WIP rewritten whole algorithm for possible moves

CheckersClient/core/src/com/mygdx/game/model/GameMode.kt

 package com.mygdx.game.model
 
 import com.badlogic.gdx.math.Vector3
-import com.sun.org.apache.xpath.internal.operations.Bool
-import java.lang.Exception
-import java.lang.NullPointerException
 
 //Holds a ruleset and a board
 
@@ -33,43 +30,80 @@ class GameMode(rules:AbstractRules? = null, board:AbstractBoard? = null) {
         return this.rules
     }
 
-    fun getPossibleMoves(position: Vector3): ArrayList<Vector3> {
-
-        fun isInBoard(pos: Vector3): Boolean {
-            var inBoard: Boolean
-            try {
-                inBoard = this.board!!.fieldExists(pos)
-            } catch (e: NullPointerException) {
-                inBoard = false
+    // Returns zeros for ones and vice versa, otherwise returns original parameter value
+    private fun flip(a: Float): Float {
+        when (a) {
+            0F -> return 1F
+            1F -> return 0F
+            else -> {
+                return a
             }
-            return inBoard
         }
+    }
 
-        fun hasPiece(pos: Vector3): Boolean {
-            return (this.board?.fields?.get(pos)?.hasPiece()) ?: false
-        }
+    // Populates an arrayList with all possible moves according to zigzag jump rules
+    private fun zigzagAlgorithm(position: Vector3, frontier: ArrayList<Vector3>,
+                                jumpRange: Int? = this.rules?.jumpRange,
+                                moveRange: Int? = this.rules?.moveRange ) {
+
+        // Repeats algorithm for each direction
+        for (direction: Vector3 in directionalUnitVectors) {
+
+            // BASIC MOVE
+
+            // Starts by moving a single field
+            var destination = position.cpy().add(direction)
+
+            // Keeps adding fields to frontier as long as they are clear and within range
+            while (destination != position.cpy().add(direction.setLength(1F + moveRange?.toFloat()!!))) {
+                if (this.board?.isPathClear(position, destination) == false) {
+                    break
+                }
+                frontier.add(destination)
+                destination.add(direction)
+            }
+
+            // JUMP MOVE
 
-        fun algorithm(pos: Vector3, frontier: ArrayList<Vector3>, iterationNumber: Int = 0) {
+            // Sets first jump target
+            destination = position.cpy().add(direction.cpy().setLength(1F + jumpRange?.toFloat()!!))
 
-            val iterationCount: Int = 1
+            // Finds the other jumping direction by switching 1 and 0, -1 is left as it is, e.g. finds
+            // the zag direction
+            var secondaryDirection = Vector3(flip(direction.x), flip(direction.y), flip(direction.z))
 
-            for (dir:Vector3 in directionalUnitVectors) {
+            // Determines if it is possible to make the jump
+            var jumpable = this.board?.isJumpPossible(position, destination) ?: false
 
-                var newPos:Vector3 = pos.add(dir)
+            // Holds whether it is a zig or a zag jump
+            var isPrimaryJumpDirection = true
 
-                if (isInBoard(newPos) && hasPiece(newPos) && iterationNumber < iterationCount) {
-                    algorithm(newPos,frontier, iterationNumber+1)
-                } else if (isInBoard(newPos) && !hasPiece(newPos)) {
-                    frontier.add(newPos)
+            while (jumpable) {
+
+                frontier.add(destination)
+                var newPosition = destination.cpy()
+
+                // Sets direction for next possible move
+                destination = if (isPrimaryJumpDirection) {
+                    destination.cpy().add(direction)
+                } else {
+                    destination.cpy().add(secondaryDirection)
                 }
+
+                jumpable = this.board?.isJumpPossible(newPosition, destination) ?: false
+                isPrimaryJumpDirection = !isPrimaryJumpDirection
+
             }
         }
+    }
+
+    fun getPossibleMoves(position: Vector3, moveRange: Int? = this.rules?.moveRange, jumpRange: Int? = this.rules?.jumpRange): ArrayList<Vector3> {
 
         var possibleMoves: ArrayList<Vector3> = arrayListOf()
-        algorithm(position, possibleMoves)
+        zigzagAlgorithm(position, possibleMoves,  moveRange = moveRange, jumpRange = jumpRange)
         return possibleMoves
-
     }
+
 }
 
 
@@ -88,3 +122,4 @@ class GameMode(rules:AbstractRules? = null, board:AbstractBoard? = null) {
 
 
 
+

CheckersClient/core/src/com/mygdx/game/model/gamemodes/boards/AbstractBoard.kt

@@ -8,4 +8,39 @@ abstract class AbstractBoard {
 
     abstract fun computeFields() // Computes all fields on the board
     abstract fun fieldExists(coordinates: Vector3): Boolean
+
+    // Determines if the path does not hold any pieces and exists
+    fun isPathClear(currentPosition: Vector3, targetPosition: Vector3): Boolean {
+
+        var direction = targetPosition.cpy().sub(currentPosition).setLength(1F)
+        var logicalStopPosition = targetPosition.cpy().add(direction)
+
+        while (currentPosition != logicalStopPosition) {
+            if (this.fields[currentPosition]?.hasPiece() == true && !fieldExists(currentPosition)) {
+                return false
+            }
+            currentPosition.add(direction)
+        }
+        return true
+    }
+
+    // Determines if a jump is possible e.g. pieces all the way except the last field and it exists
+    fun isJumpPossible(currentPosition: Vector3, destinationPosition: Vector3): Boolean {
+
+        var direction = destinationPosition.cpy().sub(currentPosition).setLength(1F)
+        currentPosition.add(direction)
+
+        while (currentPosition != destinationPosition) {
+            if (this.fields[currentPosition]?.hasPiece() == true || !fieldExists(currentPosition)) {
+                return false
+            }
+            currentPosition.add(direction)
+        }
+
+        if (this.fields[currentPosition]?.hasPiece() == true) {
+            return false
+        }
+
+        return true
+    }
 }
\ No newline at end of file

CheckersClient/core/src/com/mygdx/game/model/gamemodes/rules/AbstractRules.kt

@@ -6,7 +6,7 @@ abstract class AbstractRules {
 
     abstract var startFields: List<List<Vector3>> // List containing list of startfields for each player
     abstract var moveRange: Int // How far a piece can be moved
-    abstract var jumpRange: Int // How far a piece can jump (over other pieces)
+    abstract var jumpRange: Int // How many pieces a piece can jump over
 
     abstract fun getPlayerStartfields(playerId: Int) : List<Vector3>  // Returns a list of startfields for a given player
     abstract fun getPlayerTargetFields(playerId: Int) : List<Vector3> // Returns a list of targetfields for a given player