1 files changed, 36 insertions, 0 deletions
diff --git a/externals/grill/fftease/src/unconvert.c b/externals/grill/fftease/src/unconvert.c
new file mode 100644
index 00000000..54bb6ca1
--- /dev/null
+++ b/externals/grill/fftease/src/unconvert.c
@@ -0,0 +1,36 @@
+#include "pv.h"
+
+
+
+void unconvert(float  *C, float *S, int N2, float *lastphase, float fundamental,  float factor )
+{
+  int 		i,
+		real,
+		imag,
+		amp,
+		freq;
+  float 	mag,
+		phase;
+
+    for ( i = 0; i <= N2; i++ ) {
+
+	imag = freq = ( real = amp = i<<1 ) + 1;
+
+	if ( i == N2 )
+	  real = 1;
+
+	mag = C[amp];
+	lastphase[i] += C[freq] - i*fundamental;
+	phase = lastphase[i]*factor;
+	S[real] = mag*cos( phase );
+
+	if ( i != N2 )
+	  S[imag] = -mag*sin( phase );
+	/*
+      if( i == 10 ) {
+	fprintf(stderr,"unconvert: amp: %f freq: %f funda %f fac %f\n", C[amp],C[freq],fundamental,factor);
+      }
+	*/
+    }
+
+}