code: public static void glClearColor(float r, float g, float b, float a)
      {
          checkContextCompatibility();
          nglClearColor(r, g, b, a);
      }
docs: {@code glClearColor} specifies the red, green, blue, and alpha values used by {@link #glClear(int)} to clear the
  color buffers. Values specified by {@code glClearColor} are clamped to the range [0,1].
  
  @param r Specifies the red value used when the color buffers are cleared.
  @param g Specifies the green value used when the color buffers are cleared.
  @param b Specifies the blue value used when the color buffers are cleared.
  @param a Specifies the alpha value used when the color buffers are cleared.