102 lines
3.7 KiB
Markdown
102 lines
3.7 KiB
Markdown
# Generic jobs
|
|
|
|
Burst compiles a job in two ways:
|
|
|
|
* In the Editor, it compiles the job when it's scheduled, known as just-in-time (JIT) compilation.
|
|
* In a player build, it compiles the job as part of the built player, known as ahead-of-time (AOT) compilation.
|
|
|
|
For more information, see the documentation on [Compilation](compilation-overview.md).
|
|
|
|
If the job is a concrete type (doesn't use generics), Burst compiles it in both modes (AOT and JIT). However, a generic job might behave in an unexpected way.
|
|
|
|
While Burst supports generics, it has limited support for generic jobs or function pointers. If you notice that a job scheduled in the Editor is running at full speed, but not in a built player, it's might be a problem related to generic jobs.
|
|
|
|
The following example defines a generic job:
|
|
|
|
```c#
|
|
// Direct generic job
|
|
[BurstCompile]
|
|
struct MyGenericJob<TData> : IJob where TData : struct {
|
|
public void Execute() { ... }
|
|
}
|
|
```
|
|
|
|
You can also nest generic jobs:
|
|
|
|
```c#
|
|
// Nested generic job
|
|
public class MyGenericSystem<TData> where TData : struct {
|
|
[BurstCompile]
|
|
struct MyGenericJob : IJob {
|
|
public void Execute() { ... }
|
|
}
|
|
|
|
public void Run()
|
|
{
|
|
var myJob = new MyGenericJob(); // implicitly MyGenericSystem<TData>.MyGenericJob
|
|
myJob.Schedule();
|
|
}
|
|
}
|
|
```
|
|
|
|
Jobs that aren't Burst compiled look like this:
|
|
|
|
```c#
|
|
// Direct Generic Job
|
|
var myJob = new MyGenericJob<int>();
|
|
myJob.Schedule();
|
|
|
|
// Nested Generic Job
|
|
var myJobSystem = new MyGenericSystem<float>();
|
|
myJobSystem.Run();
|
|
```
|
|
|
|
In both cases, in a player build, the Burst compiler detects that it has to compile `MyGenericJob<int>` and `MyGenericJob<float>`. This is because the generic jobs (or the type surrounding it for the nested job) are used with fully resolved generic arguments (`int` and `float`).
|
|
|
|
However, if these jobs are used indirectly through a generic parameter, the Burst compiler can't detect the jobs it has to compile at player build time:
|
|
|
|
```c#
|
|
public static void GenericJobSchedule<TData>() where TData: struct {
|
|
// Generic argument: Generic Parameter TData
|
|
// This Job won't be detected by the Burst Compiler at standalone-player build time.
|
|
var job = new MyGenericJob<TData>();
|
|
job.Schedule();
|
|
}
|
|
|
|
// The implicit MyGenericJob<int> will run at Editor time in full Burst speed
|
|
// but won't be detected at standalone-player build time.
|
|
GenericJobSchedule<int>();
|
|
```
|
|
|
|
The same restriction applies if you declare the job in the context of generic parameter that comes from a type:
|
|
|
|
```c#
|
|
// Generic Parameter TData
|
|
public class SuperJobSystem<TData>
|
|
{
|
|
// Generic argument: Generic Parameter TData
|
|
// This Job won't be detected by the Burst Compiler at standalone-player build time.
|
|
public MyGenericJob<TData> MyJob;
|
|
}
|
|
```
|
|
|
|
If you want to use generic jobs, you must use them directly with fully resolved generic arguments (for example, `int`, `MyOtherStruct`). You can't use them with a generic parameter indirection (for example, `MyGenericJob<TContext>`).
|
|
|
|
>[!IMPORTANT]
|
|
>Burst doesn't support scheduling generic Jobs through generic methods.
|
|
|
|
## Function pointers
|
|
|
|
Function pointers are restricted because you can't use a generic delegate through a function pointer with Burst:
|
|
|
|
```c#
|
|
public delegate void MyGenericDelegate<T>(ref TData data) where TData: struct;
|
|
|
|
var myGenericDelegate = new MyGenericDelegate<int>(MyIntDelegateImpl);
|
|
// Will fail to compile this function pointer.
|
|
var myGenericFunctionPointer = BurstCompiler.CompileFunctionPointer<MyGenericDelegate<int>>(myGenericDelegate);
|
|
```
|
|
|
|
This limitation is because of a limitation of the .NET runtime to interop with such delegates.
|
|
|
|
For more information, see the documentation on [Function pointers](csharp-function-pointers.md). |