Minor cleanup

src/main/java/com/minelittlepony/unicopia/ability/magic/spell/PlaceableSpell.java

@@ -12,6 +12,7 @@ import com.minelittlepony.unicopia.entity.UEntities;
 import com.minelittlepony.unicopia.particle.OrientedBillboardParticleEffect;
 import com.minelittlepony.unicopia.particle.ParticleHandle;
 import com.minelittlepony.unicopia.particle.UParticles;
+import com.minelittlepony.unicopia.particle.ParticleHandle.Attachment;
 
 import net.minecraft.nbt.*;
 import net.minecraft.util.Identifier;
@@ -98,7 +99,7 @@ public class PlaceableSpell extends AbstractDelegatingSpell {
             particlEffect.update(getUuid(), source, spawner -> {
                 spawner.addParticle(new OrientedBillboardParticleEffect(UParticles.MAGIC_RUNES, 90, 0), source.getOriginVector(), Vec3d.ZERO);
             }).ifPresent(p -> {
-                p.setAttribute(1, spell.getType().getColor());
+                p.setAttribute(Attachment.ATTR_COLOR, spell.getType().getColor());
             });
 
             return super.tick(source, Situation.GROUND);
@@ -137,7 +138,7 @@ public class PlaceableSpell extends AbstractDelegatingSpell {
     @Override
     public void fromNBT(NbtCompound compound) {
         super.fromNBT(compound);
-        if (compound.contains("dimension")) {
+        if (compound.contains("dimension", NbtElement.STRING_TYPE)) {
             Identifier id = Identifier.tryParse(compound.getString("dimension"));
             if (id != null) {
                 dimension = RegistryKey.of(Registry.WORLD_KEY, id);

src/main/java/com/minelittlepony/unicopia/ability/magic/spell/Situation.java

@@ -1,8 +1,24 @@
 package com.minelittlepony.unicopia.ability.magic.spell;
 
+/**
+ * The situation of the spell being ticked.
+ */
 public enum Situation {
+    /**
+     * Ticks coming from living entities like the player and animals.
+     */
     BODY,
+    /**
+     * Ticks coming from flying projectiles.
+     */
     PROJECTILE,
+    /**
+     * Ticks coming from a PlaceableSpell that's being updated as a ground entity.
+     */
     GROUND,
+    /**
+     * Ticks coming directly from the ground SpellCastEntity.
+     * Handled only by PlaceableSpell. No other spell should receive this.
+     */
     GROUND_ENTITY
 }

src/main/java/com/minelittlepony/unicopia/ability/magic/spell/effect/DarkVortexSpell.java

@@ -9,6 +9,7 @@ import com.minelittlepony.unicopia.ability.magic.spell.ProjectileSpell;
 import com.minelittlepony.unicopia.ability.magic.spell.Situation;
 import com.minelittlepony.unicopia.ability.magic.spell.trait.SpellTraits;
 import com.minelittlepony.unicopia.ability.magic.spell.trait.Trait;
+import com.minelittlepony.unicopia.particle.ParticleHandle.Attachment;
 import com.minelittlepony.unicopia.particle.ParticleUtils;
 import com.minelittlepony.unicopia.particle.SphereParticleEffect;
 import com.minelittlepony.unicopia.particle.UParticles;
@@ -116,13 +117,13 @@ public class DarkVortexSpell extends AttractiveSpell implements ProjectileSpell
         particlEffect.update(getUuid(), source, spawner -> {
             spawner.addParticle(new SphereParticleEffect(UParticles.SPHERE, getType().getColor(), 0.99F, radius, SPHERE_OFFSET), source.getOriginVector(), Vec3d.ZERO);
         }).ifPresent(p -> {
-            p.setAttribute(0, radius);
+            p.setAttribute(Attachment.ATTR_RADIUS, radius);
         });
         particlEffect.update(getUuid(), "_ring", source, spawner -> {
             spawner.addParticle(new SphereParticleEffect(UParticles.DISK, 0xFFFFFFFF, 0.4F, radius + 1, SPHERE_OFFSET), getOrigin(source), Vec3d.ZERO);
         }).ifPresent(p -> {
-            p.setAttribute(0, radius * 2F);
+            p.setAttribute(Attachment.ATTR_RADIUS, radius * 2F);
-            p.setAttribute(1, 0xAAAAAA);
+            p.setAttribute(Attachment.ATTR_COLOR, 0xAAAAAA);
         });
 
         double angle = age % 260;

src/main/java/com/minelittlepony/unicopia/ability/magic/spell/effect/ShieldSpell.java

@@ -12,6 +12,7 @@ import com.minelittlepony.unicopia.particle.MagicParticleEffect;
 import com.minelittlepony.unicopia.particle.ParticleHandle;
 import com.minelittlepony.unicopia.particle.SphereParticleEffect;
 import com.minelittlepony.unicopia.particle.UParticles;
+import com.minelittlepony.unicopia.particle.ParticleHandle.Attachment;
 import com.minelittlepony.unicopia.projectile.ProjectileUtil;
 import com.minelittlepony.unicopia.util.shape.Sphere;
 
@@ -75,8 +76,8 @@ public class ShieldSpell extends AbstractSpell {
         particlEffect.update(getUuid(), source, spawner -> {
             spawner.addParticle(new SphereParticleEffect(UParticles.SPHERE, getType().getColor(), 0.3F, radius), origin, Vec3d.ZERO);
         }).ifPresent(p -> {
-            p.setAttribute(0, radius);
+            p.setAttribute(Attachment.ATTR_RADIUS, radius);
-            p.setAttribute(1, getType().getColor());
+            p.setAttribute(Attachment.ATTR_COLOR, getType().getColor());
         });
     }
 

src/main/java/com/minelittlepony/unicopia/client/particle/RunesParticle.java

@@ -71,7 +71,7 @@ public class RunesParticle extends OrientedBillboardParticle implements Attachme
 
     @Override
     public void setAttribute(int key, Object value) {
-        if (key == 1) {
+        if (key == ATTR_COLOR) {
             int tint = (int)value;
             red = Color.r(tint);
             green = Color.g(tint);

src/main/java/com/minelittlepony/unicopia/client/particle/SphereParticle.java

@@ -75,18 +75,18 @@ public class SphereParticle extends Particle implements Attachment {
 
     @Override
     public void setAttribute(int key, Object value) {
-        if (key == 0) {
+        if (key == ATTR_RADIUS) {
             toRadius = (float)value;
             steps = 20;
             lerpIncrement = (toRadius - radius) / steps;
         }
-        if (key == 1) {
+        if (key == ATTR_COLOR) {
             int tint = (int)value;
             red = Color.r(tint);
             green = Color.g(tint);
             blue = Color.b(tint);
         }
-        if (key == 2) {
+        if (key == ATTR_OPACITY) {
             alpha = (float)value;
         }
     }

src/main/java/com/minelittlepony/unicopia/particle/ParticleHandle.java

@@ -85,6 +85,10 @@ public class ParticleHandle {
     }
 
     public interface Attachment {
+        int ATTR_RADIUS = 0;
+        int ATTR_COLOR = 1;
+        int ATTR_OPACITY = 2;
+
         boolean isStillAlive();
 
         void attach(Link link);