Fixed various issues with shields

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

@@ -42,6 +42,11 @@ public class Particles<Particle> {
         return -id - 1;
     }
 
+    @Nullable
+    public void spawnParticle(int particleId, boolean ignoreDistance, Vec3d pos, Vec3d vel, int ...pars) {
+        spawnParticle(particleId, ignoreDistance, pos.x, pos.y, pos.z, vel.x, vel.y, vel.z, pars);
+    }
+
     @Nullable
     public void spawnParticle(int particleId, boolean ignoreDistance, Vec3d pos, double speedX, double speedY, double speedZ, int ...pars) {
         spawnParticle(particleId, ignoreDistance, pos.x, pos.y, pos.z, speedX, speedY, speedZ, pars);

src/main/java/com/minelittlepony/unicopia/spell/ICaster.java

@@ -46,6 +46,10 @@ public interface ICaster<E extends EntityLivingBase> extends IOwned<E>, ILevelle
         return getEntity().getPosition();
     }
 
+    default Vec3d getOriginVector() {
+        return getEntity().getPositionVector();
+    }
+
     default void spawnParticles(IShape area, int count, Consumer<Vec3d> particleSpawner) {
         Random rand = getWorld().rand;
 

src/main/java/com/minelittlepony/unicopia/spell/SpellShield.java

@@ -1,9 +1,9 @@
 package com.minelittlepony.unicopia.spell;
 
 import com.minelittlepony.unicopia.Predicates;
-import com.minelittlepony.unicopia.Race;
 import com.minelittlepony.unicopia.UParticles;
 import com.minelittlepony.unicopia.particle.Particles;
+import com.minelittlepony.unicopia.player.IPlayer;
 import com.minelittlepony.unicopia.player.PlayerSpeciesList;
 import com.minelittlepony.unicopia.power.IPower;
 import com.minelittlepony.util.ProjectileUtil;
@@ -14,7 +14,6 @@ import net.minecraft.entity.EntityLivingBase;
 import net.minecraft.entity.player.EntityPlayer;
 import net.minecraft.init.SoundEvents;
 import net.minecraft.nbt.NBTTagCompound;
-import net.minecraft.util.math.BlockPos;
 import net.minecraft.util.math.Vec3d;
 
 public class SpellShield extends AbstractSpell {
@@ -76,66 +75,87 @@ public class SpellShield extends AbstractSpell {
 		double radius = 4 + (level * 2);
 
 		Entity owner = source.getOwner();
-		BlockPos pos = source.getOrigin();
 
-		int x = pos.getX(), y = pos.getY(), z = pos.getZ();
+		boolean ownerIsValid = source.getAffinity() != SpellAffinity.BAD && Predicates.MAGI.test(owner);
 
-		boolean ownerIsValid = Predicates.MAGI.test(owner);
+		source.findAllEntitiesInRange(radius)
+	        .filter(entity -> !(ownerIsValid && entity.equals(owner)))
+	        .forEach(i -> {
+    		    double dist = Math.sqrt(i.getDistanceSq(source.getOrigin()));
 
-		source.findAllEntitiesInRange(radius).filter(entity -> !(ownerIsValid && entity.equals(owner))).forEach(i -> {
-		    double dist = i.getDistance(x, y, z);
-
-            if (ProjectileUtil.isProjectile(i)) {
-                if (!ProjectileUtil.isProjectileThrownBy(i, owner)) {
-                    if (dist < radius/2) {
-                        i.playSound(SoundEvents.ENTITY_ZOMBIE_VILLAGER_CURE, 0.1F, 1);
-                        i.setDead();
-                    } else {
-                        ricochet(i, pos);
-                    }
-                }
-            } else if (i instanceof EntityLivingBase) {
-                double force = Math.min(0.25F, dist);
-
-                if (i instanceof EntityPlayer) {
-                    force = calculateForce((EntityPlayer)i);
-                }
-
-                i.addVelocity(
-                        -(x - i.posX) / force,
-                        -(y - i.posY) / force + (dist < 1 ? dist : 0),
-                        -(z - i.posZ) / force);
-            }
+    		    applyRadialEffect(source, i, dist, radius);
     	    });
 
 		return true;
 	}
 
-	protected double calculateForce(EntityPlayer player) {
-		Race race = PlayerSpeciesList.instance().getPlayer(player).getPlayerSpecies();
+	protected void applyRadialEffect(ICaster<?> source, Entity target, double distance, double radius) {
+	    Vec3d pos = source.getOriginVector();
 
