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

     SEE ALSO
	  glClearAccum,	glClearColor, glClearDepth, glClearIndex,
	  glClearStencil, glDrawBuffer,	glScissor