From 73e4516257b952987b8904a05b087305ffcbdfcb Mon Sep 17 00:00:00 2001
From: Jeffrey Pfau <jeffrey@endrift.com>
Date: Sun, 5 Apr 2015 01:39:10 -0700
Subject: [PATCH] GBA Audio: Ability to mute individual audio channels

---
 CHANGES                    |  1 +
 src/gba/audio.c            | 87 +++++++++++++++++++++++---------------
 src/gba/audio.h            |  4 ++
 src/platform/qt/Window.cpp | 25 +++++++++++
 4 files changed, 83 insertions(+), 34 deletions(-)

diff --git a/CHANGES b/CHANGES
index 4aacbb2bb..f0747acad 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,6 +1,7 @@
 0.3.0: (Future)
 Features:
  - Ability to hide individual background layers, or OBJs
+ - Ability to mute individual audio channels
 Bugfixes:
  - GBA: Fix timers not updating timing when writing to only the reload register
  - All: Fix sanitize-deb script not cleaning up after itself
diff --git a/src/gba/audio.c b/src/gba/audio.c
index 974132801..90d0bab20 100644
--- a/src/gba/audio.c
+++ b/src/gba/audio.c
@@ -41,6 +41,13 @@ void GBAAudioInit(struct GBAAudio* audio, size_t samples) {
 #endif
 	CircleBufferInit(&audio->chA.fifo, GBA_AUDIO_FIFO_SIZE);
 	CircleBufferInit(&audio->chB.fifo, GBA_AUDIO_FIFO_SIZE);
+
+	audio->forceDisableCh[0] = false;
+	audio->forceDisableCh[1] = false;
+	audio->forceDisableCh[2] = false;
+	audio->forceDisableCh[3] = false;
+	audio->forceDisableChA = false;
+	audio->forceDisableChB = false;
 }
 
 void GBAAudioReset(struct GBAAudio* audio) {
@@ -750,55 +757,67 @@ static void _sample(struct GBAAudio* audio) {
 	int16_t sampleRight = 0;
 	int psgShift = 5 - audio->volume;
 
-	if (audio->ch1Left) {
-		sampleLeft += audio->ch1.sample;
+	if (audio->playingCh1 && !audio->forceDisableCh[0]) {
+		if (audio->ch1Left) {
+			sampleLeft += audio->ch1.sample;
+		}
+
+		if (audio->ch1Right) {
+			sampleRight += audio->ch1.sample;
+		}
 	}
 
-	if (audio->ch1Right) {
-		sampleRight += audio->ch1.sample;
+	if (audio->playingCh2 && !audio->forceDisableCh[1]) {
+		if (audio->ch2Left) {
+			sampleLeft += audio->ch2.sample;
+		}
+
+		if (audio->ch2Right) {
+			sampleRight += audio->ch2.sample;
+		}
 	}
 
-	if (audio->ch2Left) {
-		sampleLeft += audio->ch2.sample;
+	if (audio->playingCh3 && !audio->forceDisableCh[2]) {
+		if (audio->ch3Left) {
+			sampleLeft += audio->ch3.sample;
+		}
+
+		if (audio->ch3Right) {
+			sampleRight += audio->ch3.sample;
+		}
 	}
 
-	if (audio->ch2Right) {
-		sampleRight += audio->ch2.sample;
-	}
+	if (audio->playingCh4 && !audio->forceDisableCh[3]) {
+		if (audio->ch4Left) {
+			sampleLeft += audio->ch4.sample;
+		}
 
-	if (audio->ch3Left) {
-		sampleLeft += audio->ch3.sample;
-	}
-
-	if (audio->ch3Right) {
-		sampleRight += audio->ch3.sample;
-	}
-
-	if (audio->ch4Left) {
-		sampleLeft += audio->ch4.sample;
-	}
-
-	if (audio->ch4Right) {
-		sampleRight += audio->ch4.sample;
+		if (audio->ch4Right) {
+			sampleRight += audio->ch4.sample;
+		}
 	}
 
 	sampleLeft = (sampleLeft * (1 + audio->volumeLeft)) >> psgShift;
 	sampleRight = (sampleRight * (1 + audio->volumeRight)) >> psgShift;
 
