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Diffstat (limited to 'common/math.h')
| -rw-r--r-- | common/math.h | 128 |
1 files changed, 128 insertions, 0 deletions
diff --git a/common/math.h b/common/math.h new file mode 100644 index 0000000000..f787b84fa6 --- /dev/null +++ b/common/math.h @@ -0,0 +1,128 @@ +/* ScummVM - Graphic Adventure Engine + * + * ScummVM is the legal property of its developers, whose names + * are too numerous to list here. Please refer to the COPYRIGHT + * file distributed with this source distribution. + * + * 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 (at your option) 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + * + */ + +// Based on eos' math code + +#ifndef COMMON_MATH_H +#define COMMON_MATH_H + +#include "common/scummsys.h" +#ifdef _MSC_VER +// HACK: +// intrin.h on MSVC includes setjmp.h, which will fail compiling due to our +// forbidden symbol colde. Since we also can not assure that defining +// FORBIDDEN_SYMBOL_EXCEPTION_setjmp and FORBIDDEN_SYMBOL_EXCEPTION_longjmp +// will actually allow the symbols, since forbidden.h might be included +// earlier already we need to undefine them here... +#undef setjmp +#undef longjmp +#include <intrin.h> +// ...and redefine them here so no code can actually use it. +// This could be resolved by including intrin.h on MSVC in scummsys.h before +// the forbidden.h include. This might make sense, in case we use MSVC +// extensions like _BitScanReverse in more places. But for now this hack should +// be ok... +#ifndef FORBIDDEN_SYMBOL_EXCEPTION_setjmp +#undef setjmp +#define setjmp(a) FORBIDDEN_SYMBOL_REPLACEMENT +#endif + +#ifndef FORBIDDEN_SYMBOL_EXCEPTION_longjmp +#undef longjmp +#define longjmp(a,b) FORBIDDEN_SYMBOL_REPLACEMENT +#endif +#endif + +#ifndef M_SQRT1_2 + #define M_SQRT1_2 0.70710678118654752440 /* 1/sqrt(2) */ +#endif + +#ifndef M_PI + #define M_PI 3.14159265358979323846 +#endif + +#ifndef FLT_MIN + #define FLT_MIN 1E-37 +#endif + +#ifndef FLT_MAX + #define FLT_MAX 1E+37 +#endif + +namespace Common { + +/** A complex number. */ +struct Complex { + float re, im; +}; + +#if defined(__GNUC__) && (__GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4)) +inline int intLog2(uint32 v) { + // This is a slightly optimized implementation of log2 for natural numbers + // targeting gcc. It also saves some binary size over our fallback + // implementation, since it does not need any table. + if (v == 0) + return -1; + else + // This is really "sizeof(unsigned int) * CHAR_BIT - 1" but using 8 + // instead of CHAR_BIT is sane enough and it saves us from including + // limits.h + return (sizeof(unsigned int) * 8 - 1) - __builtin_clz(v); +} +#elif defined(_MSC_VER) +inline int intLog2(uint32 v) { + unsigned long result = 0; + unsigned char nonZero = _BitScanReverse(&result, v); + // _BitScanReverse stores the position of the MSB set in case its result + // is non zero, thus we can just return it as is. + return nonZero ? result : -1; +} +#else +// See http://graphics.stanford.edu/~seander/bithacks.html#IntegerLogLookup +static const char LogTable256[256] = { +#define LT(n) n, n, n, n, n, n, n, n, n, n, n, n, n, n, n, n + -1, 0, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, + LT(4), LT(5), LT(5), LT(6), LT(6), LT(6), LT(6), + LT(7), LT(7), LT(7), LT(7), LT(7), LT(7), LT(7), LT(7) +}; + +inline int intLog2(uint32 v) { + register uint32 t, tt; + + if ((tt = v >> 16)) + return (t = tt >> 8) ? 24 + LogTable256[t] : 16 + LogTable256[tt]; + else + return (t = v >> 8) ? 8 + LogTable256[t] : LogTable256[v]; +} +#endif + +inline float rad2deg(float rad) { + return rad * 180.0 / M_PI; +} + +inline float deg2rad(float deg) { + return deg * M_PI / 180.0; +} + +} // End of namespace Common + +#endif // COMMON_MATH_H |