mathlib.h

*/
// 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;

extern vec3_t vec3_origin;
extern	int nanmask;

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

#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];}

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 (vec3_t v1, 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);
int GreatestCommonDivisor (int i1, int i2);

void AngleVectors (vec3_t angles, 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);



#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)))