#12 MakeShadow "bug(s)"?

open
nobody
None
3
2005-06-30
2004-01-14
Leo
No

Hello,

On my system (Redhat Linux 9 i386), when rendering a
shadow map with MakeShadow RIB command (and upon this
call), I get lots of messages like this one:

Lamptest.rib (2210): TIFF: LZW compression is not
available to due to Unisys patent enforcement

And then when rendering the scene with the shadowmap a
lot like these:

test.rib (2210): 0: Invalid tile byte count, tile
5test.rib (2210): 0: Invalid tile byte count, tile 10
etc (just as it is, without newlines)

And the shadows do not display correctly.

Haven't tried on other systems but on my linux,
disabling compression for the texture solves the problem.
The way I've found to disable compression when making
textures from MakeShadow is to directly modify the
source code (texmake.cpp, where is says
COMPRESSION_LZW, set to COMPRESSION_NONE). Is there a
"portable" command/parameter/argument/etc to do this?

Shouldn't the default behavior be like the 'Display'
command (no compression), and maybe have a command to
enable compression when creating the texture (even
though the RIB Spec says the format is implementation
dependent)?

Also, concerning shadow maps, it seems like the
PixelFilter command doesn't have any effect on the z
component calculated. I'm no Renderman expert, but
shouldn't this filter (catmull-rom, box, etc) be done
on the z component too? For example if you want a
smooth shadow map, the filter would make a "soft shadow
effect" by bluring the z out.

Thanks, and keep up the good work, Pixie is great. :)

Just curious, how long have you been developing Pixie?

Discussion

  • George Harker

    George Harker - 2005-06-30
    • priority: 5 --> 3
     
  • George Harker

    George Harker - 2005-06-30

    Logged In: YES
    user_id=995400

    I'd really like to be able to detect the presence of a given compression
    format in LibTiff. This is possible for most of the optional compression
    schemes. Unfortunately, for LZW, it says supported, even when the
    code is actually going to bug out with LZW patent messages. If it were
    possible, I'd go for no compression if none is supported, or something
    like LZW if it is.

    However, now that the LZW patent has expired, most libtiff distros are
    available with LZW support. You could upgrade yours to get that
    support, and save your disk space ;) Please do let us know if this is
    still a major issue for you.

    Cheers

    George

     

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