NAME

glClear - clear buffers to preset values

C SPECIFICATION

void ggllCClleeaarr( GLbitfield _m_a_s_k )

        

PARAMETERS

_m_a_s_k
Bitwise OR of masks that indicate the buffers to be cleared. The four masks are GGLL__CCOOLLOORR__BBUUFFFFEERR__BBIITT, GGLL__DDEEPPTTHH__BBUUFFFFEERR__BBIITT, GGLL__AACCCCUUMM__BBUUFFFFEERR__BBIITT, and GGLL__SSTTEENNCCIILL__BBUUFFFFEERR__BBIITT.

DESCRIPTION

ggllCClleeaarr sets the bitplane area of the window to values previously selected by ggllCClleeaarrCCoolloorr, ggllCClleeaarrIInnddeexx, ggllCClleeaarrDDeepptthh, ggllCClleeaarrSStteenncciill, and ggllCClleeaarrAAccccuumm. Multiple color buffers can be cleared simultaneously by selecting more than one buffer at a time using ggllDDrraawwBBuuffffeerr.

The pixel ownership test, the scissor test, dithering, and the buffer writemasks affect the operation of ggllCClleeaarr. The scissor box bounds the cleared region. Alpha function, blend function, logical operation, stenciling, texture mapping, and depth-buffering are ignored by ggllCClleeaarr.

ggllCClleeaarr takes a single argument that is the bitwise OR of several values indicating which buffer is to be cleared.

The values are as follows:

GGLL__CCOOLLOORR__BBUUFFFFEERR__BBIITT
Indicates the buffers currently enabled for color writing.
GGLL__DDEEPPTTHH__BBUUFFFFEERR__BBIITT
Indicates the depth buffer.
GGLL__AACCCCUUMM__BBUUFFFFEERR__BBIITT
Indicates the accumulation buffer.
GGLL__SSTTEENNCCIILL__BBUUFFFFEERR__BBIITT
Indicates the stencil buffer.

The value to which each buffer is cleared depends on the setting of the clear value for that buffer.

NOTES

If a buffer is not present, then a ggllCClleeaarr directed at that buffer has no effect.

ERRORS

GGLL__IINNVVAALLIIDD__VVAALLUUEE is generated if any bit other than the four defined bits is set in _m_a_s_k.

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

ASSOCIATED GETS

ggllGGeett with argument GGLL__AACCCCUUMM__CCLLEEAARR__VVAALLUUEE
ggllGGeett with argument GGLL__DDEEPPTTHH__CCLLEEAARR__VVAALLUUEE
ggllGGeett with argument GGLL__IINNDDEEXX__CCLLEEAARR__VVAALLUUEE
ggllGGeett with argument GGLL__CCOOLLOORR__CCLLEEAARR__VVAALLUUEE
ggllGGeett with argument GGLL__SSTTEENNCCIILL__CCLLEEAARR__VVAALLUUEE

SEE ALSO

ggllCClleeaarrAAccccuumm((33GG)), ggllCClleeaarrCCoolloorr((33GG)), ggllCClleeaarrDDeepptthh((33GG)), ggllCClleeaarrIInnddeexx((33GG)), ggllCClleeaarrSStteenncciill((33GG)), ggllCCoolloorrMMaasskk((33GG)), ggllDDeepptthhMMaasskk((33GG)), ggllDDrraawwBBuuffffeerr((33GG)), ggllSScciissssoorr((33GG)), ggllSStteenncciillMMaasskk((33GG))