How can I make configoration file so I can change the value of a float? The float changes the color of something in game.

use a double and cast it to a float

How would i do this in the code?

I dunno how the forge config works, but something like

float red = (float)config.getDouble("red");

 

how to you make double in the config file?

Use config.get(category, key, defaultValue) with arguments String, string, double.

To add a float in a custom configuration file you need to do this:

 

//Using f1 as the float name.
float f1 = Float.parseFloat(config.get(Configuration.CATEGORY_GENERAL, "changetoanything", ""+3.14F).getValue());
//This basically adds 3.14 to the thing you enter.

To add a float in a custom configuration file you need to do this:

 

//Using f1 as the float name.
float f1 = Float.parseFloat(config.get(Configuration.CATEGORY_GENERAL, "changetoanything", ""+3.14F).getValue());
//This basically adds 3.14 to the thing you enter.

That works as long as the value is a valid float, but I do not recommend it - it will crash with non-numeric input and is very prone to decimal point errors.