1 files changed, 63 insertions, 0 deletions
diff --git a/patches/server/0451-Significantly-improve-performance-of-the-end-generat.patch b/patches/server/0451-Significantly-improve-performance-of-the-end-generat.patch
new file mode 100644
index 0000000000..ed3ee50bc9
--- /dev/null
+++ b/patches/server/0451-Significantly-improve-performance-of-the-end-generat.patch
@@ -0,0 +1,63 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: SuperCoder7979 <[email protected]>
+Date: Tue, 3 Nov 2020 23:48:05 -0600
+Subject: [PATCH] Significantly improve performance of the end generation
+
+This patch implements a noise cache for the end which significantly reduces the computation time of generation. This results in about a 3x improvement.
+
+Original code by SuperCoder7979 and Gegy in Lithium, licensed under LGPL-3.0 (Source: https://github.com/jellysquid3/lithium-fabric)
+
+Co-authored-by: Gegy <[email protected]>
+Co-authored-by: Dylan Xaldin <[email protected]>
+Co-authored-by: pop4959 <[email protected]>
+
+diff --git a/src/main/java/net/minecraft/world/level/levelgen/DensityFunctions.java b/src/main/java/net/minecraft/world/level/levelgen/DensityFunctions.java
+index b09bc1dac649ce9f4826edc1923c843804226993..ac8447e20531ad59d5e26c6db541d6e844d56c0f 100644
+--- a/src/main/java/net/minecraft/world/level/levelgen/DensityFunctions.java
++++ b/src/main/java/net/minecraft/world/level/levelgen/DensityFunctions.java
+@@ -509,6 +509,16 @@ public final class DensityFunctions {
+         );
+         private static final float ISLAND_THRESHOLD = -0.9F;
+         private final SimplexNoise islandNoise;
++        // Paper start - Perf: Optimize end generation
++        private static final class NoiseCache {
++            public long[] keys = new long[8192];
++            public float[] values = new float[8192];
++            public NoiseCache() {
++                java.util.Arrays.fill(keys, Long.MIN_VALUE);
++            }
++        }
++        private static final ThreadLocal<java.util.Map<SimplexNoise, NoiseCache>> noiseCache = ThreadLocal.withInitial(java.util.WeakHashMap::new);
++        // Paper end - Perf: Optimize end generation
+ 
+         public EndIslandDensityFunction(long seed) {
+             RandomSource randomSource = new LegacyRandomSource(seed);
+@@ -524,12 +534,26 @@ public final class DensityFunctions {
+             float f = 100.0F - Mth.sqrt((long) x * (long) x + (long) z * (long) z) * 8.0F; // Paper - cast ints to long to avoid integer overflow
+             f = Mth.clamp(f, -100.0F, 80.0F);
+ 
++            NoiseCache cache = noiseCache.get().computeIfAbsent(sampler, noiseKey -> new NoiseCache()); // Paper - Perf: Optimize end generation
+             for (int m = -12; m <= 12; m++) {
+                 for (int n = -12; n <= 12; n++) {
+                     long o = (long)(i + m);
+                     long p = (long)(j + n);
+-                    if (o * o + p * p > 4096L && sampler.getValue((double)o, (double)p) < -0.9F) {
+-                        float g = (Mth.abs((float)o) * 3439.0F + Mth.abs((float)p) * 147.0F) % 13.0F + 9.0F;
++                    // Paper start - Perf: Optimize end generation by using a noise cache
++                    long key = net.minecraft.world.level.ChunkPos.asLong((int) o, (int) p);
++                    int index = (int) it.unimi.dsi.fastutil.HashCommon.mix(key) & 8191;
++                    float g = Float.MIN_VALUE;
++                    if (cache.keys[index] == key) {
++                        g = cache.values[index];
++                    } else {
++                        if (o * o + p * p > 4096L && sampler.getValue((double)o, (double)p) < -0.9F) {
++                            g = (Mth.abs((float)o) * 3439.0F + Mth.abs((float)p) * 147.0F) % 13.0F + 9.0F;
++                        }
++                        cache.keys[index] = key;
++                        cache.values[index] = g;
++                    }
++                    if (g != Float.MIN_VALUE) {
++                        // Paper end - Perf: Optimize end generation
+                         float h = (float)(k - m * 2);
+                         float q = (float)(l - n * 2);
+                         float r = 100.0F - Mth.sqrt(h * h + q * q) * g;