Unity Huatuo revolutionary hot update series [1]

1.1 Why NB？huatuo revolution Unity Hot update

lately huatuo( Hua Tuo ) Hot update solutions are hot unity Development circle , At first, I thought it was hot to update , Is not a built-in script interpreter + Script language development , Such as xLua, ILRuntime, puerts.Huatuo What tricks can you play , Why is it so NB, It has attracted the attention and praise of so many programmers ？ With these questions, I read them in detail huatuo Information , Read the sample project +huatuo Source code , I also instantly became a ” Tuofen ”. Next, update a series of text tutorials + Video tutorials to explain in detail huatuo Hot update .

Here's one Game development communication group , I hope you can go in and learn and communicate together

To master huatuo Hot update , Let's first understand some underlying concepts and principles , Understanding these is mastering huatuo The key to . In this section, I will start with 3 Explain in detail in four aspects huatuo Hot update solutions :

1. il2cpp What is it? ? AOT What is it? ?
2. huatuo The technical principle of hot renewal ;
3. huatuo Revolutionary advantages of the hotter solution ;

il2cpp What is it? ? AOT What is it? ?

Say il2cpp Before , Let's talk about it first. mono, stay mono Before ,C# Good as it is , But only in windows Used on the family platform , That's it C# And Java Can't compare . So Microsoft company to ECMA The application will C# As a standard . stay 2001 year 12 month ,ECMA Released ECMA-334 C# language norm .C# stay 2003 Become a ISO standard （ISO/IEC 23270）. It means that as long as you abide by CLI（Common Language Infrastructure）, Third parties can implement any language to .Net Above the platform . With CLI Standards for ,Mono It was born , The goal of the project is to create a series of products that meet ECMA standard （Ecma-334 and Ecma-335） Of .NET Tools , Include C# Compiler and general language architecture . Microsoft .NET Framework（ Common language operation platform ） Different ,Mono Projects can not only run on Windows On the system , It can also run on Linux,FreeBSD,Unix,OS X and Solaris, Even some game platforms , for example ：Playstation 3,Wii or XBox 360 above .Mono bring C# This language is relative to Microsoft .Net With good cross platform ability .

.Net Framework Runtime library Mono Use your own Mono VM. add C# Its own rapid and friendly development ability , Eventually making Unity At the beginning of its creation, the team decided to Mono,C# As its core .

Next comes an important concept ”IL“.IL The full name is Intermediate Language, Many times you will see CIL（Common Intermediate Language, Especially in .Net Under the platform IL standard ）. stay Unity in ,IL and CIL It means the same thing ： It is a general language architecture and .NET Lower order of frame （lowest-level） Programming language . take .NET The language of the framework is compiled into CIL, Then assemble it into bytecode .CIL Similar to an object-oriented assembly language , And it's completely stack based , It runs in .net Virtual machine .

CLI When the standard comes out , There is another project :IL2CPP, hold IL Turn into static c++ Code file , Compiled into binary machine instructions by a local compiler . because C# Such high-level languages have mechanisms such as garbage collection , therefore IL Turn into static c++ After code , One more IL2CPP Of runtime(IL2CPP VM) To support these high-level language features . adopt IL2CPP technology , We IL Code to local machine code , Get good performance .Unity It's also using this technology , use unity Developed C# The code can go through .net Turn into IL Code , Re pass IL2CPP Turn to static c++ file , Then compile it into local machine code to run . Why? Unity use IL2CPP Well ？ The main reasons are :

a:Mono VM Migrate on various platforms , Maintenance is time consuming , Sometimes it's even impossible to complete .

b: Mono Version authorization is restricted , in IL2CPP,IL2CPP VM This set of completely self-developed components , It solves the authorization problem .

c: Improve operational efficiency , Switch to IL2CPP in the future , The program is compiled into hardware target machine instructions , Improve operation efficiency 1.5-2.0 times .

