* Fix dark color rendering in G-code preview by using additive specular lighting
* Revert "Fix dark color rendering in G-code preview by using additive specular lighting"
This reverts commit 2a65bc90607c1b5e9b1beb460bc81a448b011427.
* Fix dark color rendering in G-code preview (Standard & ES shaders) by using additive specular lighting
* Fix dark color preview: Increase minimum brightness to 48/255 (~19%)
* Refactor: Revert to combined lighting calculation in shaders