Graphics Extension ROM based Game - experimenting

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flibble
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Graphics Extension ROM based Game - experimenting

Postby flibble » Mon Jul 17, 2017 7:31 pm

gxr-game.png


I started playing with this little test program at Markfield earlier in the year, I finally reached a 'milestone' of sorts, I ran out of memory on the BBC B :lol:

Good
- Tile based plotting
- Animation of character in 4 steps between adjacent tiles.
- Two sprite layers, background and characters plotted on top
- Written fully in BASIC
- keyboard input on z,x,*,/
- Just about fast enough performance
- Gfx look good, (even better in the Gameboy game I borrowed them from, ahem)

Bad
- flickery (plotting BG then character in each frame)
- no mask based plotting, when the white backgrounded character walks over a darker tile it looks a bit silly.

Ugly
- with only 12 sprites (8 character, 2 facing each direction, 4 background sprites), I have already run out of memory on the Beeb B

Running

- A machine with the graphics extension ROM fitted, or a Master with the 'Spriter' romimage from the welcome disc loaded into Sideways ram
- type *SSPACE 4
- hit break
- CH."GAME"

Future
I'm not sure it's worth me running any further with this. If I did I'd be tempted to say 'BBC Master only', as you always have the GXR to hand on the welcome disk and I could use shadow ram to free up 20k for more sprites and some actual gameplay.
Attachments
spritestests.zip
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Lardo Boffin
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Re: Graphics Extension ROM based Game - experimenting

Postby Lardo Boffin » Mon Jul 17, 2017 9:29 pm

Have you considered running this over the Tube? The main program would live on the co-proc while the sprite data lives on the Beeb itself. That should help provide more space for sprites and interesting stuff!
BBC model B 32k issue 4, 16k sideways RAM, Watford 12 ROM board, Retroclinic Datacentre + HDD, matchbox co-proc, Viglen twin 40/80 5.25" discs, acorn cassette
BBC model B 32k issue 7, turboMMC, Opus Challenger 3 512k, Pi 3 coproc, Acorn 6502 coproc

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Lardo Boffin
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Re: Graphics Extension ROM based Game - experimenting

Postby Lardo Boffin » Mon Jul 17, 2017 9:59 pm

Also the Beeb can get on with just running sprite code for the ROM while the co proc handled the BASIC. Might help reduce flicker.
BBC model B 32k issue 4, 16k sideways RAM, Watford 12 ROM board, Retroclinic Datacentre + HDD, matchbox co-proc, Viglen twin 40/80 5.25" discs, acorn cassette
BBC model B 32k issue 7, turboMMC, Opus Challenger 3 512k, Pi 3 coproc, Acorn 6502 coproc

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flibble
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Re: Graphics Extension ROM based Game - experimenting

Postby flibble » Tue Jul 18, 2017 2:19 pm

Interesting idea about the 2nd processor, running a few tests in beebem the second proc *does* give the most available memory, even more than shadow ram.

master 128 LOMEM HIMEM
MODE 1 3586 12288
MODE 129 3586 32768

bbc b
MODE 1 7170 12288
bbc b 6502 second proc
MODE 1 2050 32768

But I think I'll try the master next as I think more people have one ... including me :)

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Elminster
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Re: Graphics Extension ROM based Game - experimenting

Postby Elminster » Tue Jul 18, 2017 2:52 pm

Master with shadow and HiBASIC (ad copro) will give you 44k usable if you need more.But the thing about Basic is it is to blow that as well, then you will just have to start crunching.

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Lardo Boffin
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Re: Graphics Extension ROM based Game - experimenting

Postby Lardo Boffin » Tue Jul 18, 2017 3:39 pm

flibble wrote:But I think I'll try the master next as I think more people have one ... including me :)


I guess I will have to join the master race at some point then! Although with raspberry Pi co-procs available for very little outlay hopefully most people have one by now.
BBC model B 32k issue 4, 16k sideways RAM, Watford 12 ROM board, Retroclinic Datacentre + HDD, matchbox co-proc, Viglen twin 40/80 5.25" discs, acorn cassette
BBC model B 32k issue 7, turboMMC, Opus Challenger 3 512k, Pi 3 coproc, Acorn 6502 coproc

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flibble
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Re: Graphics Extension ROM based Game - experimenting

Postby flibble » Tue Jul 18, 2017 4:22 pm

Elminster wrote:then you will just have to start crunching.


With the initial 'B' version I had already started having to shorten variable names :)

I'm currently editing the program on the PC and pasting into to Beebem for testing, I think I could add an extra step in my build process that at least stripped out the comments.

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Elminster
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Location: Essex, UK

Re: Graphics Extension ROM based Game - experimenting

Postby Elminster » Tue Jul 18, 2017 5:02 pm

I write on Mac in bbedit, crunch it using the mdfs *crunch, makes it unreadable though which is a bit of a debugging pain. You can also hack the files up to crunch and then *lik as well if not enough memory to crunch them.

Was on my todo list to do some sort of Mac runableble basic cruncher and do it there rather than on Beeb, but never got around to it.


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