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From: scott@applix.UUCP (Scott Evernden)
Newsgroups: comp.sys.amiga
Subject: Re: Rapid Stimulus Displaying on the Amiga Help
Message-ID: <446@applix.UUCP>
Date: Thu, 23-Apr-87 10:47:57 EST
Article-I.D.: applix.446
Posted: Thu Apr 23 10:47:57 1987
Date-Received: Sat, 25-Apr-87 10:04:33 EST
References: <912@watcgl.UUCP>
Reply-To: scott@applix.UUCP (Scott Evernden)
Distribution: comp
Organization: APPLiX Inc., Westboro MA
Lines: 43

In article <912@watcgl.UUCP> fdfishman@watcgl.UUCP writes:
> 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...

	In addition to Matt's color-map tricks, you may want to try some
	"double-buffering" techniques.  The idea is to create a new View
	(InitView), and then swap in the new View (LoadView) between frames.
	Max. delay would be also be until the next video frame is scanned
	(1/60 sec).  Examples of this code can be found in the Rom Kernel
	Manual, else I can post a fragment.

And, while I'm here, some more terminology:

> video gate array
	Or, VGA, is the name of the "graphics processor" found on
	the new IBM PS/2 series pcs.  The VGA provides several display
	modes for these pcs, but doesn't include a blitter or other
	high speed rendering hardware.

> blitter
	A device which can perform a "bitblt" (bit-blit) operation.
	The classic bitblt (or "rasterop") merges a source rectangle
	of graphics memory, to a destination area of graphics memory,
	with control of boolean operations, and possible including a
	"halftone" bitmap for shading, etc.  The Amiga's blitter
	generalizes this and provides a 3 source bitblt operation.
	I believe the Amiga's blitter is called a "bimmer" by
	Jay Miner (designer of chips in Amiga), meaning "bit image
	mover" (?)

> copper
	In addition to WAIT, and MOVE, the Amiga copper can SKIP -
	making it a 3 instruction processor.  A qualifier on these
	instructions allow the copper to note if the blitter is busy
	while WAITing.  Also the copper can wait for a beam position
	ANDed with a mask, allowing it to WAIT for a combination of
	scan positions.  The Amiga's copper makes possible the Amiga's:
		1) sliding multi-screen capability
		2) color map changes in mid screen
		3) animation system's control of Vsprites
	No one has yet fully exploited the power of this simple yet
	versatile device.