Search found 74 matches

by colinvella
Sat Sep 03, 2016 6:21 am
Forum: NESemdev
Topic: Mapper 58 and Game Star 68-in-1
Replies: 6
Views: 2446

Re: Mapper 58 and Game Star 68-in-1

I think my mapper 58 implementation is already in line with all your suggestions. Here's the relevant code (C#) for reading and writing to the mapper: public override byte this[ushort address] { get { if (address < 0x2000) { return Cartridge.CharacterRom[characterBank * 0x2000 + address]; } else if ...
by colinvella
Thu Sep 01, 2016 11:03 am
Forum: NESemdev
Topic: Mapper 58 and Game Star 68-in-1
Replies: 6
Views: 2446

Mapper 58 and Game Star 68-in-1

I recently implemented mapper 58 in my own emulator, which seems fairly straightforward according to the specs at http://wiki.nesdev.com/w/index.php/INES_Mapper_058 . I managed to get the Game Star 68-in-1 ROM working (CRC: 2BA377FC), except for the game Galaxin 00, Galaxin 01 etc., which for some r...
by colinvella
Sat Jul 30, 2016 12:19 am
Forum: NESemdev
Topic: Mapper 23: VRC4 rev E/F or VRC2 rev B?
Replies: 18
Views: 6018

Re: Mapper 23: VRC4 rev E/F or VRC2 rev B?

Congratulations on pedantically misinterpreting what I said as a request for details on how Castlevania 3(US) uses the MMC5. I didn't mean any offence, perhaps I have an annoying habit of rambling off topic. To be honest I have never thought through the reason why different localisations of a game ...
by colinvella
Fri Jul 29, 2016 11:20 am
Forum: NESemdev
Topic: Mapper 23: VRC4 rev E/F or VRC2 rev B?
Replies: 18
Views: 6018

Re: Mapper 23: VRC4 rev E/F or VRC2 rev B?

This is also why Castlevania 3 is on MMC5 instead of VRC6, even though it doesn't really use hardly any of the MMC5 features. I did work on an MMC5 mapper mostly to get Castlevania III running. It uses the IRQ counter, ExRam page and fill mode. I really had to restructure my code to make mappers mo...
by colinvella
Fri Jul 29, 2016 2:16 am
Forum: NESemdev
Topic: Mapper 23: VRC4 rev E/F or VRC2 rev B?
Replies: 18
Views: 6018

Re: Mapper 23: VRC4 rev E/F or VRC2 rev B?

We know of two games that used the A wiring variant of the VRC2: TwinBee 3, and Ganbare Pennant Race! Similarly, we know of four games that used the E wiring variant of the VRC4: Tiny Toon Adventures, Akumajou Special, Parodius Da, and Crisis Force. Unfortunately, some games aren't well-behaved . I...
by colinvella
Thu Jul 28, 2016 1:53 pm
Forum: NESdev
Topic: Wavy sprite effect like in Boku Dacula-kun title screen
Replies: 16
Views: 5399

Re: Wavy sprite effect like in Boku Dacula-kun title screen

I did run it on a real NES, which is how I finally understood what it was supposed to do :) I should perhaps have said "a single scroll change done with pixel precision in the middle of a scanline", since it doesn't revert on later scanlines. (I would have taken a picture and posted it in that thre...
by colinvella
Thu Jul 28, 2016 1:46 pm
Forum: NESdev
Topic: Wavy sprite effect like in Boku Dacula-kun title screen
Replies: 16
Views: 5399

Re: Wavy sprite effect like in Boku Dacula-kun title screen

I think my favourite part of this is how the tower and the rooftop do a vertical parallax, and it's by putting an extra slice of tower rows on the second nametable that it switches to for a few scanlines before switching back to the flat roof. It lets the first nametable stay unchanged during the p...
by colinvella
Thu Jul 28, 2016 8:18 am
Forum: NESdev
Topic: Wavy sprite effect like in Boku Dacula-kun title screen
Replies: 16
Views: 5399

