From 1ce43da7ac284aca5e2def87952d1d9efc125e4a Mon Sep 17 00:00:00 2001
From: bruce <bruces1@gmail.com>
Date: Mon, 23 Dec 2013 15:51:29 +0800
Subject: [PATCH] Add some quick and dirty MIDI pitch wheel control.

---
 Source/PluginProcessor.cpp | 19 +++++++++++++++++++
 Source/PluginProcessor.h   |  2 ++
 Source/hiopl.cpp           | 15 ++++++++++-----
 Source/hiopl.h             |  1 +
 4 files changed, 32 insertions(+), 5 deletions(-)

diff --git a/Source/PluginProcessor.cpp b/Source/PluginProcessor.cpp
index 0c1777f..ea71510 100644
--- a/Source/PluginProcessor.cpp
+++ b/Source/PluginProcessor.cpp
@@ -120,6 +120,7 @@ JuceOplvstiAudioProcessor::JuceOplvstiAudioProcessor()
 	for (int i = 0; i < Hiopl::CHANNELS+1; i++) {
 		active_notes[i] = NO_NOTE;
 	}
+	currentScaledBend = 1.0f;
 }
 
 void JuceOplvstiAudioProcessor::initPrograms()
@@ -366,6 +367,17 @@ void JuceOplvstiAudioProcessor::initPrograms()
 
 }
 
+void JuceOplvstiAudioProcessor::applyPitchBend()
+{   // apply the currently configured pitch bend to all active notes.
+	for (int i = 1; i <= Hiopl::CHANNELS; i++) {
+		if (NO_NOTE != active_notes[i]) {
+			float f = (float)MidiMessage::getMidiNoteInHertz(active_notes[i]);
+			f *= currentScaledBend;
+			Opl->SetFrequency(i, f);
+		}
+	}
+}
+
 JuceOplvstiAudioProcessor::~JuceOplvstiAudioProcessor()
 {
 }
@@ -658,6 +670,7 @@ void JuceOplvstiAudioProcessor::processBlock (AudioSampleBuffer& buffer, MidiBuf
 			}
 			Opl->KeyOn(ch, noteHz);
 			active_notes[ch] = n;
+			applyPitchBend();
 		}
 		else if (midi_message.isNoteOff()) {
 			int n = midi_message.getNoteNumber();
@@ -668,6 +681,12 @@ void JuceOplvstiAudioProcessor::processBlock (AudioSampleBuffer& buffer, MidiBuf
 			Opl->KeyOff(ch);
 			active_notes[ch] = NO_NOTE;
 		}
+		else if (midi_message.isPitchWheel()) {
+			int bend = midi_message.getPitchWheelValue() - 0x2000;	// range -8192 to 8191
+			// 1.05946309436 == (2^(1/1200))^100 == 1 semitone == 100 cents
+			currentScaledBend = 1.0f + bend * .05775f / 8192;
+			applyPitchBend();
+		}
 	}
 	Opl->Generate(buffer.getNumSamples(), buffer.getSampleData(0));
 }
diff --git a/Source/PluginProcessor.h b/Source/PluginProcessor.h
index 1118cc4..e3cac2f 100644
--- a/Source/PluginProcessor.h
+++ b/Source/PluginProcessor.h
@@ -24,6 +24,7 @@ public:
     //==============================================================================
     JuceOplvstiAudioProcessor();
 	void initPrograms();
+	void applyPitchBend();
     ~JuceOplvstiAudioProcessor();
 
     //==============================================================================
@@ -88,6 +89,7 @@ private:
 	bool velocity;
 	static const int NO_NOTE=-1;
 	int active_notes[Hiopl::CHANNELS+1];	// keyed by channel
+	float currentScaledBend;
 
     //==============================================================================
     JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (JuceOplvstiAudioProcessor)
diff --git a/Source/hiopl.cpp b/Source/hiopl.cpp
index 2d370ab..f6d520b 100644
--- a/Source/hiopl.cpp
+++ b/Source/hiopl.cpp
@@ -160,11 +160,7 @@ void Hiopl::SetModulatorFeedback(int ch, int level) {
 }
 
 void Hiopl::KeyOn(int ch, float frqHz) {
-	unsigned int fnum, block;
-	int offset = this->_GetOffset(ch);
-	_milliHertzToFnum((unsigned int)(frqHz * 1000.0), &fnum, &block);
-	_WriteReg(0xa0+offset, fnum % 0x100);
-	_WriteReg(0xb0+offset, 0x20|((block&0x7)<<2)|(0x3&(fnum/0x100)));
+	Hiopl::SetFrequency(ch, frqHz, true);
 }
 
 void Hiopl::KeyOff(int ch) {
@@ -172,6 +168,15 @@ void Hiopl::KeyOff(int ch) {
 	_ClearRegBits(0xb0+offset, 0x20);
 }
 
+void Hiopl::SetFrequency(int ch, float frqHz, bool keyOn) {
+	unsigned int fnum, block;
+	int offset = this->_GetOffset(ch);
+	_milliHertzToFnum((unsigned int)(frqHz * 1000.0), &fnum, &block);
+	_WriteReg(0xa0+offset, fnum % 0x100);
+	uint8 trig = (regCache[0xb0+offset] & 0x20) | (keyOn ? 0x20 : 0x00);
+	_WriteReg(0xb0+offset, trig|((block&0x7)<<2)|(0x3&(fnum/0x100)));
+}
+
 // from libgamemusic, opl-util.cpp
 void Hiopl::_milliHertzToFnum(unsigned int milliHertz,
 	unsigned int *fnum, unsigned int *block, unsigned int conversionFactor)
diff --git a/Source/hiopl.h b/Source/hiopl.h
index 34f36e6..bd05bfe 100644
--- a/Source/hiopl.h
+++ b/Source/hiopl.h
@@ -46,6 +46,7 @@ class Hiopl {
 		void SetModulatorFeedback(int ch, int level);
 		void KeyOn(int ch, float frqHz);
 		void KeyOff(int ch);
+		void SetFrequency(int ch, float frqHz, bool keyOn=false);
 		void _WriteReg(Bit32u reg, Bit8u value, Bit8u mask=0x0);
 		void _ClearRegBits(Bit32u reg, Bit8u mask);
 		~Hiopl();