Ptex Writer problem with texture exporting

[Colin Chargy]

Hi guys,

I'm trying to write an ptex export module and I'm having few issues while exporting textures.

I try to isolate the problem. Here is the thing : if I put 0 in every red channel of an image and 255 in every blue one, I don't get these values while reading the output file.

Enclosed, you can find the sample cpp I use to test it.

Can you see where I'm wrong or what am I missing ?

Thanks for your help,

Best regards,

Colin Chargy

[Brent Burley]

When I run your test (on Linux) it passes and prints "no error found".  Btw, I had to add includes for stdio.h and math.h and also fix the syntax of the FaceData ptr initialization (PtexPtr doesn't support operator=).  What values are you seeing in your getPixel result?

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[Colin Chargy]

Hi guys, Hi Brent,

Thank you for your time.

I've patched as you said and I've reduce the test to a simple 4x4 writing/reading data. When compiling and executing it on Linux and Windows (Visual Studio 2010), I have the same result : the read data is not what I've been written. I have enclosed the cpp file and the result I have on both system. Have you the same problem ?

Thank you,

Best regards,

Colin Chargy

[Brent Burley]

Your revised test compiles without error and runs successfully for me.  It would be useful to see if it is a problem reading or writing.  You can look at the data in the generated ptex file with ptxinfo.  Here's what I get with your file:

> ptxinfo -d test2.ptx 

meshType: quad

dataType: uint8

numChannels: 3

alphaChannel: (none)

uBorderMode: clamp

vBorderMode: clamp

numFaces: 1

hasEdits: no

hasMipMaps: no

numMetaKeys: 0

face 0:  res: 1 1 (2 x 2)  adjface: -1 -1 -1 -1  adjedge: 0 0 0 0  flags: (none)

  data (2 x 2):

    (0, 0):  0.000 0.000 1.000

    (1, 0):  0.000 0.004 1.000

    (0, 1):  0.000 0.008 1.000

    (1, 1):  0.000 0.012 1.000

texels: 4

Note that ptxinfo shows integer data scaled to a normalized range (1.0 = 255)

You might try calling PtexWriter::close explicitly and check the return value and error string.  You might also try reading and writing from separate test programs.

[Colin Chargy]

Hi Brent,

Thanks again.

As you suggested, I used the close function, I checked its error return (empty) and I split the code in two differents files. Still the same. I've run the ptxinfo program on the result of my test program. I get the enclosed file (still wrong). Could you try your ptxinfo on my file and send me the result ? Also, can I have your resulting .ptx (in order to test it with my ptxinfo) ? This way, I should be sure of what's wrong : my reading, writing or both.

What could make this issue happen ? Zlib or cmake version (I'm using cmake on windows) ? I've get the file as a zip from github (ptex-master), not by checkouting them with git (I don't have internet access in the dev computers). Does it matters ? I'm looking for every thing that could cause these differences ...

Thank you,

Best regards,

Colin Chargy

[Brent Burley]

I get the same output as you, so it looks like a problem writing.  I've attached my test2.ptx.

[Brent Burley]

Thanks Colin for debugging this.  It was a regression from a recent commit.  I've just pushed a fix.