don't click here

VDP bug exploiting

Discussion in 'Technical Discussion' started by Sik, Aug 24, 2008.

  1. notaz

    notaz

    Tech Member
    32
    0
    6
    Yeah, I think there should be at least one other game which used this feature. Charles' doc mentions Raiden Trad and Alien Soldier, but I haven't examined those.
     
  2. Snake

    Snake

    Tech Member
    41
    0
    0
    It is NOT a bug. It IS a feature. It's present on pretty much every system with playfields, sprites, and priority settings. It isn't specifically documented because it's bloody obvious to a games coder.

    Except, of course, it actually IS mentioned in the SNES manual.
     
  3. Overlord

    Overlord

    Now playable in Smash Bros Ultimate Moderator
    19,252
    983
    93
    Long-term happiness
    Presumably Nintendo thought its developers were a bit slow ;P
     
  4. roxahris

    roxahris

    Everyone's a hypocrite. Take my word for it. Member
    1,224
    0
    0
    Doing anything at all
    Well, at least then they wouldn't need to waste any more time than they needed to finding things with the hardware 8p
     
  5. muteKi

    muteKi

    Fuck it Member
    7,852
    131
    43
    Well, since this is active again, I was thinking a good way of exploiting this feature would be to use it to do something similar to the title card lettering of Sonic 2 GG/SMS.
     
  6. Dr. Kylstein

    Dr. Kylstein

    Member
    86
    0
    6
    Is this what the Sonic 1 and Sonic 2 title screens use to hide the characters when they move into the ring? When I comment out the object loaded by sub_12F08 in Sonic 2, I can see them when they're below the ribbon.

    [​IMG]
     
  7. Overlord

    Overlord

    Now playable in Smash Bros Ultimate Moderator
    19,252
    983
    93
    Long-term happiness
    Possibly, but I think that may just be standard layering...
     
  8. Dr. Kylstein

    Dr. Kylstein

    Member
    86
    0
    6
    The whole ring + ribbon is on scroll-A high. I have only prevented a sprite from loading.
    After looking at it in Genecyst, I think the part that is still on top in the screenshot is also using the exploit. There is a sprite there which has the top edges of the ribbon, but the part that is a full character tall has some random tiles from Tails(?). This suggests to me that it is never actually seen and only exists to make that part of A/H show up on top.

    I'm not confident in my understanding of the VDP, so I would really appreciate a response from somebody who is.
     
  9. TmEE

    TmEE

    Master of OPL3-SA2/3 Tech Member
    1,726
    2
    18
    Estonia, Rapla City
    T-04YBSC-A !
    One of the sprite masking modes would be something that you could use in a case like this... I have not done any checking though...