#define XMIN 0.0 #define XMAX 639 #define YMIN 0.0 #define YMAX 479 #define ZMIN 0.25 /* these values assume normalised */ #define ZMAX 1.0 /* z coordinates of the line */ #define EPSILON 1e-6 #define Zero(a) ((a)<EPSILON && (a)>-EPSILON) typedef struct { float x, y, z; } Point;