You'd just do the same thing, except place it in the NPC's AI method. You'll also have to replace position with npc.position and velocity with npc.velocity. You can also customize the projectile's damage; it will do double damage as whatever you put for the damage when you create the projectile, meaning it can differ from the NPC's base damage.I know this was posted ages ago, but I'd like to ask how you could achieve something similar but make it shoot out of a boss, as part of an attack. I have a worm boss, and in a feeble attempt to make it unique, I'd like to add this code (8 or so projectiles shooting out of the bosses head)
Hm, that's weird. npc.rotation is what's actually used to get the visual rotation. Just to make sure, you're using a negative AI style and using radians, right?
Basically angle measurements where a full circle is 2 pi. So for example, to get a 90 degree counterclockwise rotation, you'd set npc.rotation = (float)Math.PI / 2f.
Yeah, 180 degrees = pi radians. You just put the radians in npc.rotation (npc.rotation is assumed to be measured in radians). Also, conveniently, the methods in the Math class will return angles already in radians for you. So you can do something like:
Vector2 distance = player.Center - npc.Center;
float angle = (float)Math.Atan2(distance.Y, distance.X);
npc.rotation = angle;Decreasing the angle by that would make the sprite rotate clockwise by 90 degrees, so you'd want to add that value instead. (I think that's actually what happens with the EoC.)
Actually, now I remember. Earlier I posted this:Oops, got it the wrong way around xD Thanks, I'll see if it works now!
EDIT: Haha, the eye's backwards XD I think it was subtract
For the constant flame effect, just create several new projectiles each tick with random angle offsets on their velocities.
float angle = npc.rotation + whatever; //whatever will depend on the rotation of the NPC in the image file
Vector2 velocity = new Vector2((float)Math.Cos(angle), (float)Math.Sin(angle));
velocity *= speed; //replace speed with some float
//here you can add/subtract random amounts to the velocity's components, then use this velocity when you create the projectile
if (Main.dayTime) //do !Main.dayTime for night time
{
npc.active == false;
}
Just for the interested, the despawning mechanism works the same for all monster NPCs (whether or not it's a boss). The timeLeft property tells how long the NPC can stay off-screen before it despawns, and whenever the NPC returns to the screen, the timeLeft property is reset to NPC.activeTime. Bosses start out with a large timeLeft so they can have enough time to arrive at the player's screen regardless of how long it takes (as soon as they enter the screen it resets to the normal time). The reason the bosses don't despawn is that they keep moving towards the player and re-entering the screen, even if they do leave the screen for just a little bit. NPC.activeTime is equal to 750, which means once an NPC leaves the screen, it has 12.5 seconds to return to the screen before it despawns.
I formatted it so its much clearer to see, and here you can see the multitude of problems...
using System;
using System.Collections.Generic;
using System.Text;
using Microsoft.Xna.Framework;
using TAPI;
using Terraria;
namespace ZItemsMod.NPCs
{
public class ElectrumElemental : ModNPC
{
public override void HitEffect(int hitDirection, double damage, bool isDead)
{
if (Main.netMode != 2)
{
for (int m = 0; m < (isDead ? 20 : 5); m++)
{
int dustID = Dust.NewDust(npc.position, npc.width, npc.height, 5, npc.velocity.X * 0.2f, npc.velocity.Y * 0.2f, 100, Color.Red, isDead && m % 2 == 0 ? 3f : 1f);
if (isDead && m % 2 == 0) { Main.dust[dustID].noGravity = true; }
}
if (isDead)
{
Gore.NewGore(npc.position, npc.velocity, GoreDef.gores["ZItemsMod:ElectrumElemental"], 1f);
Gore.NewGore(npc.position, npc.velocity, GoreDef.gores["ZItemsMod:ElectrumElemental2"], 1f);
Gore.NewGore(npc.position, npc.velocity, GoreDef.gores["ZItemsMod:GoresPlate_2"], 1f);
Gore.NewGore(npc.position, npc.velocity, GoreDef.gores["ZItemsMod:GoresPlate_2"], 1f);
}
}
if (Main.netMode != 1)
{
Projectile.NewProjectile(1, 1, 1, 1, 44, 16, 2, Main.myPlayer, 0, 0);
}
}
}using System;
using Microsoft.Xna.Framework;
using Terraria;
using TAPI;
namespace COFP.NPCs
{
public class FlyingFrog : ModNPC
{
public override void AI()
{
Player player = Main.player[npc.target]; //Setting the target
npc.ai[0] += 2f;
if (npc.localAI[0] > 0f)
{
npc.localAI[0] -= 1f;
}
//Setting Shoot Vector
Vector2 center = new Vector2(npc.position.X + (float)npc.width * 0.5f, npc.position.Y + (float)npc.height * 0.5f);
float shootToX = player.position.X + (float)player.width * 0.5f - center.X;
float shootToY = player.position.Y - center.Y;
float distance = (float)System.Math.Sqrt((double)(shootToX * shootToX + shootToY * shootToY));
//Fire the projectile if the player's distance is less than 480 pixels and if there is nothing blocking the pathway to the player
if (distance < 480f && Collision.CanHit(npc.position, npc.width, npc.height, player.position, player.width, player.height))
{
if (npc.velocity.Y == 0f)
{
npc.velocity.X *= 0.9f;
}
if (Main.netMode != 1 && npc.localAI[0] == 0f)
{
//I think this is right, not so certain.
distance = 3f / distance;
shootToX *= distance * 2;
if(shootToY > 0)
{
shootToY *= (float) distance - 0.25f;
}
else
{
shootToY *= (float) distance + 0.25f;
}
npc.localAI[0] = 30f;
Projectile.NewProjectile(center.X, center.Y, shootToX, shootToY, "COFP:NPCInferno", 35, 0f, Main.myPlayer, 0f, 0f);
}
}
}
public override void SelectFrame(int frameSize)
{
Player player = Main.player[npc.target];
Vector2 center = new Vector2(npc.position.X + (float)npc.width * 0.5f, npc.position.Y + (float)npc.height * 0.5f);
float shootToX = player.position.X + (float)player.width * 0.5f - center.X;
float shootToY = player.position.Y - center.Y;
float distance = (float)System.Math.Sqrt((double)(shootToX * shootToX + shootToY * shootToY));
npc.spriteDirection = npc.direction;
npc.rotation = npc.velocity.X * 0.1f;
npc.frameCounter += 1.0;
if (distance < 480f && Collision.CanHit(npc.position, npc.width, npc.height, player.position, player.width, player.height))
{
if (npc.frameCounter <= 5)
{
npc.frame.Y = 2 * frameSize;
}
else if(npc.frameCounter <= 10)
{
npc.frame.Y = 3 * frameSize;
}
else if(npc.frameCounter >= 11)
{
npc.frameCounter = 0;
}
}
else if(npc.velocity.X != 0)
{
if (npc.frameCounter < 6.0)
{
npc.frame.Y = 0;
}
else
{
npc.frame.Y = frameSize;
if (npc.frameCounter >= 11.0)
{
npc.frameCounter = 0.0;
}
}
}
}
}
}