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author | Jared Adams <jaxad0127@gmail.com> | 2009-04-14 20:50:14 -0600 |
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committer | Jared Adams <jaxad0127@gmail.com> | 2009-04-14 20:50:14 -0600 |
commit | 31f0b79de3e23f3660c35795232020870fb38590 (patch) | |
tree | b73866045c2ef13d495ec3104901e897b070c171 | |
parent | dfd6bc3c91c7bd508b5bde820366784bd980a677 (diff) | |
download | mana-client-31f0b79de3e23f3660c35795232020870fb38590.tar.gz mana-client-31f0b79de3e23f3660c35795232020870fb38590.tar.bz2 mana-client-31f0b79de3e23f3660c35795232020870fb38590.tar.xz mana-client-31f0b79de3e23f3660c35795232020870fb38590.zip |
Add misisng mathutils files
-rw-r--r-- | src/utils/mathutils.cpp | 58 | ||||
-rw-r--r-- | src/utils/mathutils.h | 31 |
2 files changed, 89 insertions, 0 deletions
diff --git a/src/utils/mathutils.cpp b/src/utils/mathutils.cpp new file mode 100644 index 00000000..0ad8f3fb --- /dev/null +++ b/src/utils/mathutils.cpp @@ -0,0 +1,58 @@ +/* + * 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) / 2.0f; +} diff --git a/src/utils/mathutils.h b/src/utils/mathutils.h new file mode 100644 index 00000000..1b68f223 --- /dev/null +++ b/src/utils/mathutils.h @@ -0,0 +1,31 @@ +/* + * 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 + */ + +#ifndef UTILS_MATHUTILS_H +#define UTILS_MATHUTILS_H + +float fastInvSqrt(float x); + +float fastSqrt(float x); + +float weightedAverage(float n1, float n2, float w); + +#endif // UTILS_MATHUTILS_H |