tgpl

commit 22818513792d88d305d0e3c769cabcef4f110969
parent f7ea670c56c214552b33b32fd1e9a417ece843f6
Author: zerous Naveen Narayanan <zerous@nocebo.space>
Date:   Fri,  1 Mar 2019 01:32:45 +0100

Add exercise 1.6 solution

Diffstat:
A
exercise-1-6.go
 | 
59
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

1 file changed, 59 insertions(+), 0 deletions(-)
diff --git a/exercise-1-6.go b/exercise-1-6.go
@@ -0,0 +1,59 @@
+package main
+
+import (
+	"image"
+	"image/color"
+	"image/gif"
+	"io"
+	"math"
+	"math/rand"
+	"os"
+)
+
+var palette = []color.Color{color.RGBA{0x25, 0x5C, 0x1c, 0xff},
+                            color.RGBA{0x00, 0x00, 0x00, 0xff},
+			    color.RGBA{0x3B, 0x3B, 0x71, 0xff}}
+
+const (
+	greenIndex = 0
+	blackIndex = 1
+	blueIndex = 2
+)
+
+func main() {
+	lissajous(os.Stdout)
+}
+
+func lissajous(out io.Writer) {
+	const (
+		cycles 	= 5
+		res	= 0.001
+		size	= 100
+		nframes = 64
+		delay 	= 8
+	)
+	freq := rand.Float64() * 3.0
+	anim := gif.GIF{LoopCount: nframes}
+	phase := 0.0
+	for i := 0; i < nframes; i++ {
+		rect := image.Rect(0, 0, 2*size+1, 2*size+1)
+		img := image.NewPaletted(rect, palette)
+		for t := 0.0; t < cycles*2*math.Pi; t += res {
+			x := math.Sin(t)
+			y := math.Sin(t*freq + phase)
+			if t < cycles*2*math.Pi/2 {
+				img.SetColorIndex(size+int(x*size+0.5),
+				size+int(y*size+0.5),
+				blackIndex)
+			} else {
+				img.SetColorIndex(size+int(x*size+0.5),
+				size+int(y*size+0.5),
+				blueIndex)
+			}
+		}
+		phase += 0.1
+		anim.Delay = append(anim.Delay, delay)
+		anim.Image = append(anim.Image, img)
+	}
+	gif.EncodeAll(out, &anim)
+}