[1.12.1] Bind textures outside of .jar

[grand_gibus]

Hello, I'd like to know how to bind an entity a texture located outside of the jar. I've worked in an IDE and now realise I needed to move my custom assets outside of the .jar, if I want my code to be able to read them. Thanks. 
I'm so dumb, the whole mod I'm making is litterally useless if I don't figure it out 

Edited September 1, 2017 by grand_gibus

[grand_gibus]

Thank you so much! I feel like it's going to be a huge pain to implement but at least I'm not stuck anymore