From 28bee194005a60ff88d2418f9195a173fadd2aa2 Mon Sep 17 00:00:00 2001
From: Robert Vollmert <rvollmert@gmx.net>
Date: Sat, 31 Oct 2009 14:05:25 +0100
Subject: ray_def introductory comment.

---
 crawl-ref/source/ray.cc | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

(limited to 'crawl-ref/source/ray.cc')

diff --git a/crawl-ref/source/ray.cc b/crawl-ref/source/ray.cc
index bbf812009f..32b9531fd5 100644
--- a/crawl-ref/source/ray.cc
+++ b/crawl-ref/source/ray.cc
@@ -1,6 +1,14 @@
 /*
- *  File:       .cc
- *  Summary:
+ *  File:       ray.cc
+ *  Summary:    Diamond grid wrapper around geom::ray.
+ *
+ * The geom::grid diamonds is a checkerboard grid rotated
+ * by 45 degrees such that the black cells ("diamonds") lie just
+ * within the normal crawl map cells.
+ *
+ * ray_def provides for advancing and reflecting rays in
+ * map coordinates, where a ray touches a given cell if it
+ * meets the diamond.
  */
 
 #include "AppHdr.h"
-- 
cgit v1.2.3-54-g00ecf