-		double force = 4 * 8;
-
-		if (race.canUseEarth()) {
-			if (player.isSneaking()) {
-				force *= 16;
+        if (ProjectileUtil.isProjectile(target)) {
+            if (!ProjectileUtil.isProjectileThrownBy(target, source.getOwner())) {
+                if (distance < radius/2) {
+                    target.playSound(SoundEvents.ENTITY_ZOMBIE_VILLAGER_CURE, 0.1F, 1);
+                    target.setDead();
+                } else {
+                    ricochet(target, pos);
                 }
-		} else if (race.canFly()) {
+            }
+        } else if (target instanceof EntityLivingBase) {
+            double force = Math.min(0.25F, distance);
+
+            if (source.getAffinity() != SpellAffinity.BAD && target instanceof EntityPlayer) {
+                force *= calculateAdjustedForce(PlayerSpeciesList.instance().getPlayer((EntityPlayer)target));
+            }
+
+            applyForce(pos, target, force, distance);
+        }
+	}
+
+	/**
+	 * Applies a force to the given entity based on distance from the source.
+	 */
+	protected void applyForce(Vec3d pos, Entity target, double force, double distance) {
+	    pos = target.getPositionVector().subtract(pos);
+
+        target.addVelocity(
+                force / pos.x,
+                force / pos.y + (distance < 1 ? distance : 0),
+                force / pos.z
+        );
+	}
+
+	/**
+	 * Returns a force to apply based on the given player's given race.
+	 */
+	protected double calculateAdjustedForce(IPlayer player) {
+		double force = 0.75;
+
+		if (player.getPlayerSpecies().canUseEarth()) {
 		    force /= 2;
+
+			if (player.getOwner().isSneaking()) {
+				force /= 6;
+			}
+		} else if (player.getPlayerSpecies().canFly()) {
+			force *= 2;
 		}
 
 		return force;
 	}
 
-	private void ricochet(Entity projectile, BlockPos pos) {
-		Vec3d position = new Vec3d(projectile.posX, projectile.posY, projectile.posZ);
+	/**
+	 * Reverses a projectiles direction to deflect it off the shield's surface.
+	 */
+	protected void ricochet(Entity projectile, Vec3d pos) {
+		Vec3d position = projectile.getPositionVector();
 		Vec3d motion = new Vec3d(projectile.motionX, projectile.motionY, projectile.motionZ);
 
-		Vec3d normal = position.subtract(pos.getX(), pos.getY(), pos.getZ()).normalize();
+		Vec3d normal = position.subtract(pos).normalize();
 		Vec3d approach = motion.subtract(normal);
 
 		if (approach.length() >= motion.length()) {
-			ProjectileUtil.setThrowableHeading(projectile, normal.x, normal.y, normal.z, (float)motion.length(), 0);
+			ProjectileUtil.setThrowableHeading(projectile, normal, (float)motion.length(), 0);
 		}
 	}
 

src/main/java/com/minelittlepony/util/ProjectileUtil.java

@@ -1,11 +1,14 @@
 package com.minelittlepony.util;
 
+import javax.annotation.Nullable;
+
 import net.minecraft.entity.Entity;
 import net.minecraft.entity.IProjectile;
 import net.minecraft.entity.projectile.EntityArrow;
 import net.minecraft.entity.projectile.EntityFireball;
 import net.minecraft.entity.projectile.EntityLlamaSpit;
 import net.minecraft.entity.projectile.EntityThrowable;
+import net.minecraft.util.math.Vec3d;
 
 public class ProjectileUtil {
 
@@ -30,8 +33,8 @@ public class ProjectileUtil {
 	 * Checks if the given projectile was thrown by the given entity
 	 */
 	@SuppressWarnings("unchecked")
-	public static <T extends Entity> boolean isProjectileThrownBy(Entity throwable, T e) {
-		if (e == null || !isProjectile(throwable)) {
+	public static <T extends Entity> boolean isProjectileThrownBy(Entity throwable, @Nullable T e) {
+		if (e == null || !isThrowable(throwable)) {
 		    return false;
 		}
 
@@ -41,6 +44,7 @@ public class ProjectileUtil {
 	/**
 	 * Gets the thrower for a projectile or null
 	 */
+	@Nullable
 	@SuppressWarnings("unchecked")
 	public static <T extends Entity> T getThrowingEntity(Entity throwable) {
 
@@ -67,18 +71,19 @@ public class ProjectileUtil {
      * Sets the velocity and heading for a projectile.
      *
      * @param throwable     The projectile
-	 * @param x				X Direction component
-	 * @param y				Y Direction component
-	 * @param z				Z Direction component
+     * @param heading       The directional heaving vector
      * @param velocity      Velocity
      * @param inaccuracy    Inaccuracy
      * @return              True the projectile's heading was set, false otherwise
      */
-	public static void setThrowableHeading(Entity throwable, double x, double y, double z, float velocity, float inaccuracy) {
+	public static void setThrowableHeading(Entity throwable, Vec3d heading, float velocity, float inaccuracy) {
+
 		if (throwable instanceof IProjectile) {
-			((IProjectile)throwable).shoot(x, y, z, velocity, inaccuracy);
+			((IProjectile)throwable).shoot(heading.x, heading.y, heading.z, velocity, inaccuracy);
 		} else {
-		    ((Entity)throwable).setVelocity(x, y, z);
+		    heading = heading.normalize().scale(velocity);
+
+	        throwable.addVelocity(heading.x - throwable.motionX, heading.y - throwable.motionY, heading.z - throwable.motionZ);
 		}
 	}
 }