From 4d5658511228328a9e56d32448f9b598ecda696c Mon Sep 17 00:00:00 2001
From: Matthew Hoops
Date: Thu, 14 May 2015 21:07:46 -0400
Subject: AUDIO: Add a class representing a real OPL

---
 audio/fmopl.h | 43 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)

(limited to 'audio/fmopl.h')

diff --git a/audio/fmopl.h b/audio/fmopl.h
index 091e0bd88d..ba0872d87b 100644
--- a/audio/fmopl.h
+++ b/audio/fmopl.h
@@ -106,8 +106,14 @@ private:
 	static const EmulatorDescription _drivers[];
 };
 
+/**
+ * The type of the OPL timer callback functor.
+ */
 typedef Common::Functor0<void> TimerCallback;
 
+/**
+ * A representation of a Yamaha OPL chip.
+ */
 class OPL {
 private:
 	static bool _hasInstance;
@@ -194,6 +200,43 @@ protected:
 	Common::ScopedPtr<TimerCallback> _callback;
 };
 
+/**
+ * An OPL that represents a real OPL, as opposed to an emulated one.
+ *
+ * This will use an actual timer instead of using one calculated from
+ * the number of samples in an AudioStream::readBuffer call.
+ */
+class RealOPL : public OPL {
+public:
+	RealOPL();
+	virtual ~RealOPL();
+
+	// OPL API
+	void setCallbackFrequency(int timerFrequency);
+
+protected:
+	// OPL API
+	void startCallbacks(int timerFrequency);
+	void stopCallbacks();
+
+private:
+	static void timerProc(void *refCon);
+	void onTimer();
+
+	uint _baseFreq;
+	uint _remainingTicks;
+
+	enum {
+		kMaxFreq = 100
+	};
+};
+
+/**
+ * An OPL that represents an emulated OPL.
+ *
+ * This will send callbacks based on the number of samples
+ * decoded in readBuffer().
+ */
 class EmulatedOPL : public OPL, protected Audio::AudioStream {
 public:
 	EmulatedOPL();
-- 
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