quakeforge/include/QF/mathlib.h

/*
	mathlib.h

	Vector math library

	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:

		Free Software Foundation, Inc.
		59 Temple Place - Suite 330
		Boston, MA  02111-1307, USA

	$Id$
*/

#ifndef __mathlib_h
#define __mathlib_h

#include <math.h>
#include "QF/qtypes.h"

#ifndef M_PI
# define M_PI	    3.14159265358979323846  // matches value in gcc v2 math.h
#endif

struct mplane_s;

extern vec3_t vec3_origin;
extern  int nanmask;

#define IS_NAN(x) (((*(int *)&x)&nanmask)==nanmask)

#define DotProduct(a,b) ((a)[0]*(b)[0]+(a)[1]*(b)[1]+(a)[2]*(b)[2])
#define VectorSubtract(a,b,c) {(c)[0]=(a)[0]-(b)[0];(c)[1]=(a)[1]-(b)[1];(c)[2]=(a)[2]-(b)[2];}
#define VectorAdd(a,b,c) {(c)[0]=(a)[0]+(b)[0];(c)[1]=(a)[1]+(b)[1];(c)[2]=(a)[2]+(b)[2];}
#define VectorCopy(a,b) {(b)[0]=(a)[0];(b)[1]=(a)[1];(b)[2]=(a)[2];}

/*
 * VectorDistance, the distance between two points.
 * Yes, this is the same as sqrt(VectorSubtract then DotProduct), 
 * however that way would involve more vars, this is cheaper.
 */
#define VectorDistance_fast(a, b)	((((a)[0] - (b)[0]) * ((a)[0] - (b)[0])) + \
									 (((a)[1] - (b)[1]) * ((a)[1] - (b)[1])) + \
									 (((a)[2] - (b)[2]) * ((a)[2] - (b)[2])))
#define VectorDistance(a, b)	sqrt(VectorDistance_fast(a, b))


#define lhrandom(MIN,MAX) ((rand() & 32767) * (((MAX)-(MIN)) * (1.0f / 32767.0f)) + (MIN))

// up / down
#define	PITCH	0
// left / right
#define	YAW		1
// fall over
#define	ROLL	2

void VectorMA (vec3_t veca, float scale, vec3_t vecb, vec3_t vecc);

vec_t _DotProduct (vec3_t v1, vec3_t v2);
void _VectorSubtract (vec3_t veca, vec3_t vecb, vec3_t out);
void _VectorAdd (vec3_t veca, vec3_t vecb, vec3_t out);
void _VectorCopy (vec3_t in, vec3_t out);

int VectorCompare (vec3_t v1, vec3_t v2);
vec_t Length (vec3_t v);
void CrossProduct (const vec3_t v1, const vec3_t v2, vec3_t cross);
float VectorNormalize (vec3_t v);	       // returns vector length
void VectorInverse (vec3_t v);
void VectorScale (vec3_t in, vec_t scale, vec3_t out);
int Q_log2(int val);

void R_ConcatRotations (float in1[3][3], float in2[3][3], float out[3][3]);
void R_ConcatTransforms (float in1[3][4], float in2[3][4], float out[3][4]);

void FloorDivMod (double numer, double denom, int *quotient,
		int *rem);
fixed16_t Invert24To16(fixed16_t val);
fixed16_t Mul16_30(fixed16_t multiplier, fixed16_t multiplicand);
int GreatestCommonDivisor (int i1, int i2);

void AngleVectors (vec3_t angles, vec3_t forward, vec3_t right, vec3_t up);
void VectorVectors(const vec3_t forward, vec3_t right, vec3_t up);
int BoxOnPlaneSide (vec3_t emins, vec3_t emaxs, struct mplane_s *plane);
float   anglemod(float a);

void RotatePointAroundVector( vec3_t dst, const vec3_t dir, const vec3_t point, float degrees );

#define BOX_ON_PLANE_SIDE(emins, emaxs, p)				\
	(((p)->type < 3)?									\
	(													\
		((p)->dist <= (emins)[(p)->type])?				\
		1												\
		:												\
		(												\
			((p)->dist >= (emaxs)[(p)->type])?			\
			2											\
			:											\
			3											\
		)												\
	)													\
	:													\
	BoxOnPlaneSide( (emins), (emaxs), (p)))

#endif // __mathlib_h