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Indy XL TrueColor

Posted: Sat Mar 14, 2015 5:38 pm
by PowerGraphics
I have a Indy R4400 200Mhz 8bit XL graphics, 1GB HD, Irix 6.5.22.

I am analyzing the Xservers file in the /var /X11 /xdm, made the change indicated for systems with 24bit video of the original:

:0 secure /usr/bin/X11/X -bs -nobitscale -c -pseudomap 4sight -solidroot sgilightblue -cursorFG red -cursorBG white

changing this line to:

:0 secure /usr/bin/X11/X -bs -nobitscale -c -solidroot sgilightblue -cursorFG red -cursorBG white -depth 24 -class TrueColor

But the result is not being as expected, that is, the colors are still making dithered.

When using the program xli the result appears to be correct, but I intend to get a result in all full desktop system.

An important note: is that I got an excellent result doing something similar using irix 5.3 in more than 15 years ago, but lost the configuration file, and I can not remember exactly what was done.

Curiosity: On another note, the official technical description of silicon graphics on the indy 8bit XL, says it's possible to make truecolor in this system, called "virtual 24bit".

So I believe it is possible to do the same using irix 6.5.22.

Re: How to configure TrueColor in 8bit video system

Posted: Sat Mar 14, 2015 6:32 pm
by foetz
i wouldn't use 6.5.x with an indy at all. 6.2 or 5.3 run much better unless you only wanna run more recent freeware which is no fun on that box either so back to the first recommendation :P

taken the liberty of changing the topic title and moving the whole thing to the right forum

Re: Indy XL TrueColor

Posted: Sun Mar 15, 2015 11:51 am
by ClassicHasClass
I'm confused. You have an 8-bit card, but you're trying to get 24-bit output out of it?

Re: Indy XL TrueColor

Posted: Sun Mar 15, 2015 2:47 pm
by Raion-Fox
ClassicHasClass wrote:I'm confused. You have an 8-bit card, but you're trying to get 24-bit output out of it?


Appears that is what he is trying to do. Cue the facepalms.

Re: Indy XL TrueColor

Posted: Mon Mar 16, 2015 9:12 am
by robespierre
SGI's Virtual-24 technology is hardware-assisted dithering. The Xserver provides a 24-bit DirectColor visual to applications, which can run as if they had a 24-bit graphics device. The GL system dithers that visual using an 8-bit LUT optimized for the colors the application uses.

By contrast, HP's Color Recovery technology also processes the data on the backend, turning the dithering back into an approximation of the original color information. It was only found on the 715's HCRX and the 712's integrated graphics.

Re: Indy XL TrueColor

Posted: Mon Mar 16, 2015 11:15 am
by ClassicHasClass
Oh. Well, the Xservers change he has won't do that (it's what *my* XL24 has, but it's a 24-bit card).

Re: Indy XL TrueColor

Posted: Mon Mar 16, 2015 8:47 pm
by PowerGraphics
Possible is doing dithering or not, I know that was possible when I wore irix 5.3! This is true!
I managed such a feat, but I lost the configuration file to 15 years.
If only it is possible using dithering, so what should write in Xservers file then?

Re: Indy XL TrueColor

Posted: Tue Mar 17, 2015 11:27 am
by vishnu
PowerGraphics wrote:Possible is doing dithering or not, I know that was possible when I wore irix 5.3! This is true!
I managed such a feat, but I lost the configuration file to 15 years.
If only it is possible using dithering, so what should write in Xservers file then?

So wait, you said your xserver is dithering? Or isn't? The only way an 8 bit indy can support 24 bit color is through dithering, from their own press release: ...virtual 24-bit (dithered 8-bit) or true 24-bit color but I'm not sure that trick was carried through to Irix 6.5, since the last of their 8-bit workstations went off the market 20 years ago. Anyone with a 5.x workstation see anything about virtual 24 bit in the x manpage? Because the 6.5 version doesn't mention it at all.

Re: Indy XL TrueColor

Posted: Tue Mar 17, 2015 11:56 am
by robespierre
I don't have an 8-bit Indy to check, but the way to find out is to run xdpyinfo. If you see a 24-bit DirectColor (or TrueColor) visual, then you have the Virtual24 feature.
This feature wasn't specific to Indy, btw. It was also on the 8-bit Indigo. There were no other 8-bit only graphics options.

Re: Indy XL TrueColor

Posted: Tue Mar 17, 2015 3:18 pm
by PowerGraphics
How to configure the virtual 24bit using my 8bit XL system in IRIX 6.5.22, or in IRIX 6.2 or in IRIX 5.3. This is only possible using IRIX 5.3?

I'm not disagreeing with anyone here. I sincerely believe in you guys. I just said I could make it work, even if it is apparently on IRIX 5.3, and the colors seemed very clear and smooth, when you use the standard 8bit mode. But I lost the settings to 15 years ago.

Re: Indy XL TrueColor

Posted: Tue Mar 17, 2015 6:13 pm
by robespierre
All you are doing with -depth 24 is making the default visual be a 24-bit deep one. Applications don't simply use the default visual, they use the visual they were written to use. So this does not affect most programs.

Re: Indy XL TrueColor

Posted: Tue Mar 17, 2015 7:01 pm
by vishnu
Well written applications do the legwork to find the best visual that's available on the hardware they're running on, and use that. You can use xwininfo to find out what visual any application with a window open is using. But the question of the hour is does XSGI from IRIX 6.5 still have the virtual 24 capability, `man xsgi` doesn't mention it...

Re: Indy XL TrueColor

Posted: Tue Mar 17, 2015 8:45 pm
by foetz
vishnu wrote:`man xsgi` doesn't mention it...

the 5.3 manpage doesn't mention it either :P

Re: Indy XL TrueColor

Posted: Tue Mar 17, 2015 8:56 pm
by robespierre
vishnu wrote:Well written applications do the legwork to find the best visual that's available on the hardware they're running on, and use that

Yes, but we're talking SGI here. Of course every visual is supported, and several that X doesn't understand to boot (thinking of 12- and 16-bit color components here). It's the ability to use multiple colormaps of different sizes (including weird stuff like 12-bit indexed, and 8 bit DirectColor) on the screen at the same time that distinguishes these designs.

Re: Indy XL TrueColor

Posted: Wed Mar 18, 2015 4:55 pm
by PowerGraphics
If I understand well, all I need to do to my system supports 24bit (dithered or not), it would be put in the Xserver file, only the command -depth 24, and nothing else, not even put -class TrueColor (or PseudoColor or DirectColor), is this?