From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: epserv <admin@epserv.ru>
Date: Wed, 2 Dec 2020 21:47:11 +0500
Subject: [PATCH] Optimize Bukkit's MapPalette


diff --git a/src/main/java/org/bukkit/map/MapPalette.java b/src/main/java/org/bukkit/map/MapPalette.java
index 95fe3f4d081053a6cf484e4ef07b474f2dc2ab02..819362eeb8c2fd17583184730e5ed938f74d842b 100644
--- a/src/main/java/org/bukkit/map/MapPalette.java
+++ b/src/main/java/org/bukkit/map/MapPalette.java
@@ -6,6 +6,7 @@ import java.awt.Image;
 import java.awt.image.BufferedImage;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
+import java.util.Arrays;
 
 /**
  * Represents the palette that map items use.
@@ -22,15 +23,11 @@ public final class MapPalette {
         return new Color(r, g, b);
     }
 
-    private static double getDistance(@NotNull Color c1, @NotNull Color c2) {
-        double rmean = (c1.getRed() + c2.getRed()) / 2.0;
-        double r = c1.getRed() - c2.getRed();
-        double g = c1.getGreen() - c2.getGreen();
-        int b = c1.getBlue() - c2.getBlue();
-        double weightR = 2 + rmean / 256.0;
-        double weightG = 4.0;
-        double weightB = 2 + (255 - rmean) / 256.0;
-        return weightR * r * r + weightG * g * g + weightB * b * b;
+    private static int getDistance(@NotNull Color c1, @NotNull Color c2) {
+        if (c1.getRGB() == c2.getRGB())
+            return 0;
+        final int r = c1.getRed() - c2.getRed(), g = c1.getGreen() - c2.getGreen(), b = c1.getBlue() - c2.getBlue();
+        return r * r + g * g + b * b;
     }
 
     @NotNull
@@ -96,6 +93,15 @@ public final class MapPalette {
         c(14, 127, 93), c(17, 155, 114), c(20, 180, 133), c(10, 95, 70)
     };
 
+    @NotNull
+    static final int[] rgbColors = new int[colors.length];
+
+    static {
+        for (int i = 0; i < colors.length; i++)
+            rgbColors[i] = colors[i].getRGB();
+        Arrays.sort(rgbColors);
+    }
+
     // Interface
     /**
      * @deprecated Magic value
@@ -235,19 +241,29 @@ public final class MapPalette {
     public static byte matchColor(@NotNull Color color) {
         if (color.getAlpha() < 128) return 0;
 
-        int index = 0;
-        double best = -1;
+        short index = 0;
+        short binaryIndex = (short) Arrays.binarySearch(rgbColors, color.getRGB());
+        if (binaryIndex != -1)
+            return (byte) (binaryIndex < 128 ? binaryIndex : binaryIndex - 256);
+        int best = -1;
 
-        for (int i = 4; i < colors.length; i++) {
-            double distance = getDistance(color, colors[i]);
-            if (distance < best || best == -1) {
+        int distance;
+        for (short i = 4; i < MapPalette.colors.length; i++) {
+            if (i == 4) {
+                if ((best = distance = getDistance(color, MapPalette.colors[i])) == 0)
+                    return (byte) (i < 128 ? i : i - 256);
+                best = distance;
+                index = i;
+            } else if ((distance = getDistance(color, MapPalette.colors[i])) < best) {
+                if (distance == 0)
+                    return (byte) (i < 128 ? i : i - 256);
                 best = distance;
                 index = i;
             }
         }
 
         // Minecraft has 143 colors, some of which have negative byte representations
-        return (byte) (index < 128 ? index : -129 + (index - 127));
+        return (byte) (index < 128 ? index : index - 256);
     }
 
     /**