NazaraEngine/include/Nazara/Math/Algorithm.inl

468 lines
11 KiB
C++

// Copyright (C) 2015 Jérôme Leclercq
// This file is part of the "Nazara Engine - Mathematics module"
// For conditions of distribution and use, see copyright notice in Config.hpp
#include <Nazara/Core/Error.hpp>
#include <Nazara/Core/String.hpp>
#include <Nazara/Math/Config.hpp>
#include <algorithm>
#include <cstring>
#include <type_traits>
#include <Nazara/Core/Debug.hpp>
#define F(a) static_cast<T>(a)
#define F2(a) static_cast<T2>(a)
namespace
{
// https://graphics.stanford.edu/~seander/bithacks.html#IntegerLogDeBruijn
static const unsigned int MultiplyDeBruijnBitPosition[32] =
{
0, 9, 1, 10, 13, 21, 2, 29, 11, 14, 16, 18, 22, 25, 3, 30,
8, 12, 20, 28, 15, 17, 24, 7, 19, 27, 23, 6, 26, 5, 4, 31
};
static const unsigned int MultiplyDeBruijnBitPosition2[32] =
{
0, 1, 28, 2, 29, 14, 24, 3, 30, 22, 20, 15, 25, 17, 4, 8,
31, 27, 13, 23, 21, 19, 16, 7, 26, 12, 18, 6, 11, 5, 10, 9
};
template<typename T>
typename std::enable_if<sizeof(T) <= sizeof(nzUInt32), unsigned int>::type NzImplIntegralLog2(T number)
{
// https://graphics.stanford.edu/~seander/bithacks.html#IntegerLogDeBruijn
number |= number >> 1; // first round down to one less than a power of 2
number |= number >> 2;
number |= number >> 4;
number |= number >> 8;
number |= number >> 16;
return MultiplyDeBruijnBitPosition[static_cast<nzUInt32>(number * 0x07C4ACDDU) >> 27];
}
template<typename T>
// Les parenthèses autour de la condition sont nécesaires pour que GCC compile ça
typename std::enable_if<(sizeof(T) > sizeof(nzUInt32)), unsigned int>::type NzImplIntegralLog2(T number)
{
static_assert(sizeof(T) % sizeof(nzUInt32) == 0, "Assertion failed");
// L'algorithme pour le logarithme base 2 (au dessus) ne fonctionne qu'avec des nombres au plus 32bits
// ce code décompose les nombres plus grands en nombres 32 bits par masquage et bit shifting
for (int i = sizeof(T)-sizeof(nzUInt32); i >= 0; i -= sizeof(nzUInt32))
{
// Le masque 32 bits sur la partie du nombre qu'on traite actuellement
T mask = T(std::numeric_limits<nzUInt32>::max()) << i*8;
T val = (number & mask) >> i*8; // Masquage et shifting des bits vers la droite (pour le ramener sur 32bits)
// Appel de la fonction avec le nombre 32bits, si le résultat est non-nul nous avons la réponse
unsigned int log2 = NzImplIntegralLog2<nzUInt32>(val);
if (log2)
return log2 + i*8;
}
return 0;
}
template<typename T>
typename std::enable_if<sizeof(T) <= sizeof(nzUInt32), unsigned int>::type NzImplIntegralLog2Pot(T number)
{
// https://graphics.stanford.edu/~seander/bithacks.html#IntegerLogDeBruijn
return MultiplyDeBruijnBitPosition2[static_cast<nzUInt32>(number * 0x077CB531U) >> 27];
}
template<typename T>
// Les parenthèses autour de la condition sont nécesaires pour que GCC compile ça
typename std::enable_if<(sizeof(T) > sizeof(nzUInt32)), unsigned int>::type NzImplIntegralLog2Pot(T number)
{
static_assert(sizeof(T) % sizeof(nzUInt32) == 0, "Assertion failed");
// L'algorithme pour le logarithme base 2 (au dessus) ne fonctionne qu'avec des nombres au plus 32bits
// ce code décompose les nombres plus grands en nombres 32 bits par masquage et bit shifting
for (int i = sizeof(T)-sizeof(nzUInt32); i >= 0; i -= sizeof(nzUInt32))
{
// Le masque 32 bits sur la partie du nombre qu'on traite actuellement
T mask = T(std::numeric_limits<nzUInt32>::max()) << i*8;
T val = (number & mask) >> i*8; // Masquage et shifting des bits vers la droite (pour le ramener sur 32bits)
// Appel de la fonction avec le nombre 32bits, si le résultat est non-nul nous avons la réponse
