Ground pound now prevents fall damage. Fixes #351

src/main/java/com/minelittlepony/unicopia/ability/EarthPonyStompAbility.java

@@ -20,6 +20,7 @@ import com.minelittlepony.unicopia.server.world.BlockDestructionManager;
 import com.minelittlepony.unicopia.util.PosHelper;
 import com.minelittlepony.unicopia.util.VecHelper;
 
+import it.unimi.dsi.fastutil.floats.Float2FloatFunction;
 import net.minecraft.block.Block;
 import net.minecraft.block.BlockState;
 import net.minecraft.enchantment.EnchantmentHelper;
@@ -106,7 +107,8 @@ public class EarthPonyStompAbility implements Ability<Hit> {
     public boolean apply(Pony iplayer, Hit data) {
         PlayerEntity player = iplayer.asEntity();
 
-        Runnable r = () -> {
+        Float2FloatFunction r = fallDistance -> {
+            player.fallDistance = 0;
             BlockPos center = PosHelper.findSolidGroundAt(player.getEntityWorld(), player.getBlockPos(), iplayer.getPhysics().getGravitySignum());
 
             float heavyness = 1 + EnchantmentHelper.getEquipmentLevel(UEnchantments.HEAVY, player);
@@ -163,13 +165,14 @@ public class EarthPonyStompAbility implements Ability<Hit> {
 
             iplayer.subtractEnergyCost(rad);
             iplayer.asEntity().addExhaustion(3);
+            return 0F;
         };
 
         if (iplayer.asEntity().isOnGround()) {
             iplayer.setAnimation(Animation.STOMP, Animation.Recipient.ANYONE, 10);
             iplayer.asEntity().jump();
             iplayer.updateVelocity();
-            AwaitTickQueue.scheduleTask(iplayer.asWorld(), w -> r.run(), 5);
+            AwaitTickQueue.scheduleTask(iplayer.asWorld(), w -> r.get(0F), 5);
         } else {
             thrustDownwards(iplayer);
             iplayer.waitForFall(r);

src/main/java/com/minelittlepony/unicopia/entity/Living.java

@@ -1,6 +1,7 @@
 package com.minelittlepony.unicopia.entity;
 
 import java.util.*;
+import java.util.concurrent.atomic.AtomicReference;
 import java.util.stream.Stream;
 import java.util.stream.StreamSupport;
 
@@ -38,6 +39,7 @@ import com.minelittlepony.unicopia.projectile.ProjectileImpactListener;
 import com.minelittlepony.unicopia.server.world.DragonBreathStore;
 import com.minelittlepony.unicopia.util.*;
 
+import it.unimi.dsi.fastutil.floats.Float2FloatFunction;
 import it.unimi.dsi.fastutil.floats.Float2ObjectFunction;
 import net.fabricmc.fabric.api.util.TriState;
 import net.minecraft.block.BlockState;
@@ -83,7 +85,8 @@ public abstract class Living<T extends LivingEntity> implements Equine<T>, Caste
     private final Interactable jumpingHeuristic;
 
     @Nullable
-    private Runnable landEvent;
+    private final AtomicReference<Float2FloatFunction> landEvent = new AtomicReference<>();
+    private float prevFallDistance;
 
     private boolean invisible = false;
 
@@ -131,11 +134,11 @@ public abstract class Living<T extends LivingEntity> implements Equine<T>, Caste
         this.invisible = invisible;
     }
 
-    public void waitForFall(Runnable action) {
+    public void waitForFall(Float2FloatFunction action) {
         if (entity.isOnGround()) {
-            action.run();
+            action.get(0F);
         } else {
-            landEvent = action;
+            landEvent.set(action);
         }
     }
 
@@ -206,6 +209,7 @@ public abstract class Living<T extends LivingEntity> implements Equine<T>, Caste
 
