glClear
The glClear function clears buffers to preset values.
glClear( mask );
Arguments mask
The four masks are the following OpenGL constants.
Mask Buffer to be Cleared
GL_COLOR_BUFFER_BIT The buffers currently enabled for color writing.
GL_DEPTH_BUFFER_BIT The depth buffer.
GL_ACCUM_BUFFER_BIT The accumulation buffer.
GL_STENCIL_BUFFER_BIT The stencil buffer.
Remarks
The glClear function sets the bitplane area of the window to values previously selected by ClearColor, glClearIndex, ClearDepth, glClearStencil, and glClearAccum.