gl.Finish()
gl.Finish()
does not return until the effects of all previously called GL commands are complete. Such effects
include all changes to GL state, all changes to connection state, and all changes to the frame buffer contents.
gl.Finish()
requires a round trip to the server.
Please consult an OpenGL reference manual for more information.
#GL_INVALID_OPERATION
is generated if gl.Finish()
is executed between the execution of gl.Begin() and the corresponding execution of gl.End() .