Re: [9fans] Double buffering graphics

[rsc@plan9.bell-labs.com]

That depends on exactly what you are trying to
accomplish.

If you want double buffering in the video
memory itself, that will take some work
(like a video memory allocator).

One cheap way to do double buffering
is to just allocate two images and then
draw them onto the screen alternating
between them.

If all you want is for the user not to see
intermediate images, you could just allocate
one image, work there, and draw it to the screen
whenever it is presentable.

Writes from normal memory to video memory
are very fast.  The reverse operation is very slow
(I've seen faster 5400rpm disks).

Russ