Custom background renderer support for mods

core/src/mindustry/core/Renderer.java

@@ -50,6 +50,7 @@ public class Renderer implements ApplicationListener{
     /** minZoom = zooming out, maxZoom = zooming in */
     public float minZoom = 1.5f, maxZoom = 6f;
     public Seq<EnvRenderer> envRenderers = new Seq<>();
+    public ObjectMap<String, Runnable> customBackgrounds = new ObjectMap<>();
     public TextureRegion[] bubbles = new TextureRegion[16], splashes = new TextureRegion[12];
 
     private @Nullable CoreBuild landCore;
@@ -90,6 +91,10 @@ public class Renderer implements ApplicationListener{
         envRenderers.add(new EnvRenderer(mask, render));
     }
 
+    public void addCustomBackground(String name, Runnable render){
+        customBackgrounds.put(name, render);
+    }
+
     @Override
     public void init(){
         planets = new PlanetRenderer();
@@ -386,6 +391,10 @@ public class Renderer implements ApplicationListener{
             Draw.rect(Draw.wrap(backgroundBuffer.getTexture()), camera.position.x, camera.position.y, drawSize, -drawSize);
         }
 
+        if(state.rules.customBackgroundCallback != null && customBackgrounds.containsKey(state.rules.customBackgroundCallback)){
+            customBackgrounds.get(state.rules.customBackgroundCallback).run();
+        }
+
     }
 
     void updateLandParticles(){

core/src/mindustry/game/Rules.java

@@ -122,6 +122,8 @@ public class Rules{
     public boolean borderDarkness = true;
     /** special tags for additional info. */
     public StringMap tags = new StringMap();
+    /** Name of callback to call for background rendering in mods; see Renderer#addCustomBackground. Runs last. */
+    public @Nullable String customBackgroundCallback;
     /** path to background texture with extension (e.g. "sprites/space.png")*/
     public @Nullable String backgroundTexture;
     /** background texture move speed scaling - bigger numbers mean slower movement */