Catch crash if animation speed is 0 (#710)

Author: Pedro-Beirao

prboom2/src/p_spec.c

@@ -246,16 +246,22 @@ void P_InitPicAnims (void)
 
     lastanim->istexture = animdefs[i].istexture;
     lastanim->numpics = lastanim->picnum - lastanim->basepic + 1;
+    lastanim->speed = LittleLong(animdefs[i].speed);
 
     // [crispy] skip reading SMMU swirling flats
     if (lastanim->speed < 65536 && lastanim->numpics != 1)
-    { 
+    {
       if (lastanim->numpics < 2)
           I_Error ("P_InitPicAnims: bad cycle from %s to %s",
                     animdefs[i].startname,
                     animdefs[i].endname);
     }
-    lastanim->speed = LittleLong(animdefs[i].speed); // killough 5/5/98: add LONG()
+
+    if (lastanim->speed == 0)
+        I_Error ("P_InitPicAnims: %s to %s animation cannot have speed 0",
+                    animdefs[i].startname,
+                    animdefs[i].endname);
+
     lastanim++;
   }