(Question) importing arbitarary channels from EXR files

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Offline claude

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« Reply #15 on: September 23, 2019, 11:58:20 AM »
https://code.mathr.co.uk/exrtact/blob/1490e7b093aa7ca8765d843b184e50adf127edcd:/exrtact.cpp#l35 to read EXR with multiple channels, use the general API instead of the RGB API, and insert more slices into the reading framebuffer? that code is hardcoded to FLOAT (OpenEXR converts automatically), should really check the header to see what type it really is.

Offline 3DickUlus

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« Reply #16 on: September 24, 2019, 02:09:21 AM »
That's essentially what I've got, but that works fine for scanline format, I'm looking for tiled output, using a tile sized frame buffer so that there won't be any restriction on image size, a little bit trickier than the code you referenced.

I would like to get some input from others before I put a lot of time into this,
will this be used?
is it needed?
is it a requirement for project work flow?
do you have a test scenario with data?
is the only place this will get used is with KFR files?

edit: loading non-tiled with a routine that's setup for tiled will treat the file contents as one  tile afaik.

edit2: Qt loads EXR images but doesn't write them  :-\

edit3: nailed it!
« Last Edit: September 24, 2019, 05:14:23 AM by 3DickUlus »

Offline 3DickUlus

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« Reply #17 on: September 29, 2019, 11:24:35 AM »
FragM saves RGBZ EXR float format and loads them too, all channels or just one channel, for now ;)

the first image is of a quad distorted by the Z channel

the second image is a slightly zoomed and off center view

and the third image is the source of the Z channel ( generated with DepthToAlpha = ON )

it works but I don't know what to do with it  :-\

Offline claude

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« Reply #18 on: September 29, 2019, 12:24:19 PM »
Great! Looking forward to trying this next week.

Offline 3DickUlus

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« Reply #19 on: September 29, 2019, 08:44:07 PM »
I haven't pushed this to github yet, still tweaking the brute force code into something a little nicer.
« Last Edit: September 29, 2019, 09:04:48 PM by 3DickUlus »

Offline 3DickUlus

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« Reply #20 on: September 30, 2019, 12:37:35 AM »
Pushed to github for those brave explorers that want to test this, here are some reference files

one frag 5344 bytes
one RGBZ image 9973040 bytes
three test images 226506 bytes 202934 bytes 399589 bytes

or you can generate your own RGBZ test-channels.exr file and use the attached frag ;)

Offline 3DickUlus

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« Reply #21 on: October 12, 2019, 02:33:48 AM »
bump...

Idea: make a tutorial based on this thread and frag  :thumbs:

Offline claude

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« Reply #22 on: January 23, 2020, 06:14:58 PM »
I worked on this recently.

Ticket: https://github.com/3Dickulus/FragM/issues/92
Pull request: https://github.com/3Dickulus/FragM/pull/112

git clone https://github.com/claudeha/FragM.git
cd FragM
git checkout feature-exr-loader-flexible-channel-mapping-try-2

Then build as usual.

If you want an easy way to make an EXR file with non-RGB channels, try KF - if you enable derivatives you get DEX and DEY as well as the iteration count N and smooth NF, as well as RGB, when saving as EXR.


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