Cache density results per block pos and bounding box combination to reduce explosion lags

Author: quentin452

src/main/java/fr/iamacat/optimizationsandtweaks/asm/Mixin.java

@@ -15,6 +15,7 @@ public enum Mixin implements IMixin {
 
     common_core_MixinWorld(Side.COMMON, m -> OptimizationsandTweaksConfig.enableMixinWorld, "core.MixinWorld"),
     common_core_MixinEventBus(Side.COMMON, m -> OptimizationsandTweaksConfig.enableMixinEventBus, "core.MixinEventBus"),
+    common_core_MixinExplosion(Side.COMMON, m -> OptimizationsandTweaksConfig.enableMixinExplosion, "core.MixinExplosion"),
     common_core_MixinEnchantmentHelper(Side.COMMON, m -> OptimizationsandTweaksConfig.enableMixinEnchantmentHelper,
         "core.MixinEnchantmentHelper"),
     common_packagedauto_MixinNeiHandlerPackagedAuto(Side.COMMON,

src/main/java/fr/iamacat/optimizationsandtweaks/config/OptimizationsandTweaksConfig.java

@@ -112,6 +112,11 @@ public class OptimizationsandTweaksConfig {
     @Config.RequiresWorldRestart
     public static boolean enableMixinEventBus;
 
+    @Config.Comment("Optimize Explosion Class")
+    @Config.DefaultBoolean(true)
+    @Config.RequiresWorldRestart
+    public static boolean enableMixinExplosion;
+
     @Config.Comment("Optimize EnchantmentHelper Class")
     @Config.DefaultBoolean(true)
     @Config.RequiresWorldRestart

src/main/java/fr/iamacat/optimizationsandtweaks/mixins/common/core/MixinExplosion.java

@@ -0,0 +1,65 @@
+package fr.iamacat.optimizationsandtweaks.mixins.common.core;
+
+import net.minecraft.world.Explosion;
+import net.minecraft.world.World;
+import net.minecraft.entity.Entity;
+import net.minecraft.util.AxisAlignedBB;
+import net.minecraft.util.Vec3;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Redirect;
+import org.spongepowered.asm.mixin.Unique;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+@Mixin(Explosion.class)
+public abstract class MixinExplosion {
+
+    @Shadow public double explosionX;
+    @Shadow public double explosionY;
+    @Shadow public double explosionZ;
+    @Shadow public float explosionSize;
+
+    @Unique private final Map<Integer, Float> blockDensityCache = new HashMap<>();
+
+    @Unique private int densityCallCount = 0;
+
+    @Redirect(
+        method = "doExplosionA",
+        at = @At(
+            value = "INVOKE",
+            target = "Lnet/minecraft/world/World;getBlockDensity(Lnet/minecraft/util/Vec3;Lnet/minecraft/util/AxisAlignedBB;)F"
+        )
+    )
+    private float optimizeBlockDensity(World world, Vec3 vec3, AxisAlignedBB aabb) {
+        densityCallCount++;
+
+        int hash = (int)(aabb.minX * 73856093) ^ (int)(aabb.minY * 19349663) ^ (int)(aabb.minZ * 83492791);
+
+        Float cached = blockDensityCache.get(hash);
+        if (cached != null) {
+            return cached;
+        }
+
+        float density = world.getBlockDensity(vec3, aabb);
+        blockDensityCache.put(hash, density);
+        return density;
+    }
+
+    @Redirect(
+        method = "doExplosionA",
+        at = @At(
+            value = "INVOKE",
+            target = "Lnet/minecraft/world/World;getEntitiesWithinAABBExcludingEntity(Lnet/minecraft/entity/Entity;Lnet/minecraft/util/AxisAlignedBB;)Ljava/util/List;",
+            ordinal = 0
+        )
+    )
+    private List resetDensityCache(World world, Entity entity, AxisAlignedBB aabb) {
+        blockDensityCache.clear();
+        densityCallCount = 0;
+        return world.getEntitiesWithinAABBExcludingEntity(entity, aabb);
+    }
+}