Tech picker screen performance - ~45% of render time decreased with texture swap minimization tricks

android/assets/ConstructionIcons.atlas

@@ -1621,6 +1621,13 @@ UnitIcons/Circle
   orig: 178, 178
   offset: 0, 0
   index: -1
+OtherIcons/ConstructionCircle
+  rotate: false
+  xy: 4, 1362
+  size: 178, 178
+  orig: 178, 178
+  offset: 0, 0
+  index: -1
 UnitIcons/Companion Cavalry
   rotate: false
   xy: 406, 732

android/assets/Tech.atlas

@@ -6,581 +6,588 @@ filter: MipMapLinearLinear, MipMapLinearLinear
 repeat: none
 TechIcons/Acoustics
   rotate: false
-  xy: 4, 868
+  xy: 4, 652
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Advanced Ballistics
   rotate: false
-  xy: 4, 760
+  xy: 190, 838
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Agriculture
   rotate: false
-  xy: 112, 868
+  xy: 4, 544
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Animal Husbandry
   rotate: false
-  xy: 4, 652
+  xy: 298, 838
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Archaeology
   rotate: false
-  xy: 112, 760
+  xy: 4, 436
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Archery
   rotate: false
-  xy: 220, 868
+  xy: 406, 838
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Architecture
   rotate: false
-  xy: 4, 544
+  xy: 4, 328
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Astronomy
   rotate: false
-  xy: 112, 652
+  xy: 514, 838
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Atomic Theory
   rotate: false
-  xy: 220, 760
+  xy: 4, 220
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Ballistics
   rotate: false
-  xy: 328, 868
+  xy: 622, 838
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Banking
   rotate: false
-  xy: 4, 436
+  xy: 4, 112
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Biology
   rotate: false
-  xy: 112, 544
+  xy: 730, 838
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Bronze Working
   rotate: false
-  xy: 220, 652
+  xy: 4, 4
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Calendar
   rotate: false
-  xy: 328, 760
+  xy: 838, 838
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Chemistry
   rotate: false
-  xy: 436, 868
+  xy: 946, 838
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Chivalry
   rotate: false
-  xy: 4, 328
+  xy: 1054, 838
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
+TechIcons/Circle
+  rotate: false
+  xy: 4, 760
+  size: 178, 178
+  orig: 178, 178
+  offset: 0, 0
+  index: -1
 TechIcons/Civil Service
   rotate: false
-  xy: 112, 436
+  xy: 1162, 838
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Combined Arms
   rotate: false
-  xy: 220, 544
+  xy: 1270, 838
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Combustion
   rotate: false
-  xy: 328, 652
+  xy: 1378, 838
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Compass
   rotate: false
-  xy: 436, 760
+  xy: 1486, 838
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Computers
   rotate: false
-  xy: 544, 868
+  xy: 1594, 838
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Construction
   rotate: false
-  xy: 4, 220
+  xy: 1702, 838
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Currency
   rotate: false
-  xy: 112, 328
+  xy: 1810, 838
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Drama and Poetry
   rotate: false
-  xy: 220, 436
+  xy: 1918, 838
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Dynamite
   rotate: false
-  xy: 328, 544
+  xy: 112, 652
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Ecology
   rotate: false
-  xy: 436, 652
+  xy: 112, 544
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Economics
   rotate: false
-  xy: 544, 760
+  xy: 112, 436
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Education
   rotate: false
-  xy: 652, 868
+  xy: 112, 328
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Electricity
   rotate: false
-  xy: 4, 112
+  xy: 112, 220
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Electronics
   rotate: false
-  xy: 112, 220
+  xy: 112, 112
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Engineering
   rotate: false
-  xy: 220, 328
+  xy: 112, 4
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Fallback
   rotate: false
-  xy: 328, 436
+  xy: 220, 730
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Fertilizer
   rotate: false
-  xy: 436, 544
+  xy: 220, 622
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Flight
   rotate: false
-  xy: 544, 652
+  xy: 328, 730
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Future Tech
   rotate: false
-  xy: 652, 760
+  xy: 220, 514
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Globalization
   rotate: false
-  xy: 760, 868
+  xy: 328, 622
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Guilds
   rotate: false
-  xy: 4, 4
+  xy: 436, 730
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Gunpowder
   rotate: false
-  xy: 112, 112
+  xy: 220, 406
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Horseback Riding
   rotate: false
-  xy: 220, 220
+  xy: 328, 514
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Industrialization
   rotate: false
-  xy: 328, 328
+  xy: 436, 622
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Iron Working
   rotate: false
-  xy: 436, 436
+  xy: 544, 730
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Lasers
