Help with Acorn Graphics Extension Rom Hell!

Discuss all aspects of programming here. From 8-bit through to modern architectures.
User avatar
pixelblip
Posts: 487
Joined: Wed Feb 04, 2015 7:19 pm

Help with Acorn Graphics Extension Rom Hell!

Postby pixelblip » Thu Dec 08, 2016 1:26 pm

Hi there
I couldn't let it go..........I am going to start trying to get to grips with the Acorn GXR rom. I have to do it!
I've started out with basic stuff!

Can someone first explain to me who's used it - what are the goddamn co ordinates for the thing?
I am in Mode 2 and you would expect that if you were to use the command MOVE 80,160 you would find the middle of the screen as Mode 2 is 160x256 pixels wide. But no! The middle value is more like 500 or something......so how does that give.....

I am hunting through the manual but I can't spot it. Oh the joys of taking a day off work to learn and getting nowhere! :lol:

Thanks

User avatar
pixelblip
Posts: 487
Joined: Wed Feb 04, 2015 7:19 pm

Re: Help with Acorn Graphics Extension Rom Hell!

Postby pixelblip » Thu Dec 08, 2016 1:29 pm

The middle point in the screen (Mode 2) for co ordinates seems to be 640x512. Not 80x160.
So why is that???

User avatar
tricky
Posts: 1916
Joined: Tue Jun 21, 2011 8:25 am
Contact:

Re: Help with Acorn Graphics Extension Rom Hell!

Postby tricky » Thu Dec 08, 2016 1:31 pm

Disclaimer, I haven't used it for 30ish years.
The coordinates are probably 1280x1024 like the rest of the graphics on the beeb.

User avatar
pixelblip
Posts: 487
Joined: Wed Feb 04, 2015 7:19 pm

Re: Help with Acorn Graphics Extension Rom Hell!

Postby pixelblip » Thu Dec 08, 2016 1:40 pm

Thanks Tricky. It's 30 years since I've done bbc basic. It's amazing I can remember stuff like RENUMBER :lol:

Why would you say that ( 1280x1024 ?)
Mode 2 is 160x256 and I am in Mode 2.

( I am running Beeb Em by the way)

My resolution of my window is 800x600 in Beeb Em.

User avatar
danielj
Posts: 5341
Joined: Thu Oct 02, 2008 4:51 pm
Location: Manchester

Re: Help with Acorn Graphics Extension Rom Hell!

Postby danielj » Thu Dec 08, 2016 1:47 pm

All the modes (apart from 7) use the same coordinate system for draw/move/plot - 1280x1024. The OS does the relevant transposition!

d.

User avatar
pixelblip
Posts: 487
Joined: Wed Feb 04, 2015 7:19 pm

Re: Help with Acorn Graphics Extension Rom Hell!

Postby pixelblip » Thu Dec 08, 2016 1:53 pm

Oh thanks everyone. Looks like I have a big mountain to climb here.!

User avatar
danielj
Posts: 5341
Joined: Thu Oct 02, 2008 4:51 pm
Location: Manchester

Re: Help with Acorn Graphics Extension Rom Hell!

Postby danielj » Thu Dec 08, 2016 2:23 pm

pixelblip wrote:Oh thanks everyone. Looks like I have a big mountain to climb here.!


You'll be 'reet :D

d.

User avatar
pixelblip
Posts: 487
Joined: Wed Feb 04, 2015 7:19 pm

Re: Help with Acorn Graphics Extension Rom Hell!

Postby pixelblip » Thu Dec 08, 2016 3:06 pm

From tiny acorns grow mighty oak trees..........maybe not on Thursday afternoon! Just did my first pic.
It's good fun though ! Takes me right back

If anyone can recommend a good basic editor I'd be grateful................I seem to be using cursors keys and copy a lot to get to various lines.....there must be an easier way eh! :lol:
Attachments
1st Pic.jpg

User avatar
geraldholdsworth
Posts: 303
Joined: Tue Nov 04, 2014 9:42 pm
Location: Inverness, Scotland
Contact:

Re: Help with Acorn Graphics Extension Rom Hell!

Postby geraldholdsworth » Thu Dec 08, 2016 3:13 pm

pixelblip wrote:If anyone can recommend a good basic editor I'd be grateful

The BASIC Editor (Acornsoft, IIRC)
Gerald Holdsworth
Repton Resource Page
www.reptonresourcepage.co.uk

User avatar
jgharston
Posts: 2756
Joined: Thu Sep 24, 2009 11:22 am
Location: Whitby/Sheffield

Re: Help with Acorn Graphics Extension Rom Hell!

