brick-framework/GameCore/Combat/ProjectileSystem.cs

using GameCore.Combat.Effects;
using GameCore.ECS;
using GameCore.ECS.Interfaces;
using GameCore.Events;
using GameCore.Physics;

namespace GameCore.Combat;

public class ProjectileSystem : ISystem
{
    public void Update(World world, float deltaTime)
    {
        var projectiles = world.GetEntitiesWith<ProjectileComponent>();
        foreach (var projectile in projectiles)
        {
            var velocity = world.GetComponent<VelocityComponent>(projectile);
            var position = world.GetComponent<PositionComponent>(projectile);
            var projectileData = world.GetComponent<ProjectileComponent>(projectile);

            if (velocity == null || position == null || projectileData == null)
                continue;

            var newPosition = position.Position + velocity.DesiredVelocity * deltaTime;

            var hit = world.WorldQuery.Raycast(position.Position, newPosition, projectileData.Owner);
            if (hit.DidHit)
            {
                world.PublishEvent(new ProjectileImpactEvent(projectile, hit));
                var hitContext = new EffectContext
                {
                    World = world,
                    Owner = projectileData.Owner,
                    Target = hit.HitEntity
                };

                foreach (var effect in projectileData.OnHitEffects) effect.Execute(hitContext);

                world.AddComponent(projectile, new DeathComponent());
                continue;
            }

            position.Position = newPosition;
        }
    }
}