veloren/common/systems/src/projectile.rs

use common::{
    combat::{AttackSource, AttackerInfo, TargetInfo},
    comp::{
        agent::{Sound, SoundKind},
        projectile, Body, CharacterState, Combo, Energy, Group, Health, HealthSource, Inventory,
        Ori, PhysicsState, Pos, Projectile, Stats, Vel,
    },
    event::{EventBus, ServerEvent},
    outcome::Outcome,
    resources::{DeltaTime, Time},
    uid::{Uid, UidAllocator},
    util::Dir,
    GroupTarget,
};
use common_ecs::{Job, Origin, Phase, System};
use rand::{thread_rng, Rng};
use specs::{
    saveload::MarkerAllocator, shred::ResourceId, Entities, Join, Read, ReadStorage, SystemData,
    World, Write, WriteStorage,
};
use std::time::Duration;
use vek::*;

#[derive(SystemData)]
pub struct ReadData<'a> {
    time: Read<'a, Time>,
    entities: Entities<'a>,
    dt: Read<'a, DeltaTime>,
    uid_allocator: Read<'a, UidAllocator>,
    server_bus: Read<'a, EventBus<ServerEvent>>,
    uids: ReadStorage<'a, Uid>,
    positions: ReadStorage<'a, Pos>,
    physics_states: ReadStorage<'a, PhysicsState>,
    velocities: ReadStorage<'a, Vel>,
    inventories: ReadStorage<'a, Inventory>,
    groups: ReadStorage<'a, Group>,
    energies: ReadStorage<'a, Energy>,
    stats: ReadStorage<'a, Stats>,
    combos: ReadStorage<'a, Combo>,
    healths: ReadStorage<'a, Health>,
    bodies: ReadStorage<'a, Body>,
    character_states: ReadStorage<'a, CharacterState>,
}

/// This system is responsible for handling projectile effect triggers
#[derive(Default)]
pub struct Sys;
impl<'a> System<'a> for Sys {
    type SystemData = (
        ReadData<'a>,
        WriteStorage<'a, Ori>,
        WriteStorage<'a, Projectile>,
        Write<'a, Vec<Outcome>>,
    );

    const NAME: &'static str = "projectile";
    const ORIGIN: Origin = Origin::Common;
    const PHASE: Phase = Phase::Create;

    fn run(
        _job: &mut Job<Self>,
        (read_data, mut orientations, mut projectiles, mut outcomes): Self::SystemData,
    ) {
        let mut server_emitter = read_data.server_bus.emitter();
        // Attacks
        'projectile_loop: for (entity, pos, physics, vel, mut projectile) in (
            &read_data.entities,
            &read_data.positions,
            &read_data.physics_states,
            &read_data.velocities,
            &mut projectiles,
        )
            .join()
        {
            let mut rng = thread_rng();
            if physics.on_surface().is_none() && rng.gen_bool(0.05) {
                server_emitter.emit(ServerEvent::Sound {
                    sound: Sound::new(SoundKind::Projectile, pos.0, 2.0, read_data.time.0),
                });
            }

            let mut projectile_vanished: bool = false;

            // Hit entity
            for other in physics.touch_entities.iter().copied() {
                let same_group = projectile
                    .owner
                    // Note: somewhat inefficient since we do the lookup for every touching
                    // entity, but if we pull this out of the loop we would want to do it only
                    // if there is at least one touching entity
                    .and_then(|uid| read_data.uid_allocator.retrieve_entity_internal(uid.into()))
                    .and_then(|e| read_data.groups.get(e))
                    .map_or(false, |owner_group|
                        Some(owner_group) == read_data.uid_allocator
                        .retrieve_entity_internal(other.into())
                        .and_then(|e| read_data.groups.get(e))
                    );

