Hello,
( I am posting this comment with a touch of humour)
I cannot compete with the programming skills of Bored of the Rings (a highly skilled software engineer) but my ego is probably bigger than his.
Nice demo of ShaderToy. It seems to provide a user friendly solution to create shaders.
A few months ago I found a free toolsuite (unfortunately it is deprecated for the newest game engines ) with which I was able to learn the method for the creation of shaders in GLSL (OpenGL 2.0) and HLSL (DirectX 9.1) formats.
RenderMonkey is the name of that toolsuite and it is still available on the archives of "gpuopen.com" :
https://gpuopen.com/archived/rendermonkey-toolsuite/
Here is a link to a short video clip ( 7 MBytes = 6 seconds) showing one of my experiments of a GLSL shader in a video game's project (OpenGL 2.0) :
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In the time when I liked programming with Dark Basic Pro I found that the tool provided by Lee Bamber to create ones own shaders was a good one to study how shaders are coded.
Anyway it is time consuming and I don't want to learn the coding of shaders anymore. Testing and fine tuning them is difficult.
I think that it is matter that is better reserved for the game engines developers ( https://www.thegamecreators.com/team ).
I see in this forum three main categories of members : the 3D artists, the programmers and the true video games developers.
GameGuru forum and its boards have a nice community.