Jurassic Park: transparency gitch on the first stage

[vanfanel]

Hello there,

Running latest FBNeo GIT code here.
I've noticed a transparency glitch on the first stage of Jurassic Park, where brown-ish transparent bands move up and down with the cursor.
I recorded a video of it:

jpark_glitch.mp4

Seems like a Sega System 32 emulation bug.

[dinkc64]

Hi vanfanel,
Here's how it's supposed to look:
https://youtu.be/Mx0fHZOThlo?si=pflfqBvwG1VW1Y6R&t=153

I'll try to figure it out, but I can't promise anything, the Sega System 32 is kinda complex!

best regards,

• dink

[mahoneyt944]

I believe it's related to row scroll. I managed to get it working for player 2 but not player 1 in mame2003+. Player 1 might just be a priority issue though as its not shown at all but I never got any further with it. Maybe this will help here though.

https://github.com/libretro/mame2003-plus-libretro/blob/3206819c48567e759f993134ac27491b11b3dd80/src/vidhrdw/system32_vidhrdw.c#L1327-L1331

[dinkc64]

Hi mahoneyt944, thanks for the tip!
I'll see if this can be improved upon,

best regards,

• dink

[mahoneyt944]

@dinkc64 I went down the rabbit hole a little by porting newer segas32 video code over to mame2003+.... I get the same issue noted here. Curiously it's not broken for player 2 in any code base, so I'm hopeful that it's a minor adjustment needed for player 1. This issue has been present since the beginning of this video code (around mame 97u2), so it's unlikely my previous comment will help here. Player 2's render might point us in the right direction though.