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Does Intellivision use Sprites


daldude

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Not true, unless you are talking within the Intellivision community. My C=64 Programmer's Reference Guide called them "Movable Object Blocks," or MOBs for short. :P

I was only referring to how they were referenced in Intellivision programming circles, there is no evidence to support that they were ever called MOBs at APH, Mattel, or any place else that developed Intellivision software.

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I also found "MIBs" for moveable image blocks, from Commodore/mos specification sheets. And General Instrument called them "foreground objects".

 

FYI. In fall 1978 TI offered their chipset including the 9918 to Mattel. Mattel wanted changes and TI couldn't accomodate. At that time they would have already had games programmed with the GI chipset.

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Interesting, as I recently read about the TMS chipset was the fruit of a cooperation with Milton Bradley, but depending who you believe, TI ripped MB off. If they shortly thereafter offered the chipset to Mattel, being some sort of competitor to MB, it makes the history even more complex. But I'm sure there have been entire essays written on that elsewhere, so perhaps not much to reiterate here.

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Here's a page from an internal Mattel document. (Intellivision History and Philosophy p.5) Looks like there were thoughts of TI, Milton Bradley, and Mattel all making systems that are somewhat compatible. Cartridge compatible? Not sure. There is a story somewhere about what happened to Milton Bradley's game system. Milton Bradley did end up making TI peripherals. [That TI 9918 graphics chip is almost the same as what's in a coleco vision. Higher resolution but lacking scrolling and only four sprites per scanline. And ram requirements would have made it expensive in 1979.]

post-43287-0-77691900-1502806208_thumb.png

Edited by mr_me
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Interesting, as I recently read about the TMS chipset was the fruit of a cooperation with Milton Bradley, but depending who you believe, TI ripped MB off. If they shortly thereafter offered the chipset to Mattel, being some sort of competitor to MB, it makes the history even more complex. But I'm sure there have been entire essays written on that elsewhere, so perhaps not much to reiterate here.

Haven't found much about what happened between TI and Milton Bradley. http://atariage.com/forums/topic/248495-conflicting-versions-of-ti-history/

 

Looks like Milton Bradley had a TI-99/4 cartridge compatible game system and planned to produce cartridges for the common platform. There may have been a dispute around 1979 and TI refused to supply Milton Bradley with processors. Would be interested in more information.

Edited by mr_me
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I am particularly interested when, how and why TI began to supply their custom chips to other manufacturers, essentially going from custom to off-the-shelf items. With various systems based on TMS9918, SN76489 and either Z80 or 6502 emerging in 1981 or earlier, it would suggest to me that splitting with MB caused TI-99 chips to become too expensive to produce in small quantities so they may have offered combo deals on the VDP and PSG. Apparently GI's AY chip also appeared in various other systems, often in combination with TI's VDP but the STIC doesn't seem to have become an off-the-shelf chip in the same way as the VDP did, whether that is for technical reasons or that Mattel were able to sell far more Intellivisions at $299 than TI managed to sell the TI-99/4 at $1150, thus offsetting enough chips as it was.

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LOL, so did I! :)

 

Does the Intellivision give the programmer acess to both vertical blanks or is the CPU free during display?

I don't think this was answered yet, so let me try.

 

The Intellivision gives you access to the Vertical Retrace or Vertical Blanking (VBLANK) interrupt vector. In fact, that's the only time when the CPU has access to the video chip (STIC) and graphics RAM (GRAM).

 

When the VBLANK interrupt occurs, the CPU is interrupted, the system's state is stored into the stack, and a programmer-controlled Interrupt Service Routine (ISR) is called. At this point, there is a brief period while the raster retraces to the top of the screen, in which the program can access the graphics subsystem.

 

This restriction is only applicable during active display. If you disable display, you have free reign over the graphics subsystem. However, nothing will show on the screen. This is typically advantageous during long periods of initialization, for loading large amounts of graphic assets and setting up MOB registers, when the screen can be blanked for a few frames without any impact on gameplay.

 

This VBLANK period is divided into two phases, typically known as "VBLANK 1" and "VBLANK 2."

 

During VBLANK 1 is the only time you have access to the STIC registers. So MOB and screen mode updates must happen here. You can access GRAM throughout the entirety of VBLANK 1 and 2.

