Graphics.GL.Low.Error

If you issue an invalid GL command or run out of memory, the GL implementation may set an internal flag indicating that an error has occurred. You can query this flag (getGLError) to see if something went wrong with a previous command. If you ignore errors, chances are nothing will happen except perhaps some rendering weirdness. However checking this periodically is a good idea, perhaps once per frame, because it might indicate a bug in your code.

Documentation

data GLError

Detectable errors.

Constructors

InvalidEnum

Enum argument out of range.

InvalidValue

Integer argument out of range.

InvalidOperation

Operation illegal in current state.

InvalidFramebufferOperation

Framebuffer is not complete.

OutOfMemory

Instances

Show GLError

Exception GLError

getGLError :: IO (Maybe GLError)

Check for a GL Error. This call has the semantics of a dequeue. If an error is returned, then calling getGLError again may return more errors that have "stacked up." When it returns Nothing then there are no more errors to report. An error indicates that a bug in your code caused incorrect ussage of the API or that the implementation has run out of memory.

It has been suggested that using this after every single GL command may adversely affect performance (not to mention be very tedious). Since there is no reasonable way to recover from a GL error, a good idea might be to check this once per frame or even less often, and respond with a core dump.

assertNoGLError :: IO ()

Throws an exception if getGLError returns non-Nothing.