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al18
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Joined: 06/07/2019
Location: United States
Posts: 228

Posted: 05:23pm 22 Apr 2022

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Here's a program I dug up from Analog Computing magazine #7 from 1982.
While the program is short, it took nearly 3 hours to complete on an Atari 400/800.
The PicoMiteVGA version shown below runs much faster.

' Archimedes Spiral from Analog Computing Mag #7
MODE 2
CLS
xp=144:xr=4.71238985:xf=xr/xp
For zi=-64 To 64
zt=zi*2.25:z5=zt*zt
xl=Int(Sqr(20736-z5)+0.5)
For xi=0-xl To xl
xt=Sqr(xi*xi+z5)*xf
yy=(Sin(xt)+Sin(xt*3)*0.4)*56
x1=xi+zi+160:y1=90-yy+zi
Pixel x1,y1,RGB(green)
Line x1,y1+1,x1,192,,RGB(black)
Next xi
Next zi

Michal
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Joined: 02/02/2022
Location: Poland
Posts: 125

Posted: 06:30pm 22 Apr 2022

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With PicoMite and Waveshare 3.5 inches:
https://www.waveshare.com/pico-restouch-lcd-3.5.htm
16 sec

Micha?
Edited 2022-04-23 04:31 by Michal

Amnesie
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Joined: 30/06/2020
Location: Germany
Posts: 671

Posted: 06:35pm 22 Apr 2022

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Wow!!
For me it took only 7 seconds, but I overclocked the CPU.
Thank you for this! Tested it out and it is really impressive!

Greetings
Daniel
Edited 2022-04-23 04:38 by Amnesie

al18
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Joined: 06/07/2019
Location: United States
Posts: 228

Posted: 07:21pm 22 Apr 2022

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17 seconds on the PicoMiteVGA
If you change to Mode 1 it only takes 14 seconds, but the Archimedes Spiral only occupies 1/4 of the screen

al18
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Joined: 06/07/2019
Location: United States
Posts: 228

Posted: 07:21pm 22 Apr 2022

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(duplicate post deleted)
Edited 2022-04-23 05:22 by al18

Volhout
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Posted: 08:08pm 22 Apr 2022

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nice graph...
298ms on MMB4W under WINE on linux (between 200ms and 300ms depending the CPU load)
Edited 2022-04-23 06:14 by Volhout

PicomiteVGA PETSCII ROBOTS

al18
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Joined: 06/07/2019
Location: United States
Posts: 228

Posted: 09:08pm 22 Apr 2022

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For a transparent version of the spiral, change the line command to a comment

toml_12953
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Joined: 13/02/2015
Location: United States
Posts: 442

Posted: 05:30am 23 Apr 2022

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al18 said Here's a program I dug up from Analog Computing magazine #7 from 1982.
While the program is short, it took nearly 3 hours to complete on an Atari 400/800.
The PicoMiteVGA version shown below runs much faster.

' Archimedes Spiral from Analog Computing Mag #7
MODE 2
CLS
xp=144:xr=4.71238985:xf=xr/xp
For zi=-64 To 64
�zt=zi*2.25:z5=zt*zt
�xl=Int(Sqr(20736-z5)+0.5)
�For xi=0-xl To xl
� �xt=Sqr(xi*xi+z5)*xf
� �yy=(Sin(xt)+Sin(xt*3)*0.4)*56
� �x1=xi+zi+160:y1=90-yy+zi
� �Pixel x1,y1,RGB(green)
� �Line x1,y1+1,x1,192,,RGB(black)
�Next xi
Next zi

The original program was used in Compute! Magazine, March 1981 in an ad for the MTU graphics add-on for Commodore PET. Maybe Bachand got it from there.

Edited 2022-04-23 15:54 by toml_12953

al18
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Joined: 06/07/2019
Location: United States
Posts: 228

Posted: 02:41pm 23 Apr 2022

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I see the program in Analog was changed slightly from the one in the MTU ad. I can�t believe MTU sold many of those graphics boards for $495, considering in 1981 you could have bought a 16K Atari 800 that included 320 x 192 graphics and graphics commands built into Atari Basic for $200 more. Both machines had a 6502 CPU.

Rickard5

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Joined: 31/03/2022
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Posted: 03:25pm 23 Apr 2022

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al18 said ...... I can�t believe MTU sold many of those graphics boards for $495, considering in 1981 you could have bought a 16K Atari 800 that included 320 x 192 graphics and graphics commands built into Atari Basic for $200 more. Both machines had a 6502 CPU.

