-
Notifications
You must be signed in to change notification settings - Fork 4
/
mandelbrot.go
167 lines (146 loc) · 3.13 KB
/
mandelbrot.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
package main
import (
"flag"
"log"
"math/cmplx"
"runtime"
"github.com/qeedquan/go-media/image/chroma"
"github.com/qeedquan/go-media/sdl"
"github.com/qeedquan/go-media/sdl/sdlimage/sdlcolor"
)
const (
W = 800
H = 600
)
var (
screen *Display
texture *sdl.Texture
pixels []uint32
center = complex(-0.4, 0)
view = 1.1
seqlen = 100
run = true
palette []sdl.Color
div [][]int
limit = 2.0
drawchan = make(chan int, H)
)
type Display struct {
*sdl.Window
*sdl.Renderer
}
func NewDisplay(w, h int, flags sdl.WindowFlags) *Display {
window, renderer, err := sdl.CreateWindowAndRenderer(w, h, flags)
ck(err)
return &Display{window, renderer}
}
func main() {
runtime.LockOSThread()
flag.Parse()
err := sdl.Init(sdl.INIT_EVERYTHING)
ck(err)
defer sdl.Quit()
sdl.GLSetAttribute(sdl.GL_DOUBLEBUFFER, 1)
screen = NewDisplay(W, H, sdl.WINDOW_OPENGL|sdl.WINDOW_RESIZABLE)
ck(err)
screen.SetLogicalSize(W, H)
texture, err = screen.CreateTexture(sdl.PIXELFORMAT_ARGB8888, sdl.TEXTUREACCESS_STREAMING, W, H)
ck(err)
pixels = make([]uint32, W*H)
screen.SetTitle("Mandelbrot Set")
palette = make([]sdl.Color, seqlen)
buf := make([]int, W*H)
div = make([][]int, H)
for i := range div {
div[i] = buf[W*i:]
}
for i := range palette {
hsv := chroma.HSV{0.55, 1, float64(i) / float64(len(palette)) / 0.1}
palette[i] = sdl.ColorModel.Convert(hsv).(sdl.Color)
}
for run {
event()
draw()
}
}
func event() {
const step = 0.1
for {
ev := sdl.PollEvent()
if ev == nil {
break
}
switch e := ev.(type) {
case sdl.QuitEvent:
run = false
case sdl.KeyDownEvent:
switch e.Sym {
case sdl.K_ESCAPE:
run = false
case sdl.K_LEFT:
center -= complex(step, 0)
case sdl.K_RIGHT:
center += complex(step, 0)
case sdl.K_DOWN:
center -= complex(0, step)
case sdl.K_UP:
center += complex(0, step)
case sdl.K_a:
view += 0.1
case sdl.K_z:
view -= 0.1
}
}
}
}
func draw() {
screen.SetDrawColor(sdlcolor.Black)
screen.Clear()
for y := 0; y < H; y++ {
go func(y int) {
for x := 0; x < W; x++ {
div[y][x] = divergent(center, x, y)
}
drawchan <- y
}(y)
}
for y := 0; y < H; y++ {
cy := <-drawchan
for x := 0; x < W; x++ {
i := div[cy][x]
if i < 0 {
pixels[cy*W+x] = 0xFF000000
} else {
pixels[cy*W+x] = c32(palette[i])
}
}
}
texture.Update(nil, pixels, W*4)
screen.Copy(texture, nil, nil)
screen.Present()
}
func divergent(c complex128, x, y int) int {
z := coord(c, x, y)
z0 := z
for i := 0; i < seqlen; i++ {
if cmplx.Abs(z) > limit {
return i
}
z = z0 + z*z
}
return -1
}
func coord(c complex128, x, y int) complex128 {
fx, fy := float64(x), float64(y)
nr := (real(c) - view) + ((2 * (view * fx)) / W)
ni := (imag(c) + view) - ((2 * (view * fy)) / H)
return complex(nr, ni)
}
func c32(c sdl.Color) uint32 {
return uint32(c.A)<<24 | uint32(c.R)<<16 | uint32(c.G)<<8 | uint32(c.B)
}
func ck(err error) {
if err != nil {
log.Fatal(err)
}
}