Function FireWeaponFromObject

Descent3/WeaponFire.cpp:1817–2017

Given an object and a weapon, fires a shot from that object

// Given an object and a weapon, fires a shot from that object
int FireWeaponFromObject(object *obj, int weapon_num, int gun_num, bool f_force_forward, bool f_force_target) {
  ASSERT(Weapons[weapon_num].used);

  // Mass driver is hack
  static int mass_driver_id = -2;
  static int mass_driver_ring = -2;

  if (mass_driver_id == -2) {
    mass_driver_id = FindWeaponName("Mass Driver");
    mass_driver_ring = FindTextureName("CloakRing.tga1");
  }

  vector laser_pos, laser_dir;
  int objnum;

  if (gun_num == -1) {
    laser_pos = obj->pos;
    laser_dir = obj->orient.fvec;
  } else {
    // Find the initial position of the laser
    poly_model *pm = &Poly_models[obj->rtype.pobj_info.model_num];
    //		vector *pnt = &pm->gun_slots[gun_num].pnt;
    //		vector gun_point;
    //		matrix m;

    if (gun_num >= pm->n_guns) {
      // We don't have a gun point for this gun!
      mprintf(0, "Trying to fire from gun %d...we don't have that gun!\n", gun_num);
      laser_pos = obj->pos;
      laser_dir = obj->orient.fvec;
    } else {
      if (f_force_forward) {
        WeaponCalcGun(&laser_pos, NULL, obj, gun_num);
        laser_dir = obj->orient.fvec;
      } else if (f_force_target && obj->ai_info && obj->ai_info->vec_to_target_perceived != Zero_vector) {
        WeaponCalcGun(&laser_pos, NULL, obj, gun_num);
        laser_dir = obj->ai_info->vec_to_target_perceived;
      } else {
        WeaponCalcGun(&laser_pos, &laser_dir, obj, gun_num);
      }
    }
  }

  if ((obj->control_type == CT_AI) && (obj->ai_info->fire_spread || (Diff_ai_min_fire_spread[DIFF_LEVEL]))) {
    matrix rot_mat;
    angle p, h, b;

    float diff_scale = DIFF_LEVEL / (MAX_DIFFICULTY_LEVELS - 1);
    float fs = (MAX_FIRE_SPREAD * (1.0f - diff_scale)) + (MIN_FIRE_SPREAD * diff_scale);

    int16_t fire_spread = obj->ai_info->fire_spread * fs;

    if ((obj->control_type == CT_AI && ((obj->ai_info->flags & AIF_TEAM_MASK) != AIF_TEAM_REBEL)) &&
        fire_spread < Diff_ai_min_fire_spread[DIFF_LEVEL] * fs) {
      fire_spread = Diff_ai_min_fire_spread[DIFF_LEVEL] * fs;
    }

    int16_t half_fire_spread = fire_spread >> 1;