Fn: improved fmap

Signed-off-by: Rick Waldron <waldron.rick@gmail.com>
rwaldron · Jul 21, 2016 · 71ac3aa · 71ac3aa
1 parent 18ea9f3
commit 71ac3aa
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Showing 2 changed files with 13 additions and 9 deletions.
diff --git a/lib/fn.js b/lib/fn.js
@@ -20,13 +20,17 @@ Fn.toFixed = function(number, digits) {
 // Re-maps a number from one range to another.
 // Based on arduino map()
 //
-// Return float
+// Return Float32
 //
+var f32A = new Float32Array(1);
+
 Fn.fmap = function(value, fromLow, fromHigh, toLow, toHigh) {
-  return (value - fromLow) * (toHigh - toLow) /
-    (fromHigh - fromLow) + toLow;
+  f32A[0] = (value - fromLow) * (toHigh - toLow) / (fromHigh - fromLow) + toLow;
+  return f32A[0];
 };
 
+
+
 // Alias
 Fn.fscale = Fn.fmap;
 
@@ -37,8 +41,11 @@ Fn.fscale = Fn.fmap;
 //
 // Retun int
 //
+var s32A = new Int32Array(1);
+
 Fn.map = function(value, fromLow, fromHigh, toLow, toHigh) {
-  return Fn.fmap(value, fromLow, fromHigh, toLow, toHigh) | 0;
+  s32A[0] = (value - fromLow) * (toHigh - toLow) / (fromHigh - fromLow) + toLow;
+  return s32A[0];
 };
 
 // Alias

diff --git a/test/fn.js b/test/fn.js
@@ -9,19 +9,16 @@ exports["Fn"] = {
 
   map: function(test) {
     test.expect(3);
-
     test.equal(Fn.map(1009, 300, 1009, 0, 255), 255);
     test.equal(Fn.map(300, 300, 1009, 0, 255), 0);
     test.equal(Fn.map(500, 0, 1000, 0, 255), 127);
-
     test.done();
   },
 
   fmap: function(test) {
-    test.expect(1);
-
+    test.expect(2);
     test.equal(Fn.fmap(500, 0, 1000, 0, 255), 127.5);
-
+    test.equal(Fn.fmap(512, 0, 1023, 0, 255), 127.6246337890625);
     test.done();
   },