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 se‐
       lected 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 ex‐
       ecution 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