Double buffering
Draw into an off-screen buffer and swap it in all at once, so the viewer never sees a half-drawn frame.
With a single framebuffer the display can read a frame while it is still being drawn, showing tearing and flicker. Double buffering keeps two: the front buffer is scanned out to the display while the back buffer is drawn, and when the frame is done the two swap.
The swap can be a pointer flip (page flipping) or a copy (a blit). Tying it to the display's vertical blank avoids tearing but can stall the GPU — triple buffering adds a third buffer so rendering never waits. The technique predates 3D; it was standard in 2D sprite hardware and remains the default anywhere pixels move.