(WIP) David Haywood's Homepage - 模擬器

2017.09.11

"Deco Cassette in MAME 0.189"

MAME 0.189 was released the other day and one piece of progress that went
into it, which I actually feel is one of the most significant progress made
between 0.188 and 0.189 comes in the form of improvements to the DECO
Cassette System driver. AJR has put a fair bit of effort into getting these
things right, and in 0.189 it’s finally paid off.

Since it was first emulated the DECO Cassette System has proven tricky to
emulate properly, not only due to the fragile nature of the games meaning
that every dump we have should be treasured, but also because it was built as
quite a flexible system, with the video system offering a number of different
modes of operations, many only used in a handful of places. It also didn’t
help that some of the games are just plain ugly on real hardware, almost as
if even the programmers didn’t fully understand the hardware and sometimes
ended up just accepting what was displayed was the best they were going to
get, even if it wasn’t what they were aiming for.

One of the big issues the driver has always had came in the form of the way
certain colour mixing modes work; the incorrect emulation of these resulted
in a number of situations where the colours being shown in MAME did not match
those being output by the original games running on the actual system. With
MAME 0.189 it appears that this issue has finally been solved, every emulated
Deco Cassette game now perfectly matches the colours in all the original
hardware captures we have been able to find.

While not a particularly interesting game, one of the most obvious examples
of where things improved was with Lucky Poker, old MAME shots are on the
left, correct, newer MAME shots are on the right. You can see that the game
gains a green background and black text boxes ingame, and a blue background
on the title screen.

https://mamedev.emulab.it/haze/pics2017/luckypo_bad_1.png
https://mamedev.emulab.it/haze/pics2017/luckypo_good_1.png

https://mamedev.emulab.it/haze/pics2017/luckypo_bad_2.png
https://mamedev.emulab.it/haze/pics2017/luckypo_good_2.png

The Deco Cassette Multigame (an unofficial conversion for the hardware that
uses a ROM containing the games instead of cassettes) also saw the selection
menu become a lot less garish, now correctly showing a blue background.

https://mamedev.emulab.it/haze/pics2017/decomult_bad.png
https://mamedev.emulab.it/haze/pics2017/decomult_good.png

Astro Fantasia is another where the colours changed a lot, previously the
emulation looked like this, with every stage having the same colours.

https://mamedev.emulab.it/haze/pics2017/castfant__bad_1.png
https://mamedev.emulab.it/haze/pics2017/castfant__bad2.png

With the fixes each stage gains a unique palette.

https://mamedev.emulab.it/haze/pics2017/castfant_good_1.png
https://mamedev.emulab.it/haze/pics2017/castfant_good_2.png
https://mamedev.emulab.it/haze/pics2017/castfant_good_3.png
https://mamedev.emulab.it/haze/pics2017/castfant_good_4.png

We have videos of the game Manhattan which show similar colours changing
between levels, but from what I can tell that’s a different version of the
game, the one we have doesn’t even attempt to write to any registers to do
this. It isn’t uncommon for there to be multiple versions of Deco Cassette
games. One game with significant colour changes between versions, which can
now be seen is Rootin’ Tootin’ (aka LaPaPa)

In older MAME versions both versions of the game (the one with Rootin’ Tootin
’ in attract, and the one with La Pa Pa in attract) used the same default
blue background as the bios

https://mamedev.emulab.it/haze/pics2017/clapapa_bad_1.png
https://mamedev.emulab.it/haze/pics2017/clapapa_bad_2.png

With the fixed colours there’s actually a very significant difference in the
background colour of each set, one having what is actually a rather ugly
green background, and the other going for a more neon look with a black
background. While the green looks ugly, it is verified on hardware, it wouldn
’t surprise me if the set with the black background is a newer set after
players didn’t like the green much.

https://mamedev.emulab.it/haze/pics2017/clapapa_good_1.png
https://mamedev.emulab.it/haze/pics2017/clapapa_good_2.png

Highway Chase was also much improved in 0.189, with the headlight effect
working properly. The new colours are arguably uglier, with a blue road
instead of a black road, but again this was a Data East design choice, the
blue road is verified against hardware; you can see the same colours &
graphics used in the ‘madalienb’ clone of ‘madalien’ so again it was
probably something Data East changed over the course of several revisions
until they were happy with it (although no cassette versions with the grey
road have been seen) Left is Highway Chase in older MAME versions (headlight
effect not working – always on but not masking anything, black road) and on
the right is Highway Chase in newer versions (headlight masking works, road
is blue)

https://mamedev.emulab.it/haze/pics2017/chwy_bad_1.png
https://mamedev.emulab.it/haze/pics2017/chwy_good_1.png

https://mamedev.emulab.it/haze/pics2017/chwy_bad_2.png
https://mamedev.emulab.it/haze/pics2017/chwy_good_2.png

There are many other examples of places where colours have changed, and as
mentioned, in every case, even ones where things look subjectively worse, the
new colours are verified against actual hardware videos, so again, big thanks
to AJR for working on this because it really brings the actual driver for the
system up to scratch. Now here’s hoping some more rare cassettes turn up and
can be dumped before it’s too late for them


"Gaelco Mania"
https://mamedev.emulab.it/haze/2017/09/05/gaelco-mania/

"Glassic Gaming 1.0"
https://mamedev.emulab.it/haze/2017/09/05/glassic-gaming-1-0/

"Hunting Alligators"
https://mamedev.emulab.it/haze/2017/08/29/hunting-alligators/

"Spike Heels"
https://mamedev.emulab.it/haze/2017/08/26/spike-heels/


https://mamedev.emulab.it/haze/

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ポーラステーション
http://perry0517a.blogspot.tw/

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