fglClear(3G)

NAME
     fglClear - clear buffers to preset values


FORTRAN SPECIFICATION
     SUBROUTINE fglClear( INTEGER*4 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
     fglClear sets the bitplane area of the window to values previously
     selected by fglClearColor, fglClearIndex, fglClearDepth, fglClearStencil,
     and fglClearAccum.  Multiple color buffers can be cleared simultaneously
     by selecting more than one buffer at a time using fglDrawBuffer.

     The pixel ownership test, the scissor test, dithering, and the buffer
     writemasks affect the operation of fglClear.  The scissor box bounds the
     cleared region.  Alpha function, blend function, logical operation,
     stenciling, texture mapping, and depth-buffering are ignored by fglClear.

     fglClear 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 fglClear 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 fglClear is executed between the
     execution of fglBegin and the corresponding execution of fglEnd.
ASSOCIATED GETS
     fglGet with argument GL_ACCUM_CLEAR_VALUE
     fglGet with argument GL_DEPTH_CLEAR_VALUE
     fglGet with argument GL_INDEX_CLEAR_VALUE
     fglGet with argument GL_COLOR_CLEAR_VALUE
     fglGet with argument GL_STENCIL_CLEAR_VALUE


SEE ALSO
     fglClearAccum, fglClearColor, fglClearDepth, fglClearIndex,
     fglClearStencil, fglDrawBuffer, fglScissor