From: Timo Kokkonen <kaapeli@itanic.dy.fi>
Date: Fri, 8 Jul 2011 08:49:32 +0000 (+0300)
Subject: quadtree: Document subtree indexing
X-Git-Url: http://git.itanic.dy.fi/?p=sdl-planets;a=commitdiff_plain;h=4e456bac7fba5ff042186565cf9c5bd06267d476

quadtree: Document subtree indexing

As stupid as it might sound, I forgot how the subtrees are indexed in
spatially. Therefore it might make sense to simply document even the
trivial things in the header file to avoid future confusion.

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

diff --git a/quadtree.h b/quadtree.h
index aef487e..45478fa 100644
--- a/quadtree.h
+++ b/quadtree.h
@@ -8,6 +8,14 @@
 
 struct quadtree {
 	struct vector pos;
+
+	/*
+	 * Each node divide the sub-tree in following quadtrants:
+	 *
+	 *	 up left (0)  |  up right (1)
+	 *	-----------------------------
+	 *	down left (2) | down right (3)
+	 */
 	struct quadtree *child[4];
 	struct quadtree *parent;