Postby jgharston » Thu Dec 08, 2016 3:27 pm

pixelblip wrote:Can someone first explain to me who's used it - what are the goddamn co ordinates for the thing?
I am in Mode 2 and you would expect that if you were to use the command MOVE 80,160 you would find the middle of the screen as Mode 2 is 160x256 pixels wide. But no! The middle value is more like 500 or something......so how does that give.....

ALL screen modes are 1280x1024. That's the whole point, you don't recalculate for different physical resolutions.

Edit: See also: PLOT commands.
Last edited by jgharston on Thu Dec 08, 2016 3:32 pm, edited 1 time in total.

Code: Select all

$ bbcbasic
PDP11 BBC BASIC IV Version 0.25
(C) Copyright J.G.Harston 1989,2005-2015
>_

User avatar
pixelblip
Posts: 487
Joined: Wed Feb 04, 2015 7:19 pm

Re: Help with Acorn Graphics Extension Rom Hell!

Postby pixelblip » Thu Dec 08, 2016 3:30 pm

Thank you. Sorry I didn't realise ( I couldn't find it in the GXR manual). It's been a long long time since trying this stuff out.
If one can master this GXR chip then the sky is the universe. I can see some wacky pics on the horizon.

User avatar
jgharston
Posts: 2756
Joined: Thu Sep 24, 2009 11:22 am
Location: Whitby/Sheffield

Re: Help with Acorn Graphics Extension Rom Hell!

Postby jgharston » Thu Dec 08, 2016 3:33 pm

pixelblip wrote:Thank you. Sorry I didn't realise ( I couldn't find it in the GXR manual). It's been a long long time since trying this stuff out.

http://mdfs.net/Docs/Books/Manuals/AcornGXR.txt
http://mdfs.net/Docs/Books/Manuals/GXRProgs/

Code: Select all

$ bbcbasic
PDP11 BBC BASIC IV Version 0.25
(C) Copyright J.G.Harston 1989,2005-2015
>_

User avatar
geraldholdsworth
Posts: 303
Joined: Tue Nov 04, 2014 9:42 pm
Location: Inverness, Scotland
Contact:

Re: Help with Acorn Graphics Extension Rom Hell!

Postby geraldholdsworth » Thu Dec 08, 2016 5:24 pm

The GXR was also, I believe, included in BASIC IV in the Master series. And the Master User Guide covers the commands, IIRC.
Gerald Holdsworth
Repton Resource Page
www.reptonresourcepage.co.uk


User avatar
pixelblip
Posts: 487
Joined: Wed Feb 04, 2015 7:19 pm

Re: Help with Acorn Graphics Extension Rom Hell!

Postby pixelblip » Thu Dec 08, 2016 7:53 pm

Thanks a lot everyone.
I loaded the basic editor in via a Rom Slot but when I type *BEM to to start it it seems to be wanting to catalogue a disk drive. Oh the joys.

User avatar
jms2
Posts: 1838
Joined: Mon Jan 08, 2007 6:38 am
Location: Derby, UK

Re: Help with Acorn Graphics Extension Rom Hell!

Postby jms2 » Thu Dec 08, 2016 8:25 pm

geraldholdsworth wrote:The GXR was also, I believe, included in BASIC IV in the Master series. And the Master User Guide covers the commands, IIRC.

You are right, but GXR is not in Basic 4, it's in the MOS. And the sprite routines are missing.

User avatar
lurkio
Posts: 1284
Joined: Tue Apr 09, 2013 11:30 pm
Location: Doomawangara
Contact:

Re: Help with Acorn Graphics Extension Rom Hell!

Postby lurkio » Thu Dec 08, 2016 9:13 pm

pixelblip wrote:I loaded the basic editor in via a Rom Slot but when I type *BEM to to start it it seems to be wanting to catalogue a disk drive.


From Tom Seddon's BASIC Editor website:

type *BE to enter it

:idea:

User avatar
pixelblip
Posts: 487
Joined: Wed Feb 04, 2015 7:19 pm

Re: Help with Acorn Graphics Extension Rom Hell!

Postby pixelblip » Thu Dec 08, 2016 9:35 pm

Oh thanks Lurkio. Sorry for being so thick! I must have read that so many times and didn't see it.
I find it great people take time out on this forum to help each other with our busy work lives e.t.c - and with something so trivial!
Thank you.

