Limit camera movement within explored region (#8661)

* Load game resets scroll position

* Limit camera within explored region

core/src/com/unciv/UncivGame.kt

@@ -252,7 +252,7 @@ class UncivGame(parameters: UncivGameParameters) : Game() {
      *
      * Sets the returned `WorldScreen` as the only active screen.
      */
-    suspend fun loadGame(newGameInfo: GameInfo): WorldScreen = withThreadPoolContext toplevel@{
+    suspend fun loadGame(newGameInfo: GameInfo, callFromLoadScreen: Boolean = false): WorldScreen = withThreadPoolContext toplevel@{
         val prevGameInfo = gameInfo
         gameInfo = newGameInfo
 
@@ -266,7 +266,7 @@ class UncivGame(parameters: UncivGameParameters) : Game() {
         initializeResources(prevGameInfo, newGameInfo)
 
         val isLoadingSameGame = worldScreen != null && prevGameInfo != null && prevGameInfo.gameId == newGameInfo.gameId
-        val worldScreenRestoreState = if (isLoadingSameGame) worldScreen!!.getRestoreState() else null
+        val worldScreenRestoreState = if (!callFromLoadScreen && isLoadingSameGame) worldScreen!!.getRestoreState() else null
 
         lateinit var loadingScreen: LoadingScreen
 

core/src/com/unciv/logic/GameInfo.kt

@@ -542,6 +542,8 @@ class GameInfo : IsPartOfGameInfoSerialization, HasGameInfoSerializationVersion
         }) {
             for (unit in civInfo.units.getCivUnits())
                 unit.updateVisibleTiles(false) // this needs to be done after all the units are assigned to their civs and all other transients are set
+            if(civInfo.playerType == PlayerType.Human)
+                civInfo.exploredRegion.setMapParameters(tileMap.mapParameters.worldWrap, tileMap.mapParameters.mapSize.radius) // Required for the correct calculation of the explored region on world wrap maps
             civInfo.cache.updateSightAndResources() // only run ONCE and not for each unit - this is a huge performance saver!
 
             // Since this depends on the cities of ALL civilizations,

core/src/com/unciv/logic/civilization/Civilization.kt

@@ -188,6 +188,9 @@ class Civilization : IsPartOfGameInfoSerialization {
     var citiesCreated = 0
     var exploredTiles = HashSet<Vector2>()
 
+    // Limit camera within explored region
+    var exploredRegion = ExploredRegion()
+
     fun hasExplored(tile: Tile) = tile.isExplored(this)
 
     var lastSeenImprovement = HashMapVector2<String>()
@@ -271,6 +274,7 @@ class Civilization : IsPartOfGameInfoSerialization {
         // Cloning it by-pointer is a horrific move, since the serialization would go over it ANYWAY and still lead to concurrency problems.
         // Cloning it by iterating on the tilemap values may seem ridiculous, but it's a perfectly thread-safe way to go about it, unlike the other solutions.
         toReturn.exploredTiles.addAll(gameInfo.tileMap.values.asSequence().map { it.position }.filter { it in exploredTiles })
+        toReturn.exploredRegion = exploredRegion.clone()
         toReturn.lastSeenImprovement.putAll(lastSeenImprovement)
         toReturn.notifications.addAll(notifications)
         toReturn.notificationsLog.addAll(notificationsLog)

