From 154c853bbd14bca73d474ff3aba6857590004c14 Mon Sep 17 00:00:00 2001
From: Sollace <sollacea@gmail.com>
Date: Wed, 17 Feb 2021 17:05:20 +0200
Subject: [PATCH] Added an enchantment that alters the wearer's gravity

---
 .../minelittlepony/unicopia/entity/Creature.java  |  2 ++
 .../unicopia/entity/EntityPhysics.java            | 13 +++++++++++++
 .../unicopia/item/enchantment/UEnchantments.java  | 15 +++++++++++++++
 3 files changed, 30 insertions(+)

diff --git a/src/main/java/com/minelittlepony/unicopia/entity/Creature.java b/src/main/java/com/minelittlepony/unicopia/entity/Creature.java
index 14d8f601..f02aee7c 100644
--- a/src/main/java/com/minelittlepony/unicopia/entity/Creature.java
+++ b/src/main/java/com/minelittlepony/unicopia/entity/Creature.java
@@ -8,6 +8,7 @@ import com.minelittlepony.unicopia.ability.magic.Spell;
 import com.minelittlepony.unicopia.ability.magic.spell.SpellRegistry;
 import com.minelittlepony.unicopia.entity.ai.WantItNeedItTargetGoal;
 import com.minelittlepony.unicopia.entity.ai.WantItTakeItGoal;
+import com.minelittlepony.unicopia.entity.player.PlayerAttributes;
 
 import net.minecraft.entity.LivingEntity;
 import net.minecraft.entity.ai.goal.GoalSelector;
@@ -41,6 +42,7 @@ public class Creature extends Living<LivingEntity> {
     public static void registerAttributes(DefaultAttributeContainer.Builder builder) {
         builder.add(EntityAttributes.GENERIC_ATTACK_DAMAGE);
         builder.add(EntityAttributes.GENERIC_ATTACK_KNOCKBACK);
+        builder.add(PlayerAttributes.ENTITY_GRAVTY_MODIFIER);
     }
 
     @Override
diff --git a/src/main/java/com/minelittlepony/unicopia/entity/EntityPhysics.java b/src/main/java/com/minelittlepony/unicopia/entity/EntityPhysics.java
index 1607600f..bbc29424 100644
--- a/src/main/java/com/minelittlepony/unicopia/entity/EntityPhysics.java
+++ b/src/main/java/com/minelittlepony/unicopia/entity/EntityPhysics.java
@@ -1,6 +1,7 @@
 package com.minelittlepony.unicopia.entity;
 
 import com.minelittlepony.unicopia.Owned;
+import com.minelittlepony.unicopia.entity.player.PlayerAttributes;
 import com.minelittlepony.unicopia.util.Copieable;
 
 import net.minecraft.block.Block;
@@ -8,6 +9,7 @@ import net.minecraft.block.BlockRenderType;
 import net.minecraft.block.BlockState;
 import net.minecraft.block.FenceGateBlock;
 import net.minecraft.entity.Entity;
+import net.minecraft.entity.LivingEntity;
 import net.minecraft.nbt.CompoundTag;
 import net.minecraft.particle.BlockStateParticleEffect;
 import net.minecraft.particle.ParticleTypes;
@@ -89,6 +91,17 @@ public class EntityPhysics<T extends Owned<? extends Entity>> implements Physics
 
     @Override
     public float getGravityModifier() {
+        Entity master = pony.getMaster();
+
+        if (master instanceof LivingEntity) {
+            if (((LivingEntity)master).getAttributes() == null) {
+                // may be null due to order of execution in the constructor.
+                // Will have the default (1) here in any case, so it's safe to ignore the attribute at this point.
+                return gravity;
+            }
+            return gravity * (float)((LivingEntity)master).getAttributeValue(PlayerAttributes.ENTITY_GRAVTY_MODIFIER);
+        }
+
         return gravity;
     }
 
diff --git a/src/main/java/com/minelittlepony/unicopia/item/enchantment/UEnchantments.java b/src/main/java/com/minelittlepony/unicopia/item/enchantment/UEnchantments.java
index 14eb4910..60db4c5f 100644
--- a/src/main/java/com/minelittlepony/unicopia/item/enchantment/UEnchantments.java
+++ b/src/main/java/com/minelittlepony/unicopia/item/enchantment/UEnchantments.java
@@ -4,6 +4,8 @@ import java.util.ArrayList;
 import java.util.List;
 import java.util.UUID;
 
+import com.minelittlepony.unicopia.entity.player.PlayerAttributes;
+
 import net.minecraft.enchantment.Enchantment;
 import net.minecraft.enchantment.Enchantment.Rarity;
 import net.minecraft.entity.EquipmentSlot;
@@ -43,6 +45,14 @@ public interface UEnchantments {
      */
     Enchantment COLLABORATOR = register("collaborator", new CollaboratorEnchantment());
 
+    /**
+     * Alters gravity
+     */
+    Enchantment REPULSION = register("repulsion", new AttributedEnchantment(Rarity.VERY_RARE, false, 3, EquipmentSlot.FEET))
+            .addModifier(PlayerAttributes.ENTITY_GRAVTY_MODIFIER, (user, level) -> {
+                return new EntityAttributeModifier(UUID.fromString("1734bbd6-1916-4124-b710-5450ea70fbdb"), "Anti Grav", (0.5F - (0.375 * (level - 1))) - 1, Operation.MULTIPLY_TOTAL);
+            });
+
     /**
      * I want it, I neeeed it!
      *
@@ -62,6 +72,11 @@ public interface UEnchantments {
      */
     Enchantment STRESS = register("stress", new StressfulEnchantment());
 
+    /**
+     * This item just wants to be held.
+     */
+    Enchantment CLINGY = register("clingy", new SimpleEnchantment(Rarity.VERY_RARE, true, 1, EquipmentSlot.values()));
+
     static void bootstrap() { }
 
     static <T extends SimpleEnchantment> T register(String name, T enchantment) {