-extern const float FULLY_OPAQUE; ///< Alpha values must drop below this, before an object is considered to be transparent.
-extern const float FULLY_TRANSPARENT; ///< Alpha values must rise above this, before an object is considered to be visible.
+static constexpr float FULLY_OPAQUE(0.99f); ///< Alpha values must drop below this, before an object is considered to be transparent.
+static constexpr float FULLY_TRANSPARENT(0.01f); ///< Alpha values must rise above this, before an object is considered to be visible.