I am trying to plot rotating squares and it's hard work. It's like being back at school but I'm 100x slower!

BTW I thought the GXR Rom was built into the Master as well...........but not 100% on if there are differences between that and the Rom.....?

User avatar
pixelblip
Posts: 487
Joined: Wed Feb 04, 2015 7:19 pm

Re: Help with Acorn Graphics Extension Rom Hell!

Postby pixelblip » Thu Dec 08, 2016 9:40 pm

Yeh I'm trying to do this pretty much( but in 8 bits with the GXR Rom and lots of patterns/dithers)...............
Attachments
images.jpg
(39.57 KiB) Not downloaded yet
Last edited by pixelblip on Thu Dec 08, 2016 10:18 pm, edited 2 times in total.

User avatar
pixelblip
Posts: 487
Joined: Wed Feb 04, 2015 7:19 pm

Re: Help with Acorn Graphics Extension Rom Hell!

Postby pixelblip » Thu Dec 08, 2016 10:17 pm

Got loads of nice colours coming out. Don't quite know what I'm doing but like cooking you just get stuck in and run it and see what happens....one looks like a city of some kind
Attachments
G.jpg
2.jpg

User avatar
pixelblip
Posts: 487
Joined: Wed Feb 04, 2015 7:19 pm

Re: Help with Acorn Graphics Extension Rom Hell!

Postby pixelblip » Sat Dec 17, 2016 12:37 am

After battling it out I am finally making some cool progress!
Attachments
Progress.jpg

User avatar
tricky
Posts: 1916
Joined: Tue Jun 21, 2011 8:25 am
Contact:

Re: Help with Acorn Graphics Extension Rom Hell!

Postby tricky » Sat Dec 17, 2016 12:48 am

Nice.
I don't recall anything using that ROM BITD, but then I didn't get a lot of magazines and there wasn't much sharing at my school.
If you could take that back to the 80s, you could probably sell a whole load more and then you might not have so little to go on!
Time travel paradox!

User avatar
pixelblip
Posts: 487
Joined: Wed Feb 04, 2015 7:19 pm

Re: Help with Acorn Graphics Extension Rom Hell!

Postby pixelblip » Sat Dec 17, 2016 1:21 am

This chip is amazing. Once it is unlocked I can imagine the best colour images! Like the CPC the Beeb has a really vibrant palette and look about it......

I am still trying to get to grips with the shading and how that works...............it's really beautiful when you mix colours.

I still need to work out how do to my rotating squares and get them to cycle through a rainbow using dithered patterns. It's bad enough trying to work out the rotation let alone the colour changes! If I can master it the sky's the limit.
Attachments
progress 2.jpg

User avatar
pixelblip
Posts: 487
Joined: Wed Feb 04, 2015 7:19 pm

Re: Help with Acorn Graphics Extension Rom Hell!

Postby pixelblip » Sat Dec 17, 2016 3:21 am

Here's another....getting to grips a bit now
Attachments
P10.jpg

poink
Posts: 963
Joined: Tue Mar 01, 2011 10:27 am

Re: Help with Acorn Graphics Extension Rom Hell!

Postby poink » Sat Dec 17, 2016 9:05 am

pixelblip wrote:BTW I thought the GXR Rom was built into the Master as well...........but not 100% on if there are differences between that and the Rom.....?

It sounded like the Master version might be a slightly cut down version, for instance, IIRC the GXR ROM had sprite routines and the Master doesn't.

The Master Welcome disc shows off some sort of similar effects, especially with the dithering - I have particular memories of a sunset over a castle.

jregel
Posts: 65
Joined: Fri Dec 20, 2013 6:39 pm
Location: Gloucestershire

Re: Help with Acorn Graphics Extension Rom Hell!

Postby jregel » Sun Dec 18, 2016 2:45 pm

poink wrote:
pixelblip wrote:BTW I thought the GXR Rom was built into the Master as well...........but not 100% on if there are differences between that and the Rom.....?

It sounded like the Master version might be a slightly cut down version, for instance, IIRC the GXR ROM had sprite routines and the Master doesn't.

The Master Welcome disc shows off some sort of similar effects, especially with the dithering - I have particular memories of a sunset over a castle.


Yes, the sprite editor and routines is missing from the Master, but there is a SPRITER ROM image on the Welcome disc (in the "Library" directory, I think) which provides this missing functionality.
BBC Master Turbo
Retroclinic External Datacentre
VideoNuLA


Return to “programming”

Who is online

Users browsing this forum: No registered users and 2 guests