Static streaming from an image in engo

main.go

package main

import (
	"image"
	"image/color"
	"image/color/palette"
	"math/rand"
	"time"

	"github.com/EngoEngine/ecs"
	"github.com/EngoEngine/engo"
	"github.com/EngoEngine/engo/common"
)

type DefaultScene struct{}

func (*DefaultScene) Preload() {}

func (scene *DefaultScene) Setup(u engo.Updater) {
	w, _ := u.(*ecs.World)

	common.SetBackground(color.RGBA{R: 0, G: 255, B: 0, A: 255})

	w.AddSystem(&common.RenderSystem{})
	w.AddSystem(&VideoSystem{})
}

func (*DefaultScene) Type() string { return "GameWorld" }

type VideoSystem struct {
	bg      *background
	elapsed float32
}

type background struct {
	ecs.BasicEntity
	common.RenderComponent
	common.SpaceComponent
}

func (s *VideoSystem) New(w *ecs.World) {
	rand.Seed(time.Now().UnixNano())

	rect := image.Rect(0, 0, 1024, 640)
	s.bg = &background{BasicEntity: ecs.NewBasic()}
	s.bg.SpaceComponent = common.SpaceComponent{
		Position: engo.Point{X: 0, Y: 0},
		Width:    1024,
		Height:   640,
	}

	img := image.NewNRGBA(rect)
	for i := rect.Min.X; i < rect.Max.X; i++ {
		for j := rect.Min.Y; j < rect.Max.Y; j++ {
			img.Set(i, j, palette.Plan9[rand.Intn(len(palette.Plan9))])
		}
	}
	obj := common.NewImageObject(img)

	s.bg.RenderComponent = common.RenderComponent{Drawable: common.NewTextureSingle(obj)}

	for _, system := range w.Systems() {
		switch sys := system.(type) {
		case *common.RenderSystem:
			sys.Add(&s.bg.BasicEntity, &s.bg.RenderComponent, &s.bg.SpaceComponent)
		}
	}
}

func (s *VideoSystem) Add() {}

func (s *VideoSystem) Remove(basic ecs.BasicEntity) {}

func (s *VideoSystem) Update(dt float32) {
	rect := image.Rect(0, 0, 1024, 640)
	img := image.NewNRGBA(rect)
	for i := rect.Min.X; i < rect.Max.X; i++ {
		for j := rect.Min.Y; j < rect.Max.Y; j++ {
			img.Set(i, j, palette.Plan9[rand.Intn(len(palette.Plan9))])
		}
	}
	obj := common.NewImageObject(img)
	tex := common.NewTextureSingle(obj)
	s.bg.Drawable.Close()
	s.bg.Drawable = tex
}

func main() {
	opts := engo.RunOptions{
		Title:  "Animation Demo",
		Width:  1024,
		Height: 640,
	}
	engo.Run(opts, &DefaultScene{})
}