JOTEGO
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Vigilante (beta)
🕑 Added 2022-05-06 10:56:59 +0000 UTCNB: The files are available in JTBIN via update_all or in the #betafiles Discord channel
Vigilante is a game that goes with no presentation. Everyone remembers the satisfying sound that kicking and punching produced in this title. But let me talk to you about some technical curiosities:
- The game still useda Z80 as the main CPU in 1988. As this CPU was starting to be a bit slow for the increasing demands of arcade games, the engineers made a trick for the second scroll layer. Instead of going for a tile map hardware, they used a bitmap layer. This took much more memory but it meant that the CPU could drive that layer just by setting the scroll position with two memory writes. This is orders of magnitude faster than using a tile map, which is too orders of magnitude faster than the pixel-addressed memory that home computers of the time had to do
- The second Z80 on the board runs the sound and it does it really quick. It has to attend an interrupt every 142 microseconds, which for a CPU running at 3.57MHz is challenging. The sound CPU also attended interrupts from the Yamaha chip and the main CPU. All this meant that the software reacts to events very quickly. I think that’s the reason why the sound lag is so noticeable in MAME compared to the FPGA. I made a video yesterday showing this and you can try it at home too. Just insert a coin in the FPGA and then do it on MAME. You will feel the lag quite clearly. I’ve been told there are some ways to avoid this in custom MAME builts. I have only compared with the vanilla MAME
- This game has overscan, so do not expect it to fit all CRT monitors vertically. Remember you can adjust the CRT image position in the OSD.
For the next two weeks, I will be working on the NeoGeo Pocket again. The system is now quite advanced but I’m not sure whether that will be enough to finish it. I will report back about it then. This means that we will not have new betas in the next two weeks, but there may be some small bug fixes.
Esperanza resumed work on the SEGA System 18 schematics. This task is likely to take the full month. We’ll keep you posted.
Thank you for your support
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NB: Los archivos están disponibles en JTBIN a través de update_all o en el canal Discord #betafiles
Vigilante es un juego que va sin presentación. Todos recuerdan el sonido satisfactorio que producían las patadas y los puñetazos en este título. Pero déjame hablarte de algunas curiosidades técnicas:
- El juego todavía usaba un Z80 como CPU principal en 1988. Como esta CPU comenzaba a ser un poco lenta para las crecientes demandas de los juegos de arcade, los ingenieros hicieron un truco para la segunda capa de desplazamiento. En lugar de optar por un hardware de mapa de mosaicos, utilizaron una capa de mapa de bits. Esto requería mucha más memoria, pero significaba que la CPU podía controlar esa capa simplemente configurando la posición de desplazamiento con dos escrituras de memoria. Esto es órdenes de magnitud más rápido que usar un mapa de mosaicos, que es también órdenes de magnitud más rápido que la memoria direccionada píxel a píxel que los ordenadores domésticos de la época tenían que padecer.
- El segundo Z80 de la placa ejecuta el sonido y lo hace muy rápido. Tiene que atender una interrupción cada 142 microsegundos, lo que para una CPU que funciona a 3,57 MHz es un desafío. La CPU de sonido también atendió interrupciones del chip Yamaha y la CPU principal. Todo esto hace que el software reaccione a los eventos muy rápidamente. Creo que esa es la razón por la que el retraso del sonido es tan notable en MAME en comparación con FPGA. Hice un video ayer mostrando esto y también puedes probarlo en casa. Simplemente inserta una moneda en el FPGA y luego hazlo en MAME. Sentirás el retraso con bastante claridad. Me han dicho que hay algunas formas de evitar esto en las compilaciones de MAME personalizadas. Yo solo he comparado con el MAME normal.
- Este juego tiene overscan, así que no espero que se ajuste verticalmente a todos los monitores CRT. Recuerda que puedes ajustar la posición de la imagen CRT en el OSD.
Durante las próximas dos semanas, volveré a trabajar en NeoGeo Pocket. El sistema ahora está bastante avanzado, pero no estoy seguro de si eso será suficiente para terminarlo. Entonces informaré al respecto. Esto significa que no tendremos nuevas versiones beta en las próximas dos semanas, pero es posible que haya algunas correcciones de errores menores.
Esperanza reanudó el trabajo en los esquemas de SEGA System 18. Es probable que esta tarea tome todo el mes. Os mantendremos informados.
Gracias por tu apoyo.
Comments
GeorgeSpinner
You go into the options and turn on the jtbin repo download. The unlock file is from discord (I think) or here.
Phonedork
Jose, were do I get the JTBIN via update_all from?
Phonedork
Yes I notice this also
JOTEGO
I am on it. Thank you.
GeorgeSpinner
Rastan is still running in turbo mode. The action is probably slightly too fast. The music is about 100km/hr when it should be 50km/hr. I used metric for my Euro friends. 🙂 It sounds squeaky. The bootlegs (that I've seen) don't sound this way. The originals definitely do not.
JOTEGO
Hi Rui . Please check the welcome message that Patreon sent you. It contains some important notes about where files are. The recommended way of installing the beta cores is by enabling the option in MiSTer's update_all scrit. You will have to manually copy jtbeta.zip to the games/mame folder in MiSTer.
how can i install it?
JOTEGO
Yes, but not in 2022.
Tony Vo
System 18 .......I can't wait 😃
Tony Vo
Great job jotega .....off topic but will we ever see Sega system 32 in future?
JOTEGO
I've played a lot to the PC engine version. It is really good and you have to pay attention to call out the differences.
JOTEGO
I suppose it will be either be ngp or ngpc. I suppose Sorgelig will decide that detail when the time comes.
Hi there, can you tell me the required name of the game directory for NEO-GEO Pocket ROMs? Will it be NGP, NGPC or some other name?
Mark Saunders
gosh i remember the pc engine conversion back in 88-89 looked arcade perfect, very cool to have it on fpga! interesting comparisons between the two versions on the 'pc engine software bible' site!
ARCADEAGES
Go Jotego! Go Esperanza!
Holger Lagerfeldt
I found out what caused the bad “collision” problem. It was a weird chromatic aberration in the first version that meant my moves were slightly off since everything was a couple of pixels off visually. It’s fixed now in the last update and I beat the first boss on the first go without taking damage.
JOTEGO
Actually, I take back my words. With the right moves the final boss hit rate is close to 100% too
Holger Lagerfeldt
Weird, I can't seem to do the same moves as when I played it in the arcade or on my other MAME machine.
Justin Cherriman
Thanks for fixing it now Jose and on a weekend! Wow, relax and enjoy your weekend.
JOTEGO
That's the way the game was designed. If you get the nunchaku and get real close to him, the hit rate is close to 100%. Yet, wait for the final level boss, the rate is like 10% then!
Holger Lagerfeldt
Collision detection with the first boss is off, often not working?