 

Unfortunately, there is no access to Horizontal Retrace, so rate of changes (and in fact, all timing) is limited to the screen refresh rate (NTSC: 60 Hz; PAL/SECAM: 50 Hz).

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  • 2 years later...
On 8/7/2017 at 7:16 PM, Carl Mueller Jr said:
It might be fun to make a list of games that do use true software sprites. Right now I can only think of Wormwhompper and He-Man.

Ice Trek (the caribou scene) and Stampede came to mind right away.  Also many of the team-based sports titles draw the players as background sprites when not actively moving.  That is most prevalent in Baseball.

 

I originally picked up the term "Moving Objects" from the ECS Owner's Manual, and I think the Mr. BASIC instruction manual as well.  It wasn't until I read a C64 programming manual that I saw the term "sprites".

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14 minutes ago, Zendocon said:

Ice Trek (the caribou scene) and Stampede came to mind right away.  Also many of the team-based sports titles draw the players as background sprites when not actively moving.  That is most prevalent in Baseball.

 

I originally picked up the term "Moving Objects" from the ECS Owner's Manual, and I think the Mr. BASIC instruction manual as well.  It wasn't until I read a C64 programming manual that I saw the term "sprites".

Can you talk more about the caribou scene in Ice Trek? The way the caribou moved in relation to the trees in the foreground/background, not to mention the player character itself... I have about 40 Intellivision games, and that is the only time I can recall seeing that type of an effect.

 

EDIT: It almost gives me a parallax scrolling type of feeling...

Edited by Intelligentleman
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In the caribou scene in Ice Trek, the sprites are used to draw the trees at different sizes and moving at different speeds to create the parallax effect, while the caribou are drawn as "background sprites".  The main character and Athena's arrows I think are sprites as well.  I'm pretty sure the floating icebergs in the Ice Bridge scene are "background sprites" too, until you hook one.

 

Same thing with Nova Blast.  Sprites are used to draw background objects to create a parallax effect, while the enemies are drawn as background cards.  It's kind of neat to look at, but I think it hurts the actual gameplay.

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  • 2 years later...
On 8/7/2017 at 5:17 AM, mr_me said:

And they didnt use the word "sprite" back in the 1970s.

TI adopted the word in 1977.

On 8/7/2017 at 3:54 PM, Carl Mueller Jr said:

Actually, they were never called MOBs back in the day. This was an abbreviation coined by Joe Z. and adopted by the homebrew community. When I initially reversed engineered the hardware back in the early 90s, I called them MOs, but for some strange reason that never caught on.

Well, "never" is probably overstating it—there was a lot of new blood coming on quickly and management wasn't sophisticated enough to appoint grammar police. Most often they were just objects or OBJs. But interestingly enough, the programming of these OBJs

involved the introduction of some object oriented thinking.
On 8/14/2017 at 9:59 AM, DZ-Jay said:

You'd have to ask one of the old Intellivision programmers if they had a shortened name for "moveable objects".

Check out Your Friend the Exec and trivia.asm. You'll find many instances of the word "object" and a lot of identifiers with the letters OBJ in their names.

On 8/15/2017 at 6:36 AM, carlsson said:

I recently read about the TMS chipset was the fruit of a cooperation with Milton Bradley, but depending who you believe, TI ripped MB off. If they shortly thereafter offered the chipset to Mattel, being some sort of competitor to MB, it makes the history even more complex.

MB wasn't ripped off. Like GI, TI was always out to make an industry standard part available to all comers, and Milton Bradley's management was fully aware of that fact. TI was hoping that MB and then Mattel would be the first two of many, many customers. While Mattel was evaluating the chip it asked for some changes, knowing fully that TI would make those changes available to any subsequent purchasers. The best either MB or Mattel could negotiate was a short period of exclusivity.

On 8/17/2017 at 1:31 PM, DZ-Jay said:

Unfortunately, there is no access to Horizontal Retrace, so rate of changes (and in fact, all timing) is limited to the screen refresh rate (NTSC: 60 Hz; PAL/SECAM: 50 Hz).

During horizontal retrace the STIC is rather busy loading up the object shift registers from GRAM.

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