Minor issues with a new plugin


My GMIC plugin for Carrara is almost finished and I’m in the final testing stage before release.

Most of the effects work like a charm, but a few don’t.

In particular, ycbcr conversion gives black images, blend alpha gives very black images and a few other minor issues.

If it weren’t the mere fact that most of the effects are actually working like a charm, I would think it’s because I send images coded with a value from 0 to 1 per channel and not 0 to 255.
in the other hand, if you take the painting frame effect, the frame is as it should, but the image inside is very very dark, which seems to invalidate this hypothesis.

The plugin uses libcgmicstatic.lib, linked with gmic_libc so I don’t think I’m missing dependancies.

Does it ring a bell for you?

(David Tschumperlé) #2

That is certainly the cause of the issue. In G’MIC, RGB colors are expected to be in [0,255] (float-valued), so any color transformation formula assumes this range.


Thank you David for your answer.

You’re right, nothing could work in this situation. I’ve checked and I’ve discovered that, most opportunely, I used a method that translated automatically to a 0…255 range.
So the problem stands somewhere else.


I don’t know if it helps, but, on some effects, I have this strange behaviour, kind of vertical scan lines that appears when blending (here is lightning effect).
Could it be a memory alignment issue?


Don’t bother with this one, I was eventually able to debug it (sometime all you need a sounding board to find out your mistakes) :wink: Carrara was sending me an alpha channel with zero as a constant, thus failing the blend alpha operator.

What I’ve left is the ycbcr conversion


G’MIC Carrara plugin is now released.

See annoucement thread in DAZ forum here
Introduction video is here

(David Tschumperlé) #7

That looks interesting and well done @Philemo.
May I ask if the sources of the plug-in are available or not (or will be available some day?).
The CeCILL license has a ‘contaminating’ clause (just as the GPL), which means that linking a binary with the G’MIC library forces the sources of the binary to be opened as well. Is that your case ? Or don’t you have direct linking to the G’MIC library ?


The sources will be available here in a few days (some cleanup to do before publishing :slight_smile:) . All Carrara plugins in the CTS project have their sources published (one aim of the project is to promote plugin development by giving examples, hence the cleanup before publishing).
I hope it satisfies the licence requirements.

(David Tschumperlé) #9

Yes that sounds very good.
I’ve looked at your video, and the plug-in seems to be nicely done. I’ll surely have some questions about it. I’m curious and excited at the same time :slight_smile:
Maybe a first one : How did you create the list of filters and their parameters ? Did you write a parser of .gmic files or have you done this ‘manually’ ? Does your plug-in support Internet updates as well ?


I used the parser found in the Helper section of the g’mic plugin repository. It’s been a great help to me (as well as the complete plugin for reference).
Internet access doesn’t work in the plugin, seems to be firewalled at some point (I don’t know why).
Anyhow, I still have an issue with the MixRGB function that, for some reasons, doesn’t do anything. Consequentely, conversion to YCrBr doesn’t work and I had to change all defaulting using this mode and to ship a custom library. I’ll eventually revert to standart if and when I can solve this issue.

(David Tschumperlé) #11

OK, please tell me when the sources are ready so I can make a little announcement for you in the G’MIC social feeds.