Shadow of the Beast Demo

Show us your work, thrill and amaze us :)

Moderator: Programming Moderators

Alcoholics Anonymous
Posts: 781
Joined: Mon May 29, 2017 7:00 pm

Shadow of the Beast Demo

Postby Alcoholics Anonymous » Mon Dec 09, 2019 6:48 pm

An updated demo shared on facebook by Mike Dailly showing the next doing the famous parallax scrolling of the Amiga original.


User avatar
Mati
Posts: 4
Joined: Sat Nov 03, 2018 11:28 pm

Re: Shadow of the Beast Demo

Postby Mati » Tue Dec 10, 2019 3:49 am

Pretty snazzy! Mike coaxed greatness out of the SOTB PC Engine port as well if memory serves. I hope he keeps at it beyond just a demo. If you're reading this, Mike D,. thank you from the States!

Alcoholics Anonymous
Posts: 781
Joined: Mon May 29, 2017 7:00 pm

Re: Shadow of the Beast Demo

Postby Alcoholics Anonymous » Tue Dec 10, 2019 4:44 pm

The next is able to do the scrolling easily and with little cpu intervention (intervention = copper program update once per frame); I think the only time consuming part is the animated beast sprite and he mentioned the mountains may not have fit into the 256/512 tiles so he may be juggling some tile definitions during the frame. I think he said the fence foreground were also sprites. The beast sprite image is being uploaded each frame (or more likely every few frames) to animate it and it looks like it may be 8 sprites in total so 8 unique patterns at 8-bit colour = 2k memory. That's about 8K T states by dma or 64K T states by cpu per frame. He's running at 14MHz so he has 280K T states to work with.

Roughly, anyway.

User avatar
varmfskii
Posts: 287
Joined: Fri Jun 23, 2017 1:13 pm
Location: Stone Mountain, GA USA

Re: Shadow of the Beast Demo

Postby varmfskii » Tue Dec 10, 2019 8:50 pm

Remember he could be using an anchor sprite and several connected sprites for the beast and simply change the offset of the pattern number of the anchor sprite allowing the sprite animation to run through some subset of all of the available 128 16-colour sprite patterns or 64 256-colour sprites withough even having to upload new sprite patterns.
Backer #2741 - TS2068, Byte, ZX Evolution

Alcoholics Anonymous
Posts: 781
Joined: Mon May 29, 2017 7:00 pm

Re: Shadow of the Beast Demo

Postby Alcoholics Anonymous » Tue Dec 10, 2019 9:56 pm

Yes he could but I know he isn't because he told me he's uploading the sprite patterns :) The achilles heel of the next's sprites is that the pattern memory is only 16K. This makes it difficult to store a lot of animation frames in the pattern memory to use the pattern offset features of the sprite engine if you have a lot of sprites on screen at once. This is a demo now (and he's got other things on his plate like maybe lemmings and super crate box in his spare time) but he's still writing it in a practical way.

Alcoholics Anonymous
Posts: 781
Joined: Mon May 29, 2017 7:00 pm

Re: Shadow of the Beast Demo

Postby Alcoholics Anonymous » Wed Dec 11, 2019 5:48 pm

A version using the pi to play an amiga mod. The pi generates the audio and sends pcm samples to the next via an i2s interface overlaid on the gpio pins. The next hardware mixes this into the internal audio stream as 10-bit samples. This requires no cpu intervention.



Another possibility without the pi is to use the copper to play 8-bit stereo audio. This would require the cpu to set up around 312 audio samples per frame which would be used to update a running copper program that would send the audio to internal DACs at the correct sample rate.


Who is online

Users browsing this forum: No registered users and 1 guest