Added support for selecting audio capture device (fixes #220)

include/SFML/Audio/SoundRecorder.hpp

@@ -32,6 +32,7 @@
 #include <SFML/System/Thread.hpp>
 #include <SFML/System/Time.hpp>
 #include <vector>
+#include <string>
 
 
 namespace sf
@@ -59,13 +60,20 @@ public :
     /// This function uses its own thread so that it doesn't block
     /// the rest of the program while the capture runs.
     /// Please note that only one capture can happen at the same time.
+    /// You can select which capture device will be used, by passing
+    /// the name to the setDevice() method. If none was selected
+    /// before, the default capture device will be used. You can get a
+    /// list of the names of all available capture devices by calling
+    /// getAvailableDevices().
     ///
     /// \param sampleRate Desired capture rate, in number of samples per second
     ///
-    /// \see stop
+    /// \return True, if start of capture was successful
+    ///
+    /// \see stop, getAvailableDevices
     ///
     ////////////////////////////////////////////////////////////
-    void start(unsigned int sampleRate = 44100);
+    bool start(unsigned int sampleRate = 44100);
 
     ////////////////////////////////////////////////////////////
     /// \brief Stop the capture
@@ -87,6 +95,54 @@ public :
     ////////////////////////////////////////////////////////////
     unsigned int getSampleRate() const;
 
+    ////////////////////////////////////////////////////////////
+    /// \brief Get a list of the names of all availabe audio capture devices
+    ///
+    /// This function returns a vector of strings, containing
+    /// the names of all availabe audio capture devices.
+    ///
+    /// \return A vector of strings containing the names
+    ///
+    ////////////////////////////////////////////////////////////
+    static std::vector<std::string> getAvailableDevices();
+
+    ////////////////////////////////////////////////////////////
+    /// \brief Get the name of the default audio capture device
+    ///
+    /// This function returns the name of the default audio
+    /// capture device. If none is available, an empty string
+    /// is returned.
+    ///
+    /// \return The name of the default audio capture device
+    ///
+    ////////////////////////////////////////////////////////////
+    static std::string getDefaultDevice();
+
+    ////////////////////////////////////////////////////////////
+    /// \brief Set the audio capture device
+    ///
+    /// This function sets the audio capture device to the device
+    /// with the given \a name. It can be called on the fly (i.e:
+    /// while recording). If you do so while recording and
+    /// opening the device fails, it stops the recording.
+    ///
+    /// \param The name of the audio capture device
+    ///
+    /// \return True, if it was able to set the requested device
+    ///
+    /// \see getAvailableDevices, getDefaultDevice
+    ///
+    ////////////////////////////////////////////////////////////
+    bool setDevice(const std::string& name);
+
+    ////////////////////////////////////////////////////////////
+    /// \brief Get the name of the current audio capture device
+    ///
+    /// \return The name of the current audio capture device
+    ///
+    ////////////////////////////////////////////////////////////
+    const std::string& getDevice() const;
+
     ////////////////////////////////////////////////////////////
     /// \brief Check if the system supports audio capture
     ///
@@ -205,6 +261,7 @@ private :
     unsigned int       m_sampleRate;         ///< Sample rate
     sf::Time           m_processingInterval; ///< Time period between calls to onProcessSamples
     bool               m_isCapturing;        ///< Capturing state
+    std::string        m_deviceName;         ///< Name of the audio capture device
 };
 
 } // namespace sf
@@ -244,10 +301,17 @@ private :
 /// availability with the isAvailable() function. If it returns
 /// false, then any attempt to use an audio recorder will fail.
 ///
+/// If you have multiple sound input devices connected to your
+/// computer (for example: microphone, external soundcard, webcam mic, ...)
+/// you can get a list of all available devices throught the
+/// getAvailableDevices() function. You can then select a device
+/// by calling setDevice() with the appropiate device. Otherwise
+/// the default capturing device will be used.
+///
 /// It is important to note that the audio capture happens in a
 /// separate thread, so that it doesn't block the rest of the
-/// program. In particular, the onProcessSamples and onStop
-/// virtual functions (but not onStart) will be called
+/// program. In particular, the onProcessSamples virtual function
+/// (but not onStart and not onStop) will be called
 /// from this separate thread. It is important to keep this in
 /// mind, because you may have to take care of synchronization
 /// issues if you share data between threads.
@@ -285,7 +349,10 @@ private :
 /// if (CustomRecorder::isAvailable())
 /// {
 ///     CustomRecorder recorder;
-///     recorder.start();
+///
+///     if (!recorder.start())
+///         return -1;
+///
 ///     ...
 ///     recorder.stop();
 /// }

src/SFML/Audio/SoundRecorder.cpp

@@ -30,6 +30,7 @@
 #include <SFML/Audio/ALCheck.hpp>
 #include <SFML/System/Sleep.hpp>
 #include <SFML/System/Err.hpp>
+#include <cstring>
 
