gutfreund%umass-cs.csnet@CSNET-RELAY.ARPA (10/29/85)
From: "Steven H. Gutfreund" <gutfreund%umass-cs.csnet@CSNET-RELAY.ARPA> Could someone explain to me how do the various hardware features on the Amiga (like sprites) improve its performance for doing animations? What is speciffically (from a hardware viewpoint) the advantage of the sprite hardware, over a traditional RastorOp machinery (compare it to something like Bechtolsheim's SUN implementation, with the data and address lines both being used simultaneously to pump data to the RastorOp board and improve through-put). Is there any other animation hardware on the graphics board that is interesting? - Steve Gutfreund gutfreund@umass.csnet
gnu@l5.uucp (John Gilmore) (10/30/85)
In article <270@caip.RUTGERS.EDU>, Steven H. Gutfreund writes: > What is speciffically (from a hardware viewpoint) the advantage of the > sprite hardware, over a traditional RastorOp machinery (compare > it to something like Bechtolsheim's SUN implementation... A sprite is a little bitmap which can be moved to anywhere on the screen by doing one or two writes. In the Amiga, a sprite is a vertical slice 16 bits wide, 2 bits deep, and as tall as you like. It doesn't reside in the screen memory, but is fetched separately by a little DMA unit. The sprite hardware is running at the same time as the main display, and the two bit-streams are combined on their way to the monitor. This means you can paint a "scene" in the screen memory, move that (pan around) and have "characters" moving on it, all without doing any RasterOps. The effective "RasterOps" are done on the video bit streams, on the fly, not on the video image in RAM. This is great if you are building a rock-shooting game machine, and you could use it for the mouse cursor and such in a window system. It's not clear to me whether it helps much outside those circumstances, though. > Is there any other > animation hardware on the graphics board that is interesting? There's lots of interesting complicated hardware in the Amiga, and I'm sure at least 10 or 20 people will figure it all out and write some superb games. As a general purpose computer it's kind of been warped by the game mentality though -- e.g. sprites and missiles work well, but not 80-col text unless you get a non-standard monitor. Caveat: I've just read the hardware specs and followed this newsgroup, I haven't hacked on the machine. (My efforts will go toward Atari if anywhere.)