chore: Hexmath purity

build.gradle.kts

@@ -49,6 +49,9 @@ allprojects {
     configure<yairm210.purity.PurityConfiguration>{
         wellKnownPureFunctions = setOf(
             "com.unciv.logic.civilization.diplomacy.RelationshipLevel.compareTo",
+            "kotlin.math.max",
+            "kotlin.math.min",
+            "kotlin.math.abs"
         )
         wellKnownReadonlyFunctions = setOf(
             // Looks like the Collection.contains is not considered overridden :thunk:

core/src/com/unciv/logic/map/HexMath.kt

@@ -232,10 +232,12 @@ object HexMath {
     }
 
     /** Get number of hexes from [origin] to [destination] _without respecting world-wrap_ */
+    @Pure
     fun getDistance(origin: Vector2, destination: Vector2): Int {
         return getDistance(origin.x.toInt(), origin.y.toInt(), destination.x.toInt(), destination.y.toInt())
     }
 
+    @Pure
     fun getDistance(originX: Int, originY: Int, destinationX: Int, destinationY: Int): Int {
         val relativeX = originX - destinationX
         val relativeY = originY - destinationY