From 076f77c50a798ada5312543d3e340fd9781879f9 Mon Sep 17 00:00:00 2001
From: Ed Gonzalez <ed.gonzalez3@gmail.com>
Date: Wed, 5 Jun 2013 01:54:32 -0700
Subject: [PATCH] Don't crash when firing lamp of fire near the map boundary.

Applying random jitter to the path would occasionally produce points
outside the map bounds.  The random movements are now clamped to prevent
this from happening.
---
 crawl-ref/source/evoke.cc |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/crawl-ref/source/evoke.cc b/crawl-ref/source/evoke.cc
index 66164ac..e6c77dc 100644
--- a/crawl-ref/source/evoke.cc
+++ b/crawl-ref/source/evoke.cc
@@ -738,7 +738,8 @@ static vector<coord_def> _get_jitter_path(coord_def source, coord_def target,
     {
         for (int n = 0; n < NUM_TRIES; ++n)
         {
-            coord_def jitter = target + coord_def(random_range(-2, 2), random_range(-2, 2));
+            coord_def jitter = clamp_in_bounds(target + coord_def(random_range(-2, 2),
+                                                                  random_range(-2, 2)));
             if (jitter == target || jitter == source || feat_is_solid(grd(jitter)))
                 continue;
 
@@ -762,12 +763,15 @@ static vector<coord_def> _get_jitter_path(coord_def source, coord_def target,
 
     for (int n = 0; n < NUM_TRIES; ++n)
     {
-        coord_def jitter = mid + coord_def(random_range(-3, 3), random_range(-3, 3));
+        coord_def jitter = clamp_in_bounds(mid + coord_def(random_range(-3, 3),
+                                                           random_range(-3, 3)));
         if (jitter == mid || jitter.distance_from(mid) < 2 || jitter == source
             || feat_is_solid(grd(jitter))
             || !cell_see_cell(source, jitter, LOS_NO_TRANS)
             || !cell_see_cell(target, jitter, LOS_NO_TRANS))
+        {
             continue;
+        }
 
         trace_beam.aimed_at_feet = false;
         trace_beam.source = jitter;
-- 
1.7.10.4