AFP improvements

- Stop pointlessly reloading the sample everytime the amp knob is changed
- Also draw the amplitude of the waveform correctly (used to be it was drawn as 2x too "quiet")

plugins/audio_file_processor/audio_file_processor.cpp

@@ -999,13 +999,14 @@ void AudioFileProcessorWaveView::updateGraph()
 	{
 		reverse();
 	}
-	else if( m_last_from == m_from && m_last_to == m_to )
+	else if( m_last_from == m_from && m_last_to == m_to && m_sampleBuffer.amplification() == m_last_amp )
 	{
 		return;
 	}
 
 	m_last_from = m_from;
 	m_last_to = m_to;
+	m_last_amp = m_sampleBuffer.amplification();
 
 	m_graph.fill( Qt::transparent );
 	QPainter p( &m_graph );

plugins/audio_file_processor/audio_file_processor.h

@@ -239,6 +239,7 @@ private:
 	f_cnt_t m_to;
 	f_cnt_t m_last_from;
 	f_cnt_t m_last_to;
+	float m_last_amp;
 	knob * m_startKnob;
 	knob * m_endKnob;
 	knob * m_loopKnob;