From fd2893bf6df8e6dba6d5b237a715180a557212d9 Mon Sep 17 00:00:00 2001
From: Andrzej Kapolka <drzej.k@gmail.com>
Date: Wed, 4 Jun 2014 18:23:31 -0700
Subject: [PATCH] Get rid of the log calls entirely; use the same code that we
 use for the ID streamer.

---
 libraries/metavoxels/src/Bitstream.cpp | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/libraries/metavoxels/src/Bitstream.cpp b/libraries/metavoxels/src/Bitstream.cpp
index dc74594816..30d34580d7 100644
--- a/libraries/metavoxels/src/Bitstream.cpp
+++ b/libraries/metavoxels/src/Bitstream.cpp
@@ -47,11 +47,19 @@ IDStreamer::IDStreamer(Bitstream& stream) :
     _bits(1) {
 }
 
-void IDStreamer::setBitsFromValue(int value) {
-    _bits = 1;
-    while (value >= (1 << _bits) - 1) {
-        _bits++;
+static int getBitsForHighestValue(int highestValue) {
+    // if this turns out to be a bottleneck, there are fancier ways to do it (get the position of the highest set bit):
+    // http://graphics.stanford.edu/~seander/bithacks.html#IntegerLogObvious
+    int bits = 0;
+    while (highestValue != 0) {
+        bits++;
+        highestValue >>= 1;
     }
+    return bits;
+}
+
+void IDStreamer::setBitsFromValue(int value) {
+    _bits = getBitsForHighestValue(value + 1);
 }
 
 IDStreamer& IDStreamer::operator<<(int value) {
@@ -719,10 +727,6 @@ Bitstream& Bitstream::operator<(const TypeStreamer* streamer) {
     return *this;
 }
 
-static int getBitsForHighestValue(int highestValue) {
-    return (highestValue == 0) ? 0 : 1 + (int)(log((double)highestValue) / log(2.0));
-}
-
 Bitstream& Bitstream::operator>(TypeReader& reader) {
     QByteArray typeName;
     *this >> typeName;