                // Skip if in the same group
                let target_group = if same_group {
                    GroupTarget::InGroup
                } else {
                    GroupTarget::OutOfGroup
                };

                if projectile.ignore_group && same_group {
                    continue;
                }

                if projectile.owner == Some(other) {
                    continue;
                }

                let projectile = &mut *projectile;
                for effect in projectile.hit_entity.drain(..) {
                    match effect {
                        projectile::Effect::Attack(attack) => {
                            if let Some(target) = read_data
                                .uid_allocator
                                .retrieve_entity_internal(other.into())
                            {
                                if let (Some(pos), Some(ori)) =
                                    (read_data.positions.get(target), orientations.get(entity))
                                {
                                    let dir = ori.look_dir();

                                    let owner_entity = projectile.owner.and_then(|u| {
                                        read_data.uid_allocator.retrieve_entity_internal(u.into())
                                    });

                                    let attacker_info =
                                        owner_entity.zip(projectile.owner).map(|(entity, uid)| {
                                            AttackerInfo {
                                                entity,
                                                uid,
                                                energy: read_data.energies.get(entity),
                                                combo: read_data.combos.get(entity),
                                                inventory: read_data.inventories.get(entity),
                                            }
                                        });

                                    let target_info = TargetInfo {
                                        entity: target,
                                        uid: other,
                                        inventory: read_data.inventories.get(target),
                                        stats: read_data.stats.get(target),
                                        health: read_data.healths.get(target),
                                        pos: pos.0,
                                        ori: orientations.get(target),
                                        char_state: read_data.character_states.get(target),
                                    };

                                    if let Some(&body) = read_data.bodies.get(entity) {
                                        outcomes.push(Outcome::ProjectileHit {
                                            pos: pos.0,
                                            body,
                                            vel: read_data
                                                .velocities
                                                .get(entity)
                                                .map_or(Vec3::zero(), |v| v.0),
                                            source: projectile.owner,
                                            target: read_data.uids.get(target).copied(),
                                        });
                                    }

                                    attack.apply_attack(
                                        target_group,
                                        attacker_info,
                                        target_info,
                                        dir,
                                        false,
                                        1.0,
                                        AttackSource::Projectile,
                                        |e| server_emitter.emit(e),
                                        |o| outcomes.push(o),
                                    );
                                }
                            }
                        },
                        projectile::Effect::Explode(e) => {
                            server_emitter.emit(ServerEvent::Explosion {
                                pos: pos.0,
                                explosion: e,
                                owner: projectile.owner,
                            });
                        },
                        projectile::Effect::Vanish => {
                            server_emitter.emit(ServerEvent::Destroy {
                                entity,
                                cause: HealthSource::World,
                            });
                            projectile_vanished = true;
                        },
                        projectile::Effect::Possess => {
                            if other != projectile.owner.unwrap() {
                                if let Some(owner) = projectile.owner {
                                    server_emitter.emit(ServerEvent::Possess(owner, other));
                                }
                            }
                        },
                        _ => {},
                    }
                }

                if projectile_vanished {
                    continue 'projectile_loop;
                }
            }

            if physics.on_surface().is_some() {
                let projectile = &mut *projectile;
                for effect in projectile.hit_solid.drain(..) {
                    match effect {
                        projectile::Effect::Explode(e) => {
                            server_emitter.emit(ServerEvent::Explosion {
                                pos: pos.0,
                                explosion: e,
                                owner: projectile.owner,
                            });
                        },
                        projectile::Effect::Vanish => {
                            server_emitter.emit(ServerEvent::Destroy {
                                entity,
                                cause: HealthSource::World,
                            });
                            projectile_vanished = true;
                        },
                        _ => {},
                    }
                }

                if projectile_vanished {
                    continue 'projectile_loop;
                }
            } else if let Some(ori) = orientations.get_mut(entity) {
                if let Some(dir) = Dir::from_unnormalized(vel.0) {
                    *ori = dir.into();
                }
            }

            if projectile.time_left == Duration::default() {
                server_emitter.emit(ServerEvent::Destroy {
                    entity,
                    cause: HealthSource::World,
                });
            }
            projectile.time_left = projectile
                .time_left
                .checked_sub(Duration::from_secs_f32(read_data.dt.0))
                .unwrap_or_default();
        }
    }
}