From: Timo Kokkonen <kaapeli@itanic.dy.fi>
Date: Tue, 19 Jul 2011 17:16:36 +0000 (+0300)
Subject: vector.h: Introduce vector_abs_squared()
X-Git-Url: http://git.itanic.dy.fi/?p=sdl-planets;a=commitdiff_plain;h=3bc710987a74ec3b2c8245bfad5344796a56ad0e

vector.h: Introduce vector_abs_squared()

This function is identical to vector_abs but it returns the squared
distance instead. The advantage of this function is that the one
square root calculation canb e omitted. If the actual distance is not
important, this function is faster than the one which returns the
absolute distance.

Signed-off-by: Timo Kokkonen <kaapeli@itanic.dy.fi>
---

diff --git a/vector.h b/vector.h
index 875cd35..d3e265c 100644
--- a/vector.h
+++ b/vector.h
@@ -33,6 +33,11 @@ static inline double vector_abs(const struct vector *a)
 	return sqrt(a->x * a->x + a->y * a->y);
 }
 
+static inline double vector_abs_squared(const struct vector *a)
+{
+	return a->x * a->x + a->y * a->y;
+}
+
 static inline void vector_scale(const struct vector *a, const double b,
 				struct vector *res)
 {