Gui/FrameDisplayer: all visualization functions moved to same thread

README.md

@@ -69,8 +69,9 @@ The pose estimation work is based on the C++ code from [the ECCV 2016 demo](http
 3. [Output](#output)
     1. [Output Format](#output-format)
     2. [Reading Saved Results](#reading-saved-results)
-4. [Send Us Your Feedback!](#send-us-your-feedback)
-5. [Citation](#citation)
+4. [OpenPose Benchmark](#openpose-benchmark)
+5. [Send Us Your Feedback!](#send-us-your-feedback)
+6. [Citation](#citation)
 
 
 
@@ -202,8 +203,6 @@ Just comment on GibHub or make a pull request and we will answer as soon as poss
 ## Citation
 Please cite the papers in your publications if it helps your research:
 
-### Pose Estimation
-
     @inproceedings{cao2017realtime,
       author = {Zhe Cao and Tomas Simon and Shih-En Wei and Yaser Sheikh},
       booktitle = {CVPR},

include/openpose/gui/frameDisplayer.hpp

@@ -21,6 +21,9 @@ namespace op
          */
         FrameDisplayer(const cv::Size& windowedSize, const std::string& windowedName = "OpenPose Display", const bool fullScreen = false);
 
+        // Due to OpenCV visualization issues (all visualization functions must be in the same thread)
+        void initializationOnThread();
+
         /**
          * This function set the new FrameDisplayer::GuiDisplayMode (e.g. full screen).
          * @param displayMode New FrameDisplayer::GuiDisplayMode state.

include/openpose/gui/gui.hpp

@@ -18,6 +18,8 @@ namespace op
             const std::shared_ptr<std::pair<std::atomic<bool>, std::atomic<int>>>& videoSeekSharedPtr = nullptr,
             const std::vector<std::shared_ptr<PoseExtractor>>& poseExtractors = {}, const std::vector<std::shared_ptr<PoseRenderer>>& poseRenderers = {});
 
+        void initializationOnThread();
+
         void update(const cv::Mat& cvOutputData = cv::Mat{});
 
     private:

include/openpose/gui/wGui.hpp

@@ -41,6 +41,7 @@ namespace op
     WGui<TDatums>::WGui(const std::shared_ptr<Gui>& gui) :
         spGui{gui}
     {
+        spGui->initializationOnThread();
     }
 
     template<typename TDatums>

src/openpose/gui/frameDisplayer.cpp

@@ -8,6 +8,10 @@ namespace op
         mWindowedSize{windowedSize},
         mWindowName{windowedName},
         mGuiDisplayMode{(fullScreen ? GuiDisplayMode::FullScreen : GuiDisplayMode::Windowed)}
+    {
+    }
+
+    void FrameDisplayer::initializationOnThread()
     {
         try
         {
@@ -15,7 +19,8 @@ namespace op
 
             const cv::Mat blackFrame{mWindowedSize.height, mWindowedSize.width, CV_32FC3, {0,0,0}};
             FrameDisplayer::displayFrame(blackFrame);
-            cv::waitKey(100);
+            cv::waitKey(1); // This one will show most probably a white image (I guess the program does not have time to render in 1 msec)
+            // cv::waitKey(1000); // This one will show the desired black image
         }
         catch (const std::exception& e)
         {

src/openpose/gui/gui.cpp

@@ -160,6 +160,11 @@ namespace op
     {
     }
 
+    void Gui::initializationOnThread()
+    {
+        mFrameDisplayer.initializationOnThread();
+    }
+
     void Gui::update(const cv::Mat& cvOutputData)
     {
         try