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<div class="moz-cite-prefix">It would be trivial to modify the code
to add a fixed 16-entry lookup table for the output color based on
the 4-bit pixel value (just a case statement). However, due to
differences in the native color capabilities of the different
hardware platforms capable of running Oberon RISC5 (Digilent
Spartan3 board has 3-bit color, OberonStation has 6-bit color,
Pepino has 8-bit color and Pipistrello has 24-bit color) the
implementation of the lookup table table would be slightly
different. The 3-bit color output that I did is supported by all
platforms. <br>
<br>
Also, if you want the lookup table to be dynamic instead of fixed
(i.e. CPU read/write access to the table) then that would add a
bit of extra complexity but still very doable. <br>
<br>
BTW, my initial goal of the RGB version of VID.v was to implement
a RGB video system with as few changes as possible, mostly for
educational purpose since the question was asked in this mailing
list as to how such modifications could be done. Making the pixel
size a power-of-2 value minimizes both the hardware changes and
software changes at the expense of wasted memory space. <br>
<br>
Magnus<br>
<br>
<br>
On 4/19/2016 12:12 AM, Jörg Straube wrote:<br>
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<blockquote cite="mid:10E9A720-ABE0-4215-8250-F549DCCDC6FE@iaeth.ch"
type="cite">
<pre wrap="">Hi Magnus
Thx for preparing VID.v
As the original ProjectOberon has only 1M of memory, it's a pity to waste 25% of your 4 bit color layout. Basically, we could use 16 colors instead of 8.
Instead of mapping the bits directly to RGB, I would rather use the 4 bits as index into a color palette.
Display.Mod has to be adapted accordingly.
Jörg
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<blockquote type="cite">
<pre wrap="">Am 18.04.2016 um 21:59 schrieb Magnus Karlsson <a class="moz-txt-link-rfc2396E" href="mailto:magnus@saanlima.com"><magnus@saanlima.com></a>:
I have made an updated version of VID.v with support for an RGB video buffer.
The video buffer is now 4x larger (about 40% of the total 1 MB RAM) and video refresh will use up about 40% of the memory bandwidth.
See <a class="moz-txt-link-freetext" href="http://saanlima.com/forum/viewtopic.php?f=14&p=1786#p1783">http://saanlima.com/forum/viewtopic.php?f=14&p=1786#p1783</a> for Verilog code and bit files for Pepino_LX9 and Pepino_LX25.
Magnus
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