From d7fd8727860664ea0ba5b735321dcf0d1b73185b Mon Sep 17 00:00:00 2001
From: Gergo Koteles <soyer@irl.hu>
Date: Wed, 9 Jul 2025 19:15:03 +0200
Subject: [PATCH] mixer: use the buffer directly, do not copy

---
 src/effect_mixer.hpp | 14 ++++++++++++++
 src/minidexed.cpp    | 22 ++++++++++++----------
 2 files changed, 26 insertions(+), 10 deletions(-)

diff --git a/src/effect_mixer.hpp b/src/effect_mixer.hpp
index 44184ab..78efbb4 100644
--- a/src/effect_mixer.hpp
+++ b/src/effect_mixer.hpp
@@ -168,6 +168,20 @@ public:
 			arm_fill_f32(0.0f, sumbufR, buffer_length);
 	}
 
+	void getBuffers(float32_t (*buffers[2]))
+	{
+		buffers[0] = sumbufL;
+		buffers[1] = sumbufR;
+	}
+
+	void zeroFill()
+	{
+		if(sumbufL)
+			arm_fill_f32(0.0f, sumbufL, buffer_length);
+		if(sumbufR)
+			arm_fill_f32(0.0f, sumbufR, buffer_length);
+	}
+
 protected:
 	using AudioMixer<NN>::sumbufL;
 	using AudioMixer<NN>::multiplier;
diff --git a/src/minidexed.cpp b/src/minidexed.cpp
index 1b5b4f6..c4aa1b8 100644
--- a/src/minidexed.cpp
+++ b/src/minidexed.cpp
@@ -1406,25 +1406,28 @@ void CMiniDexed::ProcessSound (void)
 
 			if(nMasterVolume > 0.0)
 			{
+				// get the mix buffer of all TGs
+				float32_t (*SampleBuffer[2]);
+				tg_mixer->getBuffers(SampleBuffer);
+
+				tg_mixer->zeroFill();
+
 				for (uint8_t i = 0; i < m_nToneGenerators; i++)
 				{
 					tg_mixer->doAddMix(i,m_OutputLevel[i]);
 				}
 				// END TG mixing
 
-				// BEGIN create SampleBuffer for holding audio data
-				float32_t SampleBuffer[2][nFrames];
-				// END create SampleBuffer for holding audio data
-
-				// get the mix of all TGs
-				tg_mixer->getMix(SampleBuffer[indexL], SampleBuffer[indexR]);
-
 				// BEGIN adding reverb
 				if (m_nParameter[ParameterReverbEnable])
 				{
 					float32_t ReverbBuffer[2][nFrames];
-					float32_t ReverbSendBuffer[2][nFrames];
-					
+
+					float32_t (*ReverbSendBuffer[2]);
+					reverb_send_mixer->getBuffers(ReverbSendBuffer);
+
+					reverb_send_mixer->zeroFill();
+
 					for (uint8_t i = 0; i < m_nToneGenerators; i++)
 					{
 						reverb_send_mixer->doAddMix(i,m_OutputLevel[i]);
@@ -1432,7 +1435,6 @@ void CMiniDexed::ProcessSound (void)
 
 					m_ReverbSpinLock.Acquire ();
 
-					reverb_send_mixer->getMix(ReverbSendBuffer[indexL], ReverbSendBuffer[indexR]);
 					reverb->doReverb(ReverbSendBuffer[indexL],ReverbSendBuffer[indexR],ReverbBuffer[indexL], ReverbBuffer[indexR],nFrames);
 
 					// scale down and add left reverb buffer by reverb level