'\" e '\"! eqn | mmdoc '\"macro stdmacro .ds Vn Version 1.2 .ds Dt 24 September 1999 .ds Re Release 1.2.1 .ds Dp Jan 14 18:30 .ds Dm 01 readbuffe .ds Xs 2004 4 readbuffer.gl .TH GLREADBUFFER 3G .SH NAME .B "glReadBuffer \- select a color buffer source for pixels .SH C SPECIFICATION void \f3glReadBuffer\fP( GLenum \fImode\fP ) .nf .fi .SH PARAMETERS .TP \w'\f2mode\fP\ \ 'u \f2mode\fP Specifies a color buffer. Accepted values are \%\f3GL_FRONT_LEFT\fP, \%\f3GL_FRONT_RIGHT\fP, \%\f3GL_BACK_LEFT\fP, \%\f3GL_BACK_RIGHT\fP, \%\f3GL_FRONT\fP, \%\f3GL_BACK\fP, \%\f3GL_LEFT\fP, \%\f3GL_RIGHT\fP, and \%\f3GL_AUX\fP\f2i\fP, where \f2i\fP is between 0 and \%\f3GL_AUX_BUFFERS\fP \-1. .SH DESCRIPTION \%\f3glReadBuffer\fP specifies a color buffer as the source for subsequent \%\f3glReadPixels\fP, \%\f3glCopyTexImage1D\fP, \%\f3glCopyTexImage2D\fP, \%\f3glCopyTexSubImage1D\fP, \%\f3glCopyTexSubImage2D\fP, \%\f3glCopyTexSubImage3D\fP, and \%\f3glCopyPixels\fP commands. \f2mode\fP accepts one of twelve or more predefined values. (\%\f3GL_AUX0\fP through \%\f3GL_AUX3\fP are always defined.) In a fully configured system, \%\f3GL_FRONT\fP, \%\f3GL_LEFT\fP, and \%\f3GL_FRONT_LEFT\fP all name the front left buffer, \%\f3GL_FRONT_RIGHT\fP and \%\f3GL_RIGHT\fP name the front right buffer, and \%\f3GL_BACK_LEFT\fP and \%\f3GL_BACK\fP name the back left buffer. .P 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 \%\f3glReadBuffer\fP. .P \f2mode\fP is initially \%\f3GL_FRONT\fP in single-buffered configurations, and \%\f3GL_BACK\fP in double-buffered configurations. .SH ERRORS \%\f3GL_INVALID_ENUM\fP is generated if \f2mode\fP is not one of the twelve (or more) accepted values. .P \%\f3GL_INVALID_OPERATION\fP is generated if \f2mode\fP specifies a buffer that does not exist. .P \%\f3GL_INVALID_OPERATION\fP is generated if \%\f3glReadBuffer\fP is executed between the execution of \%\f3glBegin\fP and the corresponding execution of \%\f3glEnd\fP. .SH ASSOCIATED GETS \%\f3glGet\fP with argument \%\f3GL_READ_BUFFER\fP .SH SEE ALSO \%\f3glCopyPixels(3G)\fP, \%\f3glCopyTexImage1D(3G)\fP, \%\f3glCopyTexImage2D(3G)\fP, \%\f3glCopyTexSubImage1D(3G)\fP, \%\f3glCopyTexSubImage2D(3G)\fP, \%\f3glCopyTexSubImage3D(3G)\fP, \%\f3glDrawBuffer(3G)\fP, \%\f3glReadPixels(3G)\fP