Drawing to the RPi (SenseHat) framebuffer over the network

bouncing-pixels.go

package main

import (
	"bufio"
	"bytes"
	"image/color"
	"image/draw"
	"net/http"
	"time"

	"github.com/peterhellberg/gfx"
)

func main() {
	gfx.RandSeed(3456)

	d := 16 * time.Millisecond
	u := "http://192.168.1.3/framebuffer.png"
	p := gfx.PalettePICO8

	ticker := time.NewTicker(d)

	balls := []*Ball{
		newBall(p.Random()),
		newBall(p.Random()),
		newBall(p.Random()),
		newBall(p.Random()),
	}

	for range ticker.C {
		m := gfx.NewImage(8, 8)

		for _, ball := range balls {
			ball.Update()
			ball.Draw(m)
		}

		var b bytes.Buffer

		w := bufio.NewWriter(&b)

		gfx.EncodePNG(w, m)

		w.Flush()

		http.Post(u, "image/png", &b)
	}
}

type Ball struct {
	pos gfx.Vec
	dir gfx.Vec
	col color.Color
}

func newBall(col color.Color) *Ball {
	pos := gfx.IV(gfx.RandIntn(8), gfx.RandIntn(8))
	dir := gfx.V(gfx.RandFloat64()/4, gfx.RandFloat64()/4)

	return &Ball{pos: pos, dir: dir, col: col}
}

func (b *Ball) Update() {
	b.pos.X += b.dir.X
	b.pos.Y += b.dir.Y

	if b.pos.Y < 0 || b.pos.Y > 7 {
		b.dir.Y *= -1
	}

	if b.pos.X < 0 || b.pos.X > 7 {
		b.dir.X *= -1
	}
}

func (b *Ball) Draw(dst draw.Image) {
	t := gfx.PV(b.pos.Pt())
	d := t.To(b.pos).Len()

	if d < 0.9 {
		gfx.SetVec(dst, b.pos, b.col)
	}
}

clear-framebuffer.go

package main

import "net/http"

func main() {
	u := "http://192.168.1.3/clear"

	http.Post(u, "", nil)
}

random-pixels.go

package main

import (
	"bufio"
	"bytes"
	"net/http"
	"time"

	"github.com/peterhellberg/gfx"
)

func main() {
	gfx.RandSeed(1234)

	d := 16 * time.Millisecond
	u := "http://192.168.1.3/framebuffer.png"
	m := gfx.NewImage(8, 8)
	p := gfx.PaletteAmmo8

	ticker := time.NewTicker(d)

	for range ticker.C {
		x := gfx.RandIntn(8)
		y := gfx.RandIntn(8)
		c := p.Random()

		m.Set(x, y, c)

		var b bytes.Buffer

		w := bufio.NewWriter(&b)

		gfx.EncodePNG(w, m)

		w.Flush()

		http.Post(u, "image/png", &b)
	}
}