frame weaving

1 files changed, 31 insertions, 0 deletions

diff --git a/js/util.js b/js/util.js
index b05c7d6..948b3f6 100644
--- a/js/util.js
+++ b/js/util.js
@@ -64,3 +64,34 @@ function smoothstep(n,a,b){
   return t * t * (3.0 - 2.0 * t)
 }
 
+function shuffle(a){
+  for (var i = a.length; i > 0; i--){
+    var r = randint(i)
+    var swap = a[i-1]
+    a[i-1] = a[r]
+    a[r] = swap
+  }
+  return a
+}
+function reverse(a){
+  var reversed = []
+  for (var i = 0, _len = a.length-1; i <= _len; i++){
+    reversed[i] = a[_len-i]
+  }
+  return reversed
+}
+function deinterlace(a){
+  var odd = [], even = []
+  for (var i = 0, _len = a.length; i < _len; i++) {
+    if (i % 2) even.push(a[i])
+    else odd.push(a[i])
+  }
+  return [even, odd]
+}
+function weave(a){
+  var aa = deinterlace(a)
+  var b = []
+  aa[0].forEach(function(el){ b.push(el) })
+  reverse(aa[1]).forEach(function(el){ b.push(el) })
+  return b
+}