From abedc3f573cd8986155959ab14485c031091f93a Mon Sep 17 00:00:00 2001
From: Bjørn Lindeijer <bjorn@lindeijer.nl>
Date: Wed, 15 Apr 2009 15:01:34 +0200
Subject: Make sure math functions are still inlined

A function call could be quite a large overhead on top of a fast square
root function.
---
 src/utils/mathutils.cpp | 58 -------------------------------------------------
 src/utils/mathutils.h   | 36 +++++++++++++++++++++++++++---
 2 files changed, 33 insertions(+), 61 deletions(-)
 delete mode 100644 src/utils/mathutils.cpp

(limited to 'src/utils')

diff --git a/src/utils/mathutils.cpp b/src/utils/mathutils.cpp
deleted file mode 100644
index 7d50c68f..00000000
--- a/src/utils/mathutils.cpp
+++ /dev/null
@@ -1,58 +0,0 @@
-/*
- *  The Mana World
- *  Copyright (C) 2009  The Mana World Development Team
- *
- *  This file is part of The Mana World.
- *
- *  This program is free software; you can redistribute it and/or modify
- *  it under the terms of the GNU General Public License as published by
- *  the Free Software Foundation; either version 2 of the License, or
- *  any later version.
- *
- *  This program is distributed in the hope that it will be useful,
- *  but WITHOUT ANY WARRANTY; without even the implied warranty of
- *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *  GNU General Public License for more details.
- *
- *  You should have received a copy of the GNU General Public License
- *  along with this program; if not, write to the Free Software
- *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
- */
-
-#include "utils/mathutils.h"
-
-/* A very fast function to calculate the approximate inverse square root of a
- * floating point value and a helper function that uses it for getting the
- * normal squareroot. For an explanation of the inverse squareroot function
- * read:
- * http://www.math.purdue.edu/~clomont/Math/Papers/2003/InvSqrt.pdf
- *
- * Unfortunately the original creator of this function seems to be unknown.
- */
-
-float fastInvSqrt(float x)
-{
-    union { int i; float x; } tmp;
-    float xhalf = 0.5f * x;
-    tmp.x = x;
-    tmp.i = 0x5f375a86 - (tmp.i >> 1);
-    x = tmp.x;
-    x = x * (1.5f - xhalf * x * x);
-    return x;
-}
-
-float fastSqrt(float x)
-{
-    return 1.0f / fastInvSqrt(x);
-}
-
-float weightedAverage(float n1, float n2, float w)
-{
-    if (w < 0.0f)
-        return n1;
-
-    if (w > 1.0f)
-        return n2;
-
-    return ((w * n2) + ((1.0f - w) * n1));
-}
diff --git a/src/utils/mathutils.h b/src/utils/mathutils.h
index 1b68f223..ac59ead2 100644
--- a/src/utils/mathutils.h
+++ b/src/utils/mathutils.h
@@ -22,10 +22,40 @@
 #ifndef UTILS_MATHUTILS_H
 #define UTILS_MATHUTILS_H
 
-float fastInvSqrt(float x);
+/* A very fast function to calculate the approximate inverse square root of a
+ * floating point value and a helper function that uses it for getting the
+ * normal squareroot. For an explanation of the inverse squareroot function
+ * read:
+ * http://www.math.purdue.edu/~clomont/Math/Papers/2003/InvSqrt.pdf
+ *
+ * Unfortunately the original creator of this function seems to be unknown.
+ */
+
+inline float fastInvSqrt(float x)
+{
+    union { int i; float x; } tmp;
+    float xhalf = 0.5f * x;
+    tmp.x = x;
+    tmp.i = 0x5f375a86 - (tmp.i >> 1);
+    x = tmp.x;
+    x = x * (1.5f - xhalf * x * x);
+    return x;
+}
+
+inline float fastSqrt(float x)
+{
+    return 1.0f / fastInvSqrt(x);
+}
+
+inline float weightedAverage(float n1, float n2, float w)
+{
+    if (w < 0.0f)
+        return n1;
 
-float fastSqrt(float x);
+    if (w > 1.0f)
+        return n2;
 
-float weightedAverage(float n1, float n2, float w);
+    return w * n2 + (1.0f - w) * n1;
+}
 
 #endif // UTILS_MATHUTILS_H
-- 
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