From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: epserv <admin@epserv.ru>
Date: Mon, 21 Dec 2020 23:12:15 +0500
Subject: [PATCH] Optimise 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..04e1a902a0db732ba69ad60b03a34de69f425071 100644
--- a/src/main/java/org/bukkit/map/MapPalette.java
+++ b/src/main/java/org/bukkit/map/MapPalette.java
@@ -23,6 +23,8 @@ public final class MapPalette {
     }
 
     private static double getDistance(@NotNull Color c1, @NotNull Color c2) {
+        // Yatopia start - faster method
+        /*
         double rmean = (c1.getRed() + c2.getRed()) / 2.0;
         double r = c1.getRed() - c2.getRed();
         double g = c1.getGreen() - c2.getGreen();
@@ -31,6 +33,19 @@ public final class MapPalette {
         double weightG = 4.0;
         double weightB = 2 + (255 - rmean) / 256.0;
         return weightR * r * r + weightG * g * g + weightB * b * b;
+        */
+        if (c1.getRGB() == c2.getRGB()) { // check if colors are same
+            return 0;
+        }
+        // sqrt( (r2-r1)^2 + (g2-g1)^2 + (b2-b1)^2 )
+        double rdiff = c2.getRed() - c1.getRed(),
+            gdiff = c2.getGreen() - c1.getGreen(),
+            bdiff = c2.getBlue() - c1.getBlue();
+        double rsq = rdiff * rdiff,
+            gsq = gdiff * gdiff,
+            bsq = bdiff * bdiff;
+        return Math.sqrt(rsq + gsq + bsq);
+        // Yatopia end
     }
 
     @NotNull
@@ -95,6 +110,51 @@ public final class MapPalette {
         c(60, 31, 43), c(74, 37, 53), c(86, 44, 62), c(45, 23, 32),
         c(14, 127, 93), c(17, 155, 114), c(20, 180, 133), c(10, 95, 70)
     };
+    // Yatopia start
+    @NotNull
+    private static final int[] modifiers = {180, 220, 255, 135}; // vanilla color modifiers
+    @NotNull
+    static Color[] vanillaColors; // vanilla colors
+    @NotNull
+    static Color[][] doubleColors; // two-dimensional array where doubleColors[index] is an array of possible modifications of vanillaColors[index]
+    @NotNull
+    static int[] rgbColors; // an array of rgb values of each color
+
+    static {
+        // getting an array of rgb values of each color
+        rgbColors = java.util.Arrays.stream(colors).mapToInt(Color::getRGB).toArray();
+
+        try {
+            Class<?> materialMapColorClass = MapPalette.class.getClassLoader().loadClass("net.minecraft.server.MaterialMapColor");
+            Object[] vanillaColorObjects = (Object[]) java.util.Arrays.stream(materialMapColorClass.getFields()).filter(f -> f.getType().isArray() && f.getType().getComponentType().equals(materialMapColorClass)).findAny().get().get(null);
+            // get MaterialMapColor.rgb instance field
+            java.lang.reflect.Field rgbField = materialMapColorClass.getDeclaredField("rgb");
+            rgbField.setAccessible(true);
+            // get vanilla colors array as java.awt.Color instances array
+            vanillaColors = java.util.Arrays.stream(vanillaColorObjects).filter(java.util.Objects::nonNull).mapToInt(objColor -> {
+                try {
+                    return rgbField.getInt(materialMapColorClass.cast(objColor));
+                } catch (Exception ex) {
+                    throw new RuntimeException(ex);
+                }
+            }).mapToObj(Color::new).toArray(Color[]::new);
+            // get two-dimensional array where doubleColors[index] is an array of possible modifications of vanillaColors[index]
+            doubleColors = new Color[vanillaColors.length][modifiers.length];
+            for (int i = 0; i < vanillaColors.length; i++) {
+                Color vanillaColor = vanillaColors[i];
+                for (int j = 0; j < modifiers.length; j++) {
+                    int modifier = modifiers[j];
+                    int mr = (vanillaColor.getRed() * modifier) / 255;
+                    int mg = (vanillaColor.getGreen() * modifier) / 255;
+                    int mb = (vanillaColor.getBlue() * modifier) / 255;
+                    doubleColors[i][j] = c(mr, mg, mb);
+                }
+            }
+        } catch (Exception ex) {
+            throw new RuntimeException(ex);
+        }
+    }
+    // Yatopia end
 
     // Interface
     /**
@@ -238,6 +298,8 @@ public final class MapPalette {
         int index = 0;
         double best = -1;
 
+        // Yatopia start - foreach a maximum of 62 colors instead of 236 per pixel
+        /*
         for (int i = 4; i < colors.length; i++) {
             double distance = getDistance(color, colors[i]);
             if (distance < best || best == -1) {
@@ -245,9 +307,43 @@ public final class MapPalette {
                 index = i;
             }
         }
+         */
+        for (int i = 0; i < vanillaColors.length; i++) {
+            double distance = getDistance(color, vanillaColors[i]);
+            if (distance == 0) {
+                index = i;
+                best = 0;
+                break;
+            }
+            if (distance < best || best == -1) {
+                best = distance;
+                index = i;
+            }
+        }
+
+        if (best == 0) {
+            index = com.google.common.primitives.Ints.indexOf(rgbColors, vanillaColors[index].getRGB());
+            return (byte) (index < 128 ? index : index - 256);
+        }
+
+        Color[] modColors = doubleColors[index];
+        best = -1;
+        for (int i = 0; i < modColors.length; i++) {
+            double distance = getDistance(color, modColors[i]);
+            if (distance == 0) {
+                index = i;
+                break;
+            }
+            if (distance < best || best == -1) {
+                best = distance;
+                index = i;
+            }
+        }
+        index = com.google.common.primitives.Ints.indexOf(rgbColors, modColors[index].getRGB());
+        // Yatopia end
 
         // 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); // Yatopia
     }
 
     /**
@@ -260,7 +356,7 @@ public final class MapPalette {
     @Deprecated
     @NotNull
     public static Color getColor(byte index) {
-        if ((index > -21 && index < 0) || index > 127) {
+        if (index > -21 && index < 0) { // Yatopia
             throw new IndexOutOfBoundsException();
         } else {
             // Minecraft has 143 colors, some of which have negative byte representations