Bugfix - SampleTrack -> Play: Fix sample track not being played in the

right place when it not played from the begining.

That has created a difference between the ticks and the metronome and
the sample track.

The cause of the problem was that the calculation of the frame to play
was wrong: we had calculated `framesPerTick` according to the current
engine's sample rate instead of the SampleBuffer's sample rate.

include/Engine.h

@@ -31,6 +31,7 @@
 
 
 #include "export.h"
+#include "lmms_basics.h"
 
 class BBTrackContainer;
 class DummyTrackContainer;
@@ -100,6 +101,9 @@ class EXPORT LmmsCore : public QObject
 	{
 		return s_framesPerTick;
 	}
+
+	static float framesPerTick(sample_rate_t sample_rate);
+
 	static void updateFramesPerTick();
 
 	static inline LmmsCore * inst()

src/core/Engine.cpp

@@ -103,6 +103,12 @@ void LmmsCore::destroy()
 	delete ConfigManager::inst();
 }
 
+float LmmsCore::framesPerTick(sample_rate_t sample_rate)
+{
+	return sample_rate * 60.0f * 4 /
+			DefaultTicksPerTact / s_song->getTempo();
+}
+
 
 
 

src/tracks/SampleTrack.cpp

@@ -626,13 +626,16 @@ bool SampleTrack::play( const MidiTime & _start, const fpp_t _frames,
 		{
 			TrackContentObject * tco = getTCO( i );
 			SampleTCO * sTco = dynamic_cast<SampleTCO*>( tco );
-			float framesPerTick = Engine::framesPerTick();
+
 			if( _start >= sTco->startPosition() && _start < sTco->endPosition() )
 			{
 				if( sTco->isPlaying() == false )
 				{
-					f_cnt_t sampleStart = framesPerTick * ( _start - sTco->startPosition() );
-					f_cnt_t tcoFrameLength = framesPerTick * ( sTco->endPosition() - sTco->startPosition() );
+					auto bufferFramesPerTick = Engine::framesPerTick (sTco->sampleBuffer ()->sampleRate ());
+					f_cnt_t sampleStart = bufferFramesPerTick * ( _start - sTco->startPosition() );
+
+					f_cnt_t tcoFrameLength = bufferFramesPerTick * ( sTco->endPosition() - sTco->startPosition() );
+
 					f_cnt_t sampleBufferLength = sTco->sampleBuffer()->frames();
 					//if the Tco smaller than the sample length we play only until Tco end
 					//else we play the sample to the end but nothing more