   rotate: false
-  xy: 544, 544
+  xy: 220, 298
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Machinery
   rotate: false
-  xy: 652, 652
+  xy: 328, 406
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Masonry
   rotate: false
-  xy: 760, 760
+  xy: 436, 514
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Mass Media
   rotate: false
-  xy: 868, 868
+  xy: 544, 622
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Mathematics
   rotate: false
-  xy: 112, 4
+  xy: 652, 730
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Metal Casting
   rotate: false
-  xy: 220, 112
+  xy: 220, 190
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Metallurgy
   rotate: false
-  xy: 328, 220
+  xy: 328, 298
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Military Science
   rotate: false
-  xy: 436, 328
+  xy: 436, 406
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Mining
   rotate: false
-  xy: 544, 436
+  xy: 544, 514
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Mobile Tactics
   rotate: false
-  xy: 652, 544
+  xy: 652, 622
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Nanotechnology
   rotate: false
-  xy: 760, 652
+  xy: 760, 730
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Navigation
   rotate: false
-  xy: 868, 760
+  xy: 220, 82
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Nuclear Fission
   rotate: false
-  xy: 976, 868
+  xy: 328, 190
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Nuclear Fusion
   rotate: false
-  xy: 220, 4
+  xy: 436, 298
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Optics
   rotate: false
-  xy: 328, 112
+  xy: 544, 406
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Particle Physics
   rotate: false
-  xy: 436, 220
+  xy: 652, 514
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Pharmaceuticals
   rotate: false
-  xy: 544, 328
+  xy: 760, 622
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Philosophy
   rotate: false
-  xy: 652, 436
+  xy: 868, 730
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Physics
   rotate: false
-  xy: 760, 544
+  xy: 328, 82
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Plastics
   rotate: false
-  xy: 868, 652
+  xy: 436, 190
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Pottery
   rotate: false
-  xy: 976, 760
+  xy: 544, 298
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Printing Press
   rotate: false
-  xy: 1084, 868
+  xy: 652, 406
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Radar
   rotate: false
-  xy: 328, 4
+  xy: 760, 514
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Radio
   rotate: false
-  xy: 436, 112
+  xy: 868, 622
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Railroads
   rotate: false
-  xy: 544, 220
+  xy: 976, 730
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Refrigeration
   rotate: false
-  xy: 652, 328
+  xy: 436, 82
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Replaceable Parts
   rotate: false
-  xy: 760, 436
+  xy: 544, 190
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Rifling
   rotate: false
-  xy: 868, 544
+  xy: 652, 298
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Robotics
   rotate: false
-  xy: 976, 652
+  xy: 760, 406
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Rocketry
   rotate: false
-  xy: 1084, 760
+  xy: 868, 514
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Sailing
   rotate: false
-  xy: 1192, 868
+  xy: 976, 622
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Satellites
   rotate: false
-  xy: 436, 4
+  xy: 1084, 730
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Scientific Theory
   rotate: false
-  xy: 544, 112
+  xy: 544, 82
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Stealth
   rotate: false
-  xy: 652, 220
+  xy: 652, 190
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Steam Power
   rotate: false
-  xy: 760, 328
+  xy: 760, 298
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Steel
   rotate: false
-  xy: 868, 436
+  xy: 868, 406
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Telecommunications
   rotate: false
-  xy: 976, 544
+  xy: 976, 514
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Telegraph
   rotate: false
-  xy: 1084, 652
+  xy: 1084, 622
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/The Wheel
   rotate: false
-  xy: 1192, 760
+  xy: 1192, 730
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Theology
   rotate: false
-  xy: 1300, 868
+  xy: 652, 82
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Trapping
   rotate: false
-  xy: 544, 4
+  xy: 760, 190
   size: 100, 100
   orig: 100, 100
   offset: 0, 0
   index: -1
 TechIcons/Writing
   rotate: false
-  xy: 652, 112
+  xy: 868, 298
   size: 100, 100
   orig: 100, 100
   offset: 0, 0

core/src/com/unciv/ui/images/ImageGetter.kt

@@ -5,6 +5,7 @@ import com.badlogic.gdx.files.FileHandle
 import com.badlogic.gdx.graphics.Color
 import com.badlogic.gdx.graphics.Texture
 import com.badlogic.gdx.graphics.Texture.TextureFilter
+import com.badlogic.gdx.graphics.g2d.Batch
 import com.badlogic.gdx.graphics.g2d.NinePatch
 import com.badlogic.gdx.graphics.g2d.TextureAtlas
 import com.badlogic.gdx.graphics.g2d.TextureRegion
@@ -358,6 +359,8 @@ object ImageGetter {
             setSize(width, height)
         }
 
