added cpp file for vision stream display

CMakeLists.txt

+cmake_minimum_required (VERSION 2.8)
+
+project(tello-vision)
+
+find_package(OpenCV REQUIRED)
+
+include_directories(${OpenCV_INCLUDE_DIRS})
+
+add_executable(tello-vision tello-vision.cpp)
+
+target_link_libraries(tello-vision ${OpenCV_LIBS})

tello-vision.cpp

+#include "opencv2/opencv.hpp"
+#include <iostream>
+
+using namespace cv;
+
+int main(int argc, char** argv) {
+
+    Mat frame;
+
+    VideoCapture cap("udp://127.0.0.1:11111",CAP_FFMPEG);
+
+    cap >> frame; // get a first frame!
+
+    for(;;) {
+
+        cap >> frame;
+
+        imshow("tello vision", frame);
+
+        if ( frame.empty() ) break; // end of video stream
+
+        if( waitKey(10) == 27 ) break; // stop capturing by pressing ESC
+
+    }
+
+    // the camera will be closed automatically upon exit
+    cap.release();
+    return 0;
+
+}