Top and Chopto to Glslmulti issue

Hi folks! I don’t have much experience with GLSL or C, so anytime I can’t avoid using it I do it by following some cool dude’s tutorial. Anyways making a volumetric installation and ran into a little problem while converting from chopto and top to glslmulti. I get faded sides and other small irregularities:

BadGlsl

Expected result:

GoodGlsl

Any ideas how to fix this?
Thank you!

NewProject.1.toe (5.5 KB)