The X68000 games porting experiment

[Xerus]

It's really impressive
A Falcon in good hands can do wonders, bravo

[EvilFranky]

Incredible!!!

Any idea on the lowest frame rate?

[Anima]

Any idea on the lowest frame rate?

Good question. I need to make some tests that but keep in mind that this scene shows only a "few" sprites compared to later stage actions.

[EvilFranky]

Any idea on the lowest frame rate?

Good question. I need to make some tests that but keep in mind that this scene shows only a "few" sprites compared to later stage actions.

It's still amazing to see considering there is no dedicated sprite hardware Anima, great job.

Will be interested to see what else you can apply this technique too

[dml]

It's great! It looks like a dedicated arcade box!

[AdamK]

Great :O

Coult it be applied to Neo-Geo emulator?

[Anima]

Thanks all. Yeah, Cho Ren Sha 68k is really an extreme game but I think the DSP optimisation is helpful for some other less demanding ports (like some arcade titles of that era). ChoRenSha 68k can be considered as much as four times as "powerful" as a regular X68000 game and it's coded in C so finally there's hope to get some other titles work with a good game experience.

Edit: spelling.

[Anima]

Coult it be applied to Neo-Geo emulator?

Well, kind of. Neo Geo is different... a real sprite monster. E.g. one problem is that you have no background layer; everything's made up of sprites and 14 MB RAM will never be enough to store all of them. Of course it doesn't have to when you have an intelligent sprite caching mechanism but that's a different story. However, what I could think of is that a faster machine is indeed capable of running Neo Geo games but it requires a different preparation. I was hoping for the CT60e to get one and make some tests... well... you know it.

So in conclusion Neo Geo games are definitely too much for a stock Falcon (there are some exceptions though).

[Scarlettkitten]

Wowzers, looking ace

[calimero]

fornicating amazing!!

now Amiga finally can be used as doorstep

long time ago those ware best looking Falcon shooters:

https://www.youtube.com/watch?v=X_pmTDU3enI
https://www.youtube.com/watch?v=tdsrXupLwzs (I really like intro in this one!)
https://www.youtube.com/watch?v=9mYtzoDWiEs


EDIT: what version of x68000 Cho Ren Sha 68K requires (first 10MHz 68000 or latest 25MHz 68030?!)?

[Anima]

what version of x68000 Cho Ren Sha 68K requires (first 10MHz 68000 or latest 25MHz 68030?!)?

It runs on the entry machine (MC68000 at 10 MHz) but the sprite library requires "130%" of that power to use the more accurate routines to display the sprites with less flickering. So in fact, the original X68000 is not able to display all sprites perfectly. Watch the third(?) boss where some parts of the ship are missing when it explodes.

[ryan]

Interesting, didn't know that. Too bad, I have a copy coming in the mail for my X68000 (origina 10mhz model)

[Anima]

Short update: roadmap for an alpha release.

• Activate double buffering for the DSP sprite routine.
• Add scrolling for the DSP routine.
• Find the best spot for the sprite engine.
• Adjust sprite priorities.
• Refine frameskip function.
• Add text layer.
• Add JagPad support.

And here's a sprite stress test video showing an early frameskip function and a colourful background (for those who may think it has only four colours).

ChoRenSha 68k Atari Falcon030 DSP stress tests

Direct YouTube link: https://www.youtube.com/watch?v=6NuLlcTJyxc

[nemodhs]

Amazing!

Don't know if I could survive this frenzy for long, but still can't wait to play it.

[CiH]

Now dribbling with pure joy!

[EvilFranky]

Excellent Anima!

The frame skip really helps keep the flow of the game going.

[shoggoth]

these bricks

can't bare them anymore

bricks, I tell you

[dml]

This is seriously impressive... and I'm glad you stuck with it to get this far.

I don't know about you, but I find it takes several iterations to squeeze the last 10-15% out of the machine. So maybe there is still a tiny bit of room left. Take a week or two off and come back to it


I meant to ask - if the sprite clearing system works efficiently on a static image, what currently prevents scrolling? Is it a hard technical issue or because of the way the game must be emulated? (e.g. game layer forcing redraw of bg tiles every frame?).

The scrolling adds something to the game, and incremental updates to one border on alternate buffers + hardscroll is probably still manageable in available time - but the emulation side of it could be serious trouble, or perhaps not enough RAM. I'm just curious - I don't really know what's involved here.

[Anima]

Thanks all.

I meant to ask - if the sprite clearing system works efficiently on a static image, what currently prevents scrolling? Is it a hard technical issue or because of the way the game must be emulated? (e.g. game layer forcing redraw of bg tiles every frame?).

The scrolling adds something to the game, and incremental updates to one border on alternate buffers + hardscroll is probably still manageable in available time - but the emulation side of it could be serious trouble, or perhaps not enough RAM. I'm just curious - I don't really know what's involved here.

The RLE routine covers only the 240 visible lines but occasionally sprites are being drawn up to 15 lines over the top of the displayed screen which is then scrolled into the view later on. Also the Y sprite offsets for each scrolled frame aren't taken into account yet. It requires some additional code to address this so those aren't serious problems.

Scrolling is definitely an important part of this game and will be back in the final game.

[lotek_style]

Wow! runs at pretty decent speed now

[Anima]

Haven't had much time the last days for this project but here's a short update: sprites are now properly sorted and the text layer has been converted to compiled sprites and was preliminary implemented. So in fact the whole special sprite routine for the X68000 version is now obsolete. I.e. the sprite caching and special raster

I also found a proper replay file for the X68000 version of Cho Ren Sha 68k which shows the gameplay through all stages and one which shows the "show time" round. I need them to see if all sprites are being displayed correctly. The problem was that the replay files from the Windows version are not compatible with the X68000 game and so finding one was a real pain. I'll include both in the release version.







Things to sort out: double buffering, scrolling and proper sprite engine hookup.

[Dal]

Where did you find the x68k replay file in the end?

[Anima]

Where did you find the x68k replay file in the end?

I found them on some Japanese websites. IIRC I was searching for "超連射68K" and "rep" or "demo.rep".

[Dal]

That is true dedication to the cause!

[CiH]

Drooling in anticipation.