     @Override
     public boolean beforeUpdate() {
+        prevFallDistance = entity.fallDistance;
         if (EffectUtils.getAmplifier(entity, UEffects.PARALYSIS) > 1 && entity.getVelocity().horizontalLengthSquared() > 0) {
             entity.setVelocity(entity.getVelocity().multiply(0, 1, 0));
             updateVelocity();
@@ -236,9 +240,8 @@ public abstract class Living<T extends LivingEntity> implements Equine<T>, Caste
             invinsibilityTicks--;
         }
 
-        if (landEvent != null && entity.isOnGround() && landedChanged()) {
+        if (entity.isOnGround() && landedChanged()) {
-            landEvent.run();
+            onLanded(prevFallDistance);
-            landEvent = null;
         }
 
         if (entity.hasStatusEffect(UEffects.PARALYSIS) && entity.getVelocity().horizontalLengthSquared() > 0) {
@@ -261,6 +264,11 @@ public abstract class Living<T extends LivingEntity> implements Equine<T>, Caste
         transportation.tick();
     }
 
+    private float onLanded(float fallDistance) {
+        var event = landEvent.getAndSet(null);
+        return event == null ? fallDistance : event.get(fallDistance);
+    }
+
     public void updateAttributeModifier(UUID id, EntityAttribute attribute, float desiredValue, Float2ObjectFunction<EntityAttributeModifier> modifierSupplier, boolean permanent) {
         @Nullable
         EntityAttributeInstance instance = asEntity().getAttributeInstance(attribute);
@@ -465,10 +473,17 @@ public abstract class Living<T extends LivingEntity> implements Equine<T>, Caste
                 .isPresent();
     }
 
-    protected void handleFall(float distance, float damageMultiplier, DamageSource cause) {
+    public float onImpact(float distance, float damageMultiplier, DamageSource cause) {
+        float fallDistance = onLanded(getEffectiveFallDistance(distance));
+
         getSpellSlot().get(SpellPredicate.IS_DISGUISE, false).ifPresent(spell -> {
-            spell.getDisguise().onImpact(this, distance, damageMultiplier, cause);
+            spell.getDisguise().onImpact(this, fallDistance, damageMultiplier, cause);
         });
+        return fallDistance;
+    }
+
+    protected float getEffectiveFallDistance(float distance) {
+        return distance;
     }
 
     @Override

src/main/java/com/minelittlepony/unicopia/entity/player/Pony.java

@@ -723,9 +723,22 @@ public class Pony extends Living<PlayerEntity> implements Copyable<Pony>, Update
         });
     }
 
-    public Optional<Float> onImpact(float distance, float damageMultiplier, DamageSource cause) {
+    @Override
-        float originalDistance = distance;
+    public float onImpact(float distance, float damageMultiplier, DamageSource cause) {
+        distance = super.onImpact(distance, damageMultiplier, cause);
 
+        if (getCompositeRace().canUseEarth() && entity.isSneaking()) {
+            double radius = distance / 10;
+            if (radius > 0) {
+                EarthPonyStompAbility.spawnEffectAround(entity, entity.getSteppingPos(), radius, radius);
+            }
+        }
+
+        return distance;
+    }
+
+    @Override
+    protected float getEffectiveFallDistance(float distance) {
         boolean extraProtection = getSpellSlot().get(SpellType.SHIELD, false).isPresent();
 
         if (!entity.isCreative() && !entity.isSpectator()) {
@@ -740,14 +753,9 @@ public class Pony extends Living<PlayerEntity> implements Copyable<Pony>, Update
             if (getCompositeRace().canFly() || (getCompositeRace().canUseEarth() && entity.isSneaking())) {
                 distance -= 5;
             }
-            distance = Math.max(0, distance);
         }
 
-        handleFall(distance, damageMultiplier, cause);
+        return Math.max(0, distance);
-        if (distance != originalDistance) {
-            return Optional.of(distance);
-        }
-        return Optional.empty();
     }
 
     public void onEat(ItemStack stack) {
@@ -762,19 +770,6 @@ public class Pony extends Living<PlayerEntity> implements Copyable<Pony>, Update
         }
     }
 
