The X68000 games porting experiment

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Anima
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Re: The X68000 games porting experiment

Postby Anima » Wed May 13, 2015 8:03 am

Dal wrote:That is true dedication to the cause!

I was also trying to find the bug but that was futile... :D

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Re: The X68000 games porting experiment

Postby Strider » Sun May 17, 2015 9:31 pm

Anima, good luck for the alpha release!
According to the videos, the DSP sprite routine seems impressive.

This week I participated to a retrogaming event and I brought my Falcon (a standard one). I showed Cho Ren Sha to other exhibitors, especially those interested in shoot'em ups. They had a good feeling about it. Of course I had to explain it is an experimental adaptation of a X68000 game and the game will be improved soon. Some guys were quite impressed though. A member of http://shmup.com/ and the editor of Revival (retrogaming fanzine) enjoyed playing the game.

However I didn't showed Cho Ren Sha to the general public because it is not easy to tell kids they have to use the keyboard to play, especially when 2 joypads and 2 joysticks are connected to the Falcon (for other games). But I hope the next time I'll be able to show a joypad-enhanced version :wink:
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Re: The X68000 games porting experiment

Postby Anima » Mon May 18, 2015 7:56 am

Strider wrote:This week I participated to a retrogaming event and I brought my Falcon (a standard one). I showed Cho Ren Sha to other exhibitors, especially those interested in shoot'em ups. They had a good feeling about it. Of course I had to explain it is an experimental adaptation of a X68000 game and the game will be improved soon. Some guys were quite impressed though. A member of http://shmup.com/ and the editor of Revival (retrogaming fanzine) enjoyed playing the game.
Interesting story. Thanks for sharing. :cheers:

Strider wrote:However I didn't showed Cho Ren Sha to the general public because it is not easy to tell kids they have to use the keyboard to play, especially when 2 joypads and 2 joysticks are connected to the Falcon (for other games). But I hope the next time I'll be able to show a joypad-enhanced version :wink:
Joypad support will be included for sure because it's the best way to play it. ;)

I am currently reworking the frameskip routines. This is still the most important part and quite challenging but I hope to get it fixed soon.

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The X68000 games porting experiment

Postby calimero » Tue May 19, 2015 7:32 am

Hi Anima,
Can you write more about frame skiping, how you do it?
Do you start to draw new frame in offscreen buffer, finish it, put it on screen and before tou start to draw next frame you see that you are late with that frame (there is not enought time to finish it) so you skip it and go imidiatly on drawing next (third) frame?

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Re: The X68000 games porting experiment

Postby Anima » Tue May 19, 2015 5:33 pm

calimero wrote:Hi Anima,
Can you write more about frame skiping, how you do it?

Yeah sure. :)

The frame drawing takes place in the vertical blank interrupt routine and it uses a double frame buffering method. To skip frames I need to know when to stop (delay) drawing a frame. This is actually being done by tracking the display line counter (Timer B). The current graphics mode has 240 lines so, as an example, I am drawing the next frame as long as less than 180 lines have been counted. If the drawing has not been finished on time the execution of the current routine will be delayed to the next vertical blank interrupt call. In this case the frame buffers will not be switched an so the current visible frame will be displayed again.

One problem is that the DSP sprite clearing is highly variable and can only be estimated. This could be solved by sending the RLE clear data in chunks but I hope to find a good time estimate calculation to avoid changing the RLE code. So in fact the clearing routine knows how many RLE values will be transferred and it decides to delay it or not based on that number and the current display line.

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Re: The X68000 games porting experiment

Postby Anima » Wed Jun 17, 2015 4:32 pm

Short update: I haven't had much time in the past weeks but one nasty bug has been fixed and the sprite engine works quite well now. I guess it still needs some fine tuning but a compromise between a smooth gameplay and sprite drawing speed needs to be made. Here's a video showing the most problematic cases:

Cho Ren Sha 68k on Falcon030: "Bullet Hell"



Alternative link: https://www.youtube.com/watch?v=87EMhNkTkeo

:D

Last edited by Anima on Thu Jun 18, 2015 4:54 am, edited 2 times in total.

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Re: The X68000 games porting experiment

Postby dml » Wed Jun 17, 2015 6:02 pm

That's definitely the most bullet/sprite activity one could sensibly imagine happening in a Falcon game.

