1 files changed, 111 insertions, 0 deletions

diff --git a/heuristics.c b/heuristics.c
new file mode 100644
index 0000000..429a612
--- /dev/null
+++ b/heuristics.c
@@ -0,0 +1,111 @@
+#include <stdio.h>
+
+#include "vubars.h"
+
+static void heuristics_getGesture( int const amount, int const off, int const * const values,
+   int *dxl, int *dyl, int *dxr, int *dyr );
+
+int heuristics_getEnergy( int const amount, int const * const values ) {
+  int energy = 0;
+  int i;
+
+  for( i = 0; i < amount-1; ++i )
+    energy += values[i]*values[i+1];
+
+  return energy;
+}
+
+// Gets the two longest consecutive gestures found
+// in frames. -1 in off[ab] means no gesture found
+
+// Here what counts: the bigger abs(dx[ab]),   the longer the gesture
+//                   the bigger dy[ab]/dx[ab], the slower the gesture
+void heuristics_getGestures( int const amount, int const * const values,
+  int *offa, int *dxa, int *dya, int *dda,
+  int *offb, int *dxb, int *dyb, int *ddb )
+{
+  int    i, l = 0;
+  int dxl [ amount ], dyl [ amount ], dxr [ amount ], dyr [ amount ];
+
+  // Get the longest gestures for each point - both into left and rite
+  for( i=0; i<amount; ++i )
+    heuristics_getGesture( amount, i, values, dxl + i, dyl + i, dxr + i, dyr + i );
+
+  // "Sort" gesture by length
+  *offa = *dxa = *dya = 0;
+  for( i=0; i<amount; ++i ) {
+    if( dxr[ i ] > *dxa ) { *offa = i; *dxa = dxr[ i ]; *dya = dyr[ i ]; *dda = 1; }
+    if( dxl[ i ] > *dxa ) { *offa = i; *dxa = dxl[ i ]; *dya = dyl[ i ]; *dda =-1; }
+  }
+
+  // If no gesture found at all, invalidate off
+  // and return... second run wouldnt suddenly find a gesture
+  if( *dxa == 0 ) { *offa = *offb = -1; return; }
+
+  // Now clear the best result - this will find us the second best result
+  i = *offa;
+  if( *dda == 1 ) {
+    for( i=*offa; i < *offa + dxr[ *offa ]; ++i )
+      dxr[ i ] = 0;
+  } else {
+    for( i=*offa; i > *offa - dxl[ *offa ]; --i )
+      dxl[ i ] = 0;
+  }
+
+  // "Sort" remaining gestures by length
+  *offb = *dxb = *dyb = 0;
+  for( i=0; i<amount; ++i ) {
+    if( dxr[ i ] > *dxb ) { *offb = i; *dxb =  dxr[ i ]; *dyb = dyr[ i ]; *ddb = 1;}
+    if( dxl[ i ] > *dxb ) { *offb = i; *dxb = -dxl[ i ]; *dyb = dyl[ i ]; *ddb =-1;}
+  }
+
+  // If no secondary gesture found, invalidate off
+  if( *dxb == 0 ) *offb = -1;
+}
+
+static void heuristics_getGesture( int const amount, int const off, int const * const values,
+   int * const dxl, int * const dyl, int * const dxr, int * const dyr )
+{
+  int i;
+
+  // Initialize as "nothing happened"
+  *dxl = *dxr = *dyl = *dyr = 0;
+
+  // if this didn't peak in last frame, we're not starting
+  // a gesture here.
+  if( values[off] != VU_PEAK ) return;
+
+  if( off > 0 )        *dyl = values[off]-values[off-1];
+  if( off < amount-1 ) *dyr = values[off]-values[off+1];
+
+  if( !*dyl && !*dyr ) return;
+
+  // Depending on where this peaks seems to have come from,
+  // chose direction where to follow it
+  // try to collect enough monotonic samples and calculate a
+  // slope. Since our sample peaks, all others cant be larger 
+  if( (*dyl) && (*dyl < *dyr) ) {
+    (*dxl)++;
+    for( i=off-1; i>=0; --i ) {
+      int dy = values[i+1] - values[i];
+
+      // If it scrolled out of scope, ignore it
+      if( !values[i] || dy < 0 ) break;
+
+      (*dxl)++;
+      (*dyl) += dy;
+    }
+  } else {
+    (*dxr)++;
+    // Do the same when going right
+    for( i=off+1; i<amount; ++i ) {
+      int dy = values[i-1] - values[i];
+
+      // If it scrolled out of scope, ignore it
+      if( !values[i] || dy < 0 ) break;
+
+      (*dxr)++;
+      (*dyr) += dy;
+    }
+  }
+}