 #ifdef _MSC_VER
     #pragma warning(disable : 4355) // 'this' used in base member initializer list
@@ -51,6 +52,9 @@ m_isCapturing       (false),
 m_processingInterval(milliseconds(100))
 {
     priv::ensureALInit();
+
+    // Set the device name to the default device
+    m_deviceName = getDefaultDevice();
 }
 
 
@@ -62,28 +66,28 @@ SoundRecorder::~SoundRecorder()
 
 
 ////////////////////////////////////////////////////////////
-void SoundRecorder::start(unsigned int sampleRate)
+bool SoundRecorder::start(unsigned int sampleRate)
 {
     // Check if the device can do audio capture
     if (!isAvailable())
     {
         err() << "Failed to start capture : your system cannot capture audio data (call SoundRecorder::isAvailable to check it)" << std::endl;
-        return;
+        return false;
     }
 
     // Check that another capture is not already running
     if (captureDevice)
     {
         err() << "Trying to start audio capture, but another capture is already running" << std::endl;
-        return;
+        return false;
     }
 
     // Open the capture device for capturing 16 bits mono samples
-    captureDevice = alcCaptureOpenDevice(NULL, sampleRate, AL_FORMAT_MONO16, sampleRate);
+    captureDevice = alcCaptureOpenDevice(m_deviceName.c_str(), sampleRate, AL_FORMAT_MONO16, sampleRate);
     if (!captureDevice)
     {
-        err() << "Failed to open the audio capture device" << std::endl;
-        return;
+        err() << "Failed to open the audio capture device with the name: " << m_deviceName << std::endl;
+        return false;
     }
 
     // Clear the array of samples
@@ -101,7 +105,11 @@ void SoundRecorder::start(unsigned int sampleRate)
         // Start the capture in a new thread, to avoid blocking the main thread
         m_isCapturing = true;
         m_thread.launch();
+
+        return true;
     }
+
+    return false;
 }
 
 
@@ -111,6 +119,9 @@ void SoundRecorder::stop()
     // Stop the capturing thread
     m_isCapturing = false;
     m_thread.wait();
+
+    // Notify derived class
+    onStop();
 }
 
 
@@ -121,6 +132,77 @@ unsigned int SoundRecorder::getSampleRate() const
 }
 
 
+////////////////////////////////////////////////////////////
+std::vector<std::string> SoundRecorder::getAvailableDevices()
+{
+    std::vector<std::string> deviceNameList;
+
+    const ALchar *deviceList = alcGetString(NULL, ALC_CAPTURE_DEVICE_SPECIFIER);
+    if (deviceList)
+    {
+        while (*deviceList)
+        {
+            deviceNameList.push_back(deviceList);
+            deviceList += std::strlen(deviceList) + 1;
+        }
+    }
+
+    return deviceNameList;
+}
+
+
+////////////////////////////////////////////////////////////
+std::string SoundRecorder::getDefaultDevice()
+{
+    return alcGetString(NULL, ALC_CAPTURE_DEFAULT_DEVICE_SPECIFIER);
+}
+
+
+////////////////////////////////////////////////////////////
+bool SoundRecorder::setDevice(const std::string& name)
+{
+    // Store the device name
+    if (name.empty())
+        m_deviceName = getDefaultDevice();
+    else
+        m_deviceName = name;
+
+    if (m_isCapturing)
+    {
+        // Stop the capturing thread
+        m_isCapturing = false;
+        m_thread.wait();
+
+        // Open the requested capture device for capturing 16 bits mono samples
+        captureDevice = alcCaptureOpenDevice(name.c_str(), m_sampleRate, AL_FORMAT_MONO16, m_sampleRate);
+        if (!captureDevice)
+        {
+            // Notify derived class
+            onStop();
+
+            err() << "Failed to open the audio capture device with the name: " << m_deviceName << std::endl;
+            return false;
+        }
+
+        // Start the capture
+        alcCaptureStart(captureDevice);
+
+        // Start the capture in a new thread, to avoid blocking the main thread
+        m_isCapturing = true;
+        m_thread.launch();
+    }
+
+    return true;
+}
+
+
+////////////////////////////////////////////////////////////
+const std::string& SoundRecorder::getDevice() const
+{
+    return m_deviceName;
+}
+
+
 ////////////////////////////////////////////////////////////
 bool SoundRecorder::isAvailable()
 {
@@ -165,9 +247,6 @@ void SoundRecorder::record()
 
     // Capture is finished : clean up everything
     cleanup();
-
-    // Notify derived class
-    onStop();
 }