mirror of
https://github.com/scp-fs2open/fs2open.github.com.git
synced 2026-11-10 04:31:34 -10:00
portej05
719825f80d
I've tested this through compiling and through hand checking. Normalises line endings in ALL files to \n.
163 lines
3.3 KiB
C++
163 lines
3.3 KiB
C++
/*
|
|
* 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.
|
|
*
|
|
*/
|
|
|
|
|
|
|
|
#include <stdlib.h>
|
|
#include <math.h>
|
|
|
|
#include "globalincs/pstypes.h"
|
|
#include "math/floating.h"
|
|
#include "io/timer.h"
|
|
|
|
|
|
/*
|
|
#define LOOKUP_BITS 6
|
|
#define EXP_POS 23
|
|
#define EXP_BIAS 127
|
|
typedef float FLOAT;
|
|
|
|
#define LOOKUP_POS (EXP_POS-LOOKUP_BITS)
|
|
#define SEED_POS (EXP_POS-8)
|
|
#define TABLE_SIZE (2<<LOOKUP_BITS)
|
|
#define LOOKUP_MASK (TABLE_SIZE-1)
|
|
#define GET_EXP(a) (((a) >> EXP_POS) & 0xFF )
|
|
#define SET_EXP(a) ((a) << EXP_POS )
|
|
#define GET_EMANT(a) (((a) >> LOOKUP_POS) & LOOKUP_MASK )
|
|
#define SET_MANTSEED(a) (((unsigned long)(a)) << SEED_POS )
|
|
|
|
|
|
int fl_magic = 0x59C00000; //representation of 2^51 + 2^52
|
|
const float *p_fl_magic = (const float *)&fl_magic;
|
|
|
|
|
|
union _flint {
|
|
unsigned long i;
|
|
float f;
|
|
} fi, fo;
|
|
|
|
|
|
static unsigned char iSqrt[TABLE_SIZE];
|
|
static int iSqrt_inited = 0;
|
|
|
|
static void MakeInverseSqrtLookupTable()
|
|
{
|
|
long f;
|
|
unsigned char *h;
|
|
union _flint fi, fo;
|
|
|
|
iSqrt_inited = 1;
|
|
for ( f=0, h=iSqrt; f < TABLE_SIZE; f++ ) {
|
|
fi.i = ((EXP_BIAS-1)<<EXP_POS) | (f<<LOOKUP_POS);
|
|
fo.f = 1.0f / fl_sqrt(fi.f);
|
|
*h++ = (unsigned char)(((fo.i + (1<<(SEED_POS-2))) >>SEED_POS ) & 0xFF);
|
|
}
|
|
iSqrt[ TABLE_SIZE / 2 ] = 0xFF;
|
|
}
|
|
|
|
|
|
// HACK!
|
|
float fl_isqrt_c( float x )
|
|
{
|
|
// unsigned long a = ((union _flint *)(&x))->i;
|
|
// float arg = x;
|
|
// union _flint seed;
|
|
// FLOAT r;
|
|
|
|
int t1, t2, t3;
|
|
t1 = timer_get_microseconds();
|
|
float r1 = 1.0f / (float)sqrt((double)x);
|
|
t2 = timer_get_microseconds();
|
|
// float r2 = fl_isqrt_asm(x);
|
|
t3 = timer_get_microseconds();
|
|
|
|
return r1;
|
|
|
|
|
|
// if ( !iSqrt_inited )
|
|
// MakeInverseSqrtLookupTable();
|
|
|
|
// seed.i = SET_EXP(((3*EXP_BIAS-1) - GET_EXP(a)) >> 1 ) | SET_MANTSEED(iSqrt[GET_EMANT(a)]);
|
|
// r = seed.f;
|
|
// r = (3.0f - r * r * arg ) * r * 0.5f;
|
|
// r = (3.0f - r * r * arg ) * r * 0.5f;
|
|
// return r;
|
|
}
|
|
*/
|
|
|
|
// rounds off a floating point number to a multiple of some number
|
|
float fl_roundoff(float x, int multiple)
|
|
{
|
|
float half = (float) multiple / 2.0f;
|
|
|
|
if (x < 0)
|
|
half = -half;
|
|
|
|
x += half;
|
|
return (float) (((int) x / multiple) * multiple);
|
|
}
|
|
|
|
|
|
// Return random value in range 0.0..1.0- (1.0- means the closest number less than 1.0)
|
|
float frand()
|
|
{
|
|
int i_rval;
|
|
do {
|
|
i_rval = myrand();
|
|
} while (i_rval == RAND_MAX);
|
|
float rval = ((float) i_rval) / RAND_MAX;
|
|
return rval;
|
|
}
|
|
|
|
// Return a floating point number in the range min..max.
|
|
float frand_range(float min, float max)
|
|
{
|
|
float rval;
|
|
|
|
rval = frand();
|
|
rval = rval * (max - min) + min;
|
|
|
|
return rval;
|
|
}
|
|
|
|
// Call this in the frame interval to get TRUE chance times per second.
|
|
// If you want it to return TRUE 3 times per second, call it in the frame interval like so:
|
|
// rand_chance(flFrametime, 3.0f);
|
|
int rand_chance(float frametime, float chance) // default value for chance = 1.0f.
|
|
{
|
|
while (--chance > 0.0f)
|
|
if (frand() < frametime)
|
|
return 1;
|
|
|
|
return frand() < (frametime * (chance + 1.0f));
|
|
}
|
|
|
|
/*fix fl2f( float x )
|
|
{
|
|
float nf;
|
|
nf = x*65536.0f + 8390656.0f;
|
|
return ((*((int *)&nf)) & 0x7FFFFF)-2048;
|
|
}
|
|
*/
|
|
|
|
|
|
/*
|
|
>#define S 65536.0
|
|
>#define MAGIC (((S * S * 16) + (S*.5)) * S)
|
|
>
|
|
>#pragma inline float2int;
|
|
>
|
|
>ulong float2int( float d )
|
|
>{
|
|
> double dtemp = MAGIC + d;
|
|
> return (*(ulong *)&dtemp) - 0x80000000;
|
|
>}
|
|
|
|
*/
|