floating.h

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/*
 * Copyright (C) Volition, Inc. 1999.  All rights reserved.
 *
 * All source code herein is the property of Volition, Inc. You may not sell 
 * or otherwise commercially exploit the source or things you created based on the 
 * source.
 *
*/ 



#ifndef _FLOATING_H
#define _FLOATING_H

#include <math.h>
#include <float.h>

#include "globalincs/pstypes.h"

extern float frand();
extern int rand_chance(float frametime, float chance = 1.0f);
float frand_range(float min, float max);

// determine if a floating point number is NaN (Not a Number)
#define fl_is_nan(fl) _isnan((double)(fl))

// Handy macros to prevent type casting all over the place

#define fl_sqrt(fl) sqrtf(fl)
#define fl_isqrt(fl) (1.0f/sqrtf(fl))
#define fl_abs(fl) fabsf(fl)
#define i2fl(i) ((float)(i))
#define fl2i(fl) ((int)(fl))
#define fl2ir(fl) ((int)(fl + ((fl < 0.0f) ? -0.5f : 0.5f)))
#define flceil(fl) (int)ceil(fl)
#define flfloor(fl) (int)floor(fl)
#define f2fl(fx) ((float)(fx)/65536.0f)
#define fl2f(fl) (int)((fl)*65536.0f)
#define fl_tan(fl) tanf(fl)

// convert a measurement in degrees to radians
#define fl_radians(fl)  ((float)((fl) * (PI / 180.0f)))

// convert a measurement in radians to degrees
#define fl_degrees(fl)  ((float)((fl) * (180.0f / PI)))

// use this instead of:
// for:  (int)floor(x+0.5f) use fl_round_2048(x)
//       (int)ceil(x-0.5f)  use fl_round_2048(x)
//       (int)floor(x-0.5f) use fl_round_2048(x-1.0f)
//       (int)floor(x)      use fl_round_2048(x-0.5f)
// for values in the range -2048 to 2048
// use this instead of:
// for:  (int)floor(x+0.5f) use fl_round_2048(x)
//       (int)ceil(x-0.5f)  use fl_round_2048(x)
//       (int)floor(x-0.5f) use fl_round_2048(x-1.0f)
//       (int)floor(x)      use fl_round_2048(x-0.5f)
// for values in the range -2048 to 2048

/*
extern const float *p_fl_magic;

inline int fl_round_2048( float x )
{
        double tmp_quad;
        tmp_quad = x + *p_fl_magic;
        return *((int *)&tmp_quad);
}

inline float fl_sqrt( float x)
{
        float retval;

        _asm fld x
        _asm fsqrt
        _asm fstp retval
        
        return retval;
}

float fl_isqrt( float x )
{
        float retval;

        _asm fld x
        _asm fsqrt
        _asm fstp retval
        
        return 1.0f / retval;
} 
*/

// sees if two floating point numbers are within the minimum tolerance
inline bool fl_equal(float a, float b)
{
        return fl_abs(a - b) <= FLT_EPSILON * MAX(1.0f, MAX(fl_abs(a), fl_abs(b)));
}

// rounds off a floating point number to a multiple of some number
extern float fl_roundoff(float x, int multiple);


#endif