GL_INVALID_OPERATION

Quoted from the MSDN :

glGetError
The glGetError function returns error information.

GLenum glGetError(
void
);

Remarks
The glGetError function returns the value of the error flag. Each detectable error is assigned a numeric code and symbolic name. When an error occurs, the error flag is set to the appropriate error code value. No other errors are recorded until glGetError is called, the error code is returned, and the flag is reset to GL_NO_ERROR. If a call to glGetError returns GL_NO_ERROR, there has been no detectable error since the last call to glGetError, or since OpenGL was initialized.

To allow for distributed implementations, there may be several error flags. If any single error flag has recorded an error, the value of that flag is returned and that flag is reset to GL_NO_ERROR when glGetError is called. If more than one flag has recorded an error, glGetError returns and clears an arbitrary error flag value. If all error flags are to be reset, you should always call glGetError in a loop until it returns GL_NO_ERROR.

Initially, all error flags are set to GL_NO_ERROR.

The following are the currently defined errors:

GL_NO_ERROR
No error has been recorded. The value of this symbolic constant is guaranteed to be zero.

GL_INVALID_ENUM
An unacceptable value is specified for an enumerated argument. The offending function is ignored, having no side effect other than to set the error flag.

GL_INVALID_VALUE
A numeric argument is out of range. The offending function is ignored, having no side effect other than to set the error flag.

GL_INVALID_OPERATION
The specified operation is not allowed in the current state. The offending function is ignored, having no side effect other than to set the error flag.

GL_STACK_OVERFLOW
This function would cause a stack overflow. The offending function is ignored, having no side effect other than to set the error flag.

GL_STACK_UNDERFLOW
This function would cause a stack underflow. The offending function is ignored, having no side effect other than to set the error flag.

GL_OUT_OF_MEMORY
There is not enough memory left to execute the function. The state of OpenGL is undefined, except for the state of the error flags, after this error is recorded.
When an error flag is set, results of an OpenGL operation are undefined only if GL_OUT_OF_MEMORY has occurred. In all other cases, the function generating the error is ignored and has no effect on the OpenGL state or frame buffer contents.

Error Codes
The following are the error codes generated and their conditions.

Error Code Condition
GL_INVALID_OPERATION glGetError was called between a call to glBegin and the corresponding call to glEnd.


QuickInfo
Windows NT: Use version 3.5 and later.
Windows: Use Windows 95 and later.
Windows CE: Unsupported.
Header: Declared in gl.h.
Import Library: Link with opengl32.lib.

See Also
glBegin, glEnd

Edited by - Prosper/LOADED on March 2, 2001 2:05:20 PM

Last time I ran into that error I made a OpenGL call before I had a context. I put a texture loading routine in the constructor for my window class. Not smart.

The fanatic is incorruptible: if he kills for an idea, he can just as well get himself killed for one; in either case, tyrant or martyr, he is a monster.
--EM Cioran

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