hybridgroup.gobot/examples/hello_api_video.go

//go:build example
// +build example

//
// Do not build by default.

package main

import (
	"fmt"
	"net/http"
	"os"

	"github.com/hybridgroup/mjpeg"
	"gobot.io/x/gobot/v2"
	"gobot.io/x/gobot/v2/api"
	"gocv.io/x/gocv"
)

var (
	deviceID int
	err      error
	webcam   *gocv.VideoCapture
	stream   *mjpeg.Stream
)

func main() {
	// parse args
	deviceID := os.Args[1]

	manager := gobot.NewManager()

	a := api.NewAPI(manager)

	// add the standard C3PIO API routes manually.
	a.AddC3PIORoutes()

	// starts the API without the default C2PIO API and Robeaux web interface.
	// However, the C3PIO API was added manually using a.AddC3PIORoutes() which
	// means the REST API will be available, but not the web interface.
	a.StartWithoutDefaults()

	hello := manager.AddRobot(gobot.NewRobot("hello"))

	hello.AddCommand("hi_there", func(params map[string]interface{}) interface{} {
		return fmt.Sprintf("This command is attached to the robot %v", hello.Name)
	})

	// open webcam
	webcam, err = gocv.OpenVideoCapture(deviceID)
	if err != nil {
		fmt.Printf("Error opening capture device: %v\n", deviceID)
		return
	}
	defer webcam.Close()

	// create the mjpeg stream
	stream = mjpeg.NewStream()
	http.Handle("/video", stream)

	// start capturing
	go mjpegCapture()

	if err := manager.Start(); err != nil {
		panic(err)
	}
}

func mjpegCapture() {
	img := gocv.NewMat()
	defer img.Close()

	for {
		if ok := webcam.Read(&img); !ok {
			fmt.Printf("Device closed: %v\n", deviceID)
			return
		}
		if img.Empty() {
			continue
		}

		buf, _ := gocv.IMEncode(".jpg", img)
		stream.UpdateJPEG(buf)
	}
}