Allow empty maps in FileMapGenerator

core/src/mindustry/graphics/g3d/PlanetRenderer.java

@@ -234,7 +234,6 @@ public class PlanetRenderer implements Disposable{
             Tmp.c1.set(from).lerp(to, (f+ Time.globalTime /timeScale)%1f);
             batch.color(Tmp.c1);
             batch.vertex(Tmp.bz3.valueAt(Tmp.v32, f));
-
         }
         batch.flush(Gl.lineStrip);
     }

core/src/mindustry/maps/generators/FileMapGenerator.java

@@ -21,6 +21,16 @@ public class FileMapGenerator implements WorldGenerator{
         this.preset = preset;
     }
 
+    public FileMapGenerator(Map map, SectorPreset preset){
+        this.map = map;
+        this.preset = preset;
+    }
+
+    /** If you use this constructor, make sure to override generate()! */
+    public FileMapGenerator(SectorPreset preset){
+        this(emptyMap, preset);
+    }
+
     @Override
     public void generate(Tiles tiles){
         if(map == null) throw new RuntimeException("Generator has null map, cannot be used.");