trenches/src/enemy.cpp

#include "enemy.hpp"
#include "utils/godot_macros.hpp"
#include <godot_cpp/classes/physics_direct_space_state3d.hpp>
#include <godot_cpp/classes/physics_ray_query_parameters3d.hpp>
#include <godot_cpp/classes/timer.hpp>
#include <godot_cpp/classes/world3d.hpp>
#include <godot_cpp/variant/utility_functions.hpp>

void Enemy::_bind_methods() {
#define CLASSNAME Enemy
    GDFUNCTION_ARGS(notice_player, "player");
    GDPROPERTY(update_interval, gd::Variant::FLOAT);
}

void Enemy::_ready() {
    this->anim_tree = this->get_node<PlayerAnimTree>("CharacterModel/AnimationTree");
    this->agent = this->get_node<gd::NavigationAgent3D>("%NavigationAgent3D");
    gd::Timer *timer{memnew(gd::Timer)};
    this->add_child(timer);
    timer->start(this->update_interval);
    timer->connect("timeout", callable_mp(this, &Enemy::update));
}

void Enemy::update() {
    if(this->current_action_fn != nullptr)
        this->current_action_fn = (ActionFn)(this->*current_action_fn)();
}

void Enemy::chase_enter() {
    if(this->player != nullptr)
        this->agent->set_target_position(this->player->get_global_position());
}

void Enemy::chase() {
    bool const at_end{!this->agent->is_navigation_finished()};
    this->anim_tree->set_lock_running(at_end);
    this->anim_tree->set_aim_weapon(!at_end);
    if(at_end) {
        gd::Vector3 const global_pos{this->get_global_position()};
        gd::Vector3 const target{global_pos * 2 - this->agent->get_next_path_position()};
        this->look_at({target.x, global_pos.y, target.z});
    } else if(this->get_global_position().distance_to(this->player->get_global_position()) >= this->agent->get_target_desired_distance())
        this->chase_enter(); // repath
}

Enemy::ActionFn Enemy::wait_line_of_sight() {
    if(this->can_see_player)
        return (ActionFn)&Enemy::take_aim;
    else
        return (ActionFn)&Enemy::wait_line_of_sight;
}

Enemy::ActionFn Enemy::take_aim() {
    this->anim_tree->set_aim_weapon(true);
    if(this->anim_tree->get_current_state().begins_with("Aim"))
        return (ActionFn)&Enemy::hit;
    else
        return(ActionFn)&Enemy::take_aim;
}

Enemy::ActionFn Enemy::miss() {
    if(this->can_see_player) {
        gd::Basis const basis{this->get_global_basis()};
        this->look_at(this->get_global_position() * 2 - this->player->get_global_position() + basis.get_column(0) * 0.6f);
        this->anim_tree->set_aim_weapon(true);
        this->anim_tree->set_fire_weapon();
        ++this->missed_shots;
        return (ActionFn)&Enemy::wait_end_of_shot;
    } else {
        this->chase();
    }
    return (ActionFn)&Enemy::miss;
}

Enemy::ActionFn Enemy::hit() {
    if(this->can_see_player) {
        this->look_at(this->get_global_position() * 2 - this->player->get_global_position());
        this->anim_tree->set_aim_weapon(true);
        this->anim_tree->set_fire_weapon();
        this->missed_shots = 0;
        return (ActionFn)&Enemy::wait_end_of_shot;
    } else {
        this->chase();
    }
    return (ActionFn)&Enemy::hit;
}

Enemy::ActionFn Enemy::wait_end_of_shot() {
    if(this->anim_tree->get_current_state().begins_with("Fire") || this->anim_tree->get_fire_weapon()) // last shot still going
        return (ActionFn)&Enemy::wait_end_of_shot;
    else
        return this->missed_shots >= SHOTS_BEFORE_HIT ? (ActionFn)&Enemy::hit : (ActionFn)&Enemy::miss;

}

void Enemy::_physics_process(double delta) {
    this->update_can_see_player();
    gd::Basis const basis{this->get_global_basis()};
    gd::Vector3 const motion{this->anim_tree->get_root_motion_position()};
    this->set_velocity({
        basis.get_column(0) * motion.x +
        basis.get_column(1) * motion.y +
        basis.get_column(2) * motion.z
    });\
    this->move_and_slide();
}

void Enemy::damage() {
    this->anim_tree->death_animation();
    this->set_collision_mask(0x0);
    this->set_collision_layer(0x0);
}

void Enemy::notice_player(Player *player) {
    this->player = player;
    this->current_action_fn = (ActionFn)&Enemy::wait_line_of_sight;
}

void Enemy::update_can_see_player() {
    if(this->player == nullptr)
        return;
    gd::Vector3 origin{this->get_global_position() + gd::Vector3{0.f, 1.8f, 0.f}};
    gd::PhysicsDirectSpaceState3D *space{this->get_world_3d()->get_direct_space_state()};
    gd::Ref<gd::PhysicsRayQueryParameters3D> query{gd::PhysicsRayQueryParameters3D::create(origin, this->player->get_global_position() + gd::Vector3{0.f, 1.8f, 0.f})};
    gd::Dictionary dict{space->intersect_ray(query)};
    this->can_see_player = (dict.is_empty() || gd::Object::cast_to<Node>(dict["collider"]) == this->player);
}

void Enemy::set_update_interval(float time) {
    this->update_interval = time;
}

float Enemy::get_update_interval() const {
    return this->update_interval;
}