News: 11 March 2016 - Forum Rules
Current Moderators - DarkSol, KingMike, MathOnNapkins, Azkadellia, Danke

Author Topic: Mario Kart SNES questions about hack  (Read 1534 times)

omg

  • Newbie
  • *
  • Posts: 2
    • View Profile
Mario Kart SNES questions about hack
« on: August 12, 2020, 07:47:49 am »
Hi everybody,

A few weeks ago, some sources from SNES games leak on Internet... and a version of Mario Kart SNES  :laugh:

So I have some questions :

1- Should it be possible to program a 4 players version with it ?

2- Is possible to change Sprite Characters with Sprite from GBA version ?

Thank you.

FAST6191

  • Hero Member
  • *****
  • Posts: 2896
    • View Profile
Re: Mario Kart SNES questions about hack
« Reply #1 on: August 12, 2020, 02:57:40 pm »
Have not looked at this but in general SNES assembly is probably no better than just pressing disassemble on a commercial ROM. Likewise I am not sure if any assemblers place nicely with such code. Later systems might well have nice high level language source code but the 16 bit era, especially for high performance games like this, are all about assembly. For the most part the SNES stuff is mostly of interest to those looking for cut content and at historical programming approaches, those looking to make hacks might find a few nice comments, descriptions of compression or variable names but not much else.

1) I guess. Would face the same issues with memory (graphics and conventional) as anything else, though you might be able to subvert and expand AI racers.

2) Could have done that anyway. Indeed even with the source code and no worries about using it I would probably have looked at the ROM approach. Find the sprites in both (can probably dump them from the GBA memory/OAM/OBJ/... viewers for that part rather than learn GBA hacking), sort any size issues (GBA is a bit lower res than the SNES so... see all the fun and games with donkey kong, mario and the early ports of things), grab a palette and find out if you can happily overwrite it (which is to say some colour in it is not pulling double duty) and do as you will.

Raeven0

  • Jr. Member
  • **
  • Posts: 32
    • View Profile
Re: Mario Kart SNES questions about hack
« Reply #2 on: August 16, 2020, 03:02:52 pm »
A 4-way split in the usual 2x2 grid would not work natively. The mode-7 rendering requires different parameters per scanline per player, and changing those parameters in the middle of the screen would take too much time on top of being ugly and inconsistent.

As a workaround, you could run the game with interlaced rendering and draw the left half of the screen only on (e.g.) even scanlines, and the right half only on odd ones. This is very much in the realm of Stupid SNES Tricks, and the result might not actually be any fun, but it would be an enlightening project for someone interested in getting familiar with retro hardware.

FAST6191

  • Hero Member
  • *****
  • Posts: 2896
    • View Profile
Re: Mario Kart SNES questions about hack
« Reply #3 on: August 17, 2020, 06:11:04 am »
Hmm. In that case I would probably consider something like an emulator link setup but disable control of AI racers on one version, disable two on the other, kick control of the two to the other SNES and have all AI on the host copy + the players transmitted to the second.

Jorpho

  • Hero Member
  • *****
  • Posts: 4543
  • The cat screams with the voice of a man.
    • View Profile
Re: Mario Kart SNES questions about hack
« Reply #4 on: August 17, 2020, 09:46:30 am »
A 4-way split in the usual 2x2 grid would not work natively. The mode-7 rendering requires different parameters per scanline per player, and changing those parameters in the middle of the screen would take too much time on top of being ugly and inconsistent.

Was Top Gear 3000 the only SNES game with 4-quadrant split screen? Was that a function of the DSP-4?
https://www.youtube.com/watch?v=5OSX31hrd5M

Of course, trying to hack DSP-4 support into Mario Kart does not sound like a realistic proposition.  (Hacking Mario Kart graphics into TG3000 would probably be more feasible.)

There's also Street Racer's solution, though that is plainly a bit ridiculous.
https://www.youtube.com/watch?v=j18y3sc3fIQ

This signature is an illusion and is a trap devised by Satan. Go ahead dauntlessly! Make rapid progres!