code: public void setBackgroundColor(float r, float g, float b, float a) {
          setBackgroundColorR(r);
          setBackgroundColorG(g);
          setBackgroundColorB(b);
          setBackgroundColorA(a);
      }
docs: Sets the background color of the scene rendered by this camera.
  
  If you don't set the background color, the default is an opaque black.
  Meaningful parameter values are from 0 to 1, inclusive: values
  {@literal < 0} are clamped to 0; values {@literal > 1} are clamped to 1.