core/src/com/unciv/logic/civilization/ExploredRegion.kt

@@ -0,0 +1,165 @@
+package com.unciv.logic.civilization
+
+import com.badlogic.gdx.math.Vector2
+import com.unciv.logic.IsPartOfGameInfoSerialization
+import com.unciv.logic.map.HexMath.getLatitude
+import com.unciv.logic.map.HexMath.getLongitude
+import com.unciv.logic.map.HexMath.worldFromLatLong
+import com.unciv.ui.components.tilegroups.TileGroupMap
+import kotlin.math.abs
+
+class ExploredRegion () : IsPartOfGameInfoSerialization {
+
+    @Transient
+    private var isWorldWrap = false
+
+    @Transient
+    private var mapRadius = 0f
+
+    @Transient
+    private val tileRadius = (TileGroupMap.groupSize + 4) * 0.75f
+
+    @Transient
+    private var shouldRecalculateCoords = true
+
+    @Transient
+    private var shouldRestrictX = false
+
+    // Top left point of the explored region in stage (x;y) starting from the top left corner
+    @Transient
+    private var topLeftStage = Vector2()
+
+    // Bottom right point of the explored region in stage (x;y) starting from the top left corner
+    @Transient
+    private var bottomRightStage = Vector2()
+
+    // Top left point of the explored region in hex (long;lat) from the center of the map
+    private var topLeft = Vector2()
+
+    // Bottom right point of the explored region in hex (long;lat) from the center of the map
+    private var bottomRight = Vector2()
+
+    // Getters
+    fun shouldRecalculateCoords(): Boolean = shouldRecalculateCoords
+    fun shouldRestrictX(): Boolean = shouldRestrictX
+    fun getLeftX(): Float = topLeftStage.x
+    fun getRightX():Float = bottomRightStage.x
+    fun getTopY(): Float = topLeftStage.y
+    fun getBottomY():Float = bottomRightStage.y
+
+    fun clone(): ExploredRegion {
+        val toReturn = ExploredRegion()
+        toReturn.topLeft = topLeft
+        toReturn.bottomRight = bottomRight
+        return toReturn
+    }
+
+    fun setMapParameters(worldWrap: Boolean, radius: Int)
+    {
+        isWorldWrap = worldWrap
+        mapRadius = radius.toFloat()
+    }
+
+    // Check if tilePosition is beyond explored region
+    fun checkTilePosition(tilePosition: Vector2, explorerPosition: Vector2?) {
+        var longitude = getLongitude(tilePosition)
+        val latitude = getLatitude(tilePosition)
+
+        // First time call
+        if (topLeft == Vector2.Zero && bottomRight == Vector2.Zero) {
+            topLeft = Vector2(longitude, latitude)
+            bottomRight = Vector2(longitude, latitude)
+            return
+        }
+
+        // Check X coord
+        if (topLeft.x >= bottomRight.x) {
+            if (longitude > topLeft.x) {
+                // For world wrap maps when the maximumX is reached, we move to a minimumX - 1f
+                if (isWorldWrap && longitude == mapRadius) longitude = mapRadius * -1f
+                topLeft.x = longitude
+                shouldRecalculateCoords = true
+            } else if (longitude < bottomRight.x) {
+                // For world wrap maps when the minimumX is reached, we move to a maximumX + 1f
+                if (isWorldWrap && longitude == (mapRadius * -1f + 1f)) longitude = mapRadius + 1f
+                bottomRight.x = longitude
+                shouldRecalculateCoords = true
+            }
+        } else {
+            // When we cross the map edge with world wrap, the vectors are swapped along the x-axis
+            if (longitude < bottomRight.x && longitude > topLeft.x) {
+                val rightSideDistance: Float
+                val leftSideDistance: Float
+
+                // If we have explorerPosition, get distance to explorer
+                // This solves situations when a newly explored cell is in the middle of an unexplored area
+                if(explorerPosition != null) {
+                    val explorerLongitude = getLongitude(explorerPosition)
+
+                    rightSideDistance = if(explorerLongitude < 0 && bottomRight.x > 0)
+                            // The explorer is still on the right edge of the map, but has explored over the edge
+                            mapRadius * 2f + explorerLongitude - bottomRight.x
+                        else
+                            abs(explorerLongitude - bottomRight.x)
+
+                    leftSideDistance = if(explorerLongitude > 0 && topLeft.x < 0)
+                            // The explorer is still on the left edge of the map, but has explored over the edge
+                            mapRadius * 2f - explorerLongitude + topLeft.x
+                        else
+                            abs(topLeft.x - explorerLongitude)
+                } else {
+                    // If we don't have explorerPosition, we calculate the distance to the edges of the explored region
+                    // e.g. when capitals are revealed
+                    rightSideDistance = bottomRight.x - longitude
+                    leftSideDistance = longitude - topLeft.x
+                }
+
+                // Expand region from the nearest edge
+                if (rightSideDistance > leftSideDistance) {
+                    topLeft.x = longitude
+                    shouldRecalculateCoords = true
+                } else {
+                    bottomRight.x = longitude
+                    shouldRecalculateCoords = true
+                }
+            }
+        }
+
+        // Check Y coord
+        if (latitude > topLeft.y) {
+            topLeft.y = latitude
+            shouldRecalculateCoords = true
+        } else if (latitude < bottomRight.y) {
+            bottomRight.y = latitude
+            shouldRecalculateCoords = true
+        }
+    }
+
+    fun calculateStageCoords(mapMaxX: Float, mapMaxY: Float) {
+        shouldRecalculateCoords = false
+
+        // Check if we explored the whole world wrap map horizontally
+        shouldRestrictX = bottomRight.x - topLeft.x != 1f
+
+        // Get world (x;y)
+        val topLeftWorld = worldFromLatLong(topLeft, tileRadius)
+        val bottomRightWorld = worldFromLatLong(bottomRight, tileRadius)
+
+        // Convert X to the stage coords
+        val mapCenterX = mapMaxX * 0.5f + tileRadius
+        var left = mapCenterX + topLeftWorld.x
+        var right = mapCenterX + bottomRightWorld.x
+
+        // World wrap over edge check
+        if (left > mapMaxX) left = 10f
+        if (right < 0f) right = mapMaxX - 10f
+
+        // Convert Y to the stage coords
+        val mapCenterY = mapMaxY * 0.5f
+        val top = mapCenterY-topLeftWorld.y
+        val bottom = mapCenterY-bottomRightWorld.y
+
+        topLeftStage = Vector2(left, top)
+        bottomRightStage = Vector2(right, bottom)
+    }
+}