:o

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Re: The X68000 games porting experiment

Postby CiH » Wed Jun 17, 2015 7:30 pm

I'm out of breath from watching this.. :mrgreen:
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Re: The X68000 games porting experiment

Postby calimero » Wed Jun 17, 2015 8:04 pm

really crazy stuff on screen!
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Re: The X68000 games porting experiment

Postby Strider » Wed Jun 17, 2015 9:08 pm

"the most problematic cases"? Hey that's not so bad for a so large amount of sprites 8)
Keep up the good work.
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Re: The X68000 games porting experiment

Postby chlu600 » Wed Jun 17, 2015 9:27 pm

I'm in love! :D

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Re: The X68000 games porting experiment

Postby Xerus » Wed Jun 17, 2015 10:29 pm

I don't know what is the most impressive.
The skill of the player?
The talent of the coder?
The power of Falcon?
Er... I know, all three at once :D

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Re: The X68000 games porting experiment

Postby christos » Wed Jun 17, 2015 11:11 pm

Being able to emulate all that sprite h/w of the X68000 with the DSP is pretty impressive. I wish we had something similar when the falcon was newish. Very well done Anima!
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Re: The X68000 games porting experiment

Postby calimero » Thu Jun 18, 2015 7:15 am

Xerus wrote:The skill of the player?

lol! I think the same! :)


@anima you can animate background or it must remain still?
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Re: The X68000 games porting experiment

Postby dml » Thu Jun 18, 2015 4:56 pm

Take it apart!

https://www.youtube.com/watch?v=W40qGkp-mEU

Not exactly very informative re: the hardware bits but interesting to see how many chips are inside generally, and which Anima is magically emulating on the Falcon!

:D

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Re: The X68000 games porting experiment

Postby EvilFranky » Thu Jun 18, 2015 5:33 pm

Great stuff Anima!

Looking forward to seeing what else you might do with this new technique once you finish Cho Ren Sha :wink:

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Re: The X68000 games porting experiment

Postby Anima » Thu Jun 18, 2015 6:03 pm

Thanks all. :cheers:

I hope to find time to finalise the project to make a first beta release in the next days.

calimero wrote:@anima you can animate background or it must remain still?

Reactivating the background scrolling is definitely on the to do list. It requires some changes in the DSP code though so it has been deactivated for the time being.


Thanks Doug. It's really interesting how an X68000 looks inside - not only from an Atari user perspective.

EvilFranky wrote:Great stuff Anima!

Looking forward to seeing what else you might do with this new technique once you finish Cho Ren Sha :wink:

Cho Ren Sha 68k shows up to four times as much sprites (512) compared to the regular X68000 can handle natively. Even with the special sprite library the X68000 is not capable of displaying all the sprites properly. Also the gameplay slows down when tons of sprites are visible.

So in conclusion the DSP sprite engine is a solid basis for some less demanding X68000 games. However, many of them are using two background layers for parallax scrolling which is currently a problem in respect of doing easy ports.

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Re: The X68000 games porting experiment

Postby Anima » Mon Jun 22, 2015 12:09 am

AF is back! \o/

Sho Ren Sha 68k project update: slow but steady progress. Watch the following video while waiting for the release... :D

"Insanity" (Wait for it...)



Alternative link: http://youtu.be/voiRnr72YhQ


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Re: The X68000 games porting experiment

Postby DrTypo » Mon Jun 22, 2015 7:03 am

This stuff is mesmerizing. Great work Anima!

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Re: The X68000 games porting experiment

Postby jvas » Mon Jun 22, 2015 7:59 am

I hope, there will be an "IDDQD" mode :)

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Re: The X68000 games porting experiment

Postby dml » Mon Jun 22, 2015 8:15 am

Very impressive! And it is looking more and more like a complete game with each update.

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Re: The X68000 games porting experiment

Postby dml » Mon Jun 22, 2015 8:57 am

Sascha - could you paste some small fragments of your DSP code to look at? Not the whole thing just one or two representative slices of the whole (or send me by PM). I just remembered a random problem that I noticed during BadMooD DSP work and was curious if its also happening with your project... I'll explain if it shows up here too but it may in fact be nothing! :)

[EDIT]

(specifically - fragments of the source code vs disasm)

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Re: The X68000 games porting experiment

Postby Anima » Mon Jun 22, 2015 9:43 am

DrTypo wrote:This stuff is mesmerizing. Great work Anima!
Thanks! :cheers:

jvas wrote:I hope, there will be an "IDDQD" mode :)
In fact it has some cheats already build in but I need to check if those can be activated via joystick or keyboard...

dml wrote:Very impressive! And it is looking more and more like a complete game with each update.
:cheers:
The only missing parts are: JagPad support, fixing the text layer and scrolling. After that it'll be indeed a complete game! ;)


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Re: The X68000 games porting experiment

Postby LaurentS » Wed Apr 26, 2017 2:21 pm

Hi all,

Are pacmania, galaga 88 and other emulated games still available somewhere ?
I can't find them.

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