NAME

glReadBuffer - select a color buffer source for pixels

C SPECIFICATION

void ggllRReeaaddBBuuffffeerr( GLenum _m_o_d_e )

        

PARAMETERS

_m_o_d_e
Specifies a color buffer. Accepted values are GGLL__FFRROONNTT__LLEEFFTT, GGLL__FFRROONNTT__RRIIGGHHTT, GGLL__BBAACCKK__LLEEFFTT, GGLL__BBAACCKK__RRIIGGHHTT, GGLL__FFRROONNTT, GGLL__BBAACCKK, GGLL__LLEEFFTT, GGLL__RRIIGGHHTT, and GGLL__AAUUXX_i, where _i is between 0 and GGLL__AAUUXX__BBUUFFFFEERRSS -1.

DESCRIPTION

ggllRReeaaddBBuuffffeerr specifies a color buffer as the source for subsequent ggllRReeaaddPPiixxeellss, ggllCCooppyyTTeexxIImmaaggee11DD, ggllCCooppyyTTeexxIImmaaggee22DD, ggllCCooppyyTTeexxSSuubbIImmaaggee11DD, ggllCCooppyyTTeexxSSuubbIImmaaggee22DD, ggllCCooppyyTTeexxSSuubbIImmaaggee33DD, and ggllCCooppyyPPiixxeellss commands. _m_o_d_e accepts one of twelve or more predefined values. (GGLL__AAUUXX00 through GGLL__AAUUXX33 are always defined.) In a fully configured system, GGLL__FFRROONNTT, GGLL__LLEEFFTT, and GGLL__FFRROONNTT__LLEEFFTT all name the front left buffer, GGLL__FFRROONNTT__RRIIGGHHTT and GGLL__RRIIGGHHTT name the front right buffer, and GGLL__BBAACCKK__LLEEFFTT and GGLL__BBAACCKK 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 ggllRReeaaddBBuuffffeerr.

_m_o_d_e is initially GGLL__FFRROONNTT in single-buffered configurations, and GGLL__BBAACCKK in double-buffered configurations.

ERRORS

GGLL__IINNVVAALLIIDD__EENNUUMM is generated if _m_o_d_e is not one of the twelve (or more) accepted values.

GGLL__IINNVVAALLIIDD__OOPPEERRAATTIIOONN is generated if _m_o_d_e specifies a buffer that does not exist.

GGLL__IINNVVAALLIIDD__OOPPEERRAATTIIOONN is generated if ggllRReeaaddBBuuffffeerr is executed between the execution of ggllBBeeggiinn and the corresponding execution of ggllEEnndd.

ASSOCIATED GETS

ggllGGeett with argument GGLL__RREEAADD__BBUUFFFFEERR

SEE ALSO

ggllCCooppyyPPiixxeellss((33GG)), ggllCCooppyyTTeexxIImmaaggee11DD((33GG)), ggllCCooppyyTTeexxIImmaaggee22DD((33GG)), ggllCCooppyyTTeexxSSuubbIImmaaggee11DD((33GG)), ggllCCooppyyTTeexxSSuubbIImmaaggee22DD((33GG)), ggllCCooppyyTTeexxSSuubbIImmaaggee33DD((33GG)), ggllDDrraawwBBuuffffeerr((33GG)), ggllRReeaaddPPiixxeellss((33GG))