1 files changed, 178 insertions, 0 deletions
diff --git a/dfx-library/lfo.cpp b/dfx-library/lfo.cpp
new file mode 100755
index 0000000..58a58c3
--- /dev/null
+++ b/dfx-library/lfo.cpp
@@ -0,0 +1,178 @@
+#ifndef __lfo
+#include "lfo.h"
+#endif
+
+#include <stdio.h>
+#include <math.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+
+
+//------------------------------------------------------------------------
+LFO::LFO()
+{
+	sineTable = new float[NUM_LFO_POINTS];
+	triangleTable = new float[NUM_LFO_POINTS];
+	squareTable = new float[NUM_LFO_POINTS];
+	sawTable = new float[NUM_LFO_POINTS];
+	reverseSawTable = new float[NUM_LFO_POINTS];
+	thornTable = new float[NUM_LFO_POINTS];
+
+	fillLFOtables();
+	table = sineTable;	// just to have it pointing to something at least
+
+	srand((unsigned int)time(NULL));	// sets a seed value for rand() from the system clock
+
+	reset();
+}
+
+//------------------------------------------------------------------------
+LFO::~LFO()
+{
+	if (sineTable)
+		delete[] sineTable;
+	if (triangleTable)
+		delete[] triangleTable;
+	if (squareTable)
+		delete[] squareTable;
+	if (sawTable)
+		delete[] sawTable;
+	if (reverseSawTable)
+		delete[] reverseSawTable;
+	if (thornTable)
+		delete[] thornTable;
+}
+
+//------------------------------------------------------------------------
+void LFO::reset()
+{
+	position = 0.0f;
+	stepSize = 1.0f;	// just to avoid anything really screwy
+	oldRandomNumber = (float)rand() / (float)RAND_MAX;
+	randomNumber = (float)rand() / (float)RAND_MAX;
+	smoothSamples = 0;
+	granularityCounter = 0;
+}
+
+//-----------------------------------------------------------------------------------------
+// this function creates tables for mapping out the sine, triangle, & saw LFO shapes
+
+void LFO::fillLFOtables()
+{
+  long i, n;
+
+
+	// fill the sine waveform table (oscillates from 0 to 1 & back to 0)
+	for (i = 0; (i < NUM_LFO_POINTS); i++)
+		sineTable[i] = (sinf( ( ((float)i/(float)NUM_LFO_POINTS)-0.25f ) * 2.0f * PI ) + 1.0f) * 0.5f;
+
+	// fill the triangle waveform table
+	// ramp from 0 to 1 for the first half
+	for (i = 0; (i < NUM_LFO_POINTS/2); i++)
+		triangleTable[i] = (float)i / (float)(NUM_LFO_POINTS/2);
+	// & ramp from 1 to 0 for the second half
+	for (n = 0; (i < NUM_LFO_POINTS); n++)
+	{
+		triangleTable[i] = 1.0f - ((float)n / (float)(NUM_LFO_POINTS/2));
+		i++;
+	}
+
+	// fill the square waveform table
+	// stay at 1 for the first half
+	for (i = 0; (i < NUM_LFO_POINTS/2); i++)
+		squareTable[i] = 1.0f;
+	// & 0 for the second half
+	for (n = 0; (i < NUM_LFO_POINTS); n++)
+	{
+		squareTable[i] = 0.0f;
+		i++;
+	}
+
+	// fill the sawtooth waveform table (ramps from 0 to 1)
+	for (i = 0; (i < NUM_LFO_POINTS); i++)
+		sawTable[i] = (float)i / (float)(NUM_LFO_POINTS-1);
+
+	// fill the reverse sawtooth waveform table (ramps from 1 to 0)
+	for (i = 0; (i < NUM_LFO_POINTS); i++)
+		reverseSawTable[i] = (float)(NUM_LFO_POINTS-i-1) / (float)(NUM_LFO_POINTS-1);
+
+	// fill the thorn waveform table
+	// exponentially slope up from 0 to 1 for the first half
+	for (i = 0; (i < NUM_LFO_POINTS/2); i++)
+		thornTable[i] = powf( ((float)i / (float)(NUM_LFO_POINTS/2)), 2.0f );
+	// & exponentially slope down from 1 to 0 for the second half
+	for (n = 0; (i < NUM_LFO_POINTS); n++)
+	{
+		thornTable[i] = powf( (1.0f - ((float)n / (float)(NUM_LFO_POINTS/2))), 2.0f );
+		i++;
+	}
+}
+
+
+//--------------------------------------------------------------------------------------
+void LFO::getShapeName(char *nameString)
+{
+	switch (LFOshapeScaled(fShape))
+	{
+		case kSineLFO                : strcpy(nameString, "sine");					break;
+		case kTriangleLFO            : strcpy(nameString, "triangle");				break;
+		case kSquareLFO              : strcpy(nameString, "square");				break;
+		case kSawLFO                 : strcpy(nameString, "sawtooth");				break;
+		case kReverseSawLFO          : strcpy(nameString, "reverse sawtooth");		break;
+		case kThornLFO               : strcpy(nameString, "thorn");					break;
+		case kRandomLFO              : strcpy(nameString, "random");				break;
+		case kRandomInterpolatingLFO : strcpy(nameString, "random interpolating");	break;
+		default :																	break;
+	}
+}
+
+
+//--------------------------------------------------------------------------------------
+// this function points the LFO table pointers to the correct waveform tables
+
+void LFO::pickTheLFOwaveform()
+{
+	switch (LFOshapeScaled(fShape))
+	{
+		case kSineLFO :
+			table = sineTable;
+			break;
+		case kTriangleLFO :
+			table = triangleTable;
+			break;
+		case kSquareLFO :
+			table = squareTable;
+			break;
+		case kSawLFO :
+			table = sawTable;
+			break;
+		case kReverseSawLFO :
+			table = reverseSawTable;
+			break;
+		case kThornLFO :
+			table = thornTable;
+			break;
+		default :
+			table = sineTable;
+			break;
+	}
+}
+
+//--------------------------------------------------------------------------------------
+// calculates the position within an LFO's cycle needed to sync to the song's beat
+
+void LFO::syncToTheBeat(long samplesToBar)
+{
+  float countdown, cyclesize;
+
+	// calculate how many samples long the LFO cycle is
+	cyclesize = NUM_LFO_POINTS_FLOAT / stepSize;
+	// calculate many more samples it will take for this cycle to coincide with the beat
+	countdown = fmodf( (float)samplesToBar,  cyclesize);
+	// & convert that into the correct LFO position according to its table step size
+	position = (cyclesize - countdown) * stepSize;
+	// wrap around the new position if it is beyond the end of the LFO table
+	if (position >= NUM_LFO_POINTS_FLOAT)
+		position = fmodf(position, NUM_LFO_POINTS_FLOAT);
+}