glReadBuffer(3G) OpenGL Reference glReadBuffer(3G)NAME
glReadBuffer - select a color buffer source for pixels
C SPECIFICATION
void glReadBuffer( GLenum mode )
PARAMETERS
mode Specifies 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.
DESCRIPTION
glReadBuffer specifies a color buffer as the source for subsequent
glReadPixels, glCopyTexImage1D, glCopyTexImage2D, glCopyTexSubImage1D,
glCopyTexSubImage2D, glCopyTexSubImage3D, and glCopyPixels commands. mode
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.
mode is initially GL_FRONT in single-buffered configurations, and GL_BACK
in double-buffered configurations.
ERRORS
GL_INVALID_ENUM is generated if mode is not one of the twelve (or more)
accepted values.
GL_INVALID_OPERATION is generated if mode specifies a buffer that does
not exist.
GL_INVALID_OPERATION is generated if glReadBuffer is executed between the
execution of glBegin and the corresponding execution of glEnd.
ASSOCIATED GETS
glGet with argument GL_READ_BUFFER
SEE ALSO
glCopyPixels, glCopyTexImage1D, glCopyTexImage2D, glCopyTexSubImage1D,
glCopyTexSubImage2D, glCopyTexSubImage3D, glDrawBuffer, glReadPixels
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