Интерактивная система просмотра системных руководств (man-ов)
glClear (3)
>> glClear (3) ( Разные man: Библиотечные вызовы )
NAME
glClear
- clear buffers to preset values
C SPECIFICATION
void glClear(
GLbitfield mask )
PARAMETERS
mask
Bitwise OR of masks that indicate the buffers to be cleared.
The four masks are
GL_COLOR_BUFFER_BIT,
GL_DEPTH_BUFFER_BIT,
GL_ACCUM_BUFFER_BIT, and
GL_STENCIL_BUFFER_BIT.
DESCRIPTION
glClear sets the bitplane area of the window to values previously selected
by glClearColor, glClearIndex, glClearDepth,
glClearStencil, and glClearAccum.
Multiple color buffers can be cleared simultaneously by selecting
more than one buffer at a time using glDrawBuffer.
The pixel ownership test,
the scissor test,
dithering, and the buffer writemasks affect the operation of glClear.
The scissor box bounds the cleared region.
Alpha function,
blend function,
logical operation,
stenciling,
texture mapping,
and depth-buffering are ignored by glClear.
glClear takes a single argument that is the bitwise OR of several
values indicating which buffer is to be cleared.
The values are as follows:
GL_COLOR_BUFFER_BIT
Indicates the buffers currently enabled for color
writing.
GL_DEPTH_BUFFER_BIT
Indicates the depth buffer.
GL_ACCUM_BUFFER_BIT
Indicates the accumulation buffer.
GL_STENCIL_BUFFER_BIT
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 glClear directed at that buffer has no effect.
ERRORS
GL_INVALID_VALUE is generated if any bit other than the four defined
bits is set in mask.
GL_INVALID_OPERATION is generated if glClear
is executed between the execution of glBegin
and the corresponding execution of glEnd.
ASSOCIATED GETS
glGet with argument GL_ACCUM_CLEAR_VALUE glGet with argument GL_DEPTH_CLEAR_VALUE glGet with argument GL_INDEX_CLEAR_VALUE glGet with argument GL_COLOR_CLEAR_VALUE glGet with argument GL_STENCIL_CLEAR_VALUE
