Moonwalker, Fast Lane, public cores... (Patreon)

Moonwalker

The arcade game with arguably the most popular music ever visits us this week. JTS18 beta adds support for Michael Jackson's Moonwalker. This game has proven hard to support. First, there were problems to make it boot up because of some odd timing issue with MegaDrive's VDP chip. Then the music was severely broken, which is a show stopper for this title. And finally, the children you have to rescue were not visible.

The music bugs had been there in JTS18 all along. Some people had a feeling that there was something off with the music but we could not pin point it. For Moonwalker it was very clear though. So we could track down the bugs. You will notice that Alien Storm and Shadow Dancer sound different after today's update too.

The invisible children were a kind of bootleg protection set up by SEGA. Almost all the graphics are drawn using the arcade hardware, which is a newer version of the SEGA System 16B. But the children are drawn by the MegaDrive VDP chip. If a bootlegger wanted to copy the game, they would have a really hard time copying the VDP chip so the children wouldn't be visible and the game wouldn't really be playable.

For us the problem was about mixing the VDP graphics layer. The children must be drawn in the middle of the other layers according to some equations. We have the equations, but we did not have the meaning for most terms in the equations. We spent most of the week trying to make sense of the equations and finally got it in time for today!

Other Updates

• JTFLANE core: new beta for Analogue Pocket, featuring support for Konami's Fast Lane

• JTSHOUSE core goes public (Splatter House, PacMania, etc). The screen flip feature is missing, but we will add it in the public core directly

• JTNGP goes public as the pending work on the NGPC core can be done independently

• JTBIOCOM core goes public for the Analogue Pocket (already public in other platforms)

• The bug in Boulder Dash that made the music stop is fixed

• We have added volume balancing information to most games so you get a similar sound volume when changing cores and games. We will refine it in the following weeks but the important thing is that we now have a framework to support this feature in place

• SEGA System 18 schematics have been revised again and some connections have been corrected

• Konami's Sunset Riders schematics have been improved and renamed to ssriders.pdf

• Greetings to Ricardo from UltimateMiSTer who visited our small offices today!