Diff: LookupTables.cpp

Revision:

0:8c128e047ec9

Child:

1:099f1a4c5fc8

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/LookupTables.cpp	Tue Mar 28 08:48:23 2017 +0000
@@ -0,0 +1,67 @@
+
+#include "LookupTables.h"
+
+////////////////// COSINE SINE LOOKUP TABLES
+
+// Returns the cosine value using the lut of a given value
+float lut_cos(float value){
+	// Cosine is symmetric so convert to absolute
+	if (value < 0)
+		value = -value;
+
+	// and subtract the "offset"
+	//float actualvalue = (float)(value % (2*M_PI));
+
+	while (value >= 2 * (float)M_PI){
+		value -= 2 * (float)M_PI;
+	}
+
+	// Calculate the value to a discrete value (1024*0.00613592 = 2 pi)
+	int discreteValue = (int)(value / 0.00613592);
+
+	return cosLookupTable_f[discreteValue];
+}
+// Returns the sine value using the lut for a given value
+float lut_sin(float value){
+	// Convert to cosine
+	value -= 0.5*(float)M_PI;
+	// Cosine is symmetric so convert to absolute
+	if (value < 0)
+		value = -value;
+
+	// subtract the "offset" of the original 0-2pi
+	//float actualvalue = (float)(value % (float)(2 * M_PI));
+
+	while (value >= (2 * (float)M_PI)){
+		value -= (2 * (float)M_PI);
+	}
+
+	// Calculate the value to a discrete value (1024*0.00613592 = 2 pi)
+	int discreteValue = (int)(value / 0.00613592);
+
+	return cosLookupTable_f[discreteValue];
+}
+
+// Returns the cosine value using the lut of a given value
+// WARNING, FAST VERSION ONLY WORKS WITH VALUES 0 - 2 PI
+float lut_cos_f(float value){
+	// Calculate the value to a discrete value (1024*0.00613592 = 2 pi)
+	int discreteValue = (int)(value / 0.00613592);
+
+	return cosLookupTable_f[discreteValue];
+}
+
+////////////////// END COSINE SINE LOOKUP TABLES
+
+////////////////// HANNING LOOKUP TABLE
+
+// Applies the hanning LUT to the supplied array of data
+void applyHanningTable(float* data, int datasize){
+	if (datasize == 1024){ // Only works for 10 bit data arrays
+		for (int i = 0; i < 1024; i++){
+			data[i] *= hanningTable_f[i];
+		}
+	}
+}
+
+////////////////// END HANNING LOOKUP TABLE
\ No newline at end of file