POV-Ray : Newsgroups : povray.general : I think I found the funky hieght field trouble! : Re: I think I found the funky hieght field trouble! Server Time
28 May 2024 07:20:09 EDT (-0400)
  Re: I think I found the funky hieght field trouble!  
From: Mike Miller
Date: 12 Apr 2023 23:30:00
Message: <web.643775cec693303f59197626dabc9342@news.povray.org>
William F Pokorny <ano### [at] anonymousorg> wrote:
> On 3/27/23 15:28, Alain Martel wrote:
> > Remember that 8 bits and less are paletted formats and that 16 or more
> > are non-paletted.
>
> This doesn't look to me to be strictly true. It might be 'typically
> true' for height_field images in some formats with respect to
> traditional POV-Ray usage.
>
> > IIRC, in hight fields, when the image is 24 bits, the red and green
> > channels are used to to represent the high (green) and low (red) bytes
> > of a 16 bits value and the blue channel is ignored.
>
> In official POV-Ray releases: "when the color image is <=8 bits per RGB
> channel"
>
> And, I too flipped the importance of green and red in one of my earlier
> descriptions - probably because green in typical color to gray
> conversions matters most to luminosity / the gray level.
>
> It's not how the special (<=8 bit a channel) color to gray conversion in
> POV-Ray works where the most weight is in fact given to red.
>
> > 16 bits is often called high colour and 24 and 32 bit are called true
> > colour.
>
> Ah yes! I remember being so excited to finally be working on a true
> color display! :-)
>
> My college terminals were teletypes.
>
> I started work years on green and black IBM 3277s - and white and black,
> vector displays, I think, IBM 2250s or 3250s. Those latter displays had
> light pens you'd bang directly on a heavy glass screen for selection and
> movement.
>
> Once you got a lot of vectors up, the refresh rolled across the screen
> at a few screen refreshes a second - and selection and movement got
> really hard. The heat on our faces and the sound in the terminal rooms
> was something else when folks were really cranking.
>
> There were some black and green Tektronix displays in use too for our
> graphics. They were nice because they didn't flicker at high densities.
> The image was written on a screen sort of like an etch and sketch -
> until you refreshed. I cannot, at the moment, remember the models.
>
> My time on another planet...
>
> Bill P.

Wait, are you older than me? ...haha.
I remember those days...out of college before there was computers. :)
But I did have an old vector image setter pre 8088 & post script that used an 8"
Winchester drive... first intro to burning film negatives with machine-coded
light.
Mike...from someone born in the 50's.uggg.


Post a reply to this message

Copyright 2003-2023 Persistence of Vision Raytracer Pty. Ltd.