Prepare cscore for merge into allwpilib.

cscore/examples/usbcvstream/usbcvstream.cpp

@@ -0,0 +1,39 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2017-2018 FIRST. All Rights Reserved.                        */
+/* Open Source Software - may be modified and shared by FRC teams. The code   */
+/* must be accompanied by the FIRST BSD license file in the root directory of */
+/* the project.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#include <cstdio>
+#include <iostream>
+
+#include <opencv2/core/core.hpp>
+
+#include "cscore.h"
+
+int main() {
+  cs::UsbCamera camera{"usbcam", 0};
+  camera.SetVideoMode(cs::VideoMode::kMJPEG, 320, 240, 30);
+  cs::MjpegServer mjpegServer{"httpserver", 8081};
+  mjpegServer.SetSource(camera);
+  cs::CvSink cvsink{"cvsink"};
+  cvsink.SetSource(camera);
+  cs::CvSource cvsource{"cvsource", cs::VideoMode::kMJPEG, 320, 240, 30};
+  cs::MjpegServer cvMjpegServer{"cvhttpserver", 8082};
+  cvMjpegServer.SetSource(cvsource);
+
+  cv::Mat test;
+  cv::Mat flip;
+  for (;;) {
+    uint64_t time = cvsink.GrabFrame(test);
+    if (time == 0) {
+      std::cout << "error: " << cvsink.GetError() << std::endl;
+      continue;
+    }
+    std::cout << "got frame at time " << time << " size " << test.size()
+              << std::endl;
+    cv::flip(test, flip, 0);
+    cvsource.PutFrame(flip);
+  }
+}