next up previous
Next: Graphics Subsystem Bottlenecks Up: Hardware for Window Previous: Fast and Arbitrary

Hardware Cursors

Window systems use cursors to track mouse motion. A hardware cursor means the hardware provides special support for merging the current cursor image at the current cursor location into the displayed frame buffer image. If a hardware cursor is not supported, the X server must draw the cursor image into the frame buffer. When rendering near or under a software rendered cursor, the cursor must be undrawn and redrawn between rendering commands. Not only does this result in a flickering cursor, but it means programs rendering to the hardware must know the cursor location to correctly draw and undraw the cursor. This greatly complicates 3D rendering, so hardware cursors are extremely common for accelerated OpenGL graphics hardware.



mjk@sgi.com