#include "quakedef.h"

vec3_t vec3_origin = {0, 0, 0};

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

float
anglemod(float a)
{
	return (360.0 / 65536.0) * ((int)(a * (65536.0 / 360.0)) & 65535);
}

void
TransformVector(vec3_t in, vec3_t out, view_t *v)
{
	out[0] = DotProduct(in, v->right);
	out[1] = DotProduct(in, v->up);
	out[2] = DotProduct(in, v->pn);
}

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

	// 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:
		fatal("BoxOnPlaneSide:  Bad signbits");
		break;
	}

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

#ifndef NDEBUG
	if(sides == 0)
		fatal("BoxOnPlaneSide: sides==0");
#endif

	return sides;
}

void
AngleVectors(vec3_t angles, vec3_t forward, vec3_t right, vec3_t up)
{
	float angle, sr, sp, sy, cr, cp, cy;

	angle = angles[YAW] * (M_PI * 2 / 360.0);
	sy = sinf(angle);
	cy = cosf(angle);
	angle = angles[PITCH] * (M_PI * 2 / 360.0);
	sp = sinf(angle);
	cp = cosf(angle);
	angle = angles[ROLL] * (M_PI * 2 / 360.0);
	sr = sinf(angle);
	cr = cosf(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;
}

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];
}

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];
}

vec_t
Length(vec3_t v)
{
	return sqrtf(v[0] * v[0] + v[1] * v[1] + v[2] * v[2]);
}

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

	length = sqrtf(v[0] * v[0] + v[1] * v[1] + v[2] * v[2]);
	if(length != 0) {
		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, vec_t scale, vec3_t out)
{
	out[0] = in[0] * scale;
	out[1] = in[1] * scale;
	out[2] = in[2] * scale;
}

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];
}

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];
}

/*
 * 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 NDEBUG
	if(denom <= 0.0)
		fatal("FloorDivMod: bad denominator %g\n", denom);
	if(floor(numer) != numer || floor(denom) != denom)
		fatal("FloorDivMod: non-integer numer or denom %g %g\n", numer, denom);
#endif

	if(numer >= 0.0) {
		x = floor(numer / denom);
		q = x;
		r = 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 = floor(-numer - (x * denom));
		if(r != 0) {
			q--;
			r = (int)denom - r;
		}
	}

	*quotient = q;
	*rem = r;
}

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);
	}
}