August 1, 2020 Header

since 1998

personal website: joe crawford. code. occasional comics. toy robots. bodysurfing. san diego. california. say hi.

April 2023 Thirty-three posts

Weekend mornings are sometimes eventful! Some great corners to ride. Once again @lifeguardsofsandiego always awesome hooking me up with the hot hot water and fine foot wrapping. Stingray encounter # 5 in the last 2 years i think. First time at OB.

Programming graphics on the TI-99/4a

Back in 2019 I wrote about programming in TI-BASIC a little bit. I remembered going from graph paper to hex but the mechanics of drawing to the screen was not something I remembered.

I did remember it was pretty tedious. But rewarding! Well, the other day I was inspired to create a chunk of code (a bit of primitive jQuery, SCSS and HTML) that allows you to create that crazy hex code:

See the Pen
CALL CHAR HEX Code TI-BASIC
by Joe Crawford (@artlung)
on CodePen.light

But what about the other code, what code went around it? Well, now I know. Here’s the resulting final image.

And what does the source code look like?

It’s in BASIC, and it’s all about printing characters to the string at individual cursor positions. To do that, one has to use ASCII codes. 32 is and always was the space character, so we don’t use that.

To determine how to customize those characters, I wrote some PHP code to read a source image I created of my ARTLUNG logo sized to the specifications of a TI-99: 32 columns wide, 24 columns high. So to create graphics one can only ever do a graphic that’s those numbers times 8 – every character is an 8×8 pixel square. So, 256 by 192 pixels. For reference the first iPhone 16 years ago was 480 by 320 pixels. And a current Android Pixel screen is 2400 by 1080 pixels. In some ways that 1981 screen is not so different.

It’s very strange when a programming task like this becomes a sort of compulsion to get out of my system. Solving challenging problems, even seemingly trivial ones is so rewarding.

I’m still working on some code to create an image (my ARTLUNG signature) on an ancient (40 year old) operating system emulator. TI Extended BASIC from the TI-99/4a computer. It’s a machine with less memory than your average jpeg.

New Bot Day! GC-09 Metal Robo 55 DynaRobo is a chogokin die-cast metal toy from 1983. This lovely and very special piece was a Christmas gift from Kelly. You will note I have a backlog on bots since moving in December. More bots ahoy!

Gear

Swarm Checkins

New Bot Day! Welcome Roll Bot, a robot toy for toddlers 1-1/2+ years old. It’s an activity toy with no backstory by Canadian company Madison Joseph Battat Limited. I think it’s c.1985 but might be off.

During one ride today I lost one of my handplanes. That ride was like going down a long steep snowy hillside on my back. Incredible speed. Thrilling. I got the handplane back at the ehd. A surfer brought it to shore. She said “I thought it would be easy to bring it in but it about killed me.” I thanked her.

Summery today. Every day fresh and new. Beach parking lot blacktop getting hotter. Today was Scripps.

Kneel

Quote of the Day

I say often that computers are terrible. Nontechnical people seldom take me seriously. But people in tech, like Galloway do:

A growing vein of the tech community (Venture Catastrophists) deploy weapons of mass distraction and fear to wallpaper over an inconvenient truth: The menace unleashed on America the past two decades isn’t psychotic homeless people or a crime wave, but a tech community whose products depress our teens, polarize our public and render our discourse more coarse … making it less likely we come together and address issues including homelessness and crime. Our failure to regulate this sector, as we have done with every other sector, is stupid.

We must do better.