Auto-illumination of 2d shapes

I’ve started to work on a new G’MIC filter able to automatically illuminate 2d shapes.
This is a work in progress, I’ll post some results here when new things appears.
Also, any suggestion is appreciated.

For now, what I have currently is a code that automatically transforms an input binary shape as an illumination layer, like in the examples below.
I use a Gouraud model for the illumination.

The idea is that if the user gives an image of a disc as an input, the filter interprets it as a 3d sphere, and illuminates it accordingly:


So far, I’ve tried only simple shapes, but I think it already looks cool :slight_smile:



The plans for now are : allowing more than one shape in the input images (layers with several regions with flat colors).

What do you think ?



Game (height)map designers may find this very useful.

I like this!


  1. Is the light source’s position fixed?

  2. There’s some indication of back-reflection; is that it, or do you specify some sort of ‘fill’ light?

Again, Neat! Neat!

No, light position (in 3D) is a setting of the filter, so you can place it anywhere.

No, I’ve just implemented the formulas from and got that rendering. I haven’t checked if this was correct as the results already looked cool to me :slight_smile:

Well, I’d assert “looks cool” is a fundamental test of ‘correctness’ in imaging!

(I am the Knight who says ‘Neat!’ And so I say, ‘Illuminate a Shrubbery!!!’ )

:thinking: Makings of a good filter. First impressions:
– Illumination currently makes it look like it is over- or unevenly inflated. Something between this and the render in Gmic for animation might be an improvement.
– The sharp edges and their illumination break the illusion of 3d-ness.

Source: Wikipedia

Source: My Little Day

When this is done, could we have I chocolate filter? :wink:

Source: Wikipedia

(This might be a joke. Secretly, I am hoping for the illumination of not just empty shapes but ones with relief as well, like the ridges on the chocolate piece.)

It would like me that it was multilayer. Putting each inflammation in different “Z” levels

Looks impressive David; sort of like Bevel Reflect Logo. Maybe give option to add different types of textures to would be cool. :slight_smile:

So, here it is !
A first version of the filter Light & Shadows / Illuminate 2d shape has been published today, and should be available for users of the G’MIC plug-in for GIMP and Krita (requires version 2.2.2+).
Here is a video that shows what it can do.

Right now, I admit I’m quite enthusiastic by this filter, as it really allows shading complex shapes with a few clicks.
Remind also that this is a first version, so subject to changes.

Please let me know what you think about it !

Some before/after comparisons :


I love this! <3

The Effect could separate by layers and attain something like this:


Just select Output modes -> New layers and you will get the illumination layer alone, blended with your original image.
Then you can re-work on this illumination layer to create various effects or correct light locally if you want.

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I what thought was in slight variations for each level and something similar to colorize [interactive] for the levels.

Not planed like this sorry :slight_smile:

I will have to automate it in a script :stuck_out_tongue:

Melts from the cuteness of the lion. Awesome wizardry you have there, @David_Tschumperle!


I like it, thanks…

Processing each colour separately

The effect is less a globe and similar to the animations of 2.5D


That’s interesting.
Have you used the exact same parameters of the filter for all colors ?

yes. But no it apply it to him to line (black)