/*
Copyright (C) 1996-1997 Id Software, Inc.

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.

*/
// mathlib.c -- math primitives

#include <math.h>
#include "quakedef.h"

void Sys_Error (char *error, ...);

vec3_t vec3_origin = {0,0,0};
int nanmask = 255<<23;

/*-----------------------------------------------------------------*/

#define DEG2RAD( a ) ( a * M_PI ) / 180.0F

void ProjectPointOnPlane( vec3_t dst, const vec3_t p, const vec3_t normal )
{
  float d;
  vec3_t n;
  float inv_denom;

  inv_denom = 1.0F / DotProduct( normal, normal );

  d = DotProduct( normal, p ) * inv_denom;

  n[0] = normal[0] * inv_denom;
  n[1] = normal[1] * inv_denom;
  n[2] = normal[2] * inv_denom;

  dst[0] = p[0] - d * n[0];
  dst[1] = p[1] - d * n[1];
  dst[2] = p[2] - d * n[2];
}

/*
** assumes "src" is normalized
*/
void PerpendicularVector( vec3_t dst, const vec3_t src )
{
  int pos;
  int i;
  float minelem = 1.0F;
  vec3_t tempvec;

  /*
  ** find the smallest magnitude axially aligned vector
  */
  for ( pos = 0, i = 0; i < 3; i++ )
  {
    if ( fabs( src[i] ) < minelem )
    {
      pos = i;
      minelem = fabs( src[i] );
    }
  }
  tempvec[0] = tempvec[1] = tempvec[2] = 0.0F;
  tempvec[pos] = 1.0F;

  /*
  ** project the point onto the plane defined by src
  */
  ProjectPointOnPlane( dst, tempvec, src );

  /*
  ** normalize the result
  */
  VectorNormalize( dst );
}

#ifdef _WIN32
#pragma optimize( "", off )
#endif


void RotatePointAroundVector( vec3_t dst, const vec3_t dir, const vec3_t point, float degrees )
{
  float m[3][3];
  float im[3][3];
  float zrot[3][3];
  float tmpmat[3][3];
  float rot[3][3];
  int i;
  vec3_t vr, vup, vf;

  vf[0] = dir[0];
  vf[1] = dir[1];
  vf[2] = dir[2];

  PerpendicularVector( vr, dir );
  CrossProduct( vr, vf, vup );

  m[0][0] = vr[0];
  m[1][0] = vr[1];
  m[2][0] = vr[2];

  m[0][1] = vup[0];
  m[1][1] = vup[1];
  m[2][1] = vup[2];

  m[0][2] = vf[0];
  m[1][2] = vf[1];
  m[2][2] = vf[2];

  memcpy( im, m, sizeof( im ) );

  im[0][1] = m[1][0];
  im[0][2] = m[2][0];
  im[1][0] = m[0][1];
  im[1][2] = m[2][1];
  im[2][0] = m[0][2];
  im[2][1] = m[1][2];

  memset( zrot, 0, sizeof( zrot ) );
  zrot[0][0] = zrot[1][1] = zrot[2][2] = 1.0F;

  zrot[0][0] = cos( DEG2RAD( degrees ) );
  zrot[0][1] = sin( DEG2RAD( degrees ) );
  zrot[1][0] = -sin( DEG2RAD( degrees ) );
  zrot[1][1] = cos( DEG2RAD( degrees ) );

  R_ConcatRotations( m, zrot, tmpmat );
  R_ConcatRotations( tmpmat, im, rot );

  for ( i = 0; i < 3; i++ )
  {
    dst[i] = rot[i][0] * point[0] + rot[i][1] * point[1] + rot[i][2] * point[2];
  }
}

#ifdef _WIN32
#pragma optimize( "", on )
#endif

/*-----------------------------------------------------------------*/

float anglemod(float a)
{
#if 0
  if (a >= 0)
    a -= 360*(int)(a/360);
  else
    a += 360*( 1 + (int)(-a/360) );
#endif
  a = (360.0/65536) * ((int)(a*(65536/360.0)) & 65535);
  return a;
}

/*
==================
BOPS_Error

Split out like this for ASM to call.
==================
*/
void BOPS_Error (void)
{
  Sys_Error ("BoxOnPlaneSide:  Bad signbits");
}

