nanogui: Are we allowed to mandate GrFlush()?
Subject:
Re: [nanogui] Are we allowed to mandate GrFlush()?
From:
"Greg Haerr" ####@####.####
Date:
7 Aug 2001 16:14:02 -0000
Message-Id: <012c01c11f5b$a0582220$3aba46a6@xmission.com>
: > In any case, a GrFlush would be probably unnessesary, as a simple program
: > wouldn't really care if there are a few microseconds between drawing
: > operations, and the buffered programs would have already taken it all into
: > consideration.
:
: Well, if it were only a few microseconds then I would agree; the problem is
: that
: the copy operation from the draw buffer to the screen buffer is a little more
: involved
: than just a copy (I can't really get into the details, unfortunately, for IP
: reasons)
: and whenever it's called it may take many milliseconds to do -- so I really
: don't
: want to invoke it on every graphics operation, which is why I want to do it
: during
: the GrFlush() call, if I'm allowed to demand that the user make that call.
First, GrFlush() doesn't cause the draw buffer to be copied to the
screen buffer. Instead, it writes a few bytes from the client down
the pipe to the server, which are then interpreted, which then
result in possible drawing/clipping. Second, this client-side command
buffer is flushed automatically whenever the user executes a GrXXX
call that requires a return value, that is, when any GrXXX non-void
function is called. Finally, GrFlush is called whenever GrGetNextEvent
is called, which in most programs is after every draw operation.
So GrFlush isn't necessary, whether mandated or not.
Regards,
Greg
