166 lines
2.9 KiB
Go
166 lines
2.9 KiB
Go
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},
|
|
}
|