+        override fun draw(batch: Batch?, parentAlpha: Float) = super.draw(batch, parentAlpha)
+
         fun setLabel(color: Color, text: String, fontSize: Int = Constants.defaultFontSize) : ProgressBar {
             label = text.toLabel()
             label?.setAlignment(Align.center)

core/src/com/unciv/ui/images/Portrait.kt

@@ -1,6 +1,7 @@
 package com.unciv.ui.images
 
 import com.badlogic.gdx.graphics.Color
+import com.badlogic.gdx.graphics.g2d.Batch
 import com.badlogic.gdx.scenes.scene2d.Group
 import com.badlogic.gdx.scenes.scene2d.ui.Image
 import com.badlogic.gdx.scenes.scene2d.ui.Table
@@ -95,6 +96,9 @@ open class Portrait(val type: Type, val imageName: String, val size: Float, val
             else -> getDefaultImage().apply { color = getDefaultImageTint() }
         }
     }
+    
+    // Overridable so portraits can use circle images from their texture to minimize texture swapping
+    protected open fun getCircleImage() = ImageGetter.getCircle()
 
     /** Border / background */
     private fun getMainBackground() : Group {
@@ -105,14 +109,16 @@ open class Portrait(val type: Type, val imageName: String, val size: Float, val
             val ratioH = image.height / backgroundImage.height
             image.setSize((size + borderSize)*ratioW, (size + borderSize)*ratioH)
             return backgroundImage.toGroup(size + borderSize)
-
         } else {
             image.setSize(size*0.75f, size*0.75f)
 
-            val bg = Group().apply { isTransform = false }
+            val bg = object: Group(){
+                init { apply { isTransform = false } }
+                override fun draw(batch: Batch?, parentAlpha: Float) = super.draw(batch, parentAlpha)
+            }
 
-            val circleInner = ImageGetter.getCircle()
-            val circleOuter = ImageGetter.getCircle()
+            val circleInner = getCircleImage()
+            val circleOuter = getCircleImage()
 
             circleInner.setSize(size, size)
             circleOuter.setSize(size + borderSize, size + borderSize)
@@ -159,20 +165,29 @@ class PortraitResource(name: String, size: Float, amount: Int = 0) : Portrait(Ty
 
     override fun getDefaultInnerBackgroundTint(): Color =
         ruleset.tileResources[imageName]?.resourceType?.getColor() ?: Color.WHITE
+
+    override fun draw(batch: Batch?, parentAlpha: Float) = super.draw(batch, parentAlpha)
 }
 
 class PortraitTech(name: String, size: Float) : Portrait(Type.Tech, name, size) {
     override fun getDefaultOuterBackgroundTint(): Color = getDefaultImageTint()
     override fun getDefaultImageTint(): Color =
         ruleset.eras[ruleset.technologies[imageName]?.era()]?.getColor()?.darken(0.6f) ?: ImageGetter.CHARCOAL
+
+    override fun getCircleImage(): Image = ImageGetter.getImage("TechIcons/Circle")
+    override fun draw(batch: Batch?, parentAlpha: Float) = super.draw(batch, parentAlpha)
 }
 
 class PortraitUnit(name: String, size: Float) : Portrait(Type.Unit, name, size) {
     override fun getDefaultImageTint(): Color = Color.BLACK
+    override fun getCircleImage() = ImageGetter.getImage("OtherIcons/ConstructionCircle")
+    override fun draw(batch: Batch?, parentAlpha: Float) = super.draw(batch, parentAlpha)
 }
 
 class PortraitBuilding(name: String, size: Float) : Portrait(Type.Building, name, size) {
     override fun getDefaultImageTint(): Color = Color.BLACK
+    override fun getCircleImage() = ImageGetter.getImage("OtherIcons/ConstructionCircle")
+    override fun draw(batch: Batch?, parentAlpha: Float) = super.draw(batch, parentAlpha)
 }
 
 class PortraitUnavailableWonderForTechTree(name: String, size: Float) : Portrait(Type.Building, name, size) {
@@ -218,6 +233,8 @@ class PortraitImprovement(name: String, size: Float, dim: Boolean = false, isPil
             return getColorFromStats(improvement)
         return Color.WHITE
     }
+
+    override fun draw(batch: Batch?, parentAlpha: Float) = super.draw(batch, parentAlpha)
 }
 
