over-color.clj

(defn over-color ^Color [^Color a
                         ^Color b]
  (let [^Vector4 a (v4 (.r a) (.g a) (.b a) (.a a))
        ^Vector4 b (v4 (.r b) (.g b) (.b b)  (.a b))
        c (Vector4/op_Addition
            (Vector4/op_Multiply a (float (.w a)))
            (Vector4/op_Multiply
              (Vector4/op_Multiply b (float (.w b)))
              (- 1 (.w a))))
        blend (+ (.w a)
                (* (.w b)
                  (- 1 (.w a))))]
    (Color. (.x c) (.y c) (.z c) blend)))