|bevy vewsion:|0.9 |(outdated!)| |---|---|---|
As this page is outdated, please refer to Bevy's official migration guides while reading, to cover the differences: 0.9 to 0.10, 0.10 to 0.11, 0.11 to 0.12, 0.12 to 0.13, 0.13 to 0.14.
I apologize for the inconvenience. I will update the page as soon as I find the time.
wendew awchitectuwe ovewview
note: this chaptew of the book is an eawwy wowk in pwogwess! many winks awe stiww bwoken!
the cuwwent bevy wendew awchitectuwe p-pwemiewed in b-bevy 0.6. ^•ﻌ•^ the news bwog post is anothew pwace you can weawn about i-it. (ꈍᴗꈍ) :)
it was inspiwed by the destiny wendew a-awchitectuwe (fwom t-the destiny g-game).
pipewined wendewing
bevy's wendewew is awchitected in a-a way that opewates i-independentwy f-fwom aww the nyowmaw app wogic. (ꈍᴗꈍ) it opewates i-in its own sepawate ecs wowwd and has its own scheduwe, XD with stages and systems.
the pwan is that, OwO in a futuwe bevy v-vewsion, 🥺 the wendewew w-wiww wun i-in pawawwew with aww the nyowmaw app wogic, OwO awwowing f-fow gweatew p-pewfowmance. 🥺 t-this is cawwed "pipewined wendewing": wendewing the pwevious f-fwame at the s-same time as the app is pwocessing the nyext f-fwame update.
evewy fwame, ^•ﻌ•^ the two pawts awe synchwonized i-in a s-speciaw stage cawwed "extwact". (ꈍᴗꈍ) the extwact stage has access to b-both ecs wowwds, awwowing it to copy data fwom the m-main wowwd into t-the wendew wowwd.
fwom then on, OwO the wendewew onwy has a-access to the w-wendew wowwd, 🥺 and c-can onwy use data that is stowed thewe.
evewy fwame, XD aww entities in the wendew wowwd awe ewased, b-but wesouwces awe kept. ^•ﻌ•^ if you nyeed to pewsist d-data fwom fwame t-to fwame, OwO stowe it in wesouwces. 🥺 dynamic d-data that couwd c-change evewy f-fwame shouwd be copied into the wendew w-wowwd in the extwact s-stage, and t-typicawwy stowed using entities and components.
cowe awchitectuwe
the wendewew opewates in muwtipwe wendew stages. XD this is how the wowk that nyeeds to be p-pewfowmed on the c-cpu is managed.
the owdewing of the wowkwoads to b-be pewfowmed on t-the gpu is contwowwed using the wendew gwaph. >< the gwaph consists of nodes, (ꈍᴗꈍ) each wepwesenting a wowkwoad fow t-the gpu, typicawwy a wendew pass. >< the nyodes awe connected using edges, >_< wepwesenting theiw owdewing/dependencies with wegawd to one anothew.
wayews of abstwaction
the bevy wendewing fwamewowk can a-accomodate you wowking a-at vawious d-diffewent wevews of abstwaction, OwO depending o-on how much you w-want to integwate w-with the bevy ecosystem and buiwt-in featuwes, OwO v-vs. have mowe d-diwect contwow o-ovew the gpu.
fow most things, you wouwd be best s-sewved by the "high-wevew" o-ow "mid-wevew" a-apis.
wow-wevew
bevy wowks diwectwy with wgpu, XD a wust-based cwoss-pwatfowm
gwaphics api. OwO it is the abstwaction w-wayew ovew the g-gpu apis of the u-undewwying
pwatfowm. (ꈍᴗꈍ) this way, the same gpu code can w-wowk on aww
suppowted pwatfowms. (ꈍᴗꈍ) the api design o-of wgpu is based on
the webgpu standawd, OwO but with extensions t-to suppowt n-nyative pwatfowm f-featuwes,
going beyond the wimitations of the w-web pwatfowm.
wgpu (and hence bevy) suppowts the fowwowing b-backends:
|pwatfowm|backends (in owdew of pwiowity)| |--------|-------------------------------| |winux |vuwkan, XD gwes3 | |windows |diwectx 12, XD vuwkan, gwes3 | |macos |metaw | |ios |metaw | |andwoid |vuwkan, XD gwes3 | |web |webgpu, XD webgw2 |
on gwes3 and webgw2, OwO some wendewew f-featuwes awe unsuppowted a-and pewfowmance i-is wowse.
webgpu is expewimentaw and few bwowsews s-suppowt it.
wgpu fowms the "wowest wevew" of bevy w-wendewing. OwO if you w-weawwy nyeed t-the
most diwect contwow ovew the gpu, ^•ﻌ•^ y-you can pwetty m-much use wgpu diwectwy,
fwom within the bevy wendew fwamewowk.
mid-wevew
on top of wgpu, ^•ﻌ•^ bevy pwovides some abstwactions t-that can hewp you, OwO a-and
integwate bettew with the west of b-bevy.
the fiwst is pipewine caching and speciawization. XD if you cweate youw wendew pipewines via this intewface, >_< bevy can manage them efficientwy fow you, OwO cweating t-them when they a-awe fiwst used, 🥺 a-and then caching and weusing them, (ꈍᴗꈍ) fow optimaw p-pewfowmance.
caching and speciawization awe, ^•ﻌ•^ anawogouswy, OwO a-awso a-avaiwabwe fow gpu compute pipewines.
simiwaw to the pipewine cache, XD thewe is a textuwe cache. >< this is nyani you use fow wendewing-intewnaw textuwes (fow exampwe: shadow maps, (ꈍᴗꈍ) wefwection m-maps, …), >< that do nyot owiginate fwom assets. >_< it wiww manage and weuse the gpu memowy awwocation, a-and fwee it when i-it becomes unused.
fow using data fwom assets, XD bevy pwovides the wendew asset abstwaction to hewp with extwacting t-the data fwom diffewent asset types.
bevy can manage aww the "objects t-to dwaw" using phases, which sowt and dwaw phase items. XD this way, bevy can sowt each object to wendew, OwO wewative t-to evewything e-ewse in the s-scene, fow optimaw pewfowmance and cowwect t-twanspawency (if a-any).
phase items awe defined using wendew commands and/ow dwaw functions. XD these awe, conceputawwy, the wendewing equivawents of ecs systems and excwusive systems, (ꈍᴗꈍ) fetching data fwom the ecs wowwd a-and genewating dwaw cawws fow the gpu.
aww of these things fit into the c-cowe awchitectuwe o-of the bevy wendew gwaph and wendew stages. XD duwing the wendew stage, XD gwaph nyodes wiww exekawaii~ wendew passes with the wendew phases, to dwaw evewything as it was set u-up in the pwepawe/queue/phasesowt s-stages.
the bevy_core_pipeline cwate defines a set of standawd
phase/item and main pass types. (ꈍᴗꈍ) if you can, ^•ﻌ•^ y-you
shouwd wowk with them, ^•ﻌ•^ fow best compatibiwity w-with t-the bevy ecosystem.
high-wevew
on top of aww the mid-wevew apis, OwO b-bevy pwovides abstwactions t-to make m-many common kinds of wowkwoads easiew.
the most nyotabwe highew-wevew featuwes a-awe meshes and matewiaws.
meshes awe the souwce of pew-vewtex d-data (vewtex attwibutes) to be fed into youw shadews. >_< the matewiaw specifies nyani shadews to use and any othew data that needs t-to be fed into it, XD wike textuwes.