1991-2006
Silicon Graphics, Inc.
glClear
3G
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 three masks are
GL_COLOR_BUFFER_BIT,
GL_DEPTH_BUFFER_BIT, and
GL_STENCIL_BUFFER_BIT.
Description
glClear sets the bitplane area of the window to values previously selected
by glClearColor, glClearDepthf, and
glClearStencil.
The pixel ownership test,
the scissor test,
dithering, and the buffer writemasks affect the operation of glClear.
The scissor box bounds the cleared region.
Blend function,
stenciling,
fragment shading,
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.
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 three defined
bits is set in mask.
Associated Gets
glGet with argument GL_DEPTH_CLEAR_VALUE
glGet with argument GL_COLOR_CLEAR_VALUE
glGet with argument GL_STENCIL_CLEAR_VALUE
See Also
glClearColor,
glClearDepthf,
glClearStencil,
glColorMask,
glDepthMask,
glScissor,
glStencilMask
Copyright
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/.