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ID Category [?] Severity [?] Reproducibility Date Submitted Last Update
07985 Graphics Minor Always May 24, 2021, 23:59 Jun 4, 2021, 05:34
Tester jkburks View Status Public Platform MAME (Official Binary)
Assigned To Resolution Open OS Windows 10 (64-bit)
Status [?] Confirmed Driver mermaid.cpp
Version 0.231 Fixed in Version Build 64-bit
Fixed in Git Commit Github Pull Request #
Summary 07985: yachtmn, mermaid: Missing night graphics
Description Mermaid flyer text:
Be careful of your sailing at night
岩礁群の夜間航海に気をつけろ。
(watch out for reefs during night voyages)

This night sailing feature is currently unemulated in MAME.

When you launch either Yachtsman or Mermaid you will notice a single column of light blue pixels descend either side of the play field. This is an emulation bug that does not occur on real hardware, but it is related to the missing night graphics.

The game is composed of 5 sailing levels that repeat. The night sailing happens on levels 2, 4 & 5.

It starts with the blue pixel edges appearing suddenly on each side of the play field. They then scroll down the screen slowly and disappear. Next a siren sounds for a while as you navigate a simplified play field. Eventually the siren stops, then the blue pixels descend the screen once more and disappear.

What is supposed to happen here is the blackening of the screen like a falling curtain. Once the screen has gone black, a ray of light shines out from a location off-screen in the upper left. This beam of light rotates to simulate a spinning light house. The player must memorize the layout of the screen and navigate safely. This is why the play field has so few obstacles.

When the section ends, the light house beam and the siren stop, then the daylight descends like a curtain drop. Those blue pixel columns are some sort of fragment of this unemulated feature, though I have no idea why it occurs in the title screen.
Steps To Reproduce Launch Yachtsman and observe the blue pixel columns.

Load one of the attached save states to see where the night sailing is supposed to occur.
Additional Information I have uploaded a set of 3 save states made with MAME 0.231 – no cheats. Each file was created a few seconds before the night sailing begins. The file numbers correspond to the game level.

It is not easy to find hardware videos of this game. This twitter link shows the end of one night sailing voyage. It is filmed with a phone, but this is the best reference I have.
https://twitter.com/nyarise/status/1239456567323283456
Github Commit
Flags
Regression Version
Affected Sets / Systems yachtmn, mermaid
Attached Files
zip file icon yachtmn.zip (5,507 bytes) May 24, 2021, 23:59 Uploaded by jkburks
Yachtsman Save States MAME 0.231
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Notes
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User avatar
No.18923
jkburks
Tester
Jun 4, 2021, 05:34
http://youtu.be/watch?v=sVAfPzNc4uw

Recent Yachtsman PCB video from an arcade in Japan.

It looks like he's playing the game on a CRT in an open candy cab, but the video we see is being output through a Framemeister video Upscaler to a PC, mixed with a webcam and streamed live to Youtube with Xsplit at 720p. The aspect ratio in most of his arcade PCB videos appears slightly incorrect.

I have watched the video and noted the timestamp for each time the night sailing effect is on screen. This video confirms that the night sailing effect occurs on the title screen and that the curtain fall corresponds exactly with the blue pixel columns in MAME.

Night Sailing Timestamps

00:00:18 title screen curtain fall.
00:00:49 night sailing in attract mode.
00:01:21 operator unplugs PCB to show it on stream.
00:03:40 reconnects PCB – attract mode begins with the curtain fall.
00:04:11 attract mode night sailing

00:04:24 Level 1 coin up – game start.
00:06:34 Level 2
00:10:36 Level 4
00:15:35 Level 5

all levels repeat after this

00:20:15 Level 2 (Sunfish)
00:24:33 Level 4 (Sunfish)
00:29:17 Level 5 (Sunfish)

00:33:17 Level 2 (Octopus)
00:37:12 Level 4 (Octopus)
00:40:25 Level 5 (Octopus)

00:44:01 Level 2 (Tortoise)
00:48:06 Level 4 (Tortoise)
00:51:50 Level 5 (Tortoise)

00:55:18 Level 2 (Mermaid)
00:59:22 Level 4 (Mermaid)
01:02:47 Level 5 (Mermaid)

01:05:00 select PCB for next day’s stream.
01:07:19 game ends as last life disqualified.

01:07:25 – 4 minutes of attract mode loops.