Fixed bug in XG that prevented xlthinkers and xsthinkers from working…

… due to uninitialized line/sector (respectively) links.

Fixed bug in XG that attempted to switch-swap a material on a line sections even if there was no material to begin with.

doomsday/plugins/common/src/p_xgline.c

@@ -646,6 +646,7 @@ void XL_SetLineType(linedef_t *line, int id)
             xlthinker_t*    xl = Z_Calloc(sizeof(*xl), PU_LEVSPEC, 0);
 
             xl->thinker.function = XL_Thinker;
+            xl->line = line;
             P_ThinkerAdd(&xl->thinker);
         }
     }
@@ -1833,13 +1834,18 @@ boolean XL_SwitchSwap(sidedef_t *side, int section)
 
     // Which section of the wall are we checking?
     if(section == LWS_UPPER)
-        name = R_MaterialNameForNum(P_GetIntp(side, DMU_TOP_MATERIAL));
+        material = P_GetIntp(side, DMU_TOP_MATERIAL);
     else if(section == LWS_MID)
-        name = R_MaterialNameForNum(P_GetIntp(side, DMU_MIDDLE_MATERIAL));
-    else if(section == LWS_LOWER)
-        name = R_MaterialNameForNum(P_GetIntp(side, DMU_BOTTOM_MATERIAL));
+        material = P_GetIntp(side, DMU_MIDDLE_MATERIAL);
     else
-        return false;
+        material = P_GetIntp(side, DMU_BOTTOM_MATERIAL);
+
+    if(!material)
+        return false; // No material on this section.
+
+    name = R_MaterialNameForNum(material);
+    if(!name)
+        return false; // Most peculiar.
 
     strncpy(buf, name, 8);
     buf[8] = 0;

doomsday/plugins/common/src/p_xgsec.c

@@ -389,6 +389,7 @@ void XS_SetSectorType(struct sector_s* sec, int special)
             xsthinker_t*    xs = Z_Calloc(sizeof(*xs), PU_LEVSPEC, 0);
 
             xs->thinker.function = XS_Thinker;
+            xs->sector = sec;
             P_ThinkerAdd(&xs->thinker);
         }
     }
@@ -2608,13 +2609,7 @@ void XS_UpdateLight(sector_t *sec)
     fn = &xg->light;
     if(UPDFUNC(fn))
     {   // Changed.
-        lightlevel = fn->value / 255.f;
-
-        if(lightlevel < 0)
-            lightlevel = 0;
-        if(lightlevel > 1)
-            lightlevel = 1;
-
+        lightlevel = MINMAX_OF(0, fn->value / 255.f, 1);
         P_SetFloatp(sec, DMU_LIGHT_LEVEL, lightlevel);
     }
 
@@ -2626,11 +2621,8 @@ void XS_UpdateLight(sector_t *sec)
             continue;
 
         // Changed.
-        c = fn->value / 255.f;
-        if(c < 0)
-            c = 0;
-        if(c > 1)
-            c = 1;
+        c = MINMAX_OF(0, fn->value / 255.f, 1);
+
         P_SetFloatp(sec, TO_DMU_COLOR(i), c);
     }
 }