Moved distance-related functions to path.c/h

git-svn-id: https://rathena.svn.sourceforge.net/svnroot/rathena/trunk@11981 54d463be-8e91-2dee-dedb-b68131a5f0ec

1 files changed, 43 insertions, 0 deletions

diff --git a/src/map/path.c b/src/map/path.c
index 52dcd0ac8..549144d7b 100644
--- a/src/map/path.c
+++ b/src/map/path.c
@@ -453,3 +453,46 @@ bool path_search(struct walkpath_data *wpd,int m,int x0,int y0,int x1,int y1,int
 
 	return true;
 }
+
+
+//Distance functions, taken from http://www.flipcode.com/articles/article_fastdistance.shtml
+int check_distance(int dx, int dy, int distance)
+{
+#ifdef CIRCULAR_AREA
+	//In this case, we just do a square comparison. Add 1 tile grace for diagonal range checks.
+	return (dx*dx + dy*dy <= distance*distance + (dx&&dy?1:0));
+#else
+	if (dx < 0) dx = -dx;
+	if (dy < 0) dy = -dy;
+	return ((dx<dy?dy:dx) <= distance);
+#endif
+}
+
+unsigned int distance(int dx, int dy)
+{
+#ifdef CIRCULAR_AREA
+	unsigned int min, max;
+
+	if ( dx < 0 ) dx = -dx;
+	if ( dy < 0 ) dy = -dy;
+	//There appears to be something wrong with the aproximation below when either dx/dy is 0! [Skotlex]
+	if ( dx == 0 ) return dy;
+	if ( dy == 0 ) return dx;
+	
+	if ( dx < dy )
+	{
+		min = dx;
+		max = dy;
+	} else {
+		min = dy;
+		max = dx;
+	}
+   // coefficients equivalent to ( 123/128 * max ) and ( 51/128 * min )
+	return ((( max << 8 ) + ( max << 3 ) - ( max << 4 ) - ( max << 1 ) +
+		( min << 7 ) - ( min << 5 ) + ( min << 3 ) - ( min << 1 )) >> 8 );
+#else
+	if (dx < 0) dx = -dx;
+	if (dy < 0) dy = -dy;
+	return (dx<dy?dy:dx);
+#endif
+}