core/src/com/unciv/logic/civilization/transients/CivInfoTransientCache.kt

@@ -1,5 +1,6 @@
 package com.unciv.logic.civilization.transients
 
+import com.badlogic.gdx.math.Vector2
 import com.unciv.Constants
 import com.unciv.UncivGame
 import com.unciv.logic.city.City
@@ -74,7 +75,7 @@ class CivInfoTransientCache(val civInfo: Civilization) {
     }
 
     // This is a big performance
-    fun updateViewableTiles() {
+    fun updateViewableTiles(explorerPosition: Vector2? = null) {
         setNewViewableTiles()
 
         updateViewableInvisibleTiles()
@@ -87,7 +88,7 @@ class CivInfoTransientCache(val civInfo: Civilization) {
         // and we never actually iterate on the explored tiles (only check contains()),
         // so there's no fear of concurrency problems.
         civInfo.viewableTiles.asSequence().forEach { tile ->
-            tile.setExplored(civInfo, true)
+            tile.setExplored(civInfo, true, explorerPosition)
         }
 
 

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

@@ -48,6 +48,15 @@ object HexMath {
         return Vector2(x, y)
     }
 
+    /**
+     * Convert hex latitude and longitude into world coordinates.
+     */
+    fun worldFromLatLong(vector: Vector2, tileRadius: Float): Vector2 {
+        val x = vector.x * tileRadius * 1.5f * -1f
+        val y = vector.y * tileRadius * sqrt(3f) * 0.5f
+        return Vector2(x, y)
+    }
+
     /** returns a vector containing width and height a rectangular map should have to have
      *  approximately the same number of tiles as an hexagonal map given a height/width ratio */
     fun getEquivalentRectangularSize(size: Int, ratio: Float = 0.65f): Vector2 {

core/src/com/unciv/logic/map/mapunit/MapUnit.kt

@@ -290,7 +290,7 @@ class MapUnit : IsPartOfGameInfoSerialization {
     /**
      * Update this unit's cache of viewable tiles and its civ's as well.
      */
-    fun updateVisibleTiles(updateCivViewableTiles:Boolean = true) {
+    fun updateVisibleTiles(updateCivViewableTiles:Boolean = true, explorerPosition: Vector2? = null) {
         val oldViewableTiles = viewableTiles
 
         viewableTiles = when {
@@ -302,7 +302,7 @@ class MapUnit : IsPartOfGameInfoSerialization {
 
         // Set equality automatically determines if anything changed - https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/-abstract-set/equals.html
         if (updateCivViewableTiles && oldViewableTiles != viewableTiles)
-            civ.cache.updateViewableTiles()
+            civ.cache.updateViewableTiles(explorerPosition)
     }
 
     fun isActionUntilHealed() = action?.endsWith("until healed") == true
@@ -607,7 +607,7 @@ class MapUnit : IsPartOfGameInfoSerialization {
             promotions.addPromotion(promotion, true)
         }
 
-        updateVisibleTiles()
+        updateVisibleTiles(true, currentTile.position)
     }
 
     fun putInTile(tile: Tile) {

core/src/com/unciv/logic/map/tile/Tile.kt

@@ -245,10 +245,12 @@ open class Tile : IsPartOfGameInfoSerialization {
         return exploredBy.contains(player.civName) || player.exploredTiles.contains(position)
     }
 
