Visual Servoing Platform version 3.5.0
tutorial-grabber-opencv-threaded.cpp
1
3#include <iostream>
4
5#include <visp3/core/vpImageConvert.h>
6#include <visp3/core/vpMutex.h>
7#include <visp3/core/vpThread.h>
8#include <visp3/core/vpTime.h>
9#include <visp3/gui/vpDisplayGDI.h>
10#include <visp3/gui/vpDisplayX.h>
11
12#if (VISP_HAVE_OPENCV_VERSION >= 0x020100) && (defined(VISP_HAVE_PTHREAD) || defined(_WIN32))
13
14#include <opencv2/highgui/highgui.hpp>
15
16// Shared vars
17typedef enum { capture_waiting, capture_started, capture_stopped } t_CaptureState;
18t_CaptureState s_capture_state = capture_waiting;
19cv::Mat s_frame;
20vpMutex s_mutex_capture;
22
24vpThread::Return captureFunction(vpThread::Args args)
25{
26 cv::VideoCapture cap = *((cv::VideoCapture *)args);
27
28 if (!cap.isOpened()) { // check if we succeeded
29 std::cout << "Unable to start capture" << std::endl;
30 return 0;
31 }
32
33 cv::Mat frame_;
34 int i = 0;
35 while ((i++ < 100) && !cap.read(frame_)) {
36 }; // warm up camera by skiping unread frames
37
38 bool stop_capture_ = false;
39
40 double start_time = vpTime::measureTimeSecond();
41 while ((vpTime::measureTimeSecond() - start_time) < 30 && !stop_capture_) {
42 // Capture in progress
43 cap >> frame_; // get a new frame from camera
44
45 // Update shared data
46 {
47 vpMutex::vpScopedLock lock(s_mutex_capture);
48 if (s_capture_state == capture_stopped)
49 stop_capture_ = true;
50 else
51 s_capture_state = capture_started;
52 s_frame = frame_;
53 }
54 }
55
56 {
57 vpMutex::vpScopedLock lock(s_mutex_capture);
58 s_capture_state = capture_stopped;
59 }
60
61 std::cout << "End of capture thread" << std::endl;
62 return 0;
63}
65
67vpThread::Return displayFunction(vpThread::Args args)
68{
69 (void)args; // Avoid warning: unused parameter args
71
72 t_CaptureState capture_state_;
73 bool display_initialized_ = false;
74#if defined(VISP_HAVE_X11)
75 vpDisplayX *d_ = NULL;
76#elif defined(VISP_HAVE_GDI)
77 vpDisplayGDI *d_ = NULL;
78#endif
79
80 do {
81 s_mutex_capture.lock();
82 capture_state_ = s_capture_state;
83 s_mutex_capture.unlock();
84
85 // Check if a frame is available
86 if (capture_state_ == capture_started) {
87 // Get the frame and convert it to a ViSP image used by the display
88 // class
89 {
90 vpMutex::vpScopedLock lock(s_mutex_capture);
91 vpImageConvert::convert(s_frame, I_);
92 }
93
94 // Check if we need to initialize the display with the first frame
95 if (!display_initialized_) {
96// Initialize the display
97#if defined(VISP_HAVE_X11)
98 d_ = new vpDisplayX(I_);
99 display_initialized_ = true;
100#elif defined(VISP_HAVE_GDI)
101 d_ = new vpDisplayGDI(I_);
102 display_initialized_ = true;
103#endif
104 }
105
106 // Display the image
108
109 // Trigger end of acquisition with a mouse click
110 vpDisplay::displayText(I_, 10, 10, "Click to exit...", vpColor::red);
111 if (vpDisplay::getClick(I_, false)) {
112 vpMutex::vpScopedLock lock(s_mutex_capture);
113 s_capture_state = capture_stopped;
114 }
115
116 // Update the display
118 } else {
119 vpTime::wait(2); // Sleep 2ms
120 }
121 } while (capture_state_ != capture_stopped);
122
123#if defined(VISP_HAVE_X11) || defined(VISP_HAVE_GDI)
124 delete d_;
125#endif
126
127 std::cout << "End of display thread" << std::endl;
128 return 0;
129}
131
133int main(int argc, const char *argv[])
134{
135 int opt_device = 0;
136
137 // Command line options
138 for (int i = 0; i < argc; i++) {
139 if (std::string(argv[i]) == "--camera_device")
140 opt_device = atoi(argv[i + 1]);
141 else if (std::string(argv[i]) == "--help") {
142 std::cout << "Usage: " << argv[0] << " [--camera_device <camera device (default: 0)>] [--help]" << std::endl;
143 return 0;
144 }
145 }
146
147 // Instanciate the capture
148 cv::VideoCapture cap;
149 cap.open(opt_device);
150
151 // Start the threads
152 vpThread thread_capture((vpThread::Fn)captureFunction, (vpThread::Args)&cap);
153 vpThread thread_display((vpThread::Fn)displayFunction);
154
155 // Wait until thread ends up
156 thread_capture.join();
157 thread_display.join();
158
159 return 0;
160}
162
163#else
164int main()
165{
166#ifndef VISP_HAVE_OPENCV
167 std::cout << "You should install OpenCV to make this example working..." << std::endl;
168#elif !defined(_WIN32) && (defined(__unix__) || defined(__unix) || (defined(__APPLE__) && defined(__MACH__))) // UNIX
169 std::cout << "You should enable pthread usage and rebuild ViSP..." << std::endl;
170#else
171 std::cout << "Multi-threading seems not supported on this platform" << std::endl;
172#endif
173}
174
175#endif
static const vpColor red
Definition: vpColor.h:217
Display for windows using GDI (available on any windows 32 platform).
Definition: vpDisplayGDI.h:129
Use the X11 console to display images on unix-like OS. Thus to enable this class X11 should be instal...
Definition: vpDisplayX.h:135
static bool getClick(const vpImage< unsigned char > &I, bool blocking=true)
static void display(const vpImage< unsigned char > &I)
static void flush(const vpImage< unsigned char > &I)
static void displayText(const vpImage< unsigned char > &I, const vpImagePoint &ip, const std::string &s, const vpColor &color)
static void convert(const vpImage< unsigned char > &src, vpImage< vpRGBa > &dest)
Class that allows protection by mutex.
Definition: vpMutex.h:171
void unlock()
Definition: vpMutex.h:111
void lock()
Definition: vpMutex.h:95
void * Return
Definition: vpThread.h:78
void *(* Fn)(Args)
Definition: vpThread.h:79
void * Args
Definition: vpThread.h:77
VISP_EXPORT int wait(double t0, double t)
VISP_EXPORT double measureTimeSecond()