tbd-station-14/Content.Server/GameObjects/Components/Weapon/Ranged/Hitscan/HitscanWeaponComponent.cs

using SS14.Server.GameObjects.EntitySystems;
using SS14.Shared.Audio;
using SS14.Shared.GameObjects.EntitySystemMessages;
using SS14.Shared.Interfaces.GameObjects;
using SS14.Shared.Interfaces.GameObjects.Components;
using SS14.Shared.Interfaces.Physics;
using SS14.Shared.Interfaces.Timing;
using SS14.Shared.IoC;
using SS14.Shared.Map;
using SS14.Shared.Maths;
using SS14.Shared.Physics;
using System;

namespace Content.Server.GameObjects.Components.Weapon.Ranged.Hitscan
{
    public class HitscanWeaponComponent : RangedWeaponComponent
    {
        private const float MaxLength = 20;
        public override string Name => "HitscanWeapon";

        private const string SpriteName = "Objects/laser.png";

        protected override void Fire(IEntity user, GridLocalCoordinates clicklocation)
        {
            var userPosition = user.Transform.WorldPosition; //Remember world positions are ephemeral and can only be used instantaneously
            var angle = new Angle(clicklocation.Position - userPosition);

            var ray = new Ray(userPosition, angle.ToVec());
            var rayCastResults = IoCManager.Resolve<IPhysicsManager>().IntersectRay(ray, MaxLength,
                Owner.Transform.GetMapTransform().Owner);

            Hit(rayCastResults);
            AfterEffects(user, rayCastResults, angle);
        }

        protected virtual void Hit(RayCastResults ray)
        {
            if (ray.HitEntity != null && ray.HitEntity.TryGetComponent(out DamageableComponent damage))
            {
                damage.TakeDamage(DamageType.Heat, 10);
            }
        }

        protected virtual void AfterEffects(IEntity user, RayCastResults ray, Angle angle)
        {
            var time = IoCManager.Resolve<IGameTiming>().CurTime;
            var dist = ray.DidHitObject ? ray.Distance : MaxLength;
            var offset = angle.ToVec() * dist / 2;
            var message = new EffectSystemMessage
            {
                EffectSprite = SpriteName,
                Born = time,
                DeathTime = time + TimeSpan.FromSeconds(1),
                Size = new Vector2(dist, 1f),
                Coordinates = user.Transform.LocalPosition.Translated(offset),
                //Rotated from east facing
                Rotation = (float) angle.Theta,
                ColorDelta = new Vector4(0, 0, 0, -1500f),
                Color = new Vector4(255, 255, 255, 750),
                Shaded = false
            };
            var mgr = IoCManager.Resolve<IEntitySystemManager>();
            mgr.GetEntitySystem<EffectSystem>().CreateParticle(message);
            mgr.GetEntitySystem<AudioSystem>().Play("/Audio/laser.ogg", Owner, AudioParams.Default.WithVolume(-5));
        }
    }
}