But for $200 more all you'd have is a Home Video Game, and for Just a few bucks less you could have had a Commodore Vic 20 plus a 32k Memory expander, or in 1982 you could have had a Commodore 64, but no one was silly enough to waste 10 times as much on the TI99/4a until 1986 when TI was GIVING THEM AWAY FOR $300 WITH A $350 REBATE :)

I may be Vulgar, but , while I'm poor, I'm Industrious, Honest, and trustworthy! I Know my Place

toml_12953
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Posted: 03:51pm 23 Apr 2022

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Rickard5 said no one was silly enough to waste 10 times as much on the TI99/4a until 1986 when TI was GIVING THEM AWAY FOR $300 WITH A $350 REBATE :)

I waited until they not only gave you $50.00 for buying one but threw in a Speech Synthesizer! The TI actually wasn't a bad machine but both BASICs (internal and add-in Extended cartridge) weren't written in native 9900 code. They ran an interpreted code called GPL (Graphics Programming Language) Can you imagine running an interpreter that's executed using another interpreter? SLOW!! Microsoft wrote TI Extended BASIC but had to follow the TI syntax guidelines when doing so. That's why it's not very compatible with other versions of MS BASIC.

vegipete

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Joined: 29/01/2013
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Posts: 1132

Posted: 04:44pm 23 Apr 2022

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I messed with constants a bit to get this, which centers the image on screen and adjusts according to resolution:

' Archimedes Spiral from Analog Computing Mag #7
'MODE 2
CLS
radius = MM.HRES/10 '64
rfact = (radius*2.25)^2
xp = radius * 9/4 '144
xr = 1.5 * pi
xf = xr/xp
For zi = -radius To radius
zt = zi*2.25
z5 = zt*zt
xl = Int(Sqr(rfact-z5)+0.5)
For xi = -xl To xl
xt = Sqr(xi*xi+z5) * xf
yy = (Sin(xt) + Sin(xt*3)*0.4) * MM.VRES/8
x1 = xi+zi+MM.HRES/2
y1 = MM.VRES/2-yy+zi
Pixel x1,y1,RGB(green)
Line x1,y1+1,x1,MM.VRES,,RGB(black)
Next xi
Next zi

do : loop until inkey$ <> ""

How happy, and patient, we were 40 odd years ago with our ~1 MHz computers...

Visit Vegipete's *Mite Library for cool programs.

Mixtel90

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Joined: 05/10/2019
Location: United Kingdom
Posts: 7937

Posted: 05:05pm 23 Apr 2022

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The Sinclair Speccy is 40 years old today. :)

When it was announced several people at our Nascom user group were trying to find out if it would be a way to get colour on a Nascom-2. Existing colour boards for the Nascom-2 and 80-BUS cost a fortune.

Mick

Zilog Inside! nascom.info for Nascom & Gemini
Preliminary MMBasic docs & my PCB designs

al18
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Joined: 06/07/2019
Location: United States
Posts: 228

Posted: 05:42pm 23 Apr 2022

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I never heard of the Nascom before. I don�t think it was popular on this side of the pond. The Sinclair computers WERE popular over here - probably due to the low cost.

Speaking of video boards for Z-80 machines, I bumped into this the other day https://z80kits.com/shop/rc2014-pi-pico-vga-terminal/ - a VGA Terminal board using the Pico to generate video.

twofingers

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Joined: 02/06/2014
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Posts: 1593

Posted: 06:10pm 23 Apr 2022

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vegipete said ...
How happy, and patient, we were 40 odd years ago with our ~1 MHz computers...

I often think so too. And we knew every byte by his first name...

causality ≠ correlation ≠ coincidence

Mixtel90

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Location: United Kingdom
Posts: 7937

Posted: 08:12pm 23 Apr 2022

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mmm.... many happy hours entering hex pairs into RAM using a machine code monitor. Then hope that it manages to save to tape - and that it will read back too!

Assembler? What's that? I couldn't afford Zeap and it seemed ages before you could get BASIC to run on a Nascom-1. Oddly enough, that RC2014 setup uses a version of BASIC that was modified by Grant Searle from the Nascom ROM BASIC (Microsoft BASIC 4.07).

Mick

Zilog Inside! nascom.info for Nascom & Gemini
Preliminary MMBasic docs & my PCB designs

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