#if !id386

/*
==================
BoxOnPlaneSide

Returns 1, 2, or 1 + 2
==================
*/
int BoxOnPlaneSide (vec3_t emins, vec3_t emaxs, mplane_t *p)
{
  float dist1, dist2;
  int   sides;

#if 0 // this is done by the BOX_ON_PLANE_SIDE macro before calling this
    // function
// fast axial cases
  if (p->type < 3)
  {
    if (p->dist <= emins[p->type])
      return 1;
    if (p->dist >= emaxs[p->type])
      return 2;
    return 3;
  }
#endif
  
// general case
  switch (p->signbits)
  {
  case 0:
dist1 = p->normal[0]*emaxs[0] + p->normal[1]*emaxs[1] + p->normal[2]*emaxs[2];
dist2 = p->normal[0]*emins[0] + p->normal[1]*emins[1] + p->normal[2]*emins[2];
    break;
  case 1:
dist1 = p->normal[0]*emins[0] + p->normal[1]*emaxs[1] + p->normal[2]*emaxs[2];
dist2 = p->normal[0]*emaxs[0] + p->normal[1]*emins[1] + p->normal[2]*emins[2];
    break;
  case 2:
dist1 = p->normal[0]*emaxs[0] + p->normal[1]*emins[1] + p->normal[2]*emaxs[2];
dist2 = p->normal[0]*emins[0] + p->normal[1]*emaxs[1] + p->normal[2]*emins[2];
    break;
  case 3:
dist1 = p->normal[0]*emins[0] + p->normal[1]*emins[1] + p->normal[2]*emaxs[2];
dist2 = p->normal[0]*emaxs[0] + p->normal[1]*emaxs[1] + p->normal[2]*emins[2];
    break;
  case 4:
dist1 = p->normal[0]*emaxs[0] + p->normal[1]*emaxs[1] + p->normal[2]*emins[2];
dist2 = p->normal[0]*emins[0] + p->normal[1]*emins[1] + p->normal[2]*emaxs[2];
    break;
  case 5:
dist1 = p->normal[0]*emins[0] + p->normal[1]*emaxs[1] + p->normal[2]*emins[2];
dist2 = p->normal[0]*emaxs[0] + p->normal[1]*emins[1] + p->normal[2]*emaxs[2];
    break;
  case 6:
dist1 = p->normal[0]*emaxs[0] + p->normal[1]*emins[1] + p->normal[2]*emins[2];
dist2 = p->normal[0]*emins[0] + p->normal[1]*emaxs[1] + p->normal[2]*emaxs[2];
    break;
  case 7:
dist1 = p->normal[0]*emins[0] + p->normal[1]*emins[1] + p->normal[2]*emins[2];
dist2 = p->normal[0]*emaxs[0] + p->normal[1]*emaxs[1] + p->normal[2]*emaxs[2];
    break;
  default:
    dist1 = dist2 = 0;    // shut up compiler
    BOPS_Error ();
    break;
  }

#if 0
  int   i;
  vec3_t  corners[2];

  for (i=0 ; i<3 ; i++)
  {
    if (plane->normal[i] < 0)
    {
      corners[0][i] = emins[i];
      corners[1][i] = emaxs[i];
    }
    else
    {
      corners[1][i] = emins[i];
      corners[0][i] = emaxs[i];
    }
  }
  dist = DotProduct (plane->normal, corners[0]) - plane->dist;
  dist2 = DotProduct (plane->normal, corners[1]) - plane->dist;
  sides = 0;
  if (dist1 >= 0)
    sides = 1;
  if (dist2 < 0)
    sides |= 2;

#endif

  sides = 0;
  if (dist1 >= p->dist)
    sides = 1;
  if (dist2 < p->dist)
    sides |= 2;

