line_of_sight_manager¶
- line_of_sight_manager … end_line_of_sight_manager¶
line_of_sight_manager // Commands maximum_location_change ... vegetation_layer_masking ... debug use_height_for_ground_platforms ... // Multi-thread Commands (Applicable only in frame-step simulations) multi_thread debug_thread // Multi-thread Performance Commands (Applicable only when multi-threaded) number_of_priority_levels ... max_steps_in_priority_level ... processing_rate ... end_line_of_sight_manager
Overview¶
The Line-of-sight (LOS) manager calculates and maintains LOS information between entities and/or entity parts in the simulation on request.
For event-based simulations, the first time a LOS check is requested for a given pair, the LOS manager performs the LOS calculation and saves the result. For subsequent LOS requests for the same pair, the LOS manager checks first for movement using the maximum_location_change criteria to determine if LOS information needs updating. If neither player has moved, then the LOS manager references the saved LOS result.
For frame-step simulations, similar to the behavior in event-based simulations, the first time a LOS check is requested for a given pair, the LOS manager performs the LOS calculation and saves the result. However, for each subsequent frame, after platform-mover updates occur at the beginning of the frame, all previously requested platforms are considered again. The LOS manager checks first for movement using the same check as in event-based simulations. If movement has occurred beyond the threshold criteria, the LOS manager performs the LOS calculation and updates the LOS information for all LOS interactions it has knowledge of containing that platform.
The frame-step approach can be more computationally intensive; therefore, a multi-threading option is available. With this option enabled, the LOS manager creates a worker thread for LOS calculation processing.
Commands¶
- maximum_location_change <length-value>¶
The distance a platform must move when determining whether LOS information needs updating.
Default 0.0 meters
- vegetation_layer_masking <boolean-value>¶
Indicates that line of sight masking is to be performed with the vegetation layer of the terrain instead of the bare earth layer.
- debug¶
Writes additional information to standard output when debugging the LOS manager’s main thread logic.
Note
Debug only one thread at a time for best results.
- use_height_for_ground_platforms <boolean-value>¶
Indicates that a ground platform’s height is to be added to its altitude when doing terrain masking checks.
Multi-thread Commands¶
Applicable only in frame-step simulations.
- multi_thread¶
Creates a worker thread for processing line-of-sight calculations.
- debug_thread¶
Writes additional information to standard output when debugging the LOS manager’s worker thread logic.
Note
Debug only one thread at a time for best results.
Multi-thread Performance Commands¶
These commands provide capability to change processing performance of the LOS manager’s worker thread. Improvement is not guaranteed; use with caution.
If the worker thread is overloaded and unable to perform all LOS calculations in the current frame, the unprocessed requests are saved for the next frame. In the next frame, requests with highest priority are processed first.
By default, there are 3 priority levels (queues) each requiring 5 requests before the request before moving to a higher level. For example, assume a platform is moving at a distance greater than the maximum_location_change each frame. The LOS manager internally generates a request to update the LOS information for all LOS interactions it has knowledge of containing that platform. If the platform does not get processed for 5 frames it will move up in priority. If 5 more frames go by and the LOS interactions for that platform are still not getting updated, the platform will move up again in priority.
- number_of_priority_levels <positive integer>¶
The number of priority levels used when processing line-of-sight calculation requests.
Default 3 (minimum is 1)
- max_steps_in_priority_level <positive integer>¶
The number of requests received for a given LOS interaction required before it moves up in priority.
Default 5 (minimum is 1)
- processing_rate <positive integer>¶
The number of line-of-sight updates performed by the worker thread in one cycle. A cycle consists of processing requests, determining priority, and then updating the LOS data. This keeps the thread from getting stuck processing requests and never getting to actually updating the LOS data. It also facilitates pausing the thread, since this can only be done between cycles.
Default 10 (minimum is 1)