-    fun setExplored(player: Civilization, isExplored: Boolean) {
+    fun setExplored(player: Civilization, isExplored: Boolean, explorerPosition: Vector2? = null) {
         if (isExplored) {
             exploredBy.add(player.civName)
             player.exploredTiles.add(position)
+            if(player.playerType == PlayerType.Human)
+                player.exploredRegion.checkTilePosition(position, explorerPosition)
         } else {
             exploredBy.remove(player.civName)
             player.exploredTiles.remove(position)

core/src/com/unciv/ui/components/ZoomableScrollPane.kt

@@ -290,8 +290,8 @@ open class ZoomableScrollPane(
                 onPanStartListener?.invoke()
             }
             setScrollbarsVisible(true)
-            scrollX -= deltaX
-            scrollY += deltaY
+            scrollX = restrictX(deltaX)
+            scrollY = restrictY(deltaY)
 
             when {
                 continuousScrollingX && scrollPercentX >= 1 && deltaX < 0 -> {
@@ -316,6 +316,9 @@ open class ZoomableScrollPane(
         }
     }
 
+    open fun restrictX(deltaX: Float): Float = scrollX - deltaX
+    open fun restrictY(deltaY:Float): Float = scrollY + deltaY
+
     override fun getFlickScrollListener(): ActorGestureListener {
         return FlickScrollListener()
     }

core/src/com/unciv/ui/screens/savescreens/LoadGameScreen.kt

@@ -123,7 +123,7 @@ class LoadGameScreen : LoadOrSaveScreen() {
             try {
                 // This is what can lead to ANRs - reading the file and setting the transients, that's why this is in another thread
                 val loadedGame = game.files.loadGameByName(selectedSave)
-                game.loadGame(loadedGame)
+                game.loadGame(loadedGame, true)
             } catch (notAPlayer: UncivShowableException) {
                 launchOnGLThread {
                     val (message) = getLoadExceptionMessage(notAPlayer)
@@ -146,7 +146,7 @@ class LoadGameScreen : LoadOrSaveScreen() {
                 try {
                     val clipboardContentsString = Gdx.app.clipboard.contents.trim()
                     val loadedGame = UncivFiles.gameInfoFromString(clipboardContentsString)
-                    game.loadGame(loadedGame)
+                    game.loadGame(loadedGame, true)
                 } catch (ex: Exception) {
                     launchOnGLThread { handleLoadGameException(ex, "Could not load game from clipboard!") }
                 }
@@ -171,7 +171,7 @@ class LoadGameScreen : LoadOrSaveScreen() {
                         handleLoadGameException(result.exception!!, "Could not load game from custom location!")
                     } else if (result.isSuccessful()) {
                         Concurrency.run {
-                            game.loadGame(result.gameData!!)
+                            game.loadGame(result.gameData!!, true)
                         }
                     }
                 }

core/src/com/unciv/ui/screens/worldscreen/WorldMapHolder.kt

@@ -777,6 +777,40 @@ class WorldMapHolder(
             super.reloadMaxZoom()
     }
 
+    override fun restrictX(deltaX: Float): Float {
+        val exploredRegion = worldScreen.viewingCiv.exploredRegion
+        var result = scrollX - deltaX
+
+        if (exploredRegion.shouldRecalculateCoords()) exploredRegion.calculateStageCoords(maxX, maxY)
+
+        if (!exploredRegion.shouldRestrictX()) return result
+
+        val leftX = exploredRegion.getLeftX()
+        val rightX = exploredRegion.getRightX()
+
+        if (deltaX < 0 && scrollX <= rightX && result > rightX)
+            result = rightX
+        else if (deltaX > 0 && scrollX >= leftX && result < leftX)
+            result = leftX
+
+        return result
+    }
+
+    override fun restrictY(deltaY: Float): Float {
+        val exploredRegion = worldScreen.viewingCiv.exploredRegion
+        var result = scrollY + deltaY
+
+        if (exploredRegion.shouldRecalculateCoords()) exploredRegion.calculateStageCoords(maxX, maxY)
+
+        val topY = exploredRegion.getTopY()
+        val bottomY = exploredRegion.getBottomY()
+
+        if (result < topY) result = topY
+        else if (result > bottomY) result = bottomY
+
+        return result
+    }
+
 
     // For debugging purposes
     override fun draw(batch: Batch?, parentAlpha: Float) = super.draw(batch, parentAlpha)