implemented graceful program termination and proper error reporting

modules/v4d/include/opencv2/v4d/util.hpp

@@ -57,7 +57,8 @@ class CV_EXPORTS Global {
 	inline static std::thread::id main_thread_id_;
 	inline static thread_local bool is_main_;
 	inline static size_t workers_ready_ = 0;
-    inline static size_t workers_running_ = 0;
+    inline static size_t workers_started_ = 0;
+    inline static size_t next_worker_idx_ = 0;
 public:
 	CV_EXPORTS static std::mutex& mutex() {
     	return mtx_;
@@ -86,6 +87,7 @@ public:
 	CV_EXPORTS static const std::thread::id& default_id() {
     	return default_thread_id_;
     }
+
 	CV_EXPORTS static std::thread::id& main_id() {
     	return main_thread_id_;
     }
@@ -95,12 +97,20 @@ public:
 		return is_main_;
 	}
 
-	CV_EXPORTS static size_t& workers_ready() {
+	CV_EXPORTS static size_t& workers_started() {
-		return workers_ready_;
+		return workers_started_;
+	}
+
+	CV_EXPORTS static size_t next_worker_ready() {
+	    static std::mutex mtx;
+	    std::unique_lock<std::mutex> lock(mtx);
+		return ++workers_ready_;
 	}
 
-	CV_EXPORTS static size_t& workers_running() {
+	CV_EXPORTS static size_t next_worker_idx() {
-		return workers_running_;
+	    static std::mutex mtx;
+	    std::unique_lock<std::mutex> lock(mtx);
+		return next_worker_idx_++;
 	}
 };
 

modules/v4d/include/opencv2/v4d/v4d.hpp

@@ -576,6 +576,7 @@ public:
 				bool debug = this->debug_;
 				auto src = this->getSource();
 				auto sink = this->getSink();
+				Global::workers_started() = workers;
 				for (size_t i = 0; i < workers; ++i) {
 					threads.push_back(
 						new std::thread(
@@ -596,15 +597,6 @@ public:
 						)
 					);
 				}
-
-
-				for (int32_t i = 0; i < workers; ++i) {
-					CV_Assert(i >= 0);
-					if(!threads[i]->joinable()) {
-						--i;
-						std::this_thread::sleep_for(1ms);
-					}
-				}
 			}
 		}
 
@@ -620,18 +612,18 @@ public:
 			this->makePlan();
 			this->runPlan();
 			this->clearPlan();
-			if(!Global::is_main() && Global::workers_running() == Global::workers_ready()) {
+			if(!Global::is_main() && Global::workers_started() == Global::next_worker_ready()) {
 				cv::utils::logging::setLogLevel(cv::utils::logging::LOG_LEVEL_INFO);
 			}
 		} catch(std::exception& ex) {
-			CV_Error_(cv::Error::StsError, ("Setup plan failed: %s", ex.what()));
+			CV_Error_(cv::Error::StsError, ("pipeline setup failed: %s", ex.what()));
 		}
 
 		if(Global::is_main()) {
 			try {
 				plan->gui(self());
 			} catch(std::exception& ex) {
-				CV_Error_(cv::Error::StsError, ("GUI failed: %s", ex.what()));
+				CV_Error_(cv::Error::StsError, ("GUI setup failed: %s", ex.what()));
 			}
 		}
 
@@ -665,7 +657,7 @@ public:
 		} catch(std::exception& ex) {
 			requestFinish();
 			reseq.finish();
-			CV_Error_(cv::Error::StsError, ("Run plan failed: %s", ex.what()));
+			CV_LOG_WARNING(nullptr, "-> pipeline terminated: " << ex.what());
 		}
 
 		this->clearPlan();
@@ -676,7 +668,7 @@ public:
 			this->runPlan();
 			this->clearPlan();
 		} catch(std::exception& ex) {
-			CV_Error_(cv::Error::StsError, ("Tear-down plan failed: %s", ex.what()));
+			CV_Error_(cv::Error::StsError, ("pipeline tear-down failed: %s", ex.what()));
 		}
 
 		if(Global::is_main()) {

modules/v4d/src/detail/sourcecontext.cpp

@@ -25,7 +25,7 @@ void SourceContext::execute(std::function<void()> fn) {
 				currentSeqNr_ = p.first;
 
 				if(p.second.empty()) {
-					throw std::runtime_error("End of stream");
+					CV_Error(cv::Error::StsError, "End of stream");
 				}
 
 				resizePreserveAspectRatio(p.second, captureBufferRGB_, mainFbContext_->size());
@@ -42,7 +42,7 @@ void SourceContext::execute(std::function<void()> fn) {
 				currentSeqNr_ = p.first;
 
 				if(p.second.empty()) {
-					throw std::runtime_error("End of stream");
+					CV_Error(cv::Error::StsError, "End of stream");
 				}
 				resizePreserveAspectRatio(p.second, captureBufferRGB_, mainFbContext_->size());
 				cv::cvtColor(captureBufferRGB_, sourceBuffer(), cv::COLOR_RGB2BGRA);

modules/v4d/src/v4d.cpp

@@ -55,7 +55,7 @@ V4D::V4D(const cv::Size& size, const cv::Size& fbsize, const string& title, Allo
 
 V4D::V4D(const V4D& other, const string& title) :
         initialSize_(other.initialSize_), debug_(other.debug_), viewport_(0, 0, other.fbSize().width, other.fbSize().height), stretching_(other.stretching_), samples_(other.samples_) {
-    workerIdx_ = Global::workers_running()++;
+	workerIdx_ = Global::next_worker_idx();
     self_ = cv::Ptr<V4D>(this);
     mainFbContext_ = new detail::FrameBufferContext(*this, other.fbSize(), !other.debug_, title, 3,
                 2, other.samples_, other.debug_, other.fbCtx()->rootWindow_, other.fbCtx(), true);
@@ -81,7 +81,7 @@ const int32_t& V4D::workerIndex() const {
 }
 
 size_t V4D::workers_running() {
-	return Global::workers_running();
+	return Global::workers_started();
 }
 
 cv::ogl::Texture2D& V4D::texture() {
@@ -371,10 +371,16 @@ bool V4D::display() {
 	if (Global::is_main()) {
 		auto start = Global::start_time();
 		auto now = get_epoch_nanos();
+		auto diff = now - start;
+		double diffSeconds = diff / 1000000000.0;
+
+		if(Global::fps() > 0 && diffSeconds > 1.0) {
+			Global::start_time() += (diff / 2.0);
+			Global::frame_cnt() /= 2.0;
+		} else {
+			Global::fps() = (Global::fps() * 3.0 + (Global::frame_cnt() / diffSeconds)) / 4.0;
+		}
 
-		double diff_seconds = (now - start) / 1000000000.0;
-
-		Global::fps() = (Global::frame_cnt()) / diff_seconds;
 		if(getPrintFPS())
 			cerr << "\rFPS:" << Global::fps() << endl;
 		{