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

extern int		nanmask;
extern const vec3_t	vec3_origin;

#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];}
#define VectorMA(a,s,b,c) {(c)[0]=(a)[0]+(s)*(b)[0];(c)[1]=(a)[1]+(s)*(b)[1];(c)[2]=(a)[2]+(s)*(b)[2];}
#define Length(a) sqrt(DotProduct(a, a))

#define VectorScale(a,b,c) {(c)[0]=(a)[0]*(b);(c)[1]=(a)[1]*(b);(c)[2]=(a)[2]*(b);}
#define VectorCompare(x, y) (((x)[0] == (y)[0]) && ((x)[1] == (y)[1]) && ((x)[2] == (y)[2]))

#define VectorIsZero(a) ((a)[0] == 0 && (a)[1] == 0 && (a)[2] == 0)
#define VectorZero(a) ((a)[2] = (a)[1] = (a)[0] = 0);

#define VectorBlend(v1,v2,b,v) \
	{ \
		(v)[0] = (v1)[0] * (1 - (b)) + (v2)[0] * (b); \
		(v)[1] = (v1)[1] * (1 - (b)) + (v2)[1] * (b); \
		(v)[2] = (v1)[2] * (1 - (b)) + (v2)[2] * (b); \
	}

/*
 * 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 qfrandom(MAX) ((float) MAX * (rand() * (1.0 / (RAND_MAX + 1.0))))

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

void _VectorMA (const vec3_t veca, float scale, const vec3_t vecb,
				vec3_t vecc);
vec_t _DotProduct (const vec3_t v1, const vec3_t v2);
void _VectorSubtract (const vec3_t veca, const vec3_t vecb, vec3_t out);
void _VectorAdd (const vec3_t veca, const vec3_t vecb, vec3_t out);
void _VectorCopy (const vec3_t in, vec3_t out);

int _VectorCompare (const vec3_t v1, const 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 (const 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 (const 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 (const vec3_t emins, const vec3_t emaxs,
					struct mplane_s *plane);
float   anglemod (float a);

void RotatePointAroundVector (vec3_t dst, const vec3_t axis,
							  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)))

#define PlaneDist(point,plane)  ((plane)->type < 3 ? (point)[(plane)->type] : DotProduct((point), (plane)->normal))
#define PlaneDiff(point,plane) (((plane)->type < 3 ? (point)[(plane)->type] : DotProduct((point), (plane)->normal)) - (plane)->dist)


extern	mplane_t	frustum[4];

#ifndef IMPLEMENT_R_CullBox
extern inline
#endif
qboolean
R_CullBox (const vec3_t mins, const vec3_t maxs)
{
	int i;

	for (i=0 ; i<4 ; i++)
		if (BoxOnPlaneSide (mins, maxs, &frustum[i]) == 2)
			return true;
	return false;
}

#endif // __mathlib_h