On Monday, 20 June 2016 18:02:53 UTC+3, [email protected] wrote:
>
>
> <https://lh3.googleusercontent.com/-bPOQJTHF8Js/V2gEJqUg5jI/AAAAAAAAACI/lg6cWG0cJqo0tFl4wsuDYF2w4kycTbRPACLcB/s1600/blank.png>
>
> I am attempting to generate a random starfield, in go. This is something
> that will need to printed on actual paper, but that is another issue and I
> only mention it to give some context for what I am doing here: Using go to
> create graphics to pair with something I'm already doing in go (I've been
> through several iterations of trying to use the go parts I have with
> numerous variations of tex/latex templates using asymptote, and I reached a
> point of frustration where I figured why not just do it all in go, as it
> seems less a problem than I originally thought -- but opens a new set of
> problems to solve, one of the biggest is that I know nothing at all about
> graphics, let alone how to apply graphics in go).
>
> Cosmic1 from:
> https://gist.github.com/thrisp/1ed1785ac6a902585595fb8cb52f0a16,
> generates the above it is the first thing that even roughly approximates
> what I want to do.
>
> Any thoughts, or help cleaning that up. Maybe tell me why exactly I can't
> directly translate an opengl shader to something cpu bound(which I suspect
> is a thing, I may need to do more that I can't see right now).
>
As for the current code:
Here you are picking a random rotation for each pixel:
a1 := .5 + float64(float64(mr.Intn(size.X))/3)/float64(mr.Intn(size.X))*2
a2 := .8 + float64(float64(mr.Intn(size.X))/2)/float64(mr.Intn(size.Y))*2
This can change for every pixel (in shader the time is a constant for one
frame):
time := float64(time.Now().UTC().Unix())*speed + 0.25
In func toUint8(in float64) uint8 { you need to clamp the value between 0
and 255, otherwise the conversion overflows.
Color adjusting code doesn't match the shader code.
I suspect there are further issues in the iteration code.
PS: often with such fragments you can simplify code and achieve a similar
result with less details, e.g.
https://gist.github.com/egonelbre/b5f41ac8946e609ce1a944631dd462ef
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