Author Topic: SH3/CV1000 emulation in MAME: CPU and blitter settings for emulating slowdown  (Read 2037 times)

Offline el_rika

  • Trade Count: (0)
  • Maniac Member
  • *
  • Posts: 39
Oh, thank you for the feedback and observations!

Watching a couple of Akai Katana vids led me to believe that there's a difference due to the shot spread, but as you say, it's most likely the accumulation of greens and/or golds. Need to watch more  :righton:

Offline EOJ

  • Administrator
  • Trade Count: (+37)
  • Ultra Member
  • *
  • Posts: 7499
Type C can accumulate green energy orbs more rapidly and more often than the other ship types, which leads to more slowdown. So in that regard you could say Type C has more slowdown overall. There may be a minor effect with its shot as well, but honestly the game has so much slowdown even when you're not shooting, I don't notice anything extra that is induced merely by the act of shooting.

This should be the easiest game to get better slowdown emulation in MAME compared to the X360 port, because 50-60% of the slowdown is missing in the port. Even 60-70% accuracy in MAME would be a big improvement.
My score archive
twitter: cavexstg
XBL gamertag: eojx9999

Offline el_rika

  • Trade Count: (0)
  • Maniac Member
  • *
  • Posts: 39
Good info there. It did seem to be the case at first glance .

I always tend to settle for a bit more slowdown in these games myself. Just love the dramatic near miss feeling it gives  ^-^

Offline EOJ

  • Administrator
  • Trade Count: (+37)
  • Ultra Member
  • *
  • Posts: 7499
For emulation I think it is best to aim for accuracy, not 'a bit more slowdown than on the PCB', even though perfect accuracy is not possible in MAME. From what I have tested out thus far, no MAME emulation of any Ikeda SH3 game is more than 70% accurate (the ports are more accurate in basically every case). Yagawa stuff fares noticeably better (e.g. MMP and PS can be set to have more accurate slowdown in MAME than in the ports) except DFK BL, which is on par with the Ikeda stuff in terms of accuracy (probably because it is an Ikeda game in its core programming).



My score archive
twitter: cavexstg
XBL gamertag: eojx9999

Offline xygax

  • Ballet Hell
  • Trade Count: (0)
  • Maniac Member
  • *
  • Posts: 28
  • It Hurts
Aim for accuracy? I don't know if I should laugh or cry.

Again it is a waste of time researching this using an outdated build. For the Nth time some ingame behaviours changed a bit after the recompiler was introduced (0.192 mem loadings that can influence slowdowns in places). Also using a proper up-to-date build you wouldn't have to deal with crashes and workarounds.

In short whatever you guys find here is in part of no use to users of proper up-to-date builds, and of course no use for the future.

The people who pushed for doing the wrong, uneducated choice of going for outdated cv1k emu ruined the chance of this 'project' to be at least a little serious, as expected from the SRR (Shmuppers + Retroarch = Retardation) typical combo recipe for inacccurcy and promotion of anti-progress, and the ugly clickwhores a la Mark_MSX will surely further promote mediocrity since that's what they exist for/live off.

Aim for accurcy = start with using a proper up-to-date build period.

Retroarch culture is people who don't understand the serious problem of sticking with heavily outdated versions of software, it's a cancer of our times for the world of emulation and development as a whole, a disservice to video games.

Damned Brandolini's law is the essence of the internet.  :displeased:

Offline SuperPang

  • Moderator
  • Trade Count: (+4)
  • Ultra Member
  • *
  • Posts: 651
    • Arcade Otaku
U OK hun?

Offline EOJ

  • Administrator
  • Trade Count: (+37)
  • Ultra Member
  • *
  • Posts: 7499
I use the “proper, up-to-date build”.
My score archive
twitter: cavexstg
XBL gamertag: eojx9999

Offline el_rika

  • Trade Count: (0)
  • Maniac Member
  • *
  • Posts: 39
Testing a bit of Akai Katana, another gorgeous game full of pretty effects.

I've been studying this for the past week (still don't fully understand all the elements of proper scoring - do i actually need to graze bullets with the captured orbs and gold?! or they mature on their own after a fixed time?) and i have a good idea on what it needs to properly run in mame.

As i assumed earlier and EOJ confirmed, type C slows down the game most, and it's a very noticeable difference in slowdown, with any of the ships, between an option full of matured orbs, small orbs and no orbs.

A guy on nico did pcb runs with all characters without ever going into Bubble mode (not an easy thing to do :oogle: ), which is very helpful for testing.
There are sections in this game where, especially with C and B, the game slows down so much that i think it's in single digits. Possibly the slowest slowdown in any Cave   cv1000 game.

B ship:


Cpu 47.00 mhz
Blitter delay 68%

C ship needs a faster Cpu clock and lower blitter value (60%), while A ship needs a lower Cpu and considerably higher (i settled for 72%) blitter.