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The Intellivision Virtual Expo 2020 - MAIN EVENT Nov 21 2020


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Text of my talk. Apparently my audio was a little low.

 

State-of-the-art Game Development for Intellivision
By Oscar Toledo G. https://nanochess.org/
Nov/19/2020.

Talk for the Intellivision Virtual Expo. Nov/21/2020.

(1)
Hi all. I’m Oscar Toledo, and I’ll talk about state-of-the-art game development for Intellivision.

The game development for Intellivision started when APh Consulting started the development of first Intellivision games for Mattel Electronics.

(2)
These games were developed using PDP-11 minicomputers. Each programmer had a dumb terminal (VT100 compatible) connected to the PDP-11 to keep the source code and data files of the games. Also each programmer had a TV display, an Intellivision console, and a dedicated card to download the game into the Intellivision so they could test the game in development.

(3)
Mattel Electronics used a very complicated hardware in their Intellivision console, because it used a 16-bit processor. It was pretty impressive at the time from a technical point, and in fact it was the first game console using a 16-bit processor, something that wouldn’t be repeated until the emergence of the SNES console in 1991.

This difficult setup effectively stopped the efforts by outside companies to create cartridges for the Intellivision, and Mattel didn’t share any information with the outside world, so essentially only Mattel was able to develop and manufacture games for its console.

(4)
There existed information about Intellivision programming but it only was available inside Mattel, it was a document called “Your friend, the Exec”.

Then the inevitable things happened: Some programmers exited APh Consulting and started companies on its own, or looked for work in companies developing games.

One of these programmers was David Rolfe, who went to Cheshire Engineering to work in Intellivision games for Activision.

Other programmers went to Imagic, formed by Atari and Mattel programmers.

(5)
The fact that most programmers come from the same roots of APh Consulting, mean they created development tools pretty similar: most working on PDP-11 minicomputers or compatibles. This means that no development tools were created for microcomputers of the time, for example, Atari 2600 had development tools capable of running on Apple II computers.

The graphics and sound design were difficult, only Mattel Electronics being the initiator started coming up with graphics, music and sound design utilities, but otherwise the graphics had to be drawn on grid paper.

The music was developed manually and most programmers didn’t had a music background. It wasn’t surprising that music was missing in the launch games for the Intellivision: Las Vegas Poker & Blackjack, Armor Battle, and Backgammon, except for some jingles in Math Fun.

(6)
The available internal size of ROM chips was also important. The first wave of Intellivision games used only 4 kilowords, and the biggest game was World Series Major League Baseball with 20 kilowords.

Until 1987 was available a PC development system created by INTV Corp. but these tools also weren’t released to the public. It was a testament to the powerful secrets built around the Intellivision.

It also mean that when INTV went bankrupt, all the programming info was essentially lost.

It had to happen the reverse engineering at the end of millennium to recover the lost secrets of Intellivision, how it worked, what hardware used, how cartridges boot up, what memory areas were available, what was inside the EXEC, what predefined characters were available in the GROM. All this in order to create an emulator.

And then the development tools started to be created again, like the as1600 assembler included with the jzintv emulator by Joe Zbiciak.

(7)
The microprocessor used in the Intellivision console is the CP1610 by General Instruments, it happens it has a pretty steep learning curve. So the creation of new games was possible but it required a great deal of time, patience, and skill.

Also the integrated video chip proposes some challenges like only being able to define graphics in the moment when the video raster isn’t being updated, forcing to think differently for graphics screens.

The sound chip although similar to a sound chip of the same year, it is interfaced in a 8-bit bus with different addresses for the sound registers, and has some small yet important differences.

All this makes the development of a game to be a truly difficult task if using only the assembler language, in special for the description of the graphics and music.

(8)
In 2014 came the IntyBASIC programming language, it simplified greatly the development of new games as it wasn’t required to know the intrincated details of the Intellivision hardware.

Essentially you can code one line saying PRINT HELLO WORLD and it can be compiled immediately, assembled, and run with the emulator in less than 5 seconds.

Most simple games can be coded in a single day, this is a big difference versus assembly language coding that can take as long as one month for a game of the same size.

(9)
The utility IntyColor included with IntyBASIC is able to take a BMP image file and convert it to IntyBASIC source code in a few seconds. Basically you can take a painting program of your particular liking, and in a few minutes have the same screen replicated on your very own Intellivision console.

It is a big difference because drawing on a grid paper requires artist abilities, and a lot of time to enter the data into the computer, plus the time lost in testing the image, and correcting the data entry.

The ability to take real pictures and turn them into Intellivision artwork very easily or faster than before.

The integrated music tracker means that basic musical knowledge is enough to compose tiny jingles, or convert music sheet to IntyBASIC source code.

(10)
Other important advantage is the fact that now ROM cartridges can use the full 42K words available in the Intellivision memory map, and also that ROM memory is now pretty inexpensive.

In fact thanks to the advanced capabilities of JLP cartridges, some games reach 80 kilowords.

This means programmers aren’t limited by space anymore, and instead can introduce all the graphics screens they like, and many tracks of music.

Another thing that has changed in the development of new games for Intellivision, is the fact that many modern features are integrated, for example: graphic title screens, intro stories, background music, high-scores tables, victory screens, etcetera.

Even new graphic styles in the venue of NES games have been shown in new games.

Here are some examples of new games created for Intellivision in the last six years.

(11) Sydney Hunter and the Sacred Tribe. Fire-like animation for torch at title screen.

(12) Sydney Hunter and the Sacred Tribe. NES-style tiles for screens, and multicolor sprites.

(13) Princess Quest: Intro story, and bitmap animated title screen.

(14) Aardvark, background music in graphic title screen. Cartoon-style animated sprites.

(15) Unlucky pony, mix of several genres.

(16) Frankenstein’s Monster, game remake with better graphics, sound, music, and animation.

(17) Miner 2049er, game possible because the new cartridges with more ROM memory.

(18) Intellivania, surprising demake (not remake) of a modern game for Intellivision.

(19) Let me finish with this quote I may not have gone where I intended to go, but I think I have ended up where I intended to be. Douglas Adams

I want to say thanks to decle for the invaluable historical details contained in his document Intellivision Development Back in the Day, and published in the forums of Atariage.

(20) Questions & Answers

 

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