Separated the unit image rendering from the background rendering to avoid texture swapping when rendering unit + background

core/src/com/unciv/ui/cityscreen/CityScreen.kt

@@ -167,7 +167,7 @@ class CityScreen(internal val city: CityInfo): CameraStageBaseScreen() {
         val tileSetStrings = TileSetStrings()
         val cityTileGroups = cityInfo.getCenterTile().getTilesInDistance(5)
                 .filter { city.civInfo.exploredTiles.contains(it.position) }
-                .map { CityTileGroup(cityInfo, it, tileSetStrings).apply { unitLayerGroup.isVisible = false } }
+                .map { CityTileGroup(cityInfo, it, tileSetStrings) }
 
         for (tileGroup in cityTileGroups) {
             val tileInfo = tileGroup.tileInfo

core/src/com/unciv/ui/cityscreen/CityTileGroup.kt

@@ -21,7 +21,8 @@ class CityTileGroup(private val city: CityInfo, tileInfo: TileInfo, tileSetStrin
             icons.addPopulationIcon(ImageGetter.getImage("OtherIcons/Star")
                     .apply { color = Color.GOLD })
         }
-
+        unitLayerGroup.isVisible = false
+        unitImageLayerGroup.isVisible = false
     }
 
     fun update() {

core/src/com/unciv/ui/map/TileGroupMap.kt

@@ -35,6 +35,7 @@ class TileGroupMap<T: TileGroup>(val tileGroups: Collection<T>, val padding: Flo
         val featureLayers = ArrayList<Group>()
         val miscLayers = ArrayList<Group>()
         val unitLayers = ArrayList<Group>()
+        val unitImageLayers = ArrayList<Group>()
         val cityButtonLayers = ArrayList<Group>()
         val circleCrosshairFogLayers = ArrayList<Group>()
 
@@ -45,6 +46,7 @@ class TileGroupMap<T: TileGroup>(val tileGroups: Collection<T>, val padding: Flo
             featureLayers.add(group.terrainFeatureLayerGroup.apply { setPosition(group.x,group.y) })
             miscLayers.add(group.miscLayerGroup.apply { setPosition(group.x,group.y) })
             unitLayers.add(group.unitLayerGroup.apply { setPosition(group.x,group.y) })
+            unitImageLayers.add(group.unitImageLayerGroup.apply { setPosition(group.x,group.y) })
             cityButtonLayers.add(group.cityButtonLayerGroup.apply { setPosition(group.x,group.y) })
             circleCrosshairFogLayers.add(group.circleCrosshairFogLayerGroup.apply { setPosition(group.x,group.y) })
         }
@@ -54,6 +56,7 @@ class TileGroupMap<T: TileGroup>(val tileGroups: Collection<T>, val padding: Flo
         for(group in circleCrosshairFogLayers) addActor(group)
         for(group in tileGroups) addActor(group) // The above layers are for the visual layers, this is for the clickability of the tile
         for(group in unitLayers) addActor(group) // Aaand units above everything else.
+        for(group in unitImageLayers) addActor(group) // This is so the individual textures for the units are rendered together
         for(group in cityButtonLayers) addActor(group) // city buttons + clickability
 
 

core/src/com/unciv/ui/tilegroups/TileGroup.kt

@@ -75,7 +75,14 @@ open class TileGroup(var tileInfo: TileInfo, var tileSetStrings:TileSetStrings)
     class UnitLayerGroupClass:Group(){
         override fun draw(batch: Batch?, parentAlpha: Float) { super.draw(batch, parentAlpha) }
     }
+
+    class UnitImageLayerGroupClass:Group(){
+        override fun draw(batch: Batch?, parentAlpha: Float) { super.draw(batch, parentAlpha) }
+    }
+    // We separate the units from the units' backgrounds, because all the background elements are in the same texture, and the units' aren't
     val unitLayerGroup = UnitLayerGroupClass().apply { isTransform = false; setSize(groupSize, groupSize);touchable = Touchable.disabled }
+    val unitImageLayerGroup = UnitImageLayerGroupClass().apply { isTransform = false; setSize(groupSize, groupSize);touchable = Touchable.disabled }
+
 
     val cityButtonLayerGroup = Group().apply { setSize(groupSize, groupSize);
         touchable = Touchable.childrenOnly; setOrigin(Align.center) }

core/src/com/unciv/ui/tilegroups/TileGroupIcons.kt

@@ -65,6 +65,12 @@ class TileGroupIcons(val tileGroup: TileGroup){
             newImage.center(tileGroup)
             newImage.y += yFromCenter
 
+            // We "steal" the unit image so that all backgrounds are rendered next to each other
+            // to save texture swapping and improve framerate
+            tileGroup.unitImageLayerGroup.addActor(newImage.unitBaseImage)
+            newImage.unitBaseImage.center(tileGroup)
+            newImage.unitBaseImage.y += yFromCenter
+
             // Display number of carried air units
             if (unit.getTile().airUnits.any { unit.isTransportTypeOf(it) } && !unit.getTile().isCityCenter()) {
                 val holder = Table()

core/src/com/unciv/ui/worldscreen/WorldScreen.kt

@@ -630,7 +630,7 @@ class WorldScreen(val viewingCiv:CivilizationInfo) : CameraStageBaseScreen() {
             update()
             showTutorialsOnNextTurn()
         }
-//        topBar.selectedCivLabel.setText(Gdx.graphics.framesPerSecond) // for framerate testing
+        topBar.selectedCivLabel.setText(Gdx.graphics.framesPerSecond) // for framerate testing
 
         super.render(delta)
     }