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a month or two ago i realized that on master the reason why get_hearers_in_view() overtimes so much (ie one of our highest overtiming procs at highpop) is because when you transmit a radio signal over the common channel, it can take ~20 MILLISECONDS, which isnt good when 1. player verbs and commands usually execute after SendMaps processes for that tick, meaning they can execute AFTER the tick was supposed to start if master is overloaded and theres a lot of maptick 2. each of our server ticks are only 50 ms, so i started on optimizing this.
the main optimization was SSspatial_grid which allows searching through 15x15 spatial_grid_cell datums (one set for each z level) far faster than iterating over movables in view() to look for what you want. now all hearing sensitive movables in the 5x5 areas associated with each spatial_grid_cell datum are stored in the datum (so are client mobs). when you search for one of the stored "types" (hearable or client mob) in a radius around a center, it just needs to
iterate over the cell datums in range
add the content type you want from the datums to a list
subtract contents that arent in range, then contents not in line of sight
return the list
from benchmarks, this makes short range searches like what is used with radio code (it goes over every radio connected to a radio channel that can hear the signal then calls get_hearers_in_view() to search in the radios canhear_range which is at most 3) about 3-10 times faster depending on workload. the line of sight algorithm scales well with range but not very well if it has to check LOS to > 100 objects, which seems incredibly rare for this workload, the largest range any radio in the game searches through is only 3 tiles
the second optimization is to enforce complex setter vars for radios that removes them from the global radio list if they couldnt actually receive any radio transmissions from a given frequency in the first place.
the third optimization i did was massively reduce the number of hearables on the station by making hologram projectors not hear if dont have an active call/anything that would make them need hearing. so one of hte most common non player hearables that require view iteration to find is crossed out.
also implements a variation of an idea oranges had on how to speed up get_hearers_in_view() now that ive realized that view() cant be replicated by a raycasting algorithm. it distributes pregenerated abstract /mob/oranges_ear instances to all hearables in range such that theres at max one per turf and then iterates through only those mobs to take advantage of type-specific view() optimizations and just adds up the references in each one to create the list of hearing atoms, then puts the oranges_ear mobs back into nullspace. this is about 2x as fast as the get_hearers_in_view() on master
holy FUCK its fast. like really fucking fast. the only costly part of the radio transmission pipeline i dont touch is mob/living/Hear() which takes ~100 microseconds on live but searching through every radio in the world with get_hearers_in_radio_ranges() -> get_hearers_in_view() is much faster, as well as the filtering radios step
the spatial grid searching proc is about 36 microseconds/call at 10 range and 16 microseconds at 3 range in the captains office (relatively many hearables in view), the new get_hearers_in_view() was 4.16 times faster than get_hearers_in_view_old() at 10 range and 4.59 times faster at 3 range
SSspatial_grid could be used for a lot more things other than just radio and say code, i just didnt implement it. for example since the cells are datums you could get all cells in a radius then register for new objects entering them then activate when a player enters your radius. this is something that would require either very expensive view() calls or iterating over every player in the global list and calling get_dist() on them which isnt that expensive but is still worse than it needs to be
on normal get_hearers_in_view cost the new version that uses /mob/oranges_ear instances is about 2x faster than the old version, especially since the number of hearing sensitive movables has been brought down dramatically.
with get_hearers_in_view_oranges_ear() being the benchmark proc that implements this system and get_hearers_in_view() being a slightly optimized version of the version we have on master, get_hearers_in_view_as() being a more optimized version of the one we have on master, and get_hearers_in_LOS() being the raycasting version currently only used for radios because it cant replicate view()'s behavior perfectly.
The code in this module originally evolved from dmm_suite and has since been specialized for SS13 and otherwise tweaked to fit /tg/station's needs. dmm_suite version 1.0 Released January 30th, 2011. NOTE: Map saving functionality removed defines the object /dmm_suite - Provides the proc load_map() - Loads the specified map file onto the specified z-level. - provides the proc write_map() - Returns a text string of the map in dmm format ready for output to a file. - provides the proc save_map() - Returns a .dmm file if map is saved - Returns FALSE if map fails to save The dmm_suite provides saving and loading of map files in BYOND's native DMM map format. It approximates the map saving and loading processes of the Dream Maker and Dream Seeker programs so as to allow editing, saving, and loading of maps at runtime. ------------------------ To save a map at runtime, create an instance of /dmm_suite, and then call write_map(), which accepts three arguments: - A turf representing one corner of a three dimensional grid (Required). - Another turf representing the other corner of the same grid (Required). - Any, or a combination, of several bit flags (Optional, see documentation). The order in which the turfs are supplied does not matter, the /dmm_writer will determine the grid containing both, in much the same way as DM's block() function. write_map() will then return a string representing the saved map in dmm format; this string can then be saved to a file, or used for any other purose. ------------------------ To load a map at runtime, create an instance of /dmm_suite, and then call load_map(), which accepts two arguments: - A .dmm file to load (Required). - A number representing the z-level on which to start loading the map (Optional). The /dmm_suite will load the map file starting on the specified z-level. If no z-level was specified, world.maxz will be increased so as to fit the map. Note that if you wish to load a map onto a z-level that already has objects on it, you will have to handle the removal of those objects. Otherwise the new map will simply load the new objects on top of the old ones. Also note that all type paths specified in the .dmm file must exist in the world's code, and that the /dmm_reader trusts that files to be loaded are in fact valid .dmm files. Errors in the .dmm format will cause runtime errors.