// 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;


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");
}


/*
==================
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;
}

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)
	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);
    }
}


// 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);
}