Sprites

A discussion of sprites-and-tiles video generators used, e.g., in the TI-99/4a home computer, Colecovision, and the Nintendo Entertainment System.
EDIT: I meant to say Pac Man has a total of 4096 bytes of memory not 496 bytes
See www.cs.columbia.edu/~sedwards/... for the slides and more information

[@user-yr1uq1qe6y]

I remember programming sprites on the c64 and c128. This is a good explanation to introduce the what and why. warning for headphone users: there are some audio pops, clicks, and buzzes that murdered my ears. not too many, but they'll get your attention!

[@manuelb636]

Your videos are exactly what I like to see in technology videos. Thanks a lot, keep doing them. ❤

[@54egg]

Hello Steve, I am here watching your video because yesterday I had one of the co-patent holders for the TMS9918, Dave Ackley, sitting in my office. Dave is 87 years old and spoke about the 9918 like I would speak about a project I worked on last year. It was 45 years ago for the 9918. Dave coined the term "sprite" with respect to its use in computer graphics. Considering his name is first on the patent, I believe him! He described how the sprites were implemented and also the circuitry that encoded the NTSC video in pretty clear detail close to what I read later in the patent. To think at the same time (late 70's) I was struggling with trying to understand simple raster-scan timing chains, having to rely on mostly other people's designs (I was 15 years old) while Dave was 20 miles away building state-of-the art graphics chips. At the time if I had a little more design savvy, I would have been pushing for line drawing acceleration and possibly area filling hardware vs sprites, but I am sure would have taken more than the 1000 transistors OR so of the 9918 to implement.

[@stephen70edwards]

Did Dave know about the line buffer approach that was being used in video arcade games? What does he know about how the 9918 technology ended up in the Nintendo Famicom/NES?

[@54egg]

@@stephen70edwards I will have to ask him. If I have it right about line buffer system (looking at patent #US4398189A), looks like higher resolution (supporting interlace and 2X horizontal resolution of 9918), oriented toward frame-rate animation and 16 color (on 4096 color palette) foreground and background colors where background is limited to dictionary of blocks, allowing for composite multi-block patterns, similar to foreground. I am guessing this system is ultimately more complex and would not have been able to be placed on a single chip. Also, I assume memory bandwidth was much more limited in 9918 system. That is just me talking, and I am not a video graphics system designer. // I will ask about Nintendo...

[@54egg]

@@stephen70edwards From Dave: Unfortunately that was a very long time ago, being last century. :} So I’m not sure what all we knew about the arcade technology of that era. I think that filling the screen using tiles was well know at that time and was the basis of the TMS9918’s background. My part of the #4,243,984 patent invention was the concept of a “sprite” and giving it it’s name. This patent was submitted on March 8, 1979, issued January 6, 1981, and references some 14 other patents My sprite concept was to use/extend the basic graphic tile concept to allow the quick/fine moving of a set of tiles as sprites. I also knew that it was important to come up with a good name for these beasts and I came up with the idea of calling them “sprites”. I picked this name because sprites can appear/disappear, jump around, and take different forms. The reason for the 4 sprites per line and total of 31/32 sprites was a silicon size limitation. By the way, there was a sprite attribute that allowed it to be a doubled in size (i.e. 16x16 rather than just 8x8) by doubling each pixel horizontally and vertically. At the time we described the technology in terms of a stage (the tiled background) with the sprites being actors that passed in front of each other on the stage I really don’t recall anything about how Nintendo or the Amiga computer came about using the TM9918 Sprite concept/technology. Dave

[@mariposagoldenboy1]

Cool Video!

[@hernancoronel]

At 0:46 you meant 4 THOUSAND and 96 bytes, thanks for the video!

[@kraftwerk974]

Great explanation ! Thank you. Though I'm familiar with the C64 VIC II chip not the TI one. When it comes to coding the important thing is precise refresh timing with raster lines to avoid glittering. It would be interesting if you could make a similar video on how sprites were coded when there weren't hardware sprites (VIC 20 for instance).

[@AdMC347]

Solid production value!

[@activex7327]

4k = 4096 not 496