glReadBuffer
[New
- Windows 95, OEM Service Release 2]
The glReadBuffer
function selects a color buffer source for pixels.
void glReadBuffer(
|
GLenum mode |
|
|
); |
|
Parameters
mode
A color
buffer. Accepted values are GL_FRONT_LEFT, GL_FRONT_RIGHT, GL_BACK_LEFT,
GL_BACK_RIGHT, GL_FRONT, GL_BACK, GL_LEFT, GL_RIGHT, and GL_AUXi, where i
is between 0 and GL_AUX_BUFFERS -1.
Remarks
The glReadBuffer
function specifies a color buffer as the source for subsequent glReadPixels and glCopyPixels commands. The mode
parameter accepts one of twelve or more predefined values. (GL_AUX0 through
GL_AUX3 are always defined.) In a fully configured system, GL_FRONT, GL_LEFT,
and GL_FRONT_LEFT all name the front-left buffer, GL_FRONT_RIGHT and GL_RIGHT
name the front-right buffer, and GL_BACK_LEFT and GL_BACK name the back-left
buffer.
Nonstereo
double-buffered configurations have only a front-left and a back-left buffer.
Single-buffered configurations have a front-left and a front-right buffer if
stereo, and only a front-left buffer if nonstereo. It is an error to specify a
nonexistent buffer to glReadBuffer.
By default, mode
is GL_FRONT in single-buffered configurations, and GL_BACK in double-buffered
configurations.
The following
function retrieves information related to glReadBuffer:
glGet
with argument GL_READ_BUFFER
Error Codes
The following
are the error codes generated and their conditions.
|
Error
Code |
Condition |
|
GL_INVALID_ENUM
|
mode was not one of the twelve (or more) accepted
values. |
|
GL_INVALID_OPERATION
|
mode specified a buffer that does not exist. |
|
GL_INVALID_OPERATION
|
glReadBuffer was called between a call to glBegin and the
corresponding call to glEnd. |
See Also