From e79394f321d455748113a360e76050019d41184f Mon Sep 17 00:00:00 2001
From: Robert Vollmert <rvollmert@gmx.net>
Date: Tue, 3 Nov 2009 13:31:13 +0100
Subject: Add function to fudge corner ray into a non-solid cell.

---
 crawl-ref/source/ray.cc | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

(limited to 'crawl-ref/source')

diff --git a/crawl-ref/source/ray.cc b/crawl-ref/source/ray.cc
index 1917baf9b8..fa3aa09ba8 100644
--- a/crawl-ref/source/ray.cc
+++ b/crawl-ref/source/ray.cc
@@ -232,6 +232,28 @@ static geom::line _choose_reflect_line(bool rx, bool ry, bool rxy)
     return (l);
 }
 
+geom::vector _fudge_corner(const geom::vector &w, const reflect_grid &rg)
+{
+    geom::vector v = w;
+    if (double_is_integral(v.x))
+    {
+        // just try both sides
+        v.x += 10 * EPSILON_VALUE;
+        if (rg(round_vec(v) + rg_o))
+            v.x -= 20 * EPSILON_VALUE;
+        ASSERT(!rg(round_vec(v) + rg_o));
+    }
+    else
+    {
+        ASSERT(double_is_integral(v.y));
+        v.y += 10 * EPSILON_VALUE;
+        if (rg(round_vec(v) + rg_o))
+            v.y -= 20 * EPSILON_VALUE;
+        ASSERT(!rg(round_vec(v) + rg_o));
+    }
+    return (v);
+}
+
 void ray_def::bounce(const reflect_grid &rg)
 {
     ASSERT(_valid());
-- 
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