JOTEGO
patreon
Support for Alien Storm/Bionic Commando
🕑 Added 2024-05-31 10:46:49 +0000 UTCEspañol abajo
We have added the MegaDrive VDP chip to the JTS18 core. This chip is responsible of all the graphics and part of the audio in a MegaDrive console. On SEGA System 18 boards, it was only used for auxiliary video. Pretty much all you see in the screen is always coming from arcade-exclusive graphics chips but in some scenes of some games, the MegaDrive chip will come in to help.
How much was that help needed? It is a bit unclear. The pink flat enemies at the beginning of Alien Storm are produced by the VDP. Because the image merge is done right before sending the signal to the monitor, the player character is always drawn on top of these enemies. It is not a perfect mix and probably the reason why the enemies are not tall. I think these enemies were added as a copy protection. The VDP chip integrates a lot of functionality designed for a console and was probably very hard for bootleggers to replicate. Bootleg versions of Alien Storm do not have the pink enemies. When bootleggers first tried to copy the game, they must have faced invisible enemies attacking the player because of the missing VDP chip. That would render the game unplayable, requiring software modification. But the software was also encrypted. It must have been a very hard game to break, yet the game success pushed bootleggers to find ways around and eventually make copies that are missing the VDP graphics but are still playable.
In Shadow Dancer the VDP chip plays a smaller role. It is basically used to store a value and retrieve it immediately after. It must have been easy to get around that kind of protection. The VDP does not produce any graphics at all in this game.
There is a case where the VDP chip plays a big role in the image creation: the background of the 3D scenes in Alien Storm are drawn by the VDP, while the shelves and enemies are drawn by the arcade chipset. They problably needed the extra background layer in this case.
We are using the same VDP netlist used in the MiSTer's MegaDrive core. The configuration for this chip in the arcade board is very different from the console one, but the netlist works correctly. That is a good test of the quality of work done by NukeYT, the researcher who extracted the netlist to satisfy his own curiosity. We are thankful he shared his job.
Today's releases
JTS18 sees support for Alien Storm (2/3 player versions) today. ROM file format has changed, so the Analogue Pocket requires new .rom files.
JT cores have a horizontal stretch feature for CRT output in MiSTer. This is used for monitors that do not support overscan. We have improved this feature by centering the image regardless of the scale setting. We are looking at a different way of doing this stretch, though, to produce a better quality image. We may update this feature again next week
JTBIOCOM, supporting Bionic Commando is a new beta core for the Analogue Pocket
Thank you for your support.
Español
Hemos añadido el chip VDP de MegaDrive al núcleo JTS18. Este chip es el responsable de todos los gráficos y parte del audio en una consola MegaDrive. En las placas SEGA System 18, sólo se utilizaba para el vídeo auxiliar. Prácticamente todo lo que se ve en pantalla procede siempre de chips gráficos exclusivos de arcade, pero en algunas escenas de algunos juegos, el chip de MegaDrive entra en acción para ayudar.
¿Hasta qué punto era necesaria esa ayuda? No está muy claro. Los enemigos rosas planos del principio de Alien Storm son producidos por el VDP. Como la fusión de imágenes se hace justo antes de enviar la señal al monitor, el personaje del jugador siempre se dibuja encima de estos enemigos. No es una mezcla perfecta y probablemente sea la razón por la que los enemigos no son altos. Creo que estos enemigos se añadieron como protección anticopia. El chip VDP integra muchas funciones diseñadas para una consola y probablemente era muy difícil de replicar para los piratas del arcade. Las versiones piratas de Alien Storm no tienen los enemigos rosas. Cuando los contrabandistas intentaron copiar el juego por primera vez, debieron enfrentarse a enemigos invisibles que atacaban al jugador debido a la ausencia del chip VDP. Eso hace el juego injugable y requiere de modificación del software del juego, que a su vez estaba encriptado. Con el tiempo hubo versiones piratas pero carecen de todos los gráficos del VDP.
En Shadow Dancer, el chip VDP desempeña un papel menor. Básicamente se utiliza para almacenar un valor y recuperarlo inmediatamente después. Debió de ser fácil burlar ese tipo de protección. En este juego, el VDP no produce ningún gráfico.
Hay un caso en el que el chip VDP desempeña un papel importante en la creación de imágenes: el fondo de las escenas 3D de Alien Storm lo dibuja el VDP, mientras que las estanterías y los enemigos los dibuja el chipset arcade. Es probable que en este caso necesitaran la capa de fondo adicional.
Estamos utilizando el mismo netlist para el VDP utilizado en el núcleo MegaDrive del MiSTer. La configuración de este chip en la placa arcade es muy diferente a la de la consola, pero el netlist funciona correctamente. Esa es una buena prueba de la calidad del trabajo realizado por NukeYT, el investigador que extrajo el netlist para satisfacer su propia curiosidad. Le agradecemos que haya compartido su trabajo.
Lanzamientos de hoy
JTS18 tiene soporte para Alien Storm (2/3 jugadores). El formato de los ficheros ROM ha cambiado, así que la Analogue Pocket necesita nuevos .rom para este core.
Los núcleos JT tienen una función de estiramiento horizontal para la salida CRT en MiSTer. Esto se utiliza para los monitores que no soportan overscan. Hemos mejorado esta característica centrando la imagen independientemente del ajuste de escala. Estamos buscando una manera diferente de hacer este estrechamiento para producir una imagen de mejor calidad. Es posible que volvamos a actualizar esta función la semana que viene
JTBIOCOM, compatible con Bionic Commando es un nuevo núcleo beta para la Analogue Pocket
Gracias por vuestro apoyo.
