fix health scaling

src/mixins/java/org/spongepowered/common/mixin/core/server/level/ServerPlayerMixin_HealthScale.java

@@ -43,7 +43,6 @@
 import org.spongepowered.common.bridge.data.SpongeDataHolderBridge;
 import org.spongepowered.common.bridge.server.level.ServerPlayerEntityHealthScaleBridge;
 import org.spongepowered.common.mixin.core.world.entity.player.PlayerMixin;
-import org.spongepowered.common.util.Constants;
 
 import java.util.Collection;
 import java.util.Iterator;
@@ -58,8 +57,7 @@ public abstract class ServerPlayerMixin_HealthScale extends PlayerMixin implemen
     @Shadow public ServerGamePacketListenerImpl connection;
     // @formatter:on
 
-    private double impl$healthScale = Constants.Entity.Player.DEFAULT_HEALTH_SCALE;
-    private float impl$cachedModifiedHealth = -1;
+    private Double impl$healthScale = null;
 
     @Inject(method = "doTick", at = @At(value = "INVOKE", target = "Lnet/minecraft/server/level/ServerPlayer;getArmorValue()I", ordinal = 1))
     private void updateHealthPriorToArmor(final CallbackInfo ci) {
@@ -78,7 +76,6 @@ private void updateHealthPriorToArmor(final CallbackInfo ci) {
         }
 
         this.impl$healthScale = scale;
-        this.impl$cachedModifiedHealth = -1;
         this.lastSentHealth = -1.0F;
 
         ((SpongeDataHolderBridge) this).bridge$offer(Keys.HEALTH_SCALE, scale);
@@ -89,8 +86,7 @@ private void updateHealthPriorToArmor(final CallbackInfo ci) {
 
     @Override
     public void bridge$resetHealthScale() {
-        this.impl$healthScale = Constants.Entity.Player.DEFAULT_HEALTH_SCALE;
-        this.impl$cachedModifiedHealth = -1;
+        this.impl$healthScale = null;
         this.lastSentHealth = -1.0F;
 
         ((SpongeDataHolderBridge) this).bridge$remove(Keys.HEALTH_SCALE);
@@ -110,6 +106,7 @@ private void updateHealthPriorToArmor(final CallbackInfo ci) {
         final FoodData foodData = this.shadow$getFoodData();
         this.connection.send(new ClientboundSetHealthPacket(this.bridge$getInternalScaledHealth(), foodData.getFoodLevel(), foodData.getSaturationLevel()));
         this.connection.send(new ClientboundUpdateAttributesPacket(this.shadow$getId(), dirtyInstances));
+
         // Reset the dirty instances since they've now been manually updated on the client.
         dirtyInstances.clear();
 
@@ -130,6 +127,7 @@ private void updateHealthPriorToArmor(final CallbackInfo ci) {
                 break;
             }
         }
+
         if (!foundMax) {
             // Means we didn't find the max health attribute and need to fetch the modifiers from
             // the cached map because it wasn't marked dirty for some reason
@@ -144,6 +142,7 @@ private void updateHealthPriorToArmor(final CallbackInfo ci) {
         if (!modifiers.isEmpty()) {
             modifiers.forEach(attribute::addTransientModifier);
         }
+
         set.add(attribute);
     }
 
@@ -154,36 +153,28 @@ private void updateHealthPriorToArmor(final CallbackInfo ci) {
 
     @Override
     public float bridge$getInternalScaledHealth() {
-        if (!this.bridge$isHealthScaled()) {
-            return this.shadow$getHealth();
-        }
-        if (this.impl$cachedModifiedHealth == -1) {
-            // Because attribute modifiers from mods can add onto health and multiply health, we
-            // need to replicate what the mod may be trying to represent, regardless whether the health scale
-            // says to show only x hearts.
-            final AttributeInstance maxAttribute = this.shadow$getAttribute(Attributes.MAX_HEALTH);
-            double modifiedScale = this.impl$healthScale;
-            // Apply additive modifiers
-            for (final AttributeModifier modifier : maxAttribute.getModifiers(AttributeModifier.Operation.ADDITION)) {
-                modifiedScale += modifier.getAmount();
-            }
+        float maximumHealth = this.shadow$getMaxHealth();
+        float healthScale = maximumHealth;
 
-            for (final AttributeModifier modifier : maxAttribute.getModifiers(AttributeModifier.Operation.MULTIPLY_BASE)) {
-                modifiedScale += modifiedScale * modifier.getAmount();
-            }
+        if (this.bridge$isHealthScaled()) {
+            // Attribute modifiers from mods can add onto health and multiply health, we need to replicate
+            // what the mod may be trying to represent, regardless whether the health scale says to show
+            // only x hearts.
+            final Collection<AttributeModifier> modifiers = this.shadow$getAttribute(Attributes.MAX_HEALTH).getModifiers();
+            final AttributeInstance attribute = new AttributeInstance(Attributes.MAX_HEALTH, i -> {});
 
-            for (final AttributeModifier modifier : maxAttribute.getModifiers(AttributeModifier.Operation.MULTIPLY_TOTAL)) {
-                modifiedScale *= 1.0D + modifier.getAmount();
-            }
+            attribute.setBaseValue(this.impl$healthScale);
+            modifiers.forEach(attribute::addTransientModifier);
 
-            this.impl$cachedModifiedHealth = (float) modifiedScale;
+            healthScale = (float) attribute.getValue();
         }
-        return (this.shadow$getHealth() / this.shadow$getMaxHealth()) * this.impl$cachedModifiedHealth;
+
+        return (this.shadow$getHealth() / maximumHealth) * healthScale;
     }
 
     @Override
     public boolean bridge$isHealthScaled() {
-        return this.impl$healthScale != Constants.Entity.Player.DEFAULT_HEALTH_SCALE;
+        return this.impl$healthScale != null;
     }
 
 }