From d0701ce63df2954aa367de2416b8e4d8e0877f96 Mon Sep 17 00:00:00 2001
From: Harrison <yunyangdeng@gmail.com>
Date: Thu, 30 Apr 2020 16:26:02 -0500
Subject: [PATCH] Changed async execution setup.

Two beta threads with lower thread priority and one alpha with normal thread priority.

Implemented use of both in chunk loading.
---
 .../ca/recrown/islandsurvivalcraft/Utilities.java  | 10 ++++++----
 .../generation/IslandWorldChunkGenerator.java      | 14 +++++++-------
 2 files changed, 13 insertions(+), 11 deletions(-)

diff --git a/src/main/java/ca/recrown/islandsurvivalcraft/Utilities.java b/src/main/java/ca/recrown/islandsurvivalcraft/Utilities.java
index c542e32..ebf6391 100644
--- a/src/main/java/ca/recrown/islandsurvivalcraft/Utilities.java
+++ b/src/main/java/ca/recrown/islandsurvivalcraft/Utilities.java
@@ -11,7 +11,8 @@ import ca.recrown.islandsurvivalcraft.datatypes.Point2;
 
 public class Utilities {
     public final static int CHUNK_SIZE = 16;
-    public final static ExecutorService ISC_EXECUTOR = Executors.newFixedThreadPool(2, createThreadFactory());
+    public final static ExecutorService ISC_EXECUTOR_ALPHA = Executors.newFixedThreadPool(1, createThreadFactory("ALPHA", Thread.NORM_PRIORITY));
+    public final static ExecutorService ISC_EXECUTOR_BETA = Executors.newFixedThreadPool(2, createThreadFactory("BETA", Thread.MIN_PRIORITY));
 
     public static <K, V> HashMap<V, ArrayList<K>> invertHashMap(HashMap<K, V> hashMap) {
         HashMap<V, ArrayList<K>> res = new HashMap<>();
@@ -76,11 +77,12 @@ public class Utilities {
         return worldToLocalChunkCoordinates(worldCoordinates.x, worldCoordinates.y);
     }
 
-    public static ThreadFactory createThreadFactory() {
-        return new ThreadFactory(){
+    public static ThreadFactory createThreadFactory(final String identifier, final int priority) {
+        return new ThreadFactory() {
             @Override
             public Thread newThread(Runnable r) {
-                Thread thread = new Thread(r, "ISC-worker");
+                Thread thread = new Thread(r, String.format("ISC-worker-%s", identifier));
+                thread.setPriority(priority);
                 return thread;
             }
         };
diff --git a/src/main/java/ca/recrown/islandsurvivalcraft/world/generation/IslandWorldChunkGenerator.java b/src/main/java/ca/recrown/islandsurvivalcraft/world/generation/IslandWorldChunkGenerator.java
index bf1a859..b02b4aa 100644
--- a/src/main/java/ca/recrown/islandsurvivalcraft/world/generation/IslandWorldChunkGenerator.java
+++ b/src/main/java/ca/recrown/islandsurvivalcraft/world/generation/IslandWorldChunkGenerator.java
@@ -28,7 +28,8 @@ public class IslandWorldChunkGenerator extends ChunkGenerator implements Listene
     private final Cache<Point2, Biome[]> biomeCache = new Cache<>(262144);
     private final Cache<Point2, Boolean> chunkExistenceCache = new Cache<>(32768);
     private final BiomeSelector biomeSelector = new BiomeSelector();
-    private final ExecutorService executor = Utilities.ISC_EXECUTOR;
+    private final ExecutorService exAlpha = Utilities.ISC_EXECUTOR_ALPHA;
+    private final ExecutorService exBeta = Utilities.ISC_EXECUTOR_BETA;
     private volatile World currentWorld;
 
     public IslandWorldChunkGenerator() {
@@ -46,9 +47,9 @@ public class IslandWorldChunkGenerator extends ChunkGenerator implements Listene
         int maxHeight = world.getMaxHeight();
         LinkedList<Future<Boolean>> tasks = new LinkedList<>();
         ChunkData chunkData = createChunkData(world);
-        Future<Boolean> preLoader = executor.submit(() -> {
-            for (int x = 0; x < Utilities.CHUNK_SIZE; x++) {
-                for (int z = 0; z < Utilities.CHUNK_SIZE; z++) {
+        Future<Boolean> preLoader = exAlpha.submit(() -> {
+            for (int x = Utilities.CHUNK_SIZE - 1; x >= 0; x--) {
+                for (int z = Utilities.CHUNK_SIZE - 1; z >= 0; z--) {
                     if (Thread.currentThread().isInterrupted()) return false;
                     mapper.getWorldBlockValue(Utilities.CHUNK_SIZE * chunkX + x, Utilities.CHUNK_SIZE * chunkZ + z);
                 }
@@ -65,9 +66,8 @@ public class IslandWorldChunkGenerator extends ChunkGenerator implements Listene
                     biomeGenerator.generateBiomeColumn(biomes, world, chunkX, chunkZ, localX, localZ, mapper, biomeSelector,
                             temperatureMapGenerator, biomeCache, chunkExistenceCache);
                 }
-                
                 if (biomes[localX][localZ] == null) throw new IllegalStateException("Biome was null.");
-                tasks.add(executor.submit(() -> {
+                tasks.add(exBeta.submit(() -> {
                     for (int y = 0; y < maxHeight; y++) {
                         biomeGrid.setBiome(localX, y, localZ, biomes[localX][localZ]);
                     }
@@ -82,7 +82,7 @@ public class IslandWorldChunkGenerator extends ChunkGenerator implements Listene
         }
         chunkData.setRegion(0, 0, 0, 16, 1, 16, Material.BEDROCK);
 
-        preLoader.cancel(true);
+        preLoader.cancel(false);
         try {
             while (!tasks.isEmpty()) {
                 tasks.poll().get();