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Classic starfield… with supposedly accurate stellar colors
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package main | |
import ( | |
"image/color" | |
"math/rand" | |
"time" | |
"github.com/faiface/pixel" | |
"github.com/faiface/pixel/imdraw" | |
"github.com/faiface/pixel/pixelgl" | |
) | |
const w, h = float64(1024), float64(512) | |
var speed = float64(200) | |
var stars [1024]*star | |
func init() { | |
rand.Seed(4) | |
for i := 0; i < len(stars); i++ { | |
stars[i] = newStar() | |
} | |
} | |
type star struct { | |
pixel.Vec | |
Z float64 | |
P float64 | |
C color.RGBA | |
} | |
func newStar() *star { | |
return &star{ | |
pixel.V(random(-w, w), random(-h, h)), | |
random(0, w), 0, Colors[rand.Intn(len(Colors))], | |
} | |
} | |
func (s *star) update(d float64) { | |
s.P = s.Z | |
s.Z -= d * speed | |
if s.Z < 0 { | |
s.X = random(-w, w) | |
s.Y = random(-h, h) | |
s.Z = w | |
s.P = s.Z | |
} | |
} | |
func (s *star) draw(imd *imdraw.IMDraw) { | |
p := pixel.V( | |
scale(s.X/s.Z, 0, 1, 0, w), | |
scale(s.Y/s.Z, 0, 1, 0, h), | |
) | |
o := pixel.V( | |
scale(s.X/s.P, 0, 1, 0, w), | |
scale(s.Y/s.P, 0, 1, 0, h), | |
) | |
r := scale(s.Z, 0, w, 11, 0) | |
imd.Color = s.C | |
if p.Sub(o).Len() > 6 { | |
imd.Push(p, o) | |
imd.Line(r) | |
} | |
imd.Push(p) | |
imd.Circle(r, 0) | |
} | |
func run() { | |
win, err := pixelgl.NewWindow(pixelgl.WindowConfig{ | |
Bounds: pixel.R(0, 0, w, h), | |
VSync: true, | |
Undecorated: true, | |
}) | |
if err != nil { | |
panic(err) | |
} | |
imd := imdraw.New(nil) | |
imd.Precision = 7 | |
imd.SetMatrix(pixel.IM.Moved(win.Bounds().Center())) | |
last := time.Now() | |
for !win.Closed() { | |
win.SetClosed(win.JustPressed(pixelgl.KeyEscape) || win.JustPressed(pixelgl.KeyQ)) | |
if win.Pressed(pixelgl.KeyUp) { | |
speed += 10 | |
} | |
if win.Pressed(pixelgl.KeyDown) { | |
if speed > 10 { | |
speed -= 10 | |
} | |
} | |
if win.Pressed(pixelgl.KeySpace) { | |
speed = 100 | |
} | |
d := time.Since(last).Seconds() | |
last = time.Now() | |
imd.Clear() | |
for _, s := range stars { | |
s.update(d) | |
s.draw(imd) | |
} | |
win.Clear(color.Black) | |
imd.Draw(win) | |
win.Update() | |
} | |
} | |
func main() { | |
pixelgl.Run(run) | |
} | |
func random(min, max float64) float64 { | |
return rand.Float64()*(max-min) + min | |
} | |
func scale(unscaledNum, min, max, minAllowed, maxAllowed float64) float64 { | |
return (maxAllowed-minAllowed)*(unscaledNum-min)/(max-min) + minAllowed | |
} | |
// Colors based on stellar types listed at | |
// http://www.vendian.org/mncharity/dir3/starcolor/ | |
var Colors = []color.RGBA{ | |
color.RGBA{157, 180, 255, 255}, | |
color.RGBA{162, 185, 255, 255}, | |
color.RGBA{167, 188, 255, 255}, | |
color.RGBA{170, 191, 255, 255}, | |
color.RGBA{175, 195, 255, 255}, | |
color.RGBA{186, 204, 255, 255}, | |
color.RGBA{192, 209, 255, 255}, | |
color.RGBA{202, 216, 255, 255}, | |
color.RGBA{228, 232, 255, 255}, | |
color.RGBA{237, 238, 255, 255}, | |
color.RGBA{251, 248, 255, 255}, | |
color.RGBA{255, 249, 249, 255}, | |
color.RGBA{255, 245, 236, 255}, | |
color.RGBA{255, 244, 232, 255}, | |
color.RGBA{255, 241, 223, 255}, | |
color.RGBA{255, 235, 209, 255}, | |
color.RGBA{255, 215, 174, 255}, | |
color.RGBA{255, 198, 144, 255}, | |
color.RGBA{255, 190, 127, 255}, | |
color.RGBA{255, 187, 123, 255}, | |
color.RGBA{255, 187, 123, 255}, | |
} |
Author
peterhellberg
commented
Nov 5, 2017
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