Is it possible to disable anti-aliasing in N64 games via GameShark cheats?

Discussion in 'Nintendo Game Development' started by mdmx, Feb 4, 2016.

  1. dushbadge

    dushbadge Member

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    The OOT 1.0 code has the following modes:

    1) Dithering Filter off
    2) 16-bit pixel size
    3) Gamma Dither Enabled
    4) DIVOT enabled
    5) Aliasing off, just Resamp

    The OOT 1.1 code has the following modes:

    1) Dithering Filter off
    2) 16-bit pixel size
    3) Gamma dither disabled
    4) DIVOT disabled

    5) Aliasing off, just resamp

    Generally I have seen that only aliasing and dithering are usually altered and nothing else, so I do not really understand the rationale behind the two different codes (they both carry the same original search values and addresses).

    However,

    Personally I have not tested this enough on my end. You never know, maybe removing Gamma Dither where applicable could have a positive effect. DIVOT not so much because I think it only has an effect when there is aliasing in place.

    As I understand, Gamma Dither can add noise to pixels so it may be worth a shot to test with and without.

    If you would like to test it yourself, just modify your existing codes as follows (to remove Gamma Dither):

    (example address assuming top is 0000 and bottom is 2nd half):
    8104535C XXXX
    8104535E XAZY

    Leave X as is, change Y to 2 as shown (i.e, if you see 6, replace it with 2).

    Additionally, If you want to remove DIVOT, wherever you see Z, change it to 0 as shown (otherwise keep it as is).

    For A in the example above, I have added this because there is another aliasing mode called No Resampling or Aliasing. Normally this is set to 2 as you've seen in many codes to just make it resampling but according to earlier posts, setting this to 3 (which is no aa/resamp) could have an even greater effect on the visuals.

    But from my experience, I have had no luck. Mario 64 and Zelda for me just show 3 vertical viewports that are a quarter wide each. Someone said it works for Conkers, Banjo and Perfect dark so it could just be select games possibly.

    Also,

    Some codes end with E at the end and they have yet another mode called Gamma which is enabled. If you see this and would like to remove Gamma Dither, do not set Y to 2. Set it to A to keep Gamma on but disable Gamma Dither.

    But again, Gamma is also something worth additionally testing on/off as well. Ultimately if you want Resampling with no filters, just using 3202 is fine (or 3203 if a game uses 32-bit pixel size but I don't know which ones do that).
     
    Last edited: Jun 24, 2018
  2. demilich

    demilich Spirited Member

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    Awesome, thanks for the detailed breakdown. I'm understanding it a bit better. Lately I've been busy finding codes to remove dither and enable 16:9 aspect ratio for PS1 games, but even though I find the N64 stuff a bit more complicated, I definitely want to know what the codes do just how you explained.

    I will try what you recommended to see what differences I notice. When I initially tried both codes on OOT v1.0, the only difference I noted was one looked brighter and it made me think of something that has to do with Gamma.

    Thanks!
     
  3. demilich

    demilich Spirited Member

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    @dushbadge
    Do you know if the code for Mischief Makers NTSC U works for v1.1?
    I tried it but I don't see a difference. I'm guessing it needs different code.
     
  4. dushbadge

    dushbadge Member

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    That won't work as they are different. Use this instead.

    Mischief Makers (USA) (Rev A)
    Keycode: Mario World 64 & Others

    810EA57C 0000
    810EA57E 3212
    810EA5AC 0000
    810EA5AE 3212
     
  5. demilich

    demilich Spirited Member

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    I tried that code. I honestly don't see any difference and perhaps Mischief Makers doesn't benefit from the code?

    Thanks!
     
  6. dushbadge

    dushbadge Member

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    Personally I didn't see much of a difference either when I tested it.
     
  7. demilich

    demilich Spirited Member

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    @dushbadge

    Could you share a disable dithering code for
    Diddy Kong Racing NTSC U V1.1?

    I was looking in this thread and didn't find one. I thought I had seen it before.

    Thanks!
     
  8. dushbadge

    dushbadge Member

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    I use a code for that but I guess I forgot to add it.

    Diddy Kong Racing (USA) (V1.1)
    Keycode: Diddy, 1080, Banjo, Griffey

    DE000400 0000
    F1025000 1000
    F1025002 0002
    F105FB1C 1000
    F105FB1E 0004

    810E4DAC 0000
    810E4DAE 3216
    810E4DDC 0000
    810E4DDE 3216
     
  9. demilich

    demilich Spirited Member

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    @dushbadge Thanks for sharing the code!
    I was searching more info on dithering for the N64 and came across this video.


    It looks like it is just completely removing dithering, but it made me wonder if the current codes for Starfox, or any other n64 game would require additional codes to completely remove dithering.
    Like it was mentioned before, the Disable dithering codes are supposed to remove anti-aliasing and dithering but for some reason does not remove it. Even changes mentioned to alter in your previous explanation does not remove dithering.
     
  10. dushbadge

    dushbadge Member

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    You tried every combination?

    Personally I haven't tried it yet, but like you say, despite turning it off I still see some very evident dithering. But I have come to terms with it, and usually mask it with scanlines.

    I have found that keeping Bit 16 on as well causes these vertical light beams, making the game look worse.

    This isn't really something I'm well versed in.
     
  11. demilich

    demilich Spirited Member

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    @dushbadge

    At some point I did try different combinations for Starfox, but it seems that dithering is not going away. I wonder if there would be any difference with V1.1 of Starfox.

    On a side note, I've been testing your code for Jet Force Gemini, but it seems it is not working properly. I've tried it on 2 different Gamesharks with no luck. It plays for a little bit and then the screen goes black. At first I thought it was my RGB signal and switched to S-video, but the same thing happens.
    I even tried these end combinations: 3202,0032.

    Would this require a different code once I switch to the letterbox widescreen option?

    Jet Force Gemini (USA)
    Keycode: Zelda

    810A9EBC 0000
    810A9EBE 3216
    810A9EEC 0000
    810A9EEE 3216

    On a side note, have you messed with Toy Story 2 NTSC U any? I don't think I've seen a code that game.

    Thanks
     
  12. mdmx

    mdmx Familiar Face

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    Baku Bomberman (JP):
    8001B16D 0000
    8001B19D 0000
    8001B16E 0032
    8001B19E 0032

    Uchhannanchan no Honoo no Challenge: Denryuu IraIra Bou (aka Electric Pen) (JP):
    800D40DD 0000
    800D40DE 0032
    800D410D 0000
    800D410E 0032
     

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