AUDIO: Allow for changing the OPL timer rate

2 files changed, 26 insertions, 0 deletions

diff --git a/audio/fmopl.cpp b/audio/fmopl.cpp
index c9cb1040d6..07c5b44427 100644
--- a/audio/fmopl.cpp
+++ b/audio/fmopl.cpp
@@ -183,6 +183,14 @@ void OPL::stop() {
 	_callback.reset();
 }
 
+void OPL::setCallbackFrequency(int timerFrequency) {
+	if (!isRunning())
+		return;
+
+	stopCallbacks();
+	startCallbacks(timerFrequency);
+}
+
 bool OPL::_hasInstance = false;
 
 EmulatedOPL::EmulatedOPL() :
@@ -249,4 +257,10 @@ void EmulatedOPL::stopCallbacks() {
 	//g_system->getMixer()->stopHandle(*_handle);
 }
 
+bool EmulatedOPL::isRunning() const {
+	// TODO
+	//return g_system->getMixer()->isSoundHandleActive(*_handle);
+	return true;
+}
+
 } // End of namespace OPL
diff --git a/audio/fmopl.h b/audio/fmopl.h
index 0e2e2b2dda..243cd294e8 100644
--- a/audio/fmopl.h
+++ b/audio/fmopl.h
@@ -175,6 +175,17 @@ public:
 	 */
 	void stop();
 
+	/**
+	 * Is the OPL running?
+	 */
+	virtual bool isRunning() const = 0;
+
+	/**
+	 * Change the callback frequency. This has no effect if start()
+	 * has not already been called.
+	 */
+	void setCallbackFrequency(int timerFrequency);
+
 	enum {
 		/**
 		 * The default callback frequency that start() uses
@@ -206,6 +217,7 @@ public:
 
 	// OPL API
 	int readBuffer(int16 *buffer, const int numSamples);
+	bool isRunning() const;
 
 	int getRate() const;