qbsp: make "mixed face contents" error non-fatal if one of the leafnode or face is CONTENTS_EMPTY. from txqbsp-xt.

Fixes an issue necros was having.

qbsp/globals.c

@@ -149,4 +149,5 @@ const char *rgszWarnings[cWarnings] = {
     "Healing degenerate edge (%f) at (%.3f %.3f %.3f)",
     "No target for rotation entity \"%s\"",
     "line %d: Face with degenerate QuArK-style texture axes",
+    "Mixed face contents (%s, %s) near (%.2f %.2f %.2f)"
 };

qbsp/solidbsp.c

@@ -592,6 +592,37 @@ DivideNodeBounds(node_t *node, plane_t *split)
 		 node->children[1]->mins, node->children[1]->maxs);
 }
 
+/*
+==================
+GetContentsName
+==================
+*/
+const char *
+GetContentsName( int Contents ) {
+    switch( Contents ) {
+	case CONTENTS_EMPTY:
+	    return "Empty";
+	    
+	case CONTENTS_SOLID:
+	    return "Solid";
+	    
+	case CONTENTS_WATER:
+	    return "Water";
+	    
+	case CONTENTS_SLIME:
+	    return "Slime";
+	    
+	case CONTENTS_LAVA:
+	    return "Lava";
+	    
+	case CONTENTS_SKY:
+	    return "Sky";
+	    
+	default:
+	    return "Error";
+    }
+}
+
 /*
 ==================
 LinkConvexFaces
@@ -617,9 +648,15 @@ LinkConvexFaces(surface_t *planelist, node_t *leafnode)
 	    count++;
 	    if (!leafnode->contents)
 		leafnode->contents = f->contents[0];
-	    else if (leafnode->contents != f->contents[0])
-		Error("Mixed face contents in leafnode near (%.2f %.2f %.2f)",
-		      f->w.points[0][0], f->w.points[0][1], f->w.points[0][2]);
+	    else if (leafnode->contents != f->contents[0]) {
+		const bool OnlyWarn = leafnode->contents == CONTENTS_EMPTY || f->contents[ 0 ] == CONTENTS_EMPTY;
+		Message(msgWarning, warnMixedFaceContents,
+			GetContentsName( leafnode->contents ), GetContentsName( f->contents[ 0 ] ),
+			f->w.points[0][0], f->w.points[0][1], f->w.points[0][2]);
+		if (!OnlyWarn) {
+		    Error("Last mixed face contents was fatal");
+		}
+	    }
 	}
     }
 

qbsp/warnerr.h

@@ -46,5 +46,6 @@ enum {
     warnDegenerateEdge,
     warnNoRotateTarget,
     warnDegenerateQuArKTX,
+    warnMixedFaceContents,
     cWarnings
 };