-    @SuppressWarnings("deprecation")
-    @Override
-    protected void handleFall(float distance, float damageMultiplier, DamageSource cause) {
-        super.handleFall(distance, damageMultiplier, cause);
-
-        if (getCompositeRace().canUseEarth() && entity.isSneaking()) {
-            double radius = distance / 10;
-            if (radius > 0) {
-                EarthPonyStompAbility.spawnEffectAround(entity, entity.getLandingPos(), radius, radius);
-            }
-        }
-    }
-
     public void onKill(Entity killedEntity, DamageSource damage) {
         if (killedEntity != null && killedEntity.getType() == EntityType.PHANTOM && getPhysics().isFlying()) {
             UCriteria.KILL_PHANTOM_WHILE_FLYING.trigger(entity);

src/main/java/com/minelittlepony/unicopia/mixin/MixinLivingEntity.java

@@ -6,6 +6,7 @@ import org.spongepowered.asm.mixin.*;
 import org.spongepowered.asm.mixin.gen.Accessor;
 import org.spongepowered.asm.mixin.injection.At;
 import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.ModifyVariable;
 import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
 import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;
 
@@ -151,6 +152,11 @@ abstract class MixinLivingEntity extends Entity implements LivingEntityDuck, Equ
         get().onDamage(source, amount).ifPresent(info::setReturnValue);
     }
 
+    @ModifyVariable(method = "handleFallDamage(FFLnet/minecraft/entity/damage/DamageSource;)Z", at = @At("HEAD"), ordinal = 0, argsOnly = true)
+    private float onHandleFallDamage(float distance, float distanceAgain, float damageMultiplier, DamageSource cause) {
+        return get().onImpact(distance, damageMultiplier, cause);
+    }
+
     @Inject(method = "hurtByWater()Z", at = @At("HEAD"), cancellable = true)
     private void onCanBeHurtByWater(CallbackInfoReturnable<Boolean> info) {
         TriState hurtByWater = get().canBeHurtByWater();

src/main/java/com/minelittlepony/unicopia/mixin/MixinPlayerEntity.java

@@ -26,7 +26,6 @@ import net.minecraft.entity.damage.DamageSource;
 import net.minecraft.entity.player.PlayerEntity;
 import net.minecraft.item.ItemStack;
 import net.minecraft.server.network.ServerPlayerEntity;
-import net.minecraft.stat.Stats;
 import net.minecraft.util.Unit;
 import net.minecraft.util.math.BlockPos;
 import net.minecraft.world.World;
@@ -48,24 +47,11 @@ abstract class MixinPlayerEntity extends LivingEntity implements Equine.Containe
         Pony.registerAttributes(info.getReturnValue());
     }
 
-    @ModifyVariable(method = "applyDamage(Lnet/minecraft/entity/damage/DamageSource;F)V", at = @At("HEAD"), ordinal = 0)
+    @ModifyVariable(method = "applyDamage(Lnet/minecraft/entity/damage/DamageSource;F)V", at = @At("HEAD"), ordinal = 0, argsOnly = true)
     protected float modifyDamageAmount(float amount, DamageSource source) {
         return get().modifyDamage(source, amount).orElse(amount);
     }
 
-    @Inject(method = "handleFallDamage(FFLnet/minecraft/entity/damage/DamageSource;)Z", at = @At("HEAD"), cancellable = true)
-    private void onHandleFallDamage(float distance, float damageMultiplier, DamageSource cause, CallbackInfoReturnable<Boolean> info) {
-        get().onImpact(fallDistance, damageMultiplier, cause).ifPresent(newDistance -> {
-            PlayerEntity self = (PlayerEntity)(Object)this;
-
-            if (distance >= 2) {
-                self.increaseStat(Stats.FALL_ONE_CM, Math.round(distance * 100));
-            }
-
-            info.setReturnValue(super.handleFallDamage(newDistance, damageMultiplier, cause));
-        });
-    }
-
     @Inject(method = "eatFood(Lnet/minecraft/world/World;Lnet/minecraft/item/ItemStack;)Lnet/minecraft/item/ItemStack;", at = @At("HEAD"))
     private void onEatFood(World world, ItemStack stack, CallbackInfoReturnable<ItemStack> info) {
         get().onEat(stack);