Function TraverseShotPath

scripts/AIGame3.cpp:451–543

Traverses the straight-line shot path and gathers object data

// Traverses the straight-line shot path and gathers object data
float TraverseShotPath(tShotData *shot_data) {
  float next_scan_dist, scan_radius;
  float current_path_dist, dist;
  vector start_pos, end_pos, target_pos;
  vector shot_dir;
  int start_room, end_room;
  int flags, fate;
  ray_info ray;
  bool done, max_distance_reached;

  // Clear out any existing shot scan positions
  num_shot_path_positions = 0;

  // Setup the shot's starting data
  start_pos = shot_data->start_point;
  start_room = shot_data->start_room;
  shot_dir = shot_data->dir;
  next_scan_dist = shot_data->danger_radius;
  scan_radius = shot_data->danger_radius;

  // Start scanning
  current_path_dist = 0.0f;
  max_distance_reached = false;
  done = false;

  while (!done) {
    // Check the max shot distance
    if ((current_path_dist + next_scan_dist) >= shot_data->max_dist) {
      next_scan_dist = shot_data->max_dist - current_path_dist;
      max_distance_reached = true;
    }

    // Calculate shot's target position
    target_pos = start_pos + (shot_dir * next_scan_dist);

    // Cast a ray to see if a wall or any clutter objects lie in the target path
    flags = FQ_CHECK_OBJS | FQ_IGNORE_POWERUPS | FQ_IGNORE_WEAPONS | FQ_IGNORE_MOVING_OBJECTS |
            FQ_IGNORE_NON_LIGHTMAP_OBJECTS;
    fate =
        FVI_RayCast(shot_data->object_handle, &start_pos, &target_pos, start_room, shot_data->shot_radius, flags, &ray);

    // Store the ray hit point and room
    end_pos = ray.hit_point;
    end_room = ray.hit_room;

    // If necessary, calculate the distance from start point to the hit point
    if (fate == HIT_NONE) {
      dist = next_scan_dist;
    } else {
      dist = vm_VectorDistance(&start_pos, &end_pos);
    }

    // Add the new distance to our total shot path distance
    current_path_dist += dist;

    // If it hit a wall, change the direction (perfect reflection)
    if (fate == HIT_WALL) {
      // Calculate the bounce dir from the current dir and face normal