Inner Glow / Gradient Shader Material

I mean, it’s not just an illusion. The 4 - 8 - 16 colours show that according to the formula the colours change squarely from the centre. So the color in the corners is always brighter if you think in a circle from the center.

That’s why I have the circular formula.

// function definition (circles)
	float circ(float d, float x, float y){
		
	   return d + sqrt( x * x + y * y );

So you can create almost any form of color change if you have the right formula.

In my addons I use a wide variety of functions to create 3D shapes. Maybe you can get something out of it.

Addon. Produces almost infinite many time-varying geometries with functions

sandbox