shithub: choc

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ref: cbd744280545a38e62ecc0290a1312b3aeff9ae0
parent: a9684aecd9e8f292ac90a404b3f854df03dfd119
author: Simon Howard <[email protected]>
date: Wed May 3 15:23:54 EDT 2006 

Handle divide by zero in R_PointToDist: fixes crash in udm1.wad

Subversion-branch: /trunk/chocolate-doom
Subversion-revision: 474


--- a/src/r_main.c
+++ b/src/r_main.c
@@ -1,7 +1,7 @@
 // Emacs style mode select   -*- C++ -*- 
 //-----------------------------------------------------------------------------
 //
-// $Id: r_main.c 445 2006-03-27 22:56:14Z fraggle $
+// $Id: r_main.c 474 2006-05-03 19:23:54Z fraggle $
 //
 // Copyright(C) 1993-1996 Id Software, Inc.
 // Copyright(C) 2005 Simon Howard
@@ -49,7 +49,7 @@
 //-----------------------------------------------------------------------------
 
 
-static const char rcsid[] = "$Id: r_main.c 445 2006-03-27 22:56:14Z fraggle $";
+static const char rcsid[] = "$Id: r_main.c 474 2006-05-03 19:23:54Z fraggle $";
 
 
 
@@ -423,6 +423,7 @@
     fixed_t	dy;
     fixed_t	temp;
     fixed_t	dist;
+    fixed_t     frac;
 	
     dx = abs(x - viewx);
     dy = abs(y - viewy);
@@ -433,8 +434,19 @@
 	dx = dy;
 	dy = temp;
     }
+
+    // Fix crashes in udm1.wad
+
+    if (dx != 0)
+    {
+        frac = FixedDiv(dy, dx);
+    }
+    else
+    {
+	frac = 0;
+    }
 	
-    angle = (tantoangle[ FixedDiv(dy,dx)>>DBITS ]+ANG90) >> ANGLETOFINESHIFT;
+    angle = (tantoangle[frac>>DBITS]+ANG90) >> ANGLETOFINESHIFT;
 
     // use as cosine
     dist = FixedDiv (dx, finesine[angle] );