Comments
Jason Moskowitz
make sure you have the latest jtbeta.zip where it needs to be on your sd card because i believe the games boot but cannot be controlled (properly) i remember some detail about this in the past releases.
Adam Davis
I found that the + and the - did nothing to the config …. Started holding Shift and pushing random buttons and it appears the number keys play a role in the config adjustment but I don’t remember what ones off hand (at work). See if that works for you 👍🏼
Lee Turner
Tinkering with the 'Dirty' S18 RBF and neither Game responds to the control config, so the games cannot be started.. contrary to first BETA .
Vincenzo
ok thanks. i will check even in my mister fpga of it is working like before... about the jtbeta file do you think is a problem of matt pannella updater? i will try again now if it still says is not correct...
JOTEGO
It has never been fixed really. It is an open issue that appears intermittently to some users. We still do not have a good solution.
Vincenzo
after update jtbeta the auto updater matt pannella report error or notr correct jtbeta file. why? however after the last updates out run cores crashed again and show only road and no objects on screen like happened some months ago ... it was fixed but now happened again!
Adam Davis
I’m not quite sure myself …. If there is an alternate I don’t see it ….
Lee Turner
Did I read right in that an alternate S18 core with the different sync will be available to test via that link specifically? Gracias.
JOTEGO
It looks like the sync signals are a bit incompatible. Please track the issue here: https://github.com/jotego/jtcores/issues/692
Adam Davis
Same
m.goomba
After this update I'm getting a shaky/wobbly picture on System 18's Shadow Dancer and Alien Storm. System 16 is working correctly.
Adam Davis
Same, cannot play on my consumer CRT - sync is out of range ☹️
Count Duckula
Thank you :) The credits for the alien storm core list 'MCU/Megadrive VDP still not supported', but the pink enemies are present
Lee Turner
Hey Jose, mostly great experience for me via HDMI, but both A.storm and Sdancer go 'out of range' on 27" ILO consumer CRT, all other SEGA cores fine.
Xyne
Same issue again for me. Alien Storm, Shadow Dancer, and Bloxeed all won't sync on my arcade monitors (tried 2).
Dick Hardpill
Can confirm. Just like Shadow Dancer, I get a very high pitched whine. If I enable hq2x the wine goes away but I'm still scrambled. Thank you for all your work!
Rick S.
Thanks again jotego team! For me alien storm is scrambled using the misteraddons analog board,just like shadow dancer.
OldManBog
Alien Storm working great with the analog board no scaler, thank you! LCD monitor with the V6.1 analog board
TheGeez
Alien Storm is just 😙👌 Thank you!
Fabio Santana
Same problem here since last week too (hey, Roger!). I updated the files and am still getting scrambled image. Using it on an arcade cabinet with a 15khz monitor. System 16 cores work fine, but all System 18 games give the same scrambled image so far. Thanks for looking into it and for the awesome work, Jotego!
Mat Azel
thanks for the work you guys put in and the write-up!
Mat Kraemer
Excellent work and thank you! Really enjoy reading all the behind the scenes hardware info like the VDP chip usage. Great stuff!
Lance Bohy
Can confirm! Yay! And Turbo Outrun works too, although with still some minor screen glitching at the start.
Halla
Thanks Jotego, great job! 😀 I also get a scrambled picture on my CRT. I know you said there was work done or improvements for CRT, but are we suppose get a picture on CRTs, or is it nor ready yet?
rogerio
Thanks a lot 🙏
Shane McCafferty
Outrun is working again on my Pocket \o/ Thank you.
JOTEGO
No, it is the same as the System 16 core. I do not understand why this one is producing this effect. I will check it.
rogerio
I was wondering if JTS18 is set to an unusual refresh rate as some people (including me) are having video problems.
Fed
Works on JVC TMH-15 however
Rent Optional
hoping Pupdate has a fix for generating the files and fixing shadowdancer and bloxeed
James Eric Nolen
You all are amazing, thank you for all your efforts!!
Fed
Awesome, thanks for all the work ! I have to report that I continue to get a scrambled image on my CRT (pvm-2950) using DV.
Rick S.
Thank you! Alien Storm would be very cool.
Roland
Does this work with the updater too?
Cristian
Hi, I updated and replaced the jbeta file but when I start the game it gives me an error in the file. What am I doing wrong? Thank you
JOTEGO
The ROM file format changed. You need files for the ROM. I changed the format to speed up the loading process. Regenerating the ROM file from the MRA will fix your problem.
ufix
After updating Analogue Pocket via pupdate, System18 stopped working - Shadow Dancer and Bloxeed just show a black screen
Kent Pendragon
Exciting. Super exciting! Can't wait for this to be added to the public release!
ronalvel .
Amo el Alien Storm, gracias!!!!!
Mark Saunders
Another big game , the characters look and feel like golden axe’s. Brilliant work thanks for the in depth analysis always interesting
Big Al.
oh yes..😃
Pixel Cherry Ninja
Oh wow 👽⛈️ What a weekend 😃 Thanks JT and team.
Big Al.
Another great release. Thank you Team. I love to read about the workings of the arcade boards.. 👌
Findamember
Thank you Jotego & team 👍
Shannon Thomasson
New games! Thanks Jotego and team!
