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Comment by etaioinshrdlu | Hacker News Reader

I get that this is missing the point a bit... but this effect looks more like something you could add in post-processing, photoshop, or after effects, and not something you really need in your 3d engine.

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Surely it all depends on what you're using it for. Maybe I want to create a game where all characters look like that in real-time (think Borderlands but turned up a notch).

Your comment makes it sound like there's only one presumed use-case for this.

I thought he was only applying this to one or two outlines at a time ? I wonder if there are other performance trade offs when you outline a hundred game elements in frame or something ?

Also, FWIW, this was posted today on Reddit - a nice writeup of "5 ways to draw an outline" in Unity that also tips a hat to the OP article:

https://alexanderameye.github.io/notes/rendering-outlines/

3D outlines around objects are an increasingly necessary effect in the visual language of modern 3D video games because increases in post-processing and shader tech have made it such that it's hard to identify individual interactable objects in 3D space in increasingly photorealistic environments. the article shows some examples of how this can be used, including the The Last Of Us "rough outline of figures that you can sense behind walls" effect.

Someone writing a photo or video editing program could use this technique to process images fast. Instagram used to do filters on the CPU then changed to a shader version for a huge speedup. I use JFA in a game to generate outlines of 2D characters that are procedurally generated in the app. Also the JFA is a way of generating voronoi diagrams in log2(textureSize) steps and could be used for anything that uses voronoi diagrams. Generating a distance field is just one use.

It’s useful to have as a shader which can help define the visual style of your game. Additionally you can highlight the model from any angle, which is a useful hint to users.

Since the model may be viewed from any direction, this would be very hard to do in post, since there’s no way you can get the model to look correct from all angles.

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