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From: fdfishman@watcgl.UUCP
Newsgroups: comp.sys.amiga
Subject: Rapid Stimulus Displaying on the Amiga Help
Message-ID: <912@watcgl.UUCP>
Date: Sat, 18-Apr-87 12:27:42 EST
Article-I.D.: watcgl.912
Posted: Sat Apr 18 12:27:42 1987
Date-Received: Sun, 19-Apr-87 02:54:43 EST
Distribution: comp
Organization: U of Waterloo, Ontario
Lines: 60
Keywords: Fast, Screen, Window, RastPort, etc displays

Hi, 
 It is me again.  I am still doing some work creating psychology experiments
 for the university, as part of the experiments I have several questions.

 1)In most of the experiments we want to be able to display multiple stimulus
 "instantly" (by instantly I mean that the image is presented in one screen
 refresh, 16 milliseconds).  We were originally drawing the stimulus on
 different screens (the stimulus is generally 4 bits) and then doing a
 ScreenToFront() and this appears to work fine, however, we did some timing
 experiments and noticed that of we started a timer, did a ScreenToFront(Scr),
 and then recorded the time we got variable times.
	i.e.
		for (loop = 0; loop < 100; loop++)
			{
			Start8520Timer();
			ScreenToFront(Scr);
			Time[loop] = Get8520Time();
			Stop8520Timer();
			}
 The times were something like 0, 16 (acceptable), 21, 42, and sometimes
 really large numbers.  On further testing we noticed that if we replace the
 ScreenToFront() with WaitTOF() we get the same results (makes sense since
 ScreenToFront() calls WaitTOF() ) but we noticed that if we did a
 WaitBOVP(Scr) we got a nice constant 0 or 16 ms (which is good).  Further we
 tried using both the 8520A and the 8520B chips to do the timing (we
 require a ms grain).  Now my question is, what is not working, the timer
 routine or WaitTOF() and can either be fixed.

 2)We also tried to use the WindowToFront(), but this does not appear to be
 "Instant", since we could see each plane get copied, and we get a fade in
 effect (I actually like the effect but for an experiment it does not work), I
 figured that I could solve this problem by defining the windows as
 SuperBitMap windows, but alas, it works for small windows, but for larger
 windows we still see see the fade in (It might be noted that I still have
 free chipmemory after opening all the windows).  So my question is, is it
 possible to make a Window raise "instantly"?  Also on this note I noticed
 that when you do a WindowToFront it returns within a ms, is this because a
 WindowToFront is done in the background?

 3)Something else we played with was to exchange pointers, so we tried
 exchanging, bitmaps, rasterports, viewports, of screens and windows, but
 could not seem to get the displayed data to change, is it possible to do a
 screen to front in this manner?  And if so how?

As a note: we tried putting Forbids() and Disables() all through the code with
	not changed results.
	-The timer is the same one I posted to the net half a year ago.

-----------------------------------------------------------------------------
Now on a personal note, Leo posted a program called ing to the net awhile ago
which required a program heapmem.o to compile, what is heapmem and where could
I find a copy of it.

And since I am here anyways, I would like to thank everyone on the net for the
information and the toys that have been posted on the net.
-- 
FDFISHMAN (Flynn D. Fishman) @ WATCGL (but you can call me Flynn)
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