From 1f5167c7b129f029758a92cecd6b037f14dada36 Mon Sep 17 00:00:00 2001 From: Thomas White Date: Thu, 14 Jan 2010 10:29:24 +0100 Subject: Inline angle_between --- src/utils.h | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) (limited to 'src/utils.h') diff --git a/src/utils.h b/src/utils.h index 9aa07c8c..081d5a71 100644 --- a/src/utils.h +++ b/src/utils.h @@ -64,8 +64,6 @@ extern int quaternion_valid(struct quaternion q); /* --------------------------- Useful functions ----------------------------- */ -extern double angle_between(double x1, double y1, double z1, - double x2, double y2, double z2); extern size_t skipspace(const char *s); extern void chomp(char *s); extern void progress_bar(int val, int total, const char *text); @@ -102,6 +100,15 @@ static inline double distance3d(double x1, double y1, double z1, return modulus(x1-x2, y1-y2, z1-z2); } +/* Answer in radians */ +static inline double angle_between(double x1, double y1, double z1, + double x2, double y2, double z2) +{ + double mod1 = modulus(x1, y1, z1); + double mod2 = modulus(x2, y2, z2); + return acos( (x1*x2 + y1*y2 + z1*z2) / (mod1*mod2) ); +} + /* ----------------------------- Useful macros ------------------------------ */ -- cgit v1.2.3