Custom attribute level curve in MobEffect, restoring `getAttributeMod…

…ifierValue` (#1334)

This allows mob effects to provide non-linear attribute modifier values

patches/net/minecraft/world/effect/MobEffect.java.patch

@@ -9,18 +9,48 @@
      public static final Codec<Holder<MobEffect>> CODEC = BuiltInRegistries.MOB_EFFECT.holderByNameCodec();
      public static final StreamCodec<RegistryFriendlyByteBuf, Holder<MobEffect>> STREAM_CODEC = ByteBufCodecs.holderRegistry(Registries.MOB_EFFECT);
      private static final int AMBIENT_ALPHA = Mth.floor(38.25F);
-@@ -179,6 +_,14 @@
-     @Override
-     public FeatureFlagSet requiredFeatures() {
-         return this.requiredFeatures;
+@@ -130,6 +_,18 @@
+         return this;
+     }
+
++    /**
++     * Neo: attribute template with custom level curve, for mob effects providing non-linear attribute modifiers.
++     * @param attribute The attribute of the modifier
++     * @param id ID of the modifier
++     * @param operation Operation of the modifier
++     * @param curve A function mapping effect instance amplifier to modifier amount
++     */
++    public MobEffect addAttributeModifier(Holder<Attribute> attribute, ResourceLocation id, AttributeModifier.Operation operation, it.unimi.dsi.fastutil.ints.Int2DoubleFunction curve) {
++        this.attributeModifiers.put(attribute, new MobEffect.AttributeTemplate(id, curve.apply(0), operation, curve));
++        return this;
 +    }
 +
+     public MobEffect setBlendDuration(int p_316265_) {
+         this.blendDurationTicks = p_316265_;
+         return this;
+@@ -181,8 +_,24 @@
+         return this.requiredFeatures;
+     }
+
+-    static record AttributeTemplate(ResourceLocation id, double amount, AttributeModifier.Operation operation) {
 +    /**
 +     * Neo: Allowing mods to define client behavior for their MobEffects
 +     * @deprecated Use {@link net.neoforged.neoforge.client.extensions.common.RegisterClientExtensionsEvent} instead
 +     */
 +    @Deprecated(forRemoval = true, since = "1.21")
 +    public void initializeClient(java.util.function.Consumer<net.neoforged.neoforge.client.extensions.common.IClientMobEffectExtensions> consumer) {
++    }
++
++    static record AttributeTemplate(ResourceLocation id, double amount, AttributeModifier.Operation operation, @Nullable it.unimi.dsi.fastutil.ints.Int2DoubleFunction curve) {
++
++        public AttributeTemplate(ResourceLocation id, double amount, AttributeModifier.Operation operation) {
++            this(id, amount, operation, null);
++        }
++
+         public AttributeModifier create(int p_316614_) {
++            if (curve != null) { // Neo: Use the custom attribute value curve if one is present
++                return new AttributeModifier(this.id, this.curve.apply(p_316614_), this.operation);
++            }
+             return new AttributeModifier(this.id, this.amount * (double)(p_316614_ + 1), this.operation);
+         }
      }
-
-     static record AttributeTemplate(ResourceLocation id, double amount, AttributeModifier.Operation operation) {