unsigned int log2 = NzImplIntegralLog2Pot<nzUInt32>(val);
if (log2)
return log2 + i*8;
}
return 0;
}
}
template<typename T>
T NzApproach(T value, T objective, T increment)
{
///TODO: Marquer comme constexpr en C++14
if (value < objective)
return std::min(value + increment, objective);
else if (value > objective)
return std::max(value - increment, objective);
else
return value;
}
template<typename T>
constexpr T NzClamp(T value, T min, T max)
{
return std::max(std::min(value, max), min);
}
template<typename T>
T NzCountBits(T value)
{
// https://graphics.stanford.edu/~seander/bithacks.html#CountBitsSetKernighan
unsigned int count = 0;
while (value)
{
value &= value - 1;
count++;
}
return count;
}
template<typename T>
constexpr T NzDegreeToRadian(T degrees)
{
return degrees * F(M_PI/180.0);
}
template<typename T>
constexpr T NzFromDegrees(T degrees)
{
#if NAZARA_MATH_ANGLE_RADIAN
return NzDegreeToRadian(degrees);
#else
return degrees;
#endif
}
template<typename T>
constexpr T NzFromRadians(T radians)
{
#if NAZARA_MATH_ANGLE_RADIAN
return radians;
#else
return NzRadianToDegree(radians);
#endif
}
inline unsigned int NzGetNearestPowerOfTwo(unsigned int number)
{
///TODO: Marquer comme constexpr en C++14
unsigned int x = 1;
// Tant que x est plus petit que n, on décale ses bits vers la gauche, ce qui revient à multiplier par deux
while (x < number)
x <<= 1;
return x;
}
inline unsigned int NzGetNumberLength(signed char number)
{
///TODO: Marquer comme constexpr en C++14
// Le standard définit le char comme étant codé sur un octet
static_assert(sizeof(number) == 1, "Signed char must be one byte-sized");
if (number >= 100)
return 3;
else if (number >= 10)
return 2;
else if (number >= 0)
return 1;
else if (number > -10)
return 2;
else if (number > -100)
return 3;
else
return 4;
}
inline unsigned int NzGetNumberLength(unsigned char number)
{
///TODO: Marquer comme constexpr en C++14
// Le standard définit le char comme étant codé sur un octet
static_assert(sizeof(number) == 1, "Unsigned char must be one byte-sized");
if (number >= 100)
return 3;
else if (number >= 10)
return 2;
else
return 1;
}
inline unsigned int NzGetNumberLength(int number)
{
if (number == 0)
return 1;
return static_cast<unsigned int>(std::log10(std::abs(number)))+(number < 0 ? 2 : 1);
}
inline unsigned int NzGetNumberLength(unsigned int number)
{
if (number == 0)
return 1;
return static_cast<unsigned int>(std::log10(number))+1;
}
inline unsigned int NzGetNumberLength(long long number)
{
if (number == 0)
return 1;
return static_cast<unsigned int>(std::log10(std::abs(number)))+(number < 0 ? 2 : 1);
}
inline unsigned int NzGetNumberLength(unsigned long long number)
{
if (number == 0)
return 1;
return static_cast<unsigned int>(std::log10(number))+1;
}
inline unsigned int NzGetNumberLength(float number, nzUInt8 precision)
{
// L'imprécision des flottants nécessite un cast (log10(9.99999) = 0.99999)
return NzGetNumberLength(static_cast<long long>(number)) + precision + 1; // Plus un pour le point
}
inline unsigned int NzGetNumberLength(double number, nzUInt8 precision)
{
// L'imprécision des flottants nécessite un cast (log10(9.99999) = 0.99999)
return NzGetNumberLength(static_cast<long long>(number)) + precision + 1; // Plus un pour le point
}
inline unsigned int NzGetNumberLength(long double number, nzUInt8 precision)
{
// L'imprécision des flottants nécessite un cast (log10(9.99999) = 0.99999)
return NzGetNumberLength(static_cast<long long>(number)) + precision + 1; // Plus un pour le point
}
template<typename T>
