intial commit

webcam.h

@@ -0,0 +1,68 @@
+/** Small C++ wrapper around V4L example code to access the webcam
+**/
+
+#include <string>
+#include <memory> // unique_ptr
+#include <cstdint>
+
+#include "image.h"
+
+struct buffer {
+      void   *data;
+      size_t  size;
+};
+
+
+class Webcam {
+
+public:
+    Webcam(const std::string& device = "/dev/video0", 
+           int width = 640, 
+           int height = 480, bool mjpeg = false);
+
+    ~Webcam();
+
+    /** Captures and returns a frame from the webcam.
+     *
+     * The returned object contains a field 'data' with the image data in RGB888
+     * format (ie, RGB24), as well as 'width', 'height' and 'size' (equal to
+     * width * height * 3)
+     *
+     * This call blocks until a frame is available or until the provided
+     * timeout (in seconds). 
+     *
+     * Throws a runtime_error if the timeout is reached.
+     */
+    const Image& frame(int timeout = 2);
+
+private:
+    void init_mmap();
+
+    void open_device();
+    void close_device();
+
+    void init_device();
+    void uninit_device();
+
+    void start_capturing();
+    void stop_capturing();
+
+    bool read_frame();
+
+    std::string device;
+    int fd;
+
+    Image rgb_frame;
+    struct buffer *buffers;
+    unsigned int n_buffers;
+
+    size_t xres, yres;
+    size_t stride;
+
+    bool force_format = true;
+    uint32_t format;
+};
+
+
+
+