minecraft-src/net/minecraft/world/entity/projectile/AbstractHurtingProjectile.java

package net.minecraft.world.entity.projectile;

import net.minecraft.core.particles.ParticleOptions;
import net.minecraft.core.particles.ParticleTypes;
import net.minecraft.nbt.CompoundTag;
import net.minecraft.network.syncher.SynchedEntityData.Builder;
import net.minecraft.server.level.ServerLevel;
import net.minecraft.world.damagesource.DamageSource;
import net.minecraft.world.entity.Entity;
import net.minecraft.world.entity.EntityType;
import net.minecraft.world.entity.LivingEntity;
import net.minecraft.world.level.Level;
import net.minecraft.world.level.ClipContext.Block;
import net.minecraft.world.phys.HitResult;
import net.minecraft.world.phys.Vec3;
import net.minecraft.world.phys.HitResult.Type;
import org.jetbrains.annotations.Nullable;

public abstract class AbstractHurtingProjectile extends Projectile {
	public static final double INITAL_ACCELERATION_POWER = 0.1;
	public static final double DEFLECTION_SCALE = 0.5;
	public double accelerationPower = 0.1;

	protected AbstractHurtingProjectile(EntityType<? extends AbstractHurtingProjectile> entityType, Level level) {
		super(entityType, level);
	}

	protected AbstractHurtingProjectile(EntityType<? extends AbstractHurtingProjectile> entityType, double x, double y, double z, Level level) {
		this(entityType, level);
		this.setPos(x, y, z);
	}

	public AbstractHurtingProjectile(EntityType<? extends AbstractHurtingProjectile> entityType, double x, double y, double z, Vec3 movement, Level level) {
		this(entityType, level);
		this.snapTo(x, y, z, this.getYRot(), this.getXRot());
		this.reapplyPosition();
		this.assignDirectionalMovement(movement, this.accelerationPower);
	}

	public AbstractHurtingProjectile(EntityType<? extends AbstractHurtingProjectile> entityType, LivingEntity owner, Vec3 movement, Level level) {
		this(entityType, owner.getX(), owner.getY(), owner.getZ(), movement, level);
		this.setOwner(owner);
		this.setRot(owner.getYRot(), owner.getXRot());
	}

	@Override
	protected void defineSynchedData(Builder builder) {
	}

	@Override
	public boolean shouldRenderAtSqrDistance(double distance) {
		double d = this.getBoundingBox().getSize() * 4.0;
		if (Double.isNaN(d)) {
			d = 4.0;
		}

		d *= 64.0;
		return distance < d * d;
	}

	protected Block getClipType() {
		return Block.COLLIDER;
	}

	@Override
	public void tick() {
		Entity entity = this.getOwner();
		this.applyInertia();
		if (this.level().isClientSide || (entity == null || !entity.isRemoved()) && this.level().hasChunkAt(this.blockPosition())) {
			HitResult hitResult = ProjectileUtil.getHitResultOnMoveVector(this, this::canHitEntity, this.getClipType());
			Vec3 vec3;
			if (hitResult.getType() != Type.MISS) {
				vec3 = hitResult.getLocation();
			} else {
				vec3 = this.position().add(this.getDeltaMovement());
			}

			ProjectileUtil.rotateTowardsMovement(this, 0.2F);
			this.setPos(vec3);
			this.applyEffectsFromBlocks();
			super.tick();
			if (this.shouldBurn()) {
				this.igniteForSeconds(1.0F);
			}

			if (hitResult.getType() != Type.MISS && this.isAlive()) {
				this.hitTargetOrDeflectSelf(hitResult);
			}

			this.createParticleTrail();
		} else {
			this.discard();
		}
	}

	private void applyInertia() {
		Vec3 vec3 = this.getDeltaMovement();
		Vec3 vec32 = this.position();
		float g;
		if (this.isInWater()) {
			for (int i = 0; i < 4; i++) {
				float f = 0.25F;
				this.level().addParticle(ParticleTypes.BUBBLE, vec32.x - vec3.x * 0.25, vec32.y - vec3.y * 0.25, vec32.z - vec3.z * 0.25, vec3.x, vec3.y, vec3.z);
			}

			g = this.getLiquidInertia();
		} else {
			g = this.getInertia();
		}

		this.setDeltaMovement(vec3.add(vec3.normalize().scale(this.accelerationPower)).scale(g));
	}

	private void createParticleTrail() {
		ParticleOptions particleOptions = this.getTrailParticle();
		Vec3 vec3 = this.position();
		if (particleOptions != null) {
			this.level().addParticle(particleOptions, vec3.x, vec3.y + 0.5, vec3.z, 0.0, 0.0, 0.0);
		}
	}

	@Override
	public boolean hurtServer(ServerLevel level, DamageSource damageSource, float amount) {
		return false;
	}

	@Override
	protected boolean canHitEntity(Entity target) {
		return super.canHitEntity(target) && !target.noPhysics;
	}

	protected boolean shouldBurn() {
		return true;
	}

	@Nullable
	protected ParticleOptions getTrailParticle() {
		return ParticleTypes.SMOKE;
	}

	/**
	 * Return the motion factor for this projectile. The factor is multiplied by the original motion.
	 */
	protected float getInertia() {
		return 0.95F;
	}

	protected float getLiquidInertia() {
		return 0.8F;
	}

	@Override
	public void addAdditionalSaveData(CompoundTag tag) {
		super.addAdditionalSaveData(tag);
		tag.putDouble("acceleration_power", this.accelerationPower);
	}

	@Override
	public void readAdditionalSaveData(CompoundTag tag) {
		super.readAdditionalSaveData(tag);
		this.accelerationPower = tag.getDoubleOr("acceleration_power", 0.1);
	}

	@Override
	public float getLightLevelDependentMagicValue() {
		return 1.0F;
	}

	private void assignDirectionalMovement(Vec3 movement, double accelerationPower) {
		this.setDeltaMovement(movement.normalize().scale(accelerationPower));
		this.hasImpulse = true;
	}

	@Override
	protected void onDeflection(@Nullable Entity entity, boolean deflectedByPlayer) {
		super.onDeflection(entity, deflectedByPlayer);
		if (deflectedByPlayer) {
			this.accelerationPower = 0.1;
		} else {
			this.accelerationPower *= 0.5;
		}
	}
}