glClear — clear buffers to preset values
void glClear(
GLbitfield mask)
;
mask
Bitwise OR of masks that indicate the buffers to be cleared.
The three masks are
GL_COLOR_BUFFER_BIT
,
GL_DEPTH_BUFFER_BIT
, and
GL_STENCIL_BUFFER_BIT
.
glClear
sets the bitplane area of the window to values previously selected
by glClearColor
, glClearDepth
, and
glClearStencil
.
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_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.
glGet with argument GL_DEPTH_CLEAR_VALUE
glGet with argument GL_COLOR_CLEAR_VALUE
glGet with argument GL_STENCIL_CLEAR_VALUE
glClearColor
,
glClearDepth
,
glClearStencil
,
glColorMask,
glDepthMask,
glDrawBuffer,
glScissor,
glStencilMask
Copyright © 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see http://oss.sgi.com/projects/FreeB/.