/* 
 * defs.h  
 * based on GraphicsGems.h, by Andrew Glassner
 */

#ifndef DEFS_H
#define DEFS_H 1


/***********************/
/* one-argument macros */
/***********************/

/* absolute value of a */
#define ABS(a)		(((a)<0) ? -(a) : (a))

/* round a to nearest integer towards 0 */
#define FLOOR(a)		((a)>0 ? (int)(a) : -(int)(-a))

/* round a to nearest integer away from 0 */
#define CEILING(a) \
((a)==(int)(a) ? (a) : (a)>0 ? 1+(int)(a) : -(1+(int)(-a)))

/* round a to nearest int */
#define ROUND(a)	((a)>0 ? (int)(a+0.5) : -(int)(0.5-a))		

/* take sign of a, either -1, 0, or 1 */
#define ZSGN(a)		(((a)<0) ? -1 : (a)>0 ? 1 : 0)	

/* take binary sign of a, either -1, or 1 if >= 0 */
#define SGN(a)		(((a)<0) ? -1 : 0)

#define ODD(a)         ((a)&1)

#define EVEN(a)         (((a)&1)==0)

/* square a */
#define SQR(a)		((a)*(a))	


/***********************/
/* two-argument macros */
/***********************/

/* find minimum of a and b */
#define MIN(a,b)	(((a)<(b))?(a):(b))	

/* find maximum of a and b */
#define MAX(a,b)	(((a)>(b))?(a):(b))	

/* relative comparisons */

#define REL_EPS   1e-6

#define REL_EQ(a, b)    ((ABS((a) - (b)) > REL_EPS) ? FALSE : TRUE)

#define REL_GT(a, b)    (((a) > ((b) + REL_EPS)) ? TRUE : FALSE)

#define REL_LT(a, b)    (((a) < ((b) - REL_EPS)) ? TRUE : FALSE)

/* swap a and b */
#define SWAP(A, B, TYPE) {TYPE tmp; tmp = A; A = B; B = tmp;}

/* linear interpolation from l (when a=0) to h (when a=1)*/
/* (equal to (a*h)+((1-a)*l) */
#define LERP(a,l,h)	((l)+(((h)-(l))*(a)))

/* clamp the input to the specified range */
#define CLAMP(v,l,h)	((v)<(l) ? (l) : (v) > (h) ? (h) : v)


/****************************/
/* memory allocation macros */
/****************************/

/* create a new instance of an array of size n  */
#define NEWARRAY(n, x)	(struct x *)(malloc((unsigned)((n)*sizeof(struct x))))

/* create a new instance of a structure */
#define NEWSTRUCT(x)	(struct x *)(malloc((unsigned)sizeof(struct x)))

/* create a new instance of a type */
#define NEWTYPE(x)	(x *)(malloc((unsigned)sizeof(x)))

/* create a new instance of an array */
#define NEWTARRAY(n, x)	(x *)(malloc((unsigned)((n)*sizeof(x))))


/********************/
/* useful constants */
/********************/

#define PI		3.141592	/* the venerable pi */
#define PITIMES2	6.283185	/* 2 * pi */
#define PIOVER2		1.570796	/* pi / 2 */
#define E		2.718282	/* the venerable e */
#define SQRT2		1.414214	/* sqrt(2) */
#define SQRT3		1.732051	/* sqrt(3) */
#define GOLDEN		1.618034	/* the golden ratio */
#define DTOR		0.017453	/* convert degrees to radians */
#define RTOD		57.29578	/* convert radians to degrees */
#define MAXINT          2147483647
#define MAXDOUBLE       1.797693134862315708e+308
#define MAXFLOAT        ((float)3.40282346638528860e+38)
#define MINDOUBLE       4.94065645841246544e-324
#define MINFLOAT        ((float)1.40129846432481707e-45)
#define EPS             1e-10

/************/
/* booleans */
/************/

#define TRUE		1
#define FALSE		0
#define ON		1
#define OFF 		0
#define UNDEFINED      -1

typedef int boolean;			/* boolean data type */
typedef boolean flag;			/* flag data type */
typedef double Real;

/* LISTS */

#define LIST_INSERT(L, I, TYPE) {TYPE *l = I; l->next = L; L = l; }

#endif