-	if (audio->chALeft) {
-		sampleLeft += (audio->chA.sample << 2) >> !audio->volumeChA;
+	if (!audio->forceDisableChA) {
+		if (audio->chALeft) {
+			sampleLeft += (audio->chA.sample << 2) >> !audio->volumeChA;
+		}
+
+		if (audio->chARight) {
+			sampleRight += (audio->chA.sample << 2) >> !audio->volumeChA;
+		}
 	}
 
-	if (audio->chARight) {
-		sampleRight += (audio->chA.sample << 2) >> !audio->volumeChA;
-	}
+	if (!audio->forceDisableChB) {
+		if (audio->chBLeft) {
+			sampleLeft += (audio->chB.sample << 2) >> !audio->volumeChB;
+		}
 
-	if (audio->chBLeft) {
-		sampleLeft += (audio->chB.sample << 2) >> !audio->volumeChB;
-	}
-
-	if (audio->chBRight) {
-		sampleRight += (audio->chB.sample << 2) >> !audio->volumeChB;
+		if (audio->chBRight) {
+			sampleRight += (audio->chB.sample << 2) >> !audio->volumeChB;
+		}
 	}
 
 	sampleLeft = _applyBias(audio, sampleLeft);
diff --git a/src/gba/audio.h b/src/gba/audio.h
index 91cc84b1b..52662a984 100644
--- a/src/gba/audio.h
+++ b/src/gba/audio.h
@@ -236,6 +236,10 @@ struct GBAAudio {
 	int32_t nextSample;
 
 	int32_t sampleInterval;
+
+	bool forceDisableCh[4];
+	bool forceDisableChA;
+	bool forceDisableChB;
 };
 
 struct GBAStereoSample {
diff --git a/src/platform/qt/Window.cpp b/src/platform/qt/Window.cpp
index 01e21d221..b1c214a94 100644
--- a/src/platform/qt/Window.cpp
+++ b/src/platform/qt/Window.cpp
@@ -818,6 +818,31 @@ void Window::setupMenu(QMenuBar* menubar) {
 	m_gameActions.append(enableObj);
 	addControlledAction(videoLayers, enableObj, "enableOBJ");
 
+	QMenu* audioChannels = avMenu->addMenu(tr("Audio channels"));
+
+	for (int i = 0; i < 4; ++i) {
+		QAction* enableCh = new QAction(tr("Channel %0").arg(i + 1), audioChannels);
+		enableCh->setCheckable(true);
+		enableCh->setChecked(true);
+		connect(enableCh, &QAction::triggered, [this, i](bool enable) { m_controller->thread()->gba->audio.forceDisableCh[i] = !enable; });
+		m_gameActions.append(enableCh);
+		addControlledAction(audioChannels, enableCh, QString("enableCh%0").arg(i + 1));
+	}
+
+	QAction* enableChA = new QAction(tr("Channel A"), audioChannels);
+	enableChA->setCheckable(true);
+	enableChA->setChecked(true);
+	connect(enableChA, &QAction::triggered, [this, i](bool enable) { m_controller->thread()->gba->audio.forceDisableChA = !enable; });
+	m_gameActions.append(enableChA);
+	addControlledAction(audioChannels, enableChA, QString("enableChA"));
+
+	QAction* enableChB = new QAction(tr("Channel B"), audioChannels);
+	enableChB->setCheckable(true);
+	enableChB->setChecked(true);
+	connect(enableChB, &QAction::triggered, [this, i](bool enable) { m_controller->thread()->gba->audio.forceDisableChB = !enable; });
+	m_gameActions.append(enableChB);
+	addControlledAction(audioChannels, enableChB, QString("enableChB"));
+
 	QMenu* toolsMenu = menubar->addMenu(tr("&Tools"));
 	m_shortcutController->addMenu(toolsMenu);
 	QAction* viewLogs = new QAction(tr("View &logs..."), toolsMenu);