Unity be based on IL2CPP Architecture principle of , Pictured 1.1-1 Shown :

chart 1.1-1

Unity IL2CPP Operation diagram

The last concept AOT(Ahead of time),AOT technology It refers to the direct transformation of high-level development language into traditional compiled programming language ( Such as C/C++), Then compile it into machine instruction code and run it on hardware .IL2CPP Can be a AOT technology .

huatuo The technical principle of hot renewal

After bedding IL2CPP,AOT Wait for the concept , Next, let's talk about huatuo 了 . From the figure 1.1-1 You know Unity The final packaging run is :AOT( Local machine instruction execution )+, IL2CPP VM( Provide basic service support , Such as gc). about IL2CPP In terms of the underlying operation mode , When it's running, it's Data memory object + Code machine instructions Two parts .huatuo To be hot is to expand IL2CPP VM Service for , Let it be used Original data memory object Under the circumstances , Expanded Explain to perform IL Code The function of ( Note the use of ” Original data memory object ” Very important ). Give Way IL2CPP The operation mode of is changed to :  Data memory object +AOT Code machine instructions +Interpreter IL Instruction interpretation execution Of 3 Parts of .huatuo When it's hotter , We just need to use Unity ADF(asmdef, Assembly definition file ) The mechanism of , Give Way Unity Compile a part separately IL The directive .dll. When it is hotter ,IL2CPP_huatuo You can load IL Instructions .dll, from IL2CPP_huatuo To explain the execution . such AOT Pattern +huatuo IL Instruction interpretation execution (Interpreter) Give Way huatuo It can have the function of hot update . meanwhile huatuo Explain that execution uses original AOT Data memory object , therefore huatuo The hot update will not have the interface export required by other hot update schemes , A series of problems such as cross domain calls . Let developers without any special treatment , Direct use of ordinary unity Development technology can achieve hot update . Because it can be used directly AOT Data memory object , Memory footprint , The performance will be better . With these advantages ( No need to do any code processing can achieve hotter ), It is no wonder that Unity Developers are cheering , Because they can finally lose xLua, ILRuntime Stupid and heavy shell , Solve problems directly from the bottom . So I think the future huatuo It's going to be Unity Hot mainstream solutions .

huatuo Revolutionary advantages of hotter

After analyzing the principle , Let's see huatuo Revolutionary advantages :

huatuo The first 1 One advantage is based on AOT( Local machine code execution )+Interpreter (IL Explain to perform ) Use the same Memory data object , There is no problem of cross domain access . Let's get xLua or ILRuntime Take the heat change scheme as an example , There is a principle in these schemes , Try to minimize and Unity C# Layer interaction , But this kind of interaction is unavoidable and large , For example, we need to access it in the logic code Unity C# Of GameObject Object data , Finally, when running ,GameObject Will be in AOT Native memory data structure object in mode . because xLua or ILRuntime Have your own virtual machine , Therefore, you cannot directly access native GameObject Data objects , It is often necessary to package the data in the access as a function , This greatly increases the performance overhead . and huatuo Is in IL2CPP Interpretation execution in mode , You can directly access native data objects .

huatuo The first 2 One advantage is that our logic code is updated (1.0 Version to 2.0 edition ), If you release a new version 2.0( Reinstall the new version of app), You can directly update the logic , Use it directly AOT Compile it , No need to explain the implementation , In order to gain AOT Performance of . And based on xLua, ILRuntime Hot program development code (1.0 Version to 2.0 edition ), Even if the user reinstalls 2.0 After the client , Or explain and execute , The performance of the new version cannot be achieved AOT Performance level of .

huatuo The first 3 One advantage is that compared with traditional Lua or ILRuntime Thermogeny , He can update any part of the code . Don't look like Lua or ILRuntime equally , Heat distribution code + Framework code , The framework code has bug It can't be hotter .

With these revolutionary advantages , You have no reason not to pay attention + Use huatuo.

Today's sharing is here , Pay attention to our , There will continue to be huatuo Hotter series of tutorials .

Notice of next section : huatuo Solution source code structure and project practice