spingle/source/mathlib.c

/*
Copyright (C) 1996-2001 Id Software, Inc.
Copyright (C) 2002-2009 John Fitzgibbons and others
Copyright (C) 2007-2008 Kristian Duske
Copyright (C) 2010-2014 QuakeSpasm developers

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 "q_defs.h"

vec3_t vec3_origin = {0, 0, 0};

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


#define DEG2RAD( a ) ( (a) * PI_DIV_180 ) //johnfitz

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)
{
	int32_t pos;
	int32_t 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);
}

//johnfitz -- removed RotatePointAroundVector() becuase it's no longer used and my compiler fucked it up anyway

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


float   anglemod(float a)
{
	a = (360.0 / 65536) * ((int32_t)(a * (65536 / 360.0)) & 65535);
	return a;
}


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

Returns 1, 2, or 1 + 2
==================
*/
int32_t BoxOnPlaneSide(vec3_t emins, vec3_t emaxs, mplane_t *p)
{
	float   dist1, dist2;
	int32_t         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:
		dist1 = dist2 = 0;              // shut up compiler
		Sys_Error("BoxOnPlaneSide:  Bad signbits");
		break;
	}

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

#if defined(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] * (PI * 2 / 360);
	sy = sin(angle);
	cy = cos(angle);
	angle = angles[PITCH] * (PI * 2 / 360);
	sp = sin(angle);
	cp = cos(angle);
	angle = angles[ROLL] * (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;
}

/*
================
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, int32_t *quotient,
                 int32_t *rem)
{
	int32_t         q, r;
	double  x;

#if !defined(PARANOID)
	if(denom <= 0.0)
		Sys_Error("FloorDivMod: bad denominator %f\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 = (int32_t)x;
		r = (int32_t)floor(numer - (x * denom));
	}
	else
	{
		//
		// perform operations with positive values, and fix mod to make floor-based
		//
		x = floor(-numer / denom);
		q = -(int32_t)x;
		r = (int32_t)floor(-numer - (x * denom));
		if(r != 0)
		{
			q--;
			r = (int32_t)denom - r;
		}
	}

	*quotient = q;
	*rem = r;
}


/*
===================
GreatestCommonDivisor
====================
*/
int32_t GreatestCommonDivisor(int32_t i1, int32_t 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);
	}
}