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Re: BASIC & Screenmodes

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In message <500716b9$0$7326$5b6aafb4@news.zen.co.uk>
 on 18 Jul 2012 Robert Heaton  wrote:

> I'm working my way through the excellent book "Starting BASIC" by the 
> late Ray Favre.
> 
> The main program that is built throughout the book runs in MODE 12, I'm 
> using a Beagleboard running RISC OS 5.19 and whenever the BASIC program 
> runs, I can't see the output.
> My monitor just reports "out of range"
> 
> Is there an entry needed to the MDF file I'm using? Or can someone with 
> more BASIC knowledge recommend a more suitable MODE?

MODE 12 was 640 x 256 pixels in 16 colours.

I guess it rather depends on the program you are trying to run whether it
matters much what the mode is.  It depends on whether it does tricks like
writing direct to screen memory.

If it doesn't, then your best bet (without creating an MDF, which might be
quite a challenge for such a low resolution) would be to go for a 16 colour
mode with a larger resolution.  Part of the screen would probably be unused,
but at least you would get output.

Except I suspect that the Beagleboard may not support 16 colour modes.  Or
maybe I am getting muddled up with the Iyonix which does not support 4 colour
modes.

You can alter the mode command to specify the resolution and colours.  To get
the string for you current mode, just go to the Display Manager tool on the
iconbar, click Menu and follow the "Mode" item.  For example, on this machine
(an Iyonix) I see

X1280 Y1024 C16M EX1 EY1

The EX1 and EY1 indicate the conversion of OS units to pixels: in this case 2
OS units per pixel in both dimensions.

In more recent versions of BASIC (RISC OS 3.5 onwards, I suspect) you can do

MODE "X1280 Y1024 C16M EX1 EY1"

There are a few other options.  Try

HELP MODE

to see them.

-- 
Matthew Phillips
Durham

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Thread

BASIC & Screenmodes Robert Heaton <rob@robheaton.co.uk> - 2012-07-18 21:04 +0100
  Re: BASIC & Screenmodes Matthew Phillips <spam2011m@yahoo.co.uk> - 2012-07-18 21:46 +0100
    Re: BASIC & Screenmodes Robert Heaton <rob@robheaton.co.uk> - 2012-07-19 06:28 +0100
      Re: BASIC & Screenmodes Martin <News03@avisoft.f9.co.uk> - 2012-07-19 10:18 +0100
        Re: BASIC & Screenmodes Robert Heaton <rob@robheaton.co.uk> - 2012-07-19 20:31 +0100
    Re: BASIC & Screenmodes druck <news@druck.org.uk> - 2012-07-19 21:52 +0100
      Re: BASIC & Screenmodes Robert Heaton <rob@robheaton.co.uk> - 2012-07-20 18:53 +0100
      Re: BASIC & Screenmodes jgharston <jgh@arcade.demon.co.uk> - 2012-07-20 14:07 -0700
        Re: BASIC & Screenmodes Justin Fletcher <gerph@gerph.org> - 2012-07-21 16:53 +0100
        Re: BASIC & Screenmodes druck <news@druck.org.uk> - 2012-07-21 19:21 +0100

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