Dash vs Underscore Mexximp Confusion

[tlian7]

Hi @benjamin-heasly ,

I was trying the new versions of the ExampleScenes and ran into an issue with one scene, specifically rtbMakeSponzaAtrium. Although it was rendering, the textures weren't being read correctly by PBRT. I figured it might have to do with exr file issues, so I re-imported the scene with JPG textures so the imagemagicImage could do the conversion instead. I figured this would be more consistent in the long run anyway.

Anyway it was during this conversion that I discovered a bug. In the scene folder (with the OBJ file) there is a texture called

01_St_kp-bump.jpg

In the MTL file, this image texture is also referred to as:

map_Bump 01_St_kp-bump.jpg

During the mexximp conversion, I get an error:

docker run --rm -u 254876:254876 -v 
"/home/tlian/GitRepos/RenderToolbox4/ExampleScenes/IsetbioExamples/SponzaAtrium/Data":"/home/tlian/GitRepos/RenderToolbox4/ExampleScenes/IsetbioExamples/SponzaAtrium/Data" -v "/home/tlian/GitRepos/RenderToolbox4/ExampleScenes/IsetbioExamples/SponzaAtrium/Data":"/home/tlian/GitRepos/RenderToolbox4/ExampleScenes/IsetbioExamples/SponzaAtrium/Data" -w "/home/tlian/GitRepos/RenderToolbox4/ExampleScenes/IsetbioExamples/SponzaAtrium/Data" hblasins/imagemagic-docker convert "/home/tlian/GitRepos/RenderToolbox4/ExampleScenes/IsetbioExamples/SponzaAtrium/Data/01_St_kp_bump.jpg"  "/home/tlian/GitRepos/RenderToolbox4/ExampleScenes/IsetbioExamples/SponzaAtrium/Data/01_St_kp_bump.exr"
Error using mexximpConvertTools: convert operation failed: "convert.im6: unable to open image `/home/tlian/GitRepos/RenderToolbox4/ExampleScenes/IsetbioExamples/SponzaAtrium/Data/01_St_kp_bump.jpg': No such file or directory @ error/blob.c/OpenBlob/2641.
convert.im6: no images defined `/home/tlian/GitRepos/RenderToolbox4/ExampleScenes/IsetbioExamples/SponzaAtrium/Data/01_St_kp_bump.exr' @ error/convert.c/ConvertImageCommand/3044.

Note specifically that it's having trouble finding a file called:
/01_St_kp_bump.jpg'

It would seem that somewhere during the conversion process, the dash was turned into an underscore, causing the textures to be unrecognized. Was there a reason for this, and is there an easy fix or should we change all our texture file names to not include dashes?

Thanks!

[benjamin-heasly]

Hi @tlian7,

For some other examples with mapings files, I found that jsonlab would encode dashes as %2D, which the renderers did not understant. So I thought a good default would be to get rid of the dashes and replace them with underscores. When doing the replacement inside of mexximpCleanImport(), the scene struct should be updated to point at the file with the underscore instead of the original file with the dash.

So for some reason this is not happening. If you wanted to push up your changes, I could take a look in more detail. Being able to reproduce this error on my end would really be a big help.

But first -- I am wondering if the original texture issue is not with the exr files, but rather with the fuzzy name matching that mexximp does by default. I see that the scene uses distinct textures that have similar names, like 01_St_kp.exr and 01_St_kp-bump.exr, which might be matched incorrectly. Maybe all we need to do is change from fuzzy matching to strict matching, so that names like these don't collide?

I'll try this out and add a comment in a minute.

[benjamin-heasly]

Hi @tlian7,

I think strict matching for the textures helped. When I first generated the Sponza Atrium PBRT file I got syntax like this:

# 01_St_kp_spectrum
Texture "01_St_kp_spectrum" "spectrum" "imagemap" 
  "string filename" "resources/01_St_kp_bump.exr" 
# 01_St_kp_bump_float
Texture "01_St_kp_bump_float" "float" "imagemap" 
  "string filename" "resources/01_St_kp_bump.exr" 

With the "spectrum" and "float" textures both pointing at the bump map image, 01_St_kp_bump.exr.

I changed to strict matching and got this PBRT syntax:

# 01_St_kp_spectrum
Texture "01_St_kp_spectrum" "spectrum" "imagemap" 
  "string filename" "resources/01_St_kp.exr" 
# 01_St_kp_bump_float
Texture "01_St_kp_bump_float" "float" "imagemap" 
  "string filename" "resources/01_St_kp_bump.exr" 

Where the "spectrum" and "float" textures point at distinct images.

I will push up this change. Does this make the Sponza Atrium come out right for you?

[tlian7]

Hi @benjamin-heasly,

I just tried your changes and I don't think the strict matching fixes the exr problem. Although the image renders, if you were to pull up the command line output from PBRT you would see that it says for all the image files:

/Users/trishalian/GitRepos/render_toolbox/rtbMakeSponzaAtrium(47): Error: 

    Unable to read 

    image file 

    "/Users/trishalian/GitRepos/render_toolbox/rtbMakeSponzaAtrium/resources/01_St_kp.exr": 

    Cannot read 

    image file 

    "/Users/trishalian/GitRepos/render_toolbox/rtbMakeSponzaAtrium/resources/01_St_kp.exr". 

    File is not an 

    image file. 

This was the reason I had figured that the exr files might be corrupted somehow, since the files are present in the right folders. To check this I re-imported the scene with its original JPG texture files to have RTB4 convert them instead, but ended up with the same dash vs underscore issue.

I'm going to push the new scene with JPG files to the repo, and maybe you can give it a look over for the dash/underscore problem?

[benjamin-heasly]

Hi @tlian7,

I don't get these errors on my end, so I am wondering if this is now a matter of code versions. Could you try pulling on mexximp master, mPbrt master, and RenderToolbox4 MoreExampleScenes, and then trying again?