mathutils.h File Reference

(986a3bf)

#include "utils/cast.h"
#include <string>
#include <cmath>
#include "localconsts.h"

Go to the source code of this file.

Functions
uint16_t	getCrc16 (const std::string &str)
float	fastInvSqrt (float x)
float	fastSqrt (const float x)
float	weightedAverage (const float n1, const float n2, const float w)
int	roundDouble (const double v)
int	powerOfTwo (const unsigned int input)
int	fastSqrtInt (const unsigned int n)

Variables
static const uint16_t	crc_table [256]
static const uint8_t	square_roots [1000]

Function Documentation

fastInvSqrt()

float fastInvSqrt ( float  x )

inline

Definition at line 210 of file mathutils.h.

{
    union { int i; float x; } tmp = {0U};
    const 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;
}

References x.

Referenced by fastSqrt(), and Particle::updateSelf().

fastSqrt()

float fastSqrt ( const float  x )

inline

Definition at line 221 of file mathutils.h.

{
    return 1.0F / fastInvSqrt(x);
}

References fastInvSqrt(), and x.

fastSqrtInt()

int fastSqrtInt ( const unsigned int  n )

inline

Definition at line 245 of file mathutils.h.

{
    if (n < 1000)
        return CAST_S32(square_roots[n]);
    return CAST_S32(sqrt(n));
}

References CAST_S32, and square_roots.

Referenced by ActorManager::findMostDamagedPlayer().

getCrc16()

uint16_t getCrc16 ( const std::string &  str )

inline

Definition at line 186 of file mathutils.h.

{
    size_t f = str.size();
    uint16_t crc16 = 0xffff;
 
    while (f != 0)
    {
        f --;
        crc16 = CAST_U16(
            crc_table[(crc16 ^ (str[f])) & 0xff] ^ (crc16 >> 8));
    }
 
    return crc16;
}

References CAST_U16, and crc_table.

powerOfTwo()

int powerOfTwo ( const unsigned int  input )

inline

Definition at line 237 of file mathutils.h.

{
    unsigned int value = 1;
    while (value < input)
        value <<= 1;
    return value;
}

Referenced by AtlasManager::createSDLAtlas().

roundDouble()

int roundDouble ( const double  v )

inline

Definition at line 232 of file mathutils.h.

{
    return (v > 0.0) ? CAST_S32(v + 0.5) : CAST_S32(v - 0.5);
}

References CAST_S32.

Referenced by SetupItemSlider2::fromWidget(), and SetupItemSlider2::toWidget().

weightedAverage()

float weightedAverage ( const float  n1, const float  n2, const float  w  )

inline

Definition at line 226 of file mathutils.h.

{
    return w < 0.0F ? n1 : (w > 1.0F ? n2 : w * n2 + (1.0F - w) * n1);
}

Variable Documentation

crc_table

const uint16_t crc_table[256]

static

Definition at line 37 of file mathutils.h.

Referenced by getCrc16().

square_roots

const uint8_t square_roots[1000]

static

Definition at line 73 of file mathutils.h.

Referenced by fastSqrtInt().