Makes the top sprite visible on liquid turret icons (#4683)

* Add top region to liquid turret icons

* Attempt to change outline icon generation

* Draw regions above the outlined icon over it

* Draw regions **above** the outlined icon over it

* Add clarrifying comment

* Implement backwards compatibility for mods

* an -> any

core/src/mindustry/world/Block.java

@@ -160,8 +160,10 @@ public class Block extends UnlockableContent{
     public boolean canOverdrive = true;
     /** Outlined icon color.*/
     public Color outlineColor = Color.valueOf("404049");
-    /** Whether the icon region has an outline added. */
+    /** Whether any icon region has an outline added. */
     public boolean outlineIcon = false;
+    /** Which of the icon regions gets the outline added. */
+    public int outlinedIcon = -1;
     /** Whether this block has a shadow under it. */
     public boolean hasShadow = true;
     /** Sounds made when this block breaks.*/
@@ -768,7 +770,7 @@ public class Block extends UnlockableContent{
 
         if(outlineIcon){
             final int radius = 4;
-            PixmapRegion region = Core.atlas.getPixmap(getGeneratedIcons()[getGeneratedIcons().length-1]);
+            PixmapRegion region = Core.atlas.getPixmap(getGeneratedIcons()[outlinedIcon >= 0 ? outlinedIcon : getGeneratedIcons().length -1]);
             Pixmap out = new Pixmap(region.width, region.height);
             Color color = new Color();
             for(int x = 0; x < region.width; x++){

core/src/mindustry/world/blocks/defense/turrets/LiquidTurret.java

@@ -27,6 +27,7 @@ public class LiquidTurret extends Turret{
         hasLiquids = true;
         loopSound = Sounds.spray;
         shootSound = Sounds.none;
+        outlinedIcon = 1;
     }
 
     /** Initializes accepted ammo map. Format: [liquid1, bullet1, liquid2, bullet2...] */
@@ -63,6 +64,12 @@ public class LiquidTurret extends Turret{
         super.init();
     }
 
+    @Override
+    public TextureRegion[] icons(){
+        if(topRegion.found()) return new TextureRegion[]{baseRegion, region, topRegion};
+        return super.icons();
+    }
+
     public class LiquidTurretBuild extends TurretBuild{
         @Override
         public void draw(){