 class PortraitNation(name: String, size: Float) : Portrait(Type.Nation, name, size, size*0.1f) {

core/src/com/unciv/ui/screens/pickerscreens/TechButton.kt

@@ -1,6 +1,7 @@
 package com.unciv.ui.screens.pickerscreens
 
 import com.badlogic.gdx.graphics.Color
+import com.badlogic.gdx.graphics.g2d.Batch
 import com.badlogic.gdx.scenes.scene2d.Touchable
 import com.badlogic.gdx.scenes.scene2d.ui.Image
 import com.badlogic.gdx.scenes.scene2d.ui.Table
@@ -42,10 +43,11 @@ class TechButton(
 
         val path = "TechPickerScreen/TechButton"
         val default = BaseScreen.skinStrings.roundedEdgeRectangleMidShape
-        backgroundImage = Image(BaseScreen.skinStrings.getUiBackground(path, default))
+        backgroundImage = object : Image(BaseScreen.skinStrings.getUiBackground(path, default)){
+            override fun draw(batch: Batch?, parentAlpha: Float) = super.draw(batch, parentAlpha)
+        }
         background = BaseScreen.skinStrings.getUiBackground(path, default, Color.WHITE.darken(0.3f))
 
-        backgroundImage.toBack()
         addActor(backgroundImage)
 
         pad(5f, 5f, 5f, 0f)
@@ -67,7 +69,9 @@ class TechButton(
             add(progressBar.addBorder(1f, Color.GRAY.cpy())).padLeft(0f).padRight(5f)
         }
 
-        val rightSide = Table()
+        val rightSide = object : Table() {
+            override fun draw(batch: Batch?, parentAlpha: Float) = super.draw(batch, parentAlpha)
+        }
 
         rightSide.add(text).width(140f).top().left().padRight(15f)
         rightSide.add(turns).width(40f).top().left().padRight(10f).row()
@@ -76,6 +80,10 @@ class TechButton(
 
         rightSide.centerY(this)
         add(rightSide).expandX().left()
+        
+        // Render both Skin images adjacently to reduce a texture swap between them
+        rightSide.toBack()
+        backgroundImage.toBack()
         pack()
 
         backgroundImage.setSize(width - 3f, height - 3f)
@@ -91,7 +99,10 @@ class TechButton(
     }
 
     private fun addTechEnabledIcons(techName: String, rightSide: Table) {
-        val techEnabledIcons = Table().align(Align.left)
+        val techEnabledIcons = object : Table(){
+            init { align(Align.left) }
+            override fun draw(batch: Batch?, parentAlpha: Float) = super.draw(batch, parentAlpha)
+        }
         techEnabledIcons.background = BaseScreen.skinStrings.getUiBackground(
             "TechPickerScreen/TechButtonIconsOutline",
             BaseScreen.skinStrings.roundedEdgeRectangleSmallShape,
@@ -113,6 +124,10 @@ class TechButton(
             .prefWidth(195f)
             .maxWidth(195f)
             .expandX().left().row()
+        
+        techEnabledIcons.toBack() // First thing in the table to render so the 2 skin textures are rendered back to back
     }
 
+    override fun draw(batch: Batch?, parentAlpha: Float) = super.draw(batch, parentAlpha)
+
 }

core/src/com/unciv/ui/screens/pickerscreens/TechPickerScreen.kt

@@ -1,6 +1,7 @@
 package com.unciv.ui.screens.pickerscreens
 
 import com.badlogic.gdx.graphics.Color
+import com.badlogic.gdx.graphics.g2d.Batch
 import com.badlogic.gdx.math.Vector2
 import com.badlogic.gdx.scenes.scene2d.ui.Image
 import com.badlogic.gdx.scenes.scene2d.ui.Label
@@ -52,7 +53,9 @@ class TechPickerScreen(
      * Having this be a separate table allows us to leave the TopTable as is (that is: auto-width to fit the scrollPane)
      *  leaving us the juicy small tech tree right in the center.
      */
-    private val techTable = Table()
+    private val techTable = object : Table(){
+        override fun draw(batch: Batch?, parentAlpha: Float) = super.draw(batch, parentAlpha)
+    }
 
     // All these are to counter performance problems when updating buttons for all techs.
     private var researchableTechs = ruleset.technologies.keys
@@ -463,5 +466,4 @@ class TechPickerScreen(
             rightSideButton.disable()
         }
     }
-
 }