mirror of
https://github.com/libretro/scummvm.git
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129 lines
3.8 KiB
C++
129 lines
3.8 KiB
C++
/* ScummVM - Graphic Adventure Engine
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*
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* ScummVM is the legal property of its developers, whose names
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* are too numerous to list here. Please refer to the COPYRIGHT
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* file distributed with this source distribution.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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*/
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// Based on eos' math code
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#ifndef COMMON_MATH_H
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#define COMMON_MATH_H
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#include "common/scummsys.h"
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#ifdef _MSC_VER
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// HACK:
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// intrin.h on MSVC includes setjmp.h, which will fail compiling due to our
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// forbidden symbol colde. Since we also can not assure that defining
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// FORBIDDEN_SYMBOL_EXCEPTION_setjmp and FORBIDDEN_SYMBOL_EXCEPTION_longjmp
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// will actually allow the symbols, since forbidden.h might be included
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// earlier already we need to undefine them here...
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#undef setjmp
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#undef longjmp
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#include <intrin.h>
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// ...and redefine them here so no code can actually use it.
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// This could be resolved by including intrin.h on MSVC in scummsys.h before
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// the forbidden.h include. This might make sense, in case we use MSVC
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// extensions like _BitScanReverse in more places. But for now this hack should
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// be ok...
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#ifndef FORBIDDEN_SYMBOL_EXCEPTION_setjmp
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#undef setjmp
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#define setjmp(a) FORBIDDEN_SYMBOL_REPLACEMENT
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#endif
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#ifndef FORBIDDEN_SYMBOL_EXCEPTION_longjmp
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#undef longjmp
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#define longjmp(a,b) FORBIDDEN_SYMBOL_REPLACEMENT
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#endif
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#endif
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#ifndef M_SQRT1_2
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#define M_SQRT1_2 0.70710678118654752440 /* 1/sqrt(2) */
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#endif
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#ifndef M_PI
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#define M_PI 3.14159265358979323846
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#endif
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#ifndef FLT_MIN
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#define FLT_MIN 1E-37
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#endif
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#ifndef FLT_MAX
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#define FLT_MAX 1E+37
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#endif
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namespace Common {
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/** A complex number. */
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struct Complex {
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float re, im;
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};
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#if GCC_ATLEAST(3, 4)
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inline int intLog2(uint32 v) {
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// This is a slightly optimized implementation of log2 for natural numbers
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// targeting gcc. It also saves some binary size over our fallback
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// implementation, since it does not need any table.
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if (v == 0)
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return -1;
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else
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// This is really "sizeof(unsigned int) * CHAR_BIT - 1" but using 8
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// instead of CHAR_BIT is sane enough and it saves us from including
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// limits.h
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return (sizeof(unsigned int) * 8 - 1) - __builtin_clz(v);
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}
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#elif defined(_MSC_VER)
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inline int intLog2(uint32 v) {
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unsigned long result = 0;
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unsigned char nonZero = _BitScanReverse(&result, v);
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// _BitScanReverse stores the position of the MSB set in case its result
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// is non zero, thus we can just return it as is.
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return nonZero ? result : -1;
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}
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#else
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// See http://graphics.stanford.edu/~seander/bithacks.html#IntegerLogLookup
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static const char LogTable256[256] = {
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#define LT(n) n, n, n, n, n, n, n, n, n, n, n, n, n, n, n, n
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-1, 0, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3,
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LT(4), LT(5), LT(5), LT(6), LT(6), LT(6), LT(6),
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LT(7), LT(7), LT(7), LT(7), LT(7), LT(7), LT(7), LT(7)
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};
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inline int intLog2(uint32 v) {
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register uint32 t, tt;
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if ((tt = v >> 16))
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return (t = tt >> 8) ? 24 + LogTable256[t] : 16 + LogTable256[tt];
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else
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return (t = v >> 8) ? 8 + LogTable256[t] : LogTable256[v];
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}
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#endif
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inline float rad2deg(float rad) {
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return rad * 180.0 / M_PI;
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}
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inline float deg2rad(float deg) {
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return deg * M_PI / 180.0;
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}
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} // End of namespace Common
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#endif // COMMON_MATH_H
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