I'm getting an error when I use ModLoader.addArmor to add armor on SMP and I know there is an other way to do it.

LexManos told me to look for an open source armor mod, but I just couldn't find one.

I also looked hours for a good tutorial, but I couldn't find one. So could someone tell me how to do it?

You may want to use this method, then:

RenderingRegistry.addNewArmourRendererPrefix(armor);

This works the same as the ModLoader.addArmor(armor);, so you shouldn't have any problems if it used to work.

Ok thanks. I also found another way, just have to choose which one I want to use

What is the other way, then?

Made a function in my proxy class called addArmor, which returns 0.

So like:

proxy.addArmor("armorthing")

You should make it

public static void addArmor(String s) {
    return RenderingRegistry.addNewArmourRendererPrefix(s);
}

 

Why? Because you need that particular int for something, else it wouldn't return it. I, personally, have no clue what it is used for.