examples: add example that uses both the API and also a custom handle…

…r with MJPEG streaming from an attached camera

Signed-off-by: Ron Evans <[email protected]>

examples/hello_api_video.go

@@ -0,0 +1,78 @@
+// +build example
+//
+// Do not build by default.
+
+package main
+
+import (
+	"fmt"
+	"net/http"
+	"os"
+
+	"github.com/hybridgroup/mjpeg"
+	"gobot.io/x/gobot"
+	"gobot.io/x/gobot/api"
+	"gocv.io/x/gocv"
+)
+
+var (
+	deviceID int
+	err      error
+	webcam   *gocv.VideoCapture
+	stream   *mjpeg.Stream
+)
+
+func main() {
+	// parse args
+	deviceID := os.Args[1]
+
+	master := gobot.NewMaster()
+
+	a := api.NewAPI(master)
+	a.AddC3PIORoutes()
+	a.AddRobeauxRoutes()
+	a.StartRaw()
+
+	hello := master.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()
+
+	// start capturing
+	go mjpegCapture()
+
+	// handle video stream
+	http.Handle("/video", stream)
+
+	master.Start()
+}
+
+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)
+	}
+}