Ej fɔ Ɛmpaya: 25 Ia fɔ Pathfinding Prɔblɛm wit C++ [Video]

Age of Empires dɔn fɛt wan pan di kɔmpiuting in hadest rial-taym chalenj fɔ pas tu dikɔs: fɔ gɛt yunit dɛn frɔm pɔynt A to pɔynt B we nɔ de luk ɔltogɛda fulish. Di lijen RTS franchis in kɔntinyu strɛch wit C++ pathfinding algɔritm dɛn de sho dip lɛsin dɛn bɔt skɛlabiliti, tɛknikal dɛt, ɛn sistɛm dizayn we ɛvri mɔdan softwe bilda fɔ internalize.

Wan dip-dayv vidio we jɔs kɔmɔt na do de waka tru di ɛvolushɔn fɔ di pathfinding insay Age of Empires, frɔm di ɔrijinal 1997 rilis te to Age of Empires IV, we de ɛksplɔz aw ivin wɔl-klas injinɛri tim dɛn de res wit kɔmplisiti we sistɛm dɛn fɔ skel. Fɔ ɛnibɔdi we de bil biznɛs softwe, we de manej ɔpreshɔn, ɔ akitɔk wokflɔ, di paralel dɛn de strɛch.

Wetin mek Pathfinding dɔn So Hard fɔ Sɔlv insay Age of Empires?

Pathfinding in wan rial-taym strateji gem nɔto di sem wit fɔ rout wan singl GPS dairekshɔn. Age of Empires fɔ kɔlkul di muvmɛnt rod fɔ ɔndrɛd — sɔmtɛm tawzin — yunit dɛn wan tɛm, akɔdin to dinamik chenj tɛri, we dɛn de avɔyd fɔ kɔlishin wit bildin, tik, ɔda yunit, ɛn dɛnsɛf. Ɔl dis fɔ apin insay milisekɔnd fɔ mek yu kɔntinyu fɔ ple gem fayn fayn wan.

Di ɔrijinal Age of Empires bin yuz wan modifyed A* (A-star) algɔrithm, di gold standad fɔ grid-based pathfinding. Bɔt A* nɔmɔ de bɔkul ɔnda prɛshɔn we yu skel frɔm wan anful yunit dɛn to big ami dɛn we de naviget kɔmpleks map dɛn. Ensemble Studios, di ɔrijinal divɛlɔpa, bin spɛn ia fɔ pat edj kes dɛn: yunit dɛn we de waka insay sɛklɔ, we de stɔp pan wɔl, fɔm biznɛs kɔnga layn dɛn tru smɔl pasej dɛn, ɔ jɔs nɔ gri fɔ muv atɔl.

Di kor prɔblɛm na kɔmbinatɔrial ɛksplɔshɔn. Ɛvri adishɔnal yunit na di map de multiply di kɔmpyuta kɔst. Ɛni bildin we dɛn put kin chenj di grafik we de sho usay fɔ go. Ɛvri freym de aks fɔ mek dɛn kɔl am bak. C++ de gi divɛlɔpa dɛn lɔw-lɛvɛl kɔntrol oba mɛmori ɛn pefɔmɛns, bɔt ivin da advantej de gɛt limit we di fondamental algɔritm aprɔch nɔ kin ebul fɔ kip paz wit skel.

Us Algɔritmik Aprɔch dɛn we Divɛlɔpa dɛn dɔn Tray fɔ Ɔva 25 Ia?

Di vidio de kronikl wan fascinating evolushɔn fɔ pathfinding strateji akɔdin to di franchis:

we dɛn kɔl
• Basic A* Search (1997): Di ɔrijinal implimɛnt bin handle smɔl grup dɛn rizinɔs wan bɔt i bin degrad kwik wit ami-sayz sɛlɛkshɔn, we bin de prodyuz di infamous "stuck villager" bɔg dɛn we di pleya dɛn mɛmba te tide.
• Hierarchical Pathfinding: Leta itɛreshɔn dɛn introduks malti-lɛvɛl nevigishɔn mɛsh, brok map dɛn insay sɛktɔ so yunit dɛn kin plan rod dɛn na ay levul bifo dɛn rifin muvmɛnt lokal wan — dramatikli ridyus kɔmpyutishɔn pan wan freym.
• Flɔ Fild: Insted fɔ kɔlkul wan wan pat fɔ ɛni yunit, flɔ fil algɔritm dɛn de kɔmpyutayt wan singl dairekshɔn map we ɔl di yunit dɛn na wan grup kin fala, we de tɔn wan O(n) prɔblɛm to sɔntin we de nia O(1) fɔ ɛni yunit.
• Stia Bihayvya ɛn Lokal Avɔydɛns: Dɛn layt pan tap di glob ɔl patfayn, dɛn sistɛm ya de handle mɔnt-to-mɔmɛnt kɔlishin avɔyd so yunit dɛn nɔ go klip tru dɛnsɛf ɔ stak pan wan tayl.
• Hybrid Systems in AoE IV: Di laytst instɔlmɛnt jɔyn bɔku tɛknik dɛn — nevigishɔn mɛsh, flɔ fil, ɛn lokal stiarin — insay wan layt akitɛkɛt we de deleget difrɛn skel dɛn fɔ muv to difrɛn sabsistim dɛn.

Ɛvri jɛnɛreshɔn na di gem essentially ribild in muvmɛnt sistɛm frɔm skrach, kɛr fɔ go bifo had-wɔn lɛsin dɛn bɔt wetin de brok na skel.

Wetin Biznɛs Sɔftwɛl Tim dɛn Kin Lan frɔm Gem Injin Pathfinding?

Di Age of Empires pathfinding saga na masta klas insay wan prɔblɛm we ɛvri biznɛs we de gro de gɛt: wetin de wok na smɔl skel de shat na big skel. Wan manual prɔses we de handle 10 klaynt dɛn fɔ wan wik de fɔdɔm na 500. Wan sprɛdshit we de trak wan prɔjek kin bi unmanageable akɔdin to 50. Wan aprɔval wokflɔ we dɛn mek fɔ 5-pɔsin tim de mek botlɛn na 50 pipul dɛn.