Question ACTUAL glowing eyes?

I’ve attempting to figure this out in the past, but does anyone have any suggestions on how to make ACTUAL glowing eyes?

Not just slapping an emission on eyes.

Like make eyes that glow like they do in real life?

I suppose that would mean:

-They would only glow if facing the camera and a light source

-The pupils would show the back of the eye and rotate the retina as they move

-Because of the refraction it would look as though the glowing part is closer than the actual eye

-The color of the reflected light would shift with the angle

-It would drop dramatically the wider the angle of the light

-The light would bleed around the pupil making it appear larger depending on the distance

Any suggestions?

 

It sounds like a post effect that only comes from retinas, displaced and irridescent ...?

If so, not sure how you accomplish that.

 

Personally I looked for such question
This is something retroreflective shader does, but it depended on camera angle, not the light source, so this is the biggest question how to make it, yeah.

 

Maybe it's because I'm fairly hard-of-seeing IRL, but I've never been able to discern all of this detail in real life. I can't imagine even noticing this level of accuracy in a game, unless you are doing a cinematic cut-scene with a close-up on the face. If that is the case, though, then maybe it would be easier to just script what you want to see rather then trying to simulate it.

Edit: The question of determining the result based on the angle of the camera and lighr sounds similar to the fresnel effect that's usually calculated in water reflections, so maybe you could re-purpose that sort of math in your case.

 

Dot product is your friend

I don't think this is necessary at all unless your retina has a texture or something recognizable in it. This is already accounted for by the glow?

Refract the view vector using the cornea's surface normal, use results to offset iris UV coords.

Dot product is your friend again. Remember that when used on unit vectors, it basically returns a measure of how close to parallel two vectors are: will be 1 if parallel with the same direction, -1 if parallel with opposite direction and 0 if orthogonal: https://www.falstad.com/dotproduct/

You can use this to blend between glow colors and intensities based on view/light/normal vectors.

For anything involving angles between vectors: dot product!

Emissive + bloom?