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/**
* $Id$
*
* ***** BEGIN GPL LICENSE BLOCK *****
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
* All rights reserved.
*
* The Original Code is: some of this file.
*
* ***** END GPL LICENSE BLOCK *****
* */
#include <float.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "BLI_math.h"
/* A few small defines. Keep'em local! */
#define SMALL_NUMBER 1.e-8
float sqrt3f(float f)
{
if(f==0.0) return 0;
if(f<0) return (float)(-exp(log(-f)/3));
else return (float)(exp(log(f)/3));
}
double sqrt3d(double d)
{
if(d==0.0) return 0;
if(d<0) return -exp(log(-d)/3);
else return exp(log(d)/3);
}
float saacos(float fac)
{
if(fac<= -1.0f) return (float)M_PI;
else if(fac>=1.0f) return 0.0;
else return (float)acos(fac);
}
float saasin(float fac)
{
if(fac<= -1.0f) return (float)-M_PI/2.0f;
else if(fac>=1.0f) return (float)M_PI/2.0f;
else return (float)asin(fac);
}
float sasqrt(float fac)
{
if(fac<=0.0) return 0.0;
return (float)sqrt(fac);
}
float saacosf(float fac)
{
if(fac<= -1.0f) return (float)M_PI;
else if(fac>=1.0f) return 0.0f;
else return (float)acosf(fac);
}
float saasinf(float fac)
{
if(fac<= -1.0f) return (float)-M_PI/2.0f;
else if(fac>=1.0f) return (float)M_PI/2.0f;
else return (float)asinf(fac);
}
float sasqrtf(float fac)
{
if(fac<=0.0) return 0.0;
return (float)sqrtf(fac);
}
float interpf(float target, float origin, float fac)
{
return (fac*target) + (1.0f-fac)*origin;
}
/* useful to calculate an even width shell, by taking the angle between 2 planes.
* The return value is a scale on the offset.
* no angle between planes is 1.0, as the angle between the 2 planes approches 180d
* the distance gets very high, 180d would be inf, but this case isn't valid */
float shell_angle_to_dist(const float angle)
{
return (angle < SMALL_NUMBER) ? 1.0f : fabsf(1.0f / cosf(angle * (M_PI/180.0f)));
}
/* used for zoom values*/
float power_of_2(float val)
{
return (float)pow(2, ceil(log(val) / log(2)));
}
/* WARNING: MSVC compiling hack for double_round() */
#if (WIN32 || WIN64) && !(FREE_WINDOWS)
/* from python 3.1 pymath.c */
double copysign(double x, double y)
{
/* use atan2 to distinguish -0. from 0. */
if (y > 0. || (y == 0. && atan2(y, -1.) > 0.)) {
return fabs(x);
} else {
return -fabs(x);
}
}
/* from python 3.1 pymath.c */
double round(double x)
{
double absx, y;
absx = fabs(x);
y = floor(absx);
if (absx - y >= 0.5)
y += 1.0;
return copysign(y, x);
}
#endif
/* from python 3.1 floatobject.c
* ndigits must be between 0 and 21 */
double double_round(double x, int ndigits) {
double pow1, pow2, y, z;
if (ndigits >= 0) {
pow1 = pow(10.0, (double)ndigits);
pow2 = 1.0;
y = (x*pow1)*pow2;
/* if y overflows, then rounded value is exactly x */
if (!finite(y))
return x;
}
else {
pow1 = pow(10.0, (double)-ndigits);
pow2 = 1.0; /* unused; silences a gcc compiler warning */
y = x / pow1;
}
z = round(y);
if (fabs(y-z) == 0.5)
/* halfway between two integers; use round-half-even */
z = 2.0*round(y/2.0);
if (ndigits >= 0)
z = (z / pow2) / pow1;
else
z *= pow1;
/* if computation resulted in overflow, raise OverflowError */
return z;
}
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