/*
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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

*/
// mathlib.c -- math primitives

#include <math.h>

#include "mathlib.h"
#include "model.h"
#include "sys.h"

#ifdef SERVERONLY
#include "qwsvdef.h"
#else
#include "quakedef.h"
#endif

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 (fabsf(src[i]) < minelem) {
	    pos = i;
	    minelem = fabsf(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);
}


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];
    }
}

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

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;
}

int
SignbitsForPlane(const mplane_t *plane)
{
    int i, bits;

    // for fast box on planeside test
    bits = 0;
    for (i = 0; i < 3; i++) {
	if (plane->normal[i] < 0)
	    bits |= 1 << i;
    }
    return bits;
}

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

Split out like this for ASM to call.
==================
*/
void __attribute__((noreturn))
BOPS_Error(void)
{
    Sys_Error("%s:  Bad signbits", __func__);
}

#ifndef USE_X86_ASM

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

Returns PSIDE_FRONT, PSIDE_BACK, or PSIDE_BOTH (PSIDE_FRONT | PSIDE_BACK)
==================
*/
int
BoxOnPlaneSide(const vec3_t mins, const vec3_t maxs, const 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 <= mins[p->type])
	    return PSIDE_FRONT;
	if (p->dist >= maxs[p->type])
	    return PSIDE_BACK;
	return PSIDE_BOTH;
    }
#endif

// general case
    switch (p->signbits) {
    case 0:
	dist1 =
	    p->normal[0] * maxs[0] + p->normal[1] * maxs[1] +
	    p->normal[2] * maxs[2];
	dist2 =
	    p->normal[0] * mins[0] + p->normal[1] * mins[1] +
	    p->normal[2] * mins[2];
	break;
    case 1:
	dist1 =
	    p->normal[0] * mins[0] + p->normal[1] * maxs[1] +
	    p->normal[2] * maxs[2];
	dist2 =
	    p->normal[0] * maxs[0] + p->normal[1] * mins[1] +
	    p->normal[2] * mins[2];
	break;
    case 2:
	dist1 =
	    p->normal[0] * maxs[0] + p->normal[1] * mins[1] +
	    p->normal[2] * maxs[2];
	dist2 =
	    p->normal[0] * mins[0] + p->normal[1] * maxs[1] +
	    p->normal[2] * mins[2];
	break;
    case 3:
	dist1 =
	    p->normal[0] * mins[0] + p->normal[1] * mins[1] +
	    p->normal[2] * maxs[2];
	dist2 =
	    p->normal[0] * maxs[0] + p->normal[1] * maxs[1] +
	    p->normal[2] * mins[2];
	break;
    case 4:
	dist1 =
	    p->normal[0] * maxs[0] + p->normal[1] * maxs[1] +
	    p->normal[2] * mins[2];
	dist2 =
	    p->normal[0] * mins[0] + p->normal[1] * mins[1] +
	    p->normal[2] * maxs[2];
	break;
    case 5:
	dist1 =
	    p->normal[0] * mins[0] + p->normal[1] * maxs[1] +
	    p->normal[2] * mins[2];
	dist2 =
	    p->normal[0] * maxs[0] + p->normal[1] * mins[1] +
	    p->normal[2] * maxs[2];
	break;
    case 6:
	dist1 =
	    p->normal[0] * maxs[0] + p->normal[1] * mins[1] +
	    p->normal[2] * mins[2];
	dist2 =
	    p->normal[0] * mins[0] + p->normal[1] * maxs[1] +
	    p->normal[2] * maxs[2];
	break;
    case 7:
	dist1 =
	    p->normal[0] * mins[0] + p->normal[1] * mins[1] +
	    p->normal[2] * mins[2];
	dist2 =
	    p->normal[0] * maxs[0] + p->normal[1] * maxs[1] +
	    p->normal[2] * maxs[2];
	break;
    default:
	BOPS_Error();
	break;
    }

    sides = 0;
    if (dist1 >= p->dist)
	sides = PSIDE_FRONT;
    if (dist2 < p->dist)
	sides |= PSIDE_BACK;

#ifdef PARANOID
    if (sides == 0)
	Sys_Error("%s: sides == 0", __func__);
#endif

    return sides;
}
#endif /* USE_X86_ASM */


void
AngleVectors(const 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(const vec3_t veca, const float scale, const 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(const vec3_t v1, const 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];
}

vec_t
Length(vec3_t v)
{
    int i;
    float length;

    length = 0;
    for (i = 0; i < 3; i++)
	length += v[i] * v[i];
    length = sqrtf(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 = sqrtf(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(const vec3_t in, const 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;
}

int
Q_gcd(int a, int b)
{
    if (a < b) {
	int tmp = a;
	a = b;
	b = tmp;
    }
    if (!b)
	return a ? a : 1; /* just in case... */

    while (a % b) {
	int tmp = a;
	a = b;
	b = tmp;
	b %= a;
    }

    return b;
}

/*
================
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("%s: bad denominator %lf", __func__, denom);

//      if ((floor(numer) != numer) || (floor(denom) != denom))
//              Sys_Error ("%s: non-integer numer or denom %f %f", __func__
//                              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);
    }
}


#ifndef USE_X86_ASM

// 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 /* USE_X86_ASM */
