I found a viewer that works in the browser:
> Mandelbrot Viewer is a universal (desktop and mobile) vanilla JS implementation of a plain Mandelbrot set renderer – supporting mouse, touch and keyboard interaction.
https://mandeljs.hgreer.com/?;re=-0.751165720536567020384363...
(I don't know if this is a known compromise of your technique (I couldn't find it mentioned), but I occassionally get a ring of varying thickness centred in the render with an inverted coluring to the rest of the pixels, or sometimes a solid colour. It varies is size and comes and goes without an obvious correlation to zoom level.)
I'm representing complex numbers as (real_mantissa + i * imag_mantissa) * 2^exp where real_mantissa and imag_mantissa are themselves 32 bit floats, and I can reduce the frequency of the colored rings in my shader by keeping the mantissas around ~1000 instead of ~1 (and reducing the exponent to keep the value the same) so that they are less likely to go subnormal, but I can't seem to get rid of the colored rings entirely.
I don't actually know the pathway through the code from subnormal underflow -> colored rings, but if you run a CUDA renderer with the same algorithm, the rings appear when you set the flag for "round subnormal floats to zero."
fragColor = vec4(vec3(cos(c), cos(1.1214 * c) , cos(.8 * c)) / 2. + .5, 1.);
Now people write viewers that run lighting fast in a browser thanks to WebGPU! Like:
https://www.reddit.com/r/fractals/comments/o7l4bm/please_try...
At that time I didn't know what was a complex number, but was fascinated by the whole concept of fractals and how complex structures could be created with a relative simple program.
I ran in to the precision limit pretty quickly, same as you. I didn't understand computers well enough to know that's what the problem was, and I remember spending hours pouring over my code, trying to figure out where the bug was. Good times. :D
I still have that A500 but who knows where I put those floppies, I'm tempted to turn it on but I'm scared the PSU will blow itself...
The A500 themselves are built like tanks. Chances are it just works.
But watch out for trapdoor expansion. Most likely has a varta barrel battery in it, which will eventually leak and damage the expansion, and possibly also the computer itself.
I would recommend opening that trapdoor and removing/inspecting anything installed there as soon as possible.
These barrel batteries are only used to keep RTC, and the board will be fine w/o.
Software emulated floats on Amiga 2000 were really, really slow.
I thought "this will never work", but I was amazed that it did in fact work. I remember letting it run overnight to find a complete 160x200 4-color image the next morning. Just clearing the screen using a loop to fill 8192 bytes with 0s took over a minute.
Everything about the computers at the time was so terrible, I don't feel any nostalgia for those days or that technology.
FRACTINT was great because I could use my 286 and it was fairly fast because used integer whenever possible.
Now that's slow.
https://brazzy.de/en/Mandelbrot.php
Even for that, the actual Mandelbrot calculations were the smaller part. It's really amazing how such a trivially simple formula spawns such endless complexity.
Which implies something important, no doubt.