Homing Arrow (Entity Bounding Box Issues)

[MrArcane111]

Okay, so I have already successfully added the Homing Enchantment code to my mod, and all the methods related are being called correctly. I've added the homing code into an EntityEvent (I grabbed an instance of the EntityArrow), and when I fire the bow, the arrow locates the closest entity, and zooms to the entity's location. The problem I have is where the arrow lands up. I intended for the arrow to land in the relative center of the mob, but I have been unsuccessful. I've been using the bounding boxes of the entity as a guide, but to no avail. Usually, the arrow ends up hitting the mob, then rendering near the mob's feet. It is really an odd occurrence. Anyway, here is the code for the arrow:

 

@ForgeSubscribe
public void arrowInAir(EntityEvent event)
{
	if(event.entity instanceof EntityArrow)
	{
		EntityArrow arrow = (EntityArrow) event.entity;

		// To whomever reads this, other than myself, I am terribly sorry for the mess of code below...ugh...
		if(isHoming == true)
		{	
			if(target == null || target.velocityChanged || !target.canEntityBeSeen(arrow))
			{
				double d = arrow.posX;
				double d1 = arrow.posY;
				double d2 = arrow.posZ;
				double d3 = 6 * homingAmount;
				double d4 = -1D;
				EntityLiving entityliving = null;
				List list = arrow.worldObj.getEntitiesWithinAABB(net.minecraft.entity.EntityLiving.class, arrow.boundingBox.expand(d3, d3, d3));

				for(int i = 0; i < list.size(); i++)
				{
					EntityLiving entityliving1 = (EntityLiving) list.get(i);

					if(entityliving1 == arrow.shootingEntity)
					{
						continue;
					}

					double d5 = entityliving1.getDistance(d, d1, d2);

					if((d3 < 0.0D || d5 < d3 * d3) && (d4 == -1D || d5 < d4) && entityliving1.canEntityBeSeen(arrow))
					{
						d4 = d5;
						entityliving = entityliving1;
					}
				}

				target = entityliving;
			}

			if(target != null)
			{
				// All these fancy calculations guarantee that it will hit an entity dead on
				double d = (target.boundingBox.minX + (target.boundingBox.maxX - target.boundingBox.minX) / 2D) - arrow.posX;
				double d1 = (target.boundingBox.minY + (target.boundingBox.maxY - target.boundingBox.minY) / 2D) - arrow.posY;
				double d2 = (target.boundingBox.minZ + (target.boundingBox.maxZ - target.boundingBox.minZ) / 2D) - arrow.posZ;*/
				arrow.setThrowableHeading(d, d1, d2, 1.5F, 0.0F);
				//homingAmount = 0;
			}
		}

 

Thanks to anyone who can help. This site has an amazing support group, and I am thankful for that.

[coolAlias]

First, when using Events make sure to use the most specific Event you can find, as using classes higher up on the hierarchy will call EVERY child event, and TONS of events extend EntityEvent. Why not use EntityJoinWorldEvent to check if the entity is your custom arrow?

 

As for the homing, my advice would be to look at how Ghast fireballs work - the code in there is set up perfectly for a homing type effect.

[MrArcane111]

The EntityJoinedWorld Event will call if it is a homing arrow, however, the entity event is called every time the specified entity is updated; I do not believe the EntityJoinedWorld event does that. Thanks for the Fireball suggestion. I will check it out and post my results here.

[MrArcane111]

Okay, well, I checked out the Ghast code, and this is what I've got now:

 

double d = target.posX - arrow.posX;
double d1 = target.boundingBox.minY + (double) (target.height / 2.0F) - (arrow.posY + (double) (arrow.height / 2.0F));
double d2 = target.posZ - arrow.posZ;

 

It's certainly a lot cleaner and more accurate, but there are still some weird bounding box glitches. I still cannot determine whether it is the game's rendering issues or my homing code.

[coolAlias]

You don't need a Forge Event for updating your entity every tick, that's what the Entity's own onUpdate method is for. Simply override that in your custom Entity class instead of using an Event. I suggested EntityJoinWorldEvent as a way to acquire the initial target only, not for updating the position

 

What kind of bounding box glitches are you getting?