OpenEuphoria

Re: Poke, poke....

• Posted by mtsreborn_again at yahoo.com Nov 26, 2001
• 385 views

First of all,
mode 18 is 640*480 in size,
you can't just poke values for a 640*480 screen to
#A0000 or you'll get a machine exception.
Any screen larger than 320*240 can't be poked to video
memory directly.
You ought to use bank switching to divide a larger
screen up into 320*240 parts.
So basically what I'm saying is that poking only works
in mode 19.

Use Vesa20.e to be able to draw your backbuffers to
the screen in any video mode.
Make sure you remember that a 256-color display needs
1-byte per color, 16-bit color 2, and 24/32 bit color
4 bytes.
So 'back = allocate(640*480)' for a 256-color
backbuffer, and 'back = allocate(640*480*4)' for a
32-bit color backbuffer, for example.
Use poke() and poke4() to write the colors to the
backbuffer.


--- mistertrik at hotmail.com wrote:
> 
> Hey Euphoria people....
> 
> I'm making a simple graphics library that will be
> able to do page flipping 
> style graphics...
> ie: draw everything to buffer, then call update() to
> show it onscreen, to 
> stop flickering.
> 
> I haven't been able to find anything of the sort on
> the website, and I 
> wanted something of the sort.
> 
> My problem is:
> 
> If I am in graphics mode 18... I can just poke the
> color value I wish into 
> the correct memory location.
> However, in any other mode.. it does these strange
> monochrome patterns.. I 
> guess corresponding to the bits of the number I
> inserted. How do I poke the 
> values properly?
> 
> Another thing, where are the machine code libraries?
> and their 
> documentation?
> 
> Thatz all for now
>
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