func connect()

in vncgl/vncgl.go [215:320]
89 lines of code
12 McCabe index (conditional complexity)

func connect(imgs chan *image.RGBA) (*vncclient.ClientConn, error) {
	tcp, err := net.Dial("tcp", "172.16.163.128:5900")
	if err != nil {
		return nil, errors.Annotate(err, "could not connect to server")
	}

	errCh := make(chan error)
	serverMessageCh := make(chan vncclient.ServerMessage)
	conn, err, _ := vncclient.Client(tcp, &vncclient.ClientConfig{
		Auth: []vncclient.ClientAuth{
			&vncclient.PasswordAuth{
				Password: "openai",
			},
		},
		ServerMessageCh: serverMessageCh,
		ErrorCh:         errCh,
	})
	if err != nil {
		return nil, errors.Annotate(err, "could not establish VNC connection to server")
	}

	go func() {
		err := <-errCh
		panic(errors.ErrorStack(err))
	}()

	updates := make(chan *vncclient.FramebufferUpdateMessage)

	// Message thread
	go func() {
		// Ensure standard format
		conn.SetPixelFormat(&vncclient.PixelFormat{
			BPP:        32,
			Depth:      24,
			BigEndian:  false,
			TrueColor:  true,
			RedMax:     255,
			GreenMax:   255,
			BlueMax:    255,
			RedShift:   0,
			GreenShift: 8,
			BlueShift:  16,
		})

		conn.SetEncodings([]vncclient.Encoding{
			&vncclient.ZRLEEncoding{},
			&vncclient.TightEncoding{},
			&vncclient.RawEncoding{},
		})

		conn.FramebufferUpdateRequest(true, 0, 0, conn.FramebufferWidth, conn.FramebufferHeight)

		for {
			select {
			case msg := <-serverMessageCh:
				switch msg := msg.(type) {
				case *vncclient.FramebufferUpdateMessage:
					updates <- msg
					// Keep re-requesting!
					conn.FramebufferUpdateRequest(true, 0, 0, conn.FramebufferWidth, conn.FramebufferHeight)
				}
			}
		}
	}()

	vncgl := &VNCGL{}
	if err := vncgl.Init(conn.FramebufferWidth, conn.FramebufferHeight, conn.DesktopName, nil); err != nil {
		return nil, err
	}

	// Apply those updates
	var frames int
	target := time.Now().UnixNano()
	printTarget := time.Now().UnixNano()
	for {
		target += int64(1000 * 1000 * 1000 / 60)
		frames += 1

		if time.Now().UnixNano() > printTarget {
			printTarget = time.Now().UnixNano() + 1000*1000*1000
			log.Infof("effective framerate: %v", frames)
			frames = 0
		}

		var done bool
		for !done {
			select {
			case msg := <-updates:
				msgs := []*vncclient.FramebufferUpdateMessage{msg}
				vncgl.Apply(msgs)
			default:
				done = true
			}
		}

		vncgl.Render()

		delta := time.Duration(target-time.Now().UnixNano()) * time.Nanosecond
		if delta > 0 {
			log.Infof("sleeping: %v", delta)
			time.Sleep(delta)
		} else {
			log.Infof("fell behind by: %v", delta)
		}
	}
}