/*
 *  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
 *
 *
 *  $Id$
 */

// mathlib.c -- math primitives
//#include <math.h>
//#include "quakedef.h"
#include "g_local.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);
}

#if defined(_WIN32) && defined(_MSC_VER)
#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];
	}
}

#if defined(_WIN32) && defined(_MSC_VER)
#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;
}

int VectorCompareF(vec3_t v1, float x, float y, float z)
{

	if ((v1[0] != x) || (v1[1] != y) || (v1[2] != z))
	{
		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 VectorLength(vec3_t v)
{
	float length;

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

	return length;
}

float VectorDistance(vec3_t v1, vec3_t v2)
{
	vec3_t diff;

	VectorSubtract(v1, v2, diff);

	return vlen(diff);
}

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 (fixed16_t)0xFFFFFFFF;
	}

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

#endif