#ifdef PARANOID
if (sides == 0)
  Sys_Error ("BoxOnPlaneSide: sides==0");
#endif

  return sides;
}

#endif


void AngleVectors (vec3_t angles, vec3_t forward, vec3_t right, vec3_t up)
{
  float   angle;
  float   sr, sp, sy, cr, cp, cy;
  
  angle = angles[YAW] * (M_PI*2 / 360);
  sy = sin(angle);
  cy = cos(angle);
  angle = angles[PITCH] * (M_PI*2 / 360);
  sp = sin(angle);
  cp = cos(angle);
  angle = angles[ROLL] * (M_PI*2 / 360);
  sr = sin(angle);
  cr = cos(angle);

  forward[0] = cp*cy;
  forward[1] = cp*sy;
  forward[2] = -sp;
  right[0] = (-1*sr*sp*cy+-1*cr*-sy);
  right[1] = (-1*sr*sp*sy+-1*cr*cy);
  right[2] = -1*sr*cp;
  up[0] = (cr*sp*cy+-sr*-sy);
  up[1] = (cr*sp*sy+-sr*cy);
  up[2] = cr*cp;
}

int VectorCompare (vec3_t v1, vec3_t v2)
{
  int   i;
  
  for (i=0 ; i<3 ; i++)
    if (v1[i] != v2[i])
      return 0;
      
  return 1;
}

void VectorMA (vec3_t veca, float scale, vec3_t vecb, vec3_t vecc)
{
  vecc[0] = veca[0] + scale*vecb[0];
  vecc[1] = veca[1] + scale*vecb[1];
  vecc[2] = veca[2] + scale*vecb[2];
}


vec_t _DotProduct (vec3_t v1, vec3_t v2)
{
  return v1[0]*v2[0] + v1[1]*v2[1] + v1[2]*v2[2];
}

void _VectorSubtract (vec3_t veca, vec3_t vecb, vec3_t out)
{
  out[0] = veca[0]-vecb[0];
  out[1] = veca[1]-vecb[1];
  out[2] = veca[2]-vecb[2];
}

void _VectorAdd (vec3_t veca, vec3_t vecb, vec3_t out)
{
  out[0] = veca[0]+vecb[0];
  out[1] = veca[1]+vecb[1];
  out[2] = veca[2]+vecb[2];
}

void _VectorCopy (vec3_t in, vec3_t out)
{
  out[0] = in[0];
  out[1] = in[1];
  out[2] = in[2];
}

void CrossProduct (vec3_t v1, vec3_t v2, vec3_t cross)
{
  cross[0] = v1[1]*v2[2] - v1[2]*v2[1];
  cross[1] = v1[2]*v2[0] - v1[0]*v2[2];
  cross[2] = v1[0]*v2[1] - v1[1]*v2[0];
}

double sqrt(double x);

vec_t Length(vec3_t v)
{
  int   i;
  float length;
  
  length = 0;
  for (i=0 ; i< 3 ; i++)
    length += v[i]*v[i];
  length = sqrt (length);   // FIXME

  return length;
}

float VectorNormalize (vec3_t v)
{
  float length, ilength;

  length = v[0]*v[0] + v[1]*v[1] + v[2]*v[2];
  length = sqrt (length);   // FIXME

  if (length)
  {
    ilength = 1/length;
    v[0] *= ilength;
    v[1] *= ilength;
    v[2] *= ilength;
  }
    
  return length;

}

void VectorInverse (vec3_t v)
{
  v[0] = -v[0];
  v[1] = -v[1];
  v[2] = -v[2];
}

void VectorScale (vec3_t in, vec_t scale, vec3_t out)
{
  out[0] = in[0]*scale;
  out[1] = in[1]*scale;
  out[2] = in[2]*scale;
}


int Q_log2(int val)
{
  int answer=0;
  while ((val>>=1) != 0)
    answer++;
  return answer;
}


/*
================
R_ConcatRotations
================
*/
void R_ConcatRotations (float in1[3][3], float in2[3][3], float out[3][3])
{
  out[0][0] = in1[0][0] * in2[0][0] + in1[0][1] * in2[1][0] +
        in1[0][2] * in2[2][0];
  out[0][1] = in1[0][0] * in2[0][1] + in1[0][1] * in2[1][1] +
        in1[0][2] * in2[2][1];
  out[0][2] = in1[0][0] * in2[0][2] + in1[0][1] * in2[1][2] +
        in1[0][2] * in2[2][2];
  out[1][0] = in1[1][0] * in2[0][0] + in1[1][1] * in2[1][0] +
        in1[1][2] * in2[2][0];
  out[1][1] = in1[1][0] * in2[0][1] + in1[1][1] * in2[1][1] +
        in1[1][2] * in2[2][1];
  out[1][2] = in1[1][0] * in2[0][2] + in1[1][1] * in2[1][2] +
        in1[1][2] * in2[2][2];
  out[2][0] = in1[2][0] * in2[0][0] + in1[2][1] * in2[1][0] +
        in1[2][2] * in2[2][0];
  out[2][1] = in1[2][0] * in2[0][1] + in1[2][1] * in2[1][1] +
        in1[2][2] * in2[2][1];
  out[2][2] = in1[2][0] * in2[0][2] + in1[2][1] * in2[1][2] +
        in1[2][2] * in2[2][2];
}


