@@ 10,6 10,17 @@ type ChannelMixer struct {
 	// XXX ?
 	InstrumentPlayers []*InstrumentPlayer
 	
+	// XXX
+	// channel render tick buffers ?
+	// data with current tick buffer (channels')
+	renderTickBuf [][][2]float64
+	// XXX (?)
+	// render buf accumulator ?
+	// optional ?
+	// can be used for wave display (?)
+	channelRenderBufAcc [][][2]float64
+	channelRenderBufAccLen int
+	
 	// test
 	outTestFile *os.File
 }