public ColorRGBA addLocal(ColorRGBA c) {
        set(c.r + r, c.g + g, c.b + b, c.a + a);
        return this;
    }
Adds each component to the corresponding component of the argument
and returns the result (this).
Used as a way of combining colors and lights.

@param c The color to add.
@return this+c
jme3-core/src/main/java/com/jme3/math/ColorRGBA.java