C
glClear
Chapter 3
50
glClear
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.
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