Speedup of rotated screen
Staffan Ulfberg
staffanu+xorg at multivac.fatburen.org
Thu Sep 22 03:00:53 PDT 2005
Matthieu Herrb <matthieu.herrb at laas.fr> writes:
> > I have been hacking a bit on getting the code that blits a rotated
> > shadow onto the display a bit faster and came up with the patch
> > available at https://bugs.freedesktop.org/show_bug.cgi?id=4537
> We also need some tests on other platforms to make sure it doesn't
> create a regression with some other drivers that support rotation.
I have a question myself about the original code: This is the function
call to get the address in the destination frame buffer to write to:
win = (FbBits *) (*pBuf->window) (pScreen,
scr_y,
scr_x << 2,
SHADOW_WINDOW_WRITE,
&winSize,
pBuf->closure);
The "scr_x << 2" part seems, to me, to assume that
sizeof(FbBits) == 4. Am I missing something, or is this really
correct? Anyway, my patch does not make this problem either better
or worse.
Staffan
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