Anyone got a real VT100 screen they can photograph close up?
Heater.
Posts: 21,230
I've been getting into HTML5 and it's canvas and webgl recently. So I want to build a VT100 or other CRT terminal screen emulator in webgl.
Here is the plan:
1) High resolution bitmap images of CRT text display font characters.
2) Used as webgl textures, just drop them into a grid of 80 lines by 24 or whatever as required.
2) Green, white, orange, whatever.
3) Authentic dotty, fuzzy characters hiding in phosphor burn kind of thing.
4) Large dark green (or other color) image as the background.
5) Large transparent white overlay to give shiny glass screen effect.
6) websocket connection back to server an hence connecting the thing to a Propeller, via serial, running CP/M (or whatever you like).
So my problem is the font bit maps. Googling around I find lot's of green screen images but none close up and of high resolution.
My guess is the best thing is a close up shot of a screen containing the entire font taken in the dark so that the background shades all match up in use.
Second approach is if anyone knows the dot font patterns they could be recreated in some drawing program but then they would never look so authentic.
Here is the plan:
1) High resolution bitmap images of CRT text display font characters.
2) Used as webgl textures, just drop them into a grid of 80 lines by 24 or whatever as required.
2) Green, white, orange, whatever.
3) Authentic dotty, fuzzy characters hiding in phosphor burn kind of thing.
4) Large dark green (or other color) image as the background.
5) Large transparent white overlay to give shiny glass screen effect.
6) websocket connection back to server an hence connecting the thing to a Propeller, via serial, running CP/M (or whatever you like).
So my problem is the font bit maps. Googling around I find lot's of green screen images but none close up and of high resolution.
My guess is the best thing is a close up shot of a screen containing the entire font taken in the dark so that the background shades all match up in use.
Second approach is if anyone knows the dot font patterns they could be recreated in some drawing program but then they would never look so authentic.
Comments
Read the manual and take a look at the screen dumps.
Try this? Google images
Interesting that this fellow shows up in that search
That image reminds me of one important detail. The bighness of the dot depends on how long the beam is switched on. So verical lines can be less bright than horizontal features of a character. In you image the brighness turns horizontal parts from orange to almost white.
Jazzed,
Can't see anything useful in that inage search, most don't load here.
Wow. Thanks for mentioning that. I learned something new today. Interesting that the images don't load everywhere.
Here is a VT-100 Technical Manual with characters on pages 4-78, 4-79...
http://vt100.net/docs/vt100-tm/ek-vt100-tm-002.pdf
The character rom for the VT100 and a lot of the other terminals of that era generally used a maximum 7x7 matrix for the character and stored it in 8 bytes. The crt display was generally 350 non interlaced lines so the scan lines did not overlap thus producing those "pixelly" characters. To reproduce that on one of today's high rez displays would probably require a 7x11 matrix with every third line left blank.
BTW, wish I had so much time to play.
kwinn,
I'm not going to worry about the high resolution. Using webgl we can use high res images of characters (even if we make them by hand in some graphics program). Each character might be a 64 by 64 image. They will be scaled by webgl using you graphics accelerator hardware to produce the final screen pixels.
No time to play yet, just getting the plan in my head.
We threw the last dozen away about 18 months ago; taking up too much valuable space, and for what???, however..... there might still be an orphan lurking around. I will check on Monday.
I do have a VT 220 on my workbench though if that's of any interest...... never gets powered up; I should chuck it!
Cheers,
Peter (pjv)
You are breaking my heart. All those beautiful terminals in the landfill. The VT220 is definitely worth hanging on to, at least until it is of interest to a museum. I'd take it off your hands but getting it to Finland is not on the cards.
I'm obviously entering my dotage. It's not just the terminals and old computers, I'm beginning to miss all the "real" things I grew up with. Big old telephones, record players, cars with starting handles, gas cookers built like tanks, even cast iron drain pipes on houses. Seems we have moved into a world where everything is lightweight, cheap, tacky, plastic. Pretty much every familiar item has disappeared into the land fill. It's a bit disturbing to find household items I used to use everyday now in the museum...