Real-time Compositor

In this article, Omar introduces the real-time compositor project, its current state, and shows off some of its capabilities through a series of demos.

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The Project

The aim of this project is to develop a new compositor back-end, taking advantage of GPU acceleration to be performant enough for real-time interaction.

As a first step, this new back-end will be used to power the Viewport Compositor, a new shading option that applies the result of the Compositor Editor node-tree directly in the 3D Viewport. Artists will not have to wait for a full render to start compositing, allowing for faster and more interactive iterations on one’s projects.

In the long term, the goal is for it to power the existing Compositor Editor.

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How To Use It

To use the Viewport Compositor, you will need to use an experimental branch:

• In Preferences → Experimental, enable Real-time Compositor.
• In the 3D Viewport, turn on Compositor under the Viewport Shading panel while in Material Preview or Rendered view.
• Open the Compositor Editor and start compositing as usual.

Note: not all nodes have been implemented yet. See the list.

How to enable the Viewport Compositor

Demos

In this scene, we add a watercolor texture for the background, overlay that texture on the ghost, generate a smooth outline from the blurred alpha, and mix it with the image.

Ghost demo

Next, a simple product visualization of a flashlight with a transparent background rendered in EEVEE. A dark background is added via the Alpha Over node, later a sharpen filter, add some lens dirt from an image, lens distortion, and finally some color grading.

Flashlight demo.

In fact, one can just ignore the 3D Viewport and simply use external resources, for instance, a movie clip.

Using external sources.

Current State

Even though the project is still a work-in-progress, it is already in a usable state. The plan is to land it in master as an experimental feature and continue development there. Being a work in progress, many of the nodes are still not supported and there are a number of known issues and limitations, refer to T99210 for more information on the current state of the project.

Try It Out

Experimental builds are available at builder.blender.org. The code has been already submitted for review, so it should be available (marked as experimental) as part of the daily builds soon (not for Blender 3.3 since the window for adding large features to it is over).