/*
 * def.h contains some useful definitions for "C" programs.
 *
 * Version:  2.2 (11/17/87)
 * Author:  Eric Haines, 3D/Eye, Inc.
 *
 * Modified: 1 October 1992
 *           Alexander R. Enzmann
 */

#define EPSILON 5.0e-6

#ifndef FALSE
#define FALSE 0
#endif

#ifndef NULL
#define NULL 0
#endif

#ifndef TRUE
#define TRUE 1
#endif

#ifndef PI
#define PI 3.141592653589793
#endif

typedef double MATRIX[4][4] ;  /* row major form */

typedef struct {
   double x, y, z, w;
   } COORD4, *COORD4_P;

#define POW(A,B)     ( (A) == 0 ? 0 : ( (B) == 0 ? 1 : pow(A, B) ) )
#define SGN(A)       ( (A) < 0 ? -1 : ( (A) > 0 ? 1 : 0) )
#define ABS(A)       ( (A) < 0 ? -(A) : (A) )
#define FRACTION(A)  ( (A) - (long)(A) )
#define MAX(A,B)     ( (A) > (B) ? (A) : (B) )
#define MAX3(A,B,C)  ( MAX( MAX( A,B ), C ) )
#define MIN(A,B)     ( (A) < (B) ? (A) : (B) )
#define MIN3(A,B,C)  ( MIN( MIN( A,B ), C ) )
#define SQR(A)       ( (A) * (A) )

#define ADD2_COORD(r,a)   { (r).x += (a).x; (r).y += (a).y;\
                            (r).z += (a).z; }
#define ADD3_COORD(r,a,b) { (r).x = (a).x + (b).x;\
                            (r).y = (a).y + (b).y;\
                            (r).z = (a).z + (b).z; }
#define COPY_COORD(r,a)   { (r).x = (a).x; (r).y = (a).y; (r).z = (a).z;}
#define COPY_COORD4(r,a)  { (r).x = (a).x; (r).y = (a).y; (r).z = (a).z;\
                            (r).w = (a).w; }
#define CROSS(r,a,b)      { (r).x = (a).y * (b).z - (a).z * (b).y;\
                            (r).y = (a).z * (b).x - (a).x * (b).z;\
                            (r).z = (a).x * (b).y - (a).y * (b).x; }
#define DOT_PRODUCT(a,b)  ( (a).x * (b).x +\
                            (a).y * (b).y +\
                            (a).z * (b).z )
#define SET_COORD(r,a,b,c) { (r).x = (a); (r).y = (b); (r).z = (c); }
#define SET_COORD4(r,a,b,c,d) { (r).x = (a); (r).y = (b); (r).z = (c);\
                                 (r).w = (d); }
#define SUB2_COORD(r,a)         { (r).x -= (a).x; (r).y -= (a).y;\
                                (r).z -= (a).z; }
#define SUB3_COORD(r,a,b)    { (r).x = (a).x - (b).x;\
                                 (r).y = (a).y - (b).y;\
                                 (r).z = (a).z - (b).z; }