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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