Moved lfos and sample-and-hold in own source file

1 files changed, 77 insertions, 0 deletions

diff --git a/synth/lfos.cpp b/synth/lfos.cpp
new file mode 100644
index 0000000..5916937
--- /dev/null
+++ b/synth/lfos.cpp
@@ -0,0 +1,77 @@
+#include <math.h>
+#include <stdlib.h>
+
+#include "lfos.h"
+#include "globals.h"
+#include "fixed.h"
+#include "defines.h"
+
+void uninit_lfo(int i)
+{
+	if (lfo[i])
+	{
+		for (int j=0;j<lfo_res[i];j++)
+			delete [] lfo[i][j];
+		
+		delete [] lfo[i];
+		lfo[i]=NULL;
+	}
+}
+
+void init_lfo(int i)
+{
+	//two possible divisions by zero are avoided, because
+	//values <= 0 will make the program use the default
+	//(nonzero) values.
+	lfo_res[i]=samp_rate/lfo_freq_hz[i]/lfo_update_frames;
+
+	lfo[i]=new fixed_t* [lfo_res[i]];
+	for (int j=0;j<lfo_res[i];j++)
+	{
+		lfo[i][j]=new fixed_t [N_LFO_LEVELS];
+		float temp=sin(j*2.0*3.141592654/lfo_res[i]);
+		for (int k=0;k<N_LFO_LEVELS;k++)
+			lfo[i][j][k]= (1.0 + temp*(float(LFO_MAX)*k/N_LFO_LEVELS)) * ONE;
+	}
+
+}
+
+void init_snh()
+{
+	sample_and_hold_frames=samp_rate/snh_freq_hz;
+}
+
+void maybe_calc_lfos()
+{
+	static int lfocnt=0;
+	static int snhcnt=0;
+	
+	if (lfocnt==0)
+	{
+		lfocnt=lfo_update_frames;
+		
+		for (int i=0;i<N_LFOS;i++)
+		{
+			lfo_phase[i]=(lfo_phase[i]+1)%lfo_res[i];
+			curr_lfo[i]=lfo[i][lfo_phase[i]];
+		}
+	}
+	
+	if (snhcnt==0)
+	{
+		snhcnt=sample_and_hold_frames;
+
+		//temp ranges between -ONE and ONE
+		fixed_t temp = (float(rand())/(RAND_MAX/2)  - 1.0) * ONE;
+		
+		for (int i=0;i<N_LFO_LEVELS;i++)
+			sample_and_hold[i]= temp*i/(N_LFO_LEVELS-1) + ONE;
+		
+		curr_lfo[SNH_LFO]=sample_and_hold;
+		// could be moved to some init function, but looks clearer and
+		// does not eat up the cpu too much ;)
+	}
+	
+	lfocnt--;
+	snhcnt--;
+}