From 3941aa3fe4b1dcfa7cd1a1413868286a7b895d2c Mon Sep 17 00:00:00 2001
From: Evan Debenham <Evan@ShatteredPixel.com>
Date: Wed, 24 Aug 2016 14:50:15 -0400
Subject: [PATCH] v0.4.2: array managment optimizations to Pathfinder

---
 .../java/com/watabou/utils/PathFinder.java    | 22 +++++++++++++------
 1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/SPD-classes/src/main/java/com/watabou/utils/PathFinder.java b/SPD-classes/src/main/java/com/watabou/utils/PathFinder.java
index 50e0e173c..741f3b98a 100644
--- a/SPD-classes/src/main/java/com/watabou/utils/PathFinder.java
+++ b/SPD-classes/src/main/java/com/watabou/utils/PathFinder.java
@@ -27,6 +27,7 @@ import java.util.LinkedList;
 public class PathFinder {
 	
 	public static int[] distance;
+	private static int[] maxVal;
 	
 	private static boolean[] goals;
 	private static int[] queue;
@@ -49,13 +50,20 @@ public class PathFinder {
 		goals = new boolean[size];
 		queue = new int[size];
 
+		maxVal = new int[size];
+		Arrays.fill(maxVal, Integer.MAX_VALUE);
+
 		dir = new int[]{-1, +1, -width, +width, -width-1, -width+1, +width-1, +width+1};
 
 		NEIGHBOURS4 = new int[]{-width, +1, +width, -1};
 		NEIGHBOURS8 = new int[]{-width, +1-width, +1, +1+width, +width, -1+width, -1, -1-width};
 		NEIGHBOURS9 = new int[]{0, -width, +1-width, +1, +1+width, +width, -1+width, -1, -1-width};
 	}
-	
+
+	//TODO currently this isn't used, and all pathfinding is recomputed each step.
+	// Computing each step is performance expensive, but pre-computing a path leads to incorrect
+	// pathing in cases where passable changes. Need to look into a compromise, something that's
+	// correct but is less costly
 	public static Path find( int from, int to, boolean[] passable ) {
 
 		if (!buildDistanceMap( from, to, passable )) {
@@ -146,8 +154,8 @@ public class PathFinder {
 		if (from == to) {
 			return false;
 		}
-		
-		Arrays.fill( distance, Integer.MAX_VALUE );
+
+		System.arraycopy(maxVal, 0, distance, 0, maxVal.length);
 		
 		boolean pathFound = false;
 		
@@ -185,7 +193,7 @@ public class PathFinder {
 	
 	public static void buildDistanceMap( int to, boolean[] passable, int limit ) {
 		
-		Arrays.fill( distance, Integer.MAX_VALUE );
+		System.arraycopy(maxVal, 0, distance, 0, maxVal.length);
 		
 		int head = 0;
 		int tail = 0;
@@ -223,7 +231,7 @@ public class PathFinder {
 			return false;
 		}
 		
-		Arrays.fill( distance, Integer.MAX_VALUE );
+		System.arraycopy(maxVal, 0, distance, 0, maxVal.length);
 		
 		boolean pathFound = false;
 		
@@ -265,7 +273,7 @@ public class PathFinder {
 	
 	private static int buildEscapeDistanceMap( int cur, int from, float factor, boolean[] passable ) {
 		
-		Arrays.fill( distance, Integer.MAX_VALUE );
+		System.arraycopy(maxVal, 0, distance, 0, maxVal.length);
 		
 		int destDist = Integer.MAX_VALUE;
 		
@@ -312,7 +320,7 @@ public class PathFinder {
 	@SuppressWarnings("unused")
 	private static void buildDistanceMap( int to, boolean[] passable ) {
 		
-		Arrays.fill( distance, Integer.MAX_VALUE );
+		System.arraycopy(maxVal, 0, distance, 0, maxVal.length);
 		
 		int head = 0;
 		int tail = 0;