(Feature): Deep Image Compositing

[charlesangus]

Make sure to follow our issue report guidelines

• I have read the feature request guidelines
• I have followed the contributing guidelines to the best of my understanding
• This feature is not on the issue tracker and is not a duplicate

Provide a description of your feature request

Deep images store multiple depth and alpha samples per pixel. This allows for automatic merging of volumetric data, and reduces the need for re-rendering. It is also required for e.g. accurate defocus of transparent/semi-transparent objects or strong motion blur.

Deep images are widely used in production compositing workflows, but currently Nuke is the only compositor with anything like full support. In order for Natron to be considered for production work at studios, Deep image compositing would be a required feature.

Would require at least the following new nodes:

DeepMerge
DeepGrade
DeepRecolour
DeepToImage
DeepFromImage

And would require the ability to read and write OpenEXR images with Deep data in them.

Is this a realistically implementable feature?

• My feature is realistically implementable
• My feature is NOT realistically implementable

Can you contribute in creating this feature?

• I am unable, or not willing to contribute to creating this feature
• I am able and willing to contribute to the creation of this feature

Additional details

Some more info on Deep images:

https://en.wikipedia.org/wiki/Deep_image_compositing
https://openexr.com/en/latest/InterpretingDeepPixels.html
http://www.graphics.stanford.edu/papers/deepshadows/
https://web.archive.org/web/20110713112546/http://www.johannessaam.com/deepImage.pdf

I have written some very simple Deep nodes for Nuke, but I'm not sure how Natron's image-processing framework would handle Deep images. It may require a native (i.e. non-OFX) image-processing framework - I'm not totally clear, but I think all Natron nodes are OFX right now? I don't think OFX supports deep data, but I could be wrong.