From 210286514e11d3ee765a046960abbe0bfa65234a Mon Sep 17 00:00:00 2001
From: "Adrian.Conlon" <adrian.conlon@gmail.com>
Date: Sat, 23 Sep 2017 00:26:06 +0100
Subject: [PATCH] Calculate voice step length adjustments.

Signed-off-by: Adrian.Conlon <adrian.conlon@gmail.com>
---
 LR35902/inc/Audio.h   | 8 ++++++++
 LR35902/src/Audio.cpp | 6 +++++-
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/LR35902/inc/Audio.h b/LR35902/inc/Audio.h
index e107b2a..04b6067 100644
--- a/LR35902/inc/Audio.h
+++ b/LR35902/inc/Audio.h
@@ -375,6 +375,14 @@ namespace EightBit {
 			std::array<std::shared_ptr<AudioVoice>, 4> m_voices;
 			std::array<OutputChannel, 2> m_channels;
 			bool m_enabled;
+
+			template<class T>
+			static void stepLength(T* voice) {
+				if (voice->length() > 0) {
+					auto current = voice->length();
+					voice->setLength(--current);
+				}
+			}
 		};
 	}
 }
\ No newline at end of file
diff --git a/LR35902/src/Audio.cpp b/LR35902/src/Audio.cpp
index 71a3d34..8863726 100644
--- a/LR35902/src/Audio.cpp
+++ b/LR35902/src/Audio.cpp
@@ -47,7 +47,7 @@ void EightBit::GameBoy::Envelope::step() {
 			auto volume = m_volume + (m_direction == Amplify ? +1 : -1);
 			if (volume >= 0 || volume <= 15)
 				m_volume = volume;
-			m_position == m_period;
+			m_position = m_period;
 		}
 	}
 }
@@ -784,6 +784,10 @@ void EightBit::GameBoy::Audio::Sequencer_FrameStep(const int step) {
 }
 
 void EightBit::GameBoy::Audio::Sequencer_LengthStep(const int step) {
+	stepLength(voice1());
+	stepLength(voice2());
+	stepLength(voice3());
+	stepLength(voice4());
 }
 
 void EightBit::GameBoy::Audio::Sequencer_VolumeStep(const int step) {