string = glu.ErrorString(errorCode)
glu.ErrorString() produces an error string from a GL or GLU error code. The string is in ISO Latin 1 format. For example, glu.ErrorString(#GL_OUT_OF_MEMORY)
returns the string "Out of memory".
The standard GLU error codes are #GLU_INVALID_ENUM, #GLU_INVALID_VALUE, and #GLU_OUT_OF_MEMORY. Certain other GLU functions can return specialized
error codes through callbacks. See gl.GetError for the list of GL error codes.
Please consult an OpenGL reference manual for more information.