/*
================
R_ConcatTransforms
================
*/
void R_ConcatTransforms (float in1[3][4], float in2[3][4], float out[3][4])
{
  out[0][0] = in1[0][0] * in2[0][0] + in1[0][1] * in2[1][0] +
        in1[0][2] * in2[2][0];
  out[0][1] = in1[0][0] * in2[0][1] + in1[0][1] * in2[1][1] +
        in1[0][2] * in2[2][1];
  out[0][2] = in1[0][0] * in2[0][2] + in1[0][1] * in2[1][2] +
        in1[0][2] * in2[2][2];
  out[0][3] = in1[0][0] * in2[0][3] + in1[0][1] * in2[1][3] +
        in1[0][2] * in2[2][3] + in1[0][3];
  out[1][0] = in1[1][0] * in2[0][0] + in1[1][1] * in2[1][0] +
        in1[1][2] * in2[2][0];
  out[1][1] = in1[1][0] * in2[0][1] + in1[1][1] * in2[1][1] +
        in1[1][2] * in2[2][1];
  out[1][2] = in1[1][0] * in2[0][2] + in1[1][1] * in2[1][2] +
        in1[1][2] * in2[2][2];
  out[1][3] = in1[1][0] * in2[0][3] + in1[1][1] * in2[1][3] +
        in1[1][2] * in2[2][3] + in1[1][3];
  out[2][0] = in1[2][0] * in2[0][0] + in1[2][1] * in2[1][0] +
        in1[2][2] * in2[2][0];
  out[2][1] = in1[2][0] * in2[0][1] + in1[2][1] * in2[1][1] +
        in1[2][2] * in2[2][1];
  out[2][2] = in1[2][0] * in2[0][2] + in1[2][1] * in2[1][2] +
        in1[2][2] * in2[2][2];
  out[2][3] = in1[2][0] * in2[0][3] + in1[2][1] * in2[1][3] +
        in1[2][2] * in2[2][3] + in1[2][3];
}


/*
===================
FloorDivMod

Returns mathematically correct (floor-based) quotient and remainder for
numer and denom, both of which should contain no fractional part. The
quotient must fit in 32 bits.
====================
*/

void FloorDivMod (double numer, double denom, int *quotient,
    int *rem)
{
  int   q, r;
  double  x;

#ifndef PARANOID
  if (denom <= 0.0)
    Sys_Error ("FloorDivMod: bad denominator %d\n", denom);

//  if ((floor(numer) != numer) || (floor(denom) != denom))
//    Sys_Error ("FloorDivMod: non-integer numer or denom %f %f\n",
//        numer, denom);
#endif

  if (numer >= 0.0)
  {

    x = floor(numer / denom);
    q = (int)x;
    r = (int)floor(numer - (x * denom));
  }
  else
  {
  //
  // perform operations with positive values, and fix mod to make floor-based
  //
    x = floor(-numer / denom);
    q = -(int)x;
    r = (int)floor(-numer - (x * denom));
    if (r != 0)
    {
      q--;
      r = (int)denom - r;
    }
  }

  *quotient = q;
  *rem = r;
}


/*
===================
GreatestCommonDivisor
====================
*/
int GreatestCommonDivisor (int i1, int i2)
{
  if (i1 > i2)
  {
    if (i2 == 0)
      return (i1);
    return GreatestCommonDivisor (i2, i1 % i2);
  }
  else
  {
    if (i1 == 0)
      return (i2);
    return GreatestCommonDivisor (i1, i2 % i1);
  }
}


#if !id386

// TODO: move to nonintel.c

/*
===================
Invert24To16

Inverts an 8.24 value to a 16.16 value
====================
*/

fixed16_t Invert24To16(fixed16_t val)
{
  if (val < 256)
    return (0xFFFFFFFF);

  return (fixed16_t)
      (((double)0x10000 * (double)0x1000000 / (double)val) + 0.5);
}

#endif