mathlib.h

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

*/
// mathlib.h

typedef	float	vec_t;
typedef	vec_t	vec3_t[3];
typedef	vec_t	vec5_t[5];

typedef	int	fixed4_t;
typedef	int	fixed8_t;
typedef	int	fixed16_t;

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

struct mplane_s;

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

#define NANMASK (255 << 23)
#define	IS_NAN(x) (((*(int *) & x) & NANMASK) == NANMASK)

#define Q_rint(x) ((x) > 0 ? (int)((x) + 0.5) : (int)((x) - 0.5))

#define DotProduct(x, y)	((x)[0] * (y)[0] + (x)[1] * (y)[1] + (x)[2] * (y)[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 VectorClear(a)		((a)[0] = (a)[1] = (a)[2] = 0)
#define VectorNegate(a, b)	((b)[0] = -(a)[0], (b)[1] = -(a)[1], (b)[2] = -(a)[2])
#define VectorSet(v, x, y, z)	((v)[0] = (x), (v)[1] = (y), (v)[2] = (z))
#define VectorOffset(v, n)	((v)[0] += (n), (v)[1] += (n), (v)[2] += (n))

#define CrossProduct(v1, v2, x)					\
	((x)[0] = (v1)[1] * (v2)[2] - (v1)[2] * (v2)[1],	\
	(x)[1] = (v1)[2] * (v2)[0] - (v1)[0] * (v2)[2],		\
	(x)[2] = (v1)[0] * (v2)[1] - (v1)[1] * (v2)[0])

#define VectorSupCompare(v, w, m)								\
	(_mathlib_temp_float1 = m,								\
	(v)[0] - (w)[0] > -_mathlib_temp_float1 && (v)[0] - (w)[0] < _mathlib_temp_float1 &&	\
	(v)[1] - (w)[1] > -_mathlib_temp_float1 && (v)[1] - (w)[1] < _mathlib_temp_float1 &&	\
	(v)[2] - (w)[2] > -_mathlib_temp_float1 && (v)[2] - (w)[2] < _mathlib_temp_float1)

#define VectorL2Compare(v, w, m)				\
	(_mathlib_temp_float1 = (m) * (m),			\
	_mathlib_temp_vec1[0] = (v)[0] - (w)[0], _mathlib_temp_vec1[1] = (v)[1] - (w)[1], _mathlib_temp_vec1[2] = (v)[2] - (w)[2],\
	_mathlib_temp_vec1[0] * _mathlib_temp_vec1[0] +		\
	_mathlib_temp_vec1[1] * _mathlib_temp_vec1[1] +		\
	_mathlib_temp_vec1[2] * _mathlib_temp_vec1[2] < _mathlib_temp_float1)

#define VectorCompare(v, w)	((v)[0] == (w)[0] && (v)[1] == (w)[1] && (v)[2] == (w)[2])

#define VectorMA(a, _f, b, c)					\
do {								\
	_mathlib_temp_float1 = (_f);				\
	(c)[0] = (a)[0] + _mathlib_temp_float1 * (b)[0];	\
	(c)[1] = (a)[1] + _mathlib_temp_float1 * (b)[1];	\
	(c)[2] = (a)[2] + _mathlib_temp_float1 * (b)[2];	\
} while(0)

#define VectorScale(in, _scale, out)					\
do {									\
	float	scale = (_scale);					\
	(out)[0] = (in)[0] * (scale); (out)[1] = (in)[1] * (scale); (out)[2] = (in)[2] * (scale);\
} while(0)

#define anglemod(a)	((360.0 / 65536) * ((int)((a) * (65536 / 360.0)) & 65535))

#ifdef _WIN32
  #define VectorNormalizeFast(_v)							\
  do {										\
	_mathlib_temp_float1 = DotProduct((_v), (_v));				\
	if (_mathlib_temp_float1) {						\
		_mathlib_temp_float2 = 0.5f * _mathlib_temp_float1;		\
		_mathlib_temp_int1 = *((int *)&_mathlib_temp_float1);		\
		_mathlib_temp_int1 = 0x5f375a86 - (_mathlib_temp_int1 >> 1);	\
		_mathlib_temp_float1 = *((float *)&_mathlib_temp_int1);	\
		_mathlib_temp_float1 = _mathlib_temp_float1 * (1.5f - _mathlib_temp_float2 * _mathlib_temp_float1 * _mathlib_temp_float1);\
		VectorScale((_v), _mathlib_temp_float1, (_v));			\
	}									\
  } while(0)
#else
  #define VectorNormalizeFast VectorNormalize
#endif

#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)

void PerpendicularVector (vec3_t dst, const vec3_t src);
void VectorVectors (const vec3_t forward, vec3_t right, vec3_t up);
vec_t VectorLength (const vec3_t v);
float VectorNormalize (vec3_t v);		// returns vector length

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

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

void vectoangles (const vec3_t vec, vec3_t ang);
void AngleVectors (const vec3_t angles, vec3_t forward, vec3_t right, vec3_t up);
int BoxOnPlaneSide (const vec3_t emins, const vec3_t emaxs, const struct mplane_s *plane);

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

extern	vec3_t	vec3_origin;
extern	int	_mathlib_temp_int1, _mathlib_temp_int2;
extern	float	_mathlib_temp_float1, _mathlib_temp_float2;
extern	vec3_t	_mathlib_temp_vec1;

#ifdef HEXEN2_SUPPORT

#if defined(_WIN32) && defined(_MSC_VER)
	_inline float fastfabs(float _X)
	{
		*((long*)&_X) &= 0x7fffffff;
		return (_X);
	}
#else
	// get multiple definitions and warning for above code on gcc
	extern float fastfabs(float);
#endif


#endif		// #ifdef HEXEN2_SUPPORT