unsigned int NzIntegralLog2(T number)
{
// Proxy nécessaire pour éviter un problème de surcharge
return NzImplIntegralLog2<T>(number);
}
template<typename T>
unsigned int NzIntegralLog2Pot(T pot)
{
return NzImplIntegralLog2Pot<T>(pot);
}
inline unsigned int NzIntegralPow(unsigned int base, unsigned int exponent)
{
///TODO: Marquer comme constexpr en C++14
unsigned int r = 1;
for (unsigned int i = 0; i < exponent; ++i)
r *= base;
return r;
}
template<typename T, typename T2>
T NzLerp(T from, T to, T2 interpolation)
{
#ifdef NAZARA_DEBUG
if (interpolation < F2(0.0) || interpolation > F2(1.0))
NazaraWarning("Interpolation should be in range [0..1] (Got " + NzString::Number(interpolation) + ')');
#endif
return from + interpolation*(to - from);
}
template<typename T>
T NzMultiplyAdd(T x, T y, T z)
{
return x*y + z;
}
#ifdef FP_FAST_FMAF
template<>
inline float NzMultiplyAdd(float x, float y, float z)
{
return std::fmaf(x, y, z);
}
#endif
#ifdef FP_FAST_FMA
template<>
inline double NzMultiplyAdd(double x, double y, double z)
{
return std::fma(x, y, z);
}
#endif
#ifdef FP_FAST_FMAL
template<>
inline long double NzMultiplyAdd(long double x, long double y, long double z)
{
return std::fmal(x, y, z);
}
#endif
template<typename T>
T NzNormalizeAngle(T angle)
{
#if NAZARA_MATH_ANGLE_RADIAN
const T limit = F(M_PI);
#else
const T limit = F(180.0);
#endif
const T twoLimit = limit*F(2.0);
angle = std::fmod(angle + limit, twoLimit);
if (angle < F(0.0))
angle += twoLimit;
return angle - limit;
}
template<typename T>
bool NzNumberEquals(T a, T b)
{
return NzNumberEquals(a, b, std::numeric_limits<T>::epsilon());
}
template<typename T>
bool NzNumberEquals(T a, T b, T maxDifference)
{
T diff = a - b;
if (diff < F(0.0))
diff = -diff;
return diff <= maxDifference;
}
inline NzString NzNumberToString(long long number, nzUInt8 radix)
{
#if NAZARA_MATH_SAFE
if (radix < 2 || radix > 36)
{
NazaraError("Base must be between 2 and 36");
return NzString();
}
#endif
if (number == 0)
return NzString('0');
static const char* symbols = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
bool negative;
if (number < 0)
{
negative = true;
number = -number;
}
else
negative = false;
NzString str;
str.Reserve(NzGetNumberLength(number)); // Prends en compte le signe négatif
do
{
str.Append(symbols[number % radix]);
number /= radix;
}
while (number > 0);
if (negative)
str.Append('-');
return str.Reverse();
}
template<typename T>
T NzRadianToDegree(T radians)
{
return radians * F(180.0/M_PI);
}
inline long long NzStringToNumber(NzString str, nzUInt8 radix, bool* ok)
{
#if NAZARA_MATH_SAFE
if (radix < 2 || radix > 36)
{
NazaraError("Radix must be between 2 and 36");
if (ok)
*ok = false;
return 0;
}
#endif
static const char* symbols = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
str.Simplify();
if (radix > 10)
str = str.ToUpper();
bool negative = str.StartsWith('-');
char* digit = &str[(negative) ? 1 : 0];
unsigned long long total = 0;
do
{
if (*digit == ' ')
continue;
total *= radix;
const char* c = std::strchr(symbols, *digit);
if (c && c-symbols < radix)
total += c-symbols;
else
{
if (ok)
*ok = false;
return 0;
}
}
while (*++digit);
if (ok)
*ok = true;
return (negative) ? -static_cast<long long>(total) : total;
}
template<typename T>
constexpr T NzToDegrees(T angle)
{
#if NAZARA_MATH_ANGLE_RADIAN
return NzRadianToDegree(angle);
#else
return angle;
#endif
}
template<typename T>
constexpr T NzToRadians(T angle)
{
#if NAZARA_MATH_ANGLE_RADIAN
return angle;
#else
return NzDegreeToRadian(angle);
#endif
}
#undef F2
#undef F
#include <Nazara/Core/DebugOff.hpp>