Re: Wavy sprite effect like in Boku Dacula-kun title screen

It's background scrolling in a sinusoidal pattern. The same effect is used for warp zones in the port of Super Mario Bros. 2: Mario Madness in Super Mario All-Stars and for the title screen of Solar Wars . Try logging writes to $2005 and $2006 while that animation plays. I suspected so, but what ab...
by colinvella
Thu Jul 28, 2016 8:01 am
Forum: NESdev
Topic: Wavy sprite effect like in Boku Dacula-kun title screen
Replies: 16
Views: 5399

Wavy sprite effect like in Boku Dacula-kun title screen

Whilst working on my emulator project to get VRC2/VRC4 games working, I couldn;t help but wonder how the wavy moon to monster sprite animation is implemented in the game Bocu Dracula-kun. Anyone care to shed light on this? Is the PPU mid-frame scroll technique being used on a small region of the bac...
by colinvella
Thu Jul 28, 2016 7:50 am
Forum: NESemdev
Topic: Mapper 23: VRC4 rev E/F or VRC2 rev B?
Replies: 18
Views: 6018

Re: Mapper 23: VRC4 rev E/F or VRC2 rev B?

Solved. And once again it was all due to a stupid bug on my part. I was essentially modulating the character bank pages by the ROM's character bank count (a habitual precaution to ensure that out of range CHR bank numbers wrap around) and forgot to take into consideration that for Rev A, all bank re...
by colinvella
Thu Jul 28, 2016 5:55 am
Forum: NESemdev
Topic: Mapper 23: VRC4 rev E/F or VRC2 rev B?
Replies: 18
Views: 6018

Re: Mapper 23: VRC4 rev E/F or VRC2 rev B?

With some class refactoring, I got the IRQ functionality working in both VRC2 and VRC4 mappers. This is Boku Dracula-kun: http://i.imgur.com/Vm3LrR2.gif One remaining mystery now is the title screen in Twinbee 3, which runs on VRC2 Rev A (mapper 22). Only the title screen is garbled - the game itsel...
by colinvella
Thu Jul 28, 2016 4:11 am
Forum: NESemdev
Topic: Mapper 23: VRC4 rev E/F or VRC2 rev B?
Replies: 18
Views: 6018

Re: Mapper 23: VRC4 rev E/F or VRC2 rev B?

My heuristic solution for determining the low bits seems to have worked, at least to the point where both Wai Wai World and Boku Dracula-kun show the correct tiles. Obviously, because I am now trying to cater for VRC4 Rev 3 in my VRC2 mapper, I will need to add the IRQ counter - it seems that Boku u...
by colinvella
Thu Jul 28, 2016 3:48 am
Forum: NESemdev
Topic: Mapper 23: VRC4 rev E/F or VRC2 rev B?
Replies: 18
Views: 6018

Re: Mapper 23: VRC4 rev E/F or VRC2 rev B?

Thanks for all the guidance guys. So Mapper 23 can be either VRC2 Rev B or VRC4 Rev E, and the "low" address bits of interest may thus be (A0, A1) or (A2, A3). Perhaps, short of resorting to checksums, I can try making the mask less restrictive (say, $F00F) and try to determine which bits in the ran...
by colinvella
Thu Jul 28, 2016 2:54 am
Forum: NESemdev
Topic: Mapper 23: VRC4 rev E/F or VRC2 rev B?
Replies: 18
Views: 6018

Re: Mapper 23: VRC4 rev E/F or VRC2 rev B?

Indeed, masking addresses by $F003 when writing to $8000 and higher seems to have solved the problem. Now I just have to deal with the incorrect CHR tiles, which for some reason are not working well. This is strange since, for instance, Wai Wai World is working fine.

Image
by colinvella
Thu Jul 28, 2016 2:30 am
Forum: NESemdev
Topic: Mapper 23: VRC4 rev E/F or VRC2 rev B?
Replies: 18
Views: 6018

Re: Mapper 23: VRC4 rev E/F or VRC2 rev B?

You're right, I'll try to be a bit more specific, but I think it's best if I present specific examples one at a time, so as not to flood the thread. For instance, the game Akumajou Special - Boku Dracula-kun (Japan), which uses mapper 23, seems to write to $8FFF and $AFFF in what seems to be an atte...