2.33a not dithering on linux?

Support Basics & Interface
#1

Hello Folks,

We’ve been using our linux machines to chunk out renderings and we just discoverd that the viewer output of large and flat surfaces come out with what looks like a poor dithering. This seems to be a new phenomenon from 2.28.

This seems true of almost any surface that is large and flat with gradual tonal changes due to shadowing. This does not seem to be true under windows.

We are going to keep working to find the cause.

Anybody else seeing this?

Thanks,
Matt

#2

The rendering code is the same no matter which platform you are on. Some possibilities:

  1. Are you sure that you are using the same colour depth in windows and your linux X server?

  2. Are you sure that your not rendering to a jpg or lossy format. What you are describing sounds very much like a jpg artifact.

Do the renders made in linux display correctly when transfered to a windows machine? What about the other way around, a render made on a windows machine displayed on your linux machine?

GreyBeard

edit can you post a small eg. of the same file rendered both under windows and linux?

#3

First go look at:
http://projects.blender.org/tracker/download.php/9/126/1523/312/blender_view_output.jpg

That is the image as seen in the render viewer on linux. The only difference between that and the windows version or the output files shown under another render are the colored lines on the walls.

As to your questions:

  1. Yup same color depth across the board
  2. Nope always to tgas. Further more, the example above is a screen capture of the window that blender uses for the display and to get the imagery to upload I had to use jpg (the tga was 2 megs).
  3. The actual output files look fine. It is ONLY the viewer. I suspect that it is an issue with X, the viewer, or both.

Thanks,
Matt

#4

If you view your tga image in another program under linux do you still see the artifacts? If not, there is probably a bug. If so, I’m still thinking its a colour depth problem. On my machine starting X with
“startx – -fbbpp 32” yields
http://members.shaw.ca/rjplus/snapshot3.png

and “startx – -fbbpp 16” yields
http://members.shaw.ca/rjplus/snapshot2.png
The lighting above was purposely set to accentuate the artifacts and is similar to what your seeing.

GreyBeard

#5

It looks like my X install defaults to 16bpp, which is lower than I thought (I just upgraded) but…
the gimp displays the image perfectly. No problems what so ever. So I still have a large enough pallete to display the image properly.

I dunno, it still looks like the viewer is not making best use of the display.
I checked with several other viewers (the kde default and eye of the gnome) both with no problems.

Thanks,
Matt

#6

Well, that cures the problem. Sorry I didn’t see it sooner. The banding is gone, but I still have to wonder why the GIMP is not suffering the same illness?

Doesn’t make a whole lot of sense to me. It still seems like somthing might be handled differently or better.

Thanks again,
Matt