glClear - clear buffers to preset values
GLbitfield 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.
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
The values are as follows: Indicates the buffers currently
enabled for color writing. Indicates the depth buffer.
Indicates the accumulation buffer. Indicates the stencil
The value to which each buffer is cleared depends on the
setting of the clear value for that buffer.
If a buffer is not present, then a glClear() directed at
that buffer has no effect.
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().
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
glClearAccum(3), glClearColor(3), glClearDepth(3),
glClearIndex(3), glClearStencil(3), glColorMask(3),
glDepthMask(3), glDrawBuffer(3), glScissor(3), glStencilMask(3)
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