WGL_ARB_buffer_region
http://www.opengl.org/registry/specs/ARB/wgl_buffer_region.txt
WGL_ARB_buffer_region
WGL_FRONT_COLOR_BUFFER_BIT_ARB 0x00000001
WGL_BACK_COLOR_BUFFER_BIT_ARB 0x00000002
WGL_DEPTH_BUFFER_BIT_ARB 0x00000004
WGL_STENCIL_BUFFER_BIT_ARB 0x00000008
HANDLE wglCreateBufferRegionARB (HDC hDC, int iLayerPlane, UINT uType)
VOID wglDeleteBufferRegionARB (HANDLE hRegion)
BOOL wglRestoreBufferRegionARB (HANDLE hRegion, int x, int y, int width, int height, int xSrc, int ySrc)
BOOL wglSaveBufferRegionARB (HANDLE hRegion, int x, int y, int width, int height)