russel (attributed)

  2. #2
    ServBot (Level 11) kedawa's Avatar
    Join Date
    Nov 2005
    Location
    Toronto
    Posts
    3,429
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    0
    Thanked in
    0 Posts

    Default

    There are all sorts of weird raster tricks that older hardware uses, but I've never heard of analog sprite scaling.

  3. #3
    Chaos Knight
    Mayhem's Avatar
    Join Date
    Jul 2002
    Location
    London, England
    Posts
    8,916
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    0
    Thanked in
    0 Posts
    Xbox LIVE
    Mayhem64

    Default

    Possible supposition... usually back then you had to draw all the individual frames of animation, so there was a need to store images of all the ship sizes from small to large. Maybe the circuitry automatically calculated and created the correct sprite size for the ship on the fly instead?

  4. #4
    Pretzel (Level 4) APE992's Avatar
    Join Date
    Jun 2007
    Location
    Chico, CA
    Posts
    999
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    0
    Thanked in
    0 Posts
    Xbox LIVE
    APE992

    Default

    If its analog it can't be digitally emulated, only simulated.
    I fix things. You name it, I'll work on it. Want something modded? Recapped?

  5. #5
    Insert Coin (Level 0) Drath's Avatar
    Join Date
    May 2011
    Posts
    57
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    0
    Thanked in
    0 Posts

    Default

    Just my idea, not 100% on this:

    The "analog" in that phrase is kind of a misnomer. It just means it uses the screen resolution (analog) to scale the sprites rather than through hardware. This would be hard in terms of emulation because the game/chip detects the analog screen resolution to scale the sprites which isn't there through emulation.

  6. #6
    Pretzel (Level 4) APE992's Avatar
    Join Date
    Jun 2007
    Location
    Chico, CA
    Posts
    999
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    0
    Thanked in
    0 Posts
    Xbox LIVE
    APE992

    Default

    Perhaps. I did some googling and found this:

    - 0.108u2: Removed machine\turbo.c. Further turbo driver cleanup. Still in WIP. [Aaron Giles]: Derived sprite scaling from PROMs and R/C values (still not 100%). Rewrote most of the video/sprite handling.
    Seems Giles was reverse engineering the data on hand to do so. Obviously if the machine relied on an analog value to determine how to scale the sprites they'd have to simulate it at best. A few games on MAME rely entirely on samples store as WAV files to have actual sound due to their hardware being impossible to emulate (analog generated audio) or incomplete knowledge of the hardware not allowing them to even start work. I believe one of the Star Wars games was (maybe still is) like this.
    I fix things. You name it, I'll work on it. Want something modded? Recapped?

Similar Threads

  1. Replies: 128
    Last Post: 05-24-2019, 01:06 PM
  2. MadCatz "PC CON" Analog Joystick Malfunctioning
    By Jorpho in forum Technical and Restoration Society
    Replies: 1
    Last Post: 10-21-2012, 11:59 PM
  3. PlayStation "Dual Analog" Controller
    By Shulamana in forum Buying and Selling
    Replies: 13
    Last Post: 03-10-2012, 02:03 AM
  4. analog on PS3 sixaxis won't register "down"
    By carlcarlson in forum Technical and Restoration Society
    Replies: 1
    Last Post: 03-15-2009, 07:55 PM
  5. "Special" PS2 controller for PS analog games
    By RJ in forum Buying and Selling
    Replies: 13
    Last Post: 11-18-2005, 03:02 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •