Enemy AI

obj_setup_pathway - place in room

----------------
//adjust if needed
grid = mp_grid_create(0, 0, room_width/32, room_height/32, 32, 32);

mp_grid_add_instances(grid, obj_wall, 0);



obj_enemy

---------------
~create
s_emit = audio_emitter_create();
max_audio = 200;
drop_audio = 100;

audio_falloff_set_model(audio_falloff_linear_distance);
audio_emitter_position(s_emit, obj_enemy.x, obj_enemy.y, 0);
audio_emitter_falloff(s_emit, drop_audio, max_audio, 1);

state = 0;

seen = false;

fade_alpha = 0;
path = path_add();
seen = false;
target_x = obj_player.x;
target_y = obj_player.y;

xspd = 0;
yspd = 0;

move_spd = 0.8;

alarm[0] = 1;

hit_play = true;

----------------
~step

if (state == 0){
    audio_play_sound_on(s_emit, snd_footstep, true, 1);

    state = 1;
}
audio_emitter_position(s_emit, x, y, 0);

var _pd = direction - 90;
var _ad = angle_difference(image_angle, _pd);
image_angle -= min(abs(_ad), 10) * sign(_ad);
image_alpha = fade_alpha;
if (collision_line(x, y, obj_player.x, obj_player.y, obj_wall, 1, 0)) {
  fade_alpha -= 0.12;
  if (fade_alpha <= 0) {
      seen = false;
      visible = false;
      fade_alpha = 0;
  }
} else {
  if (fade_alpha < 1) {
      fade_alpha += 0.12;
  }
  visible = true;
  seen = true;
}



---------------
~alarm 0
path_delete(path);
path = path_add();

target_x = obj_player.x;
target_y = obj_player.y;

//chase state if seen or within the radius
if(collision_circle(x, y, 64, obj_player, false, false)) && seen == true{
    if (hit_play){
        audio_sound_pitch(snd_approach, 1.1);
        audio_play_sound(snd_approach, 1.3, false);
        hit_play = false;
    }
    move_spd = 1.53

    mp_grid_path(obj_setup_pathway.grid, path, x, y, target_x, target_y, 1);
    path_start(path, move_spd, path_action_stop, true);
    audio_emitter_gain(s_emit, 100);
    audio_emitter_pitch(s_emit, 1.45);
}

//patrol mode
else{
    move_spd = 1.2;
    mp_grid_path(obj_setup_pathway.grid, path, x, y, target_x, target_y, 1);
    audio_emitter_pitch(s_emit, 1);
    audio_emitter_gain(s_emit, 0.3);
    path_start(path, move_spd, path_action_stop, true);
    seen = false;
    hit_play = true;
}


alarm_set(0, 10);
--------------
~destroy
audio_emitter_free(s_emit);

audio_stop_sound(snd_footstep);