虚幻4 编译Shader 5

解决上一个文档的问题，哪里相应了Shader编译完成的消息。

Engine 的LOOP里面调用了这个：

if (GShaderCompilingManager){// Process any asynchronous shader compile results that are ready, limit execution timeQUICK_SCOPE_CYCLE_COUNTER(STAT_FEngineLoop_Tick_GShaderCompilingManager);GShaderCompilingManager->ProcessAsyncResults(true, false);}

ShaderCompilingManage管理了一个编译的线程，那个线程是用来和Worker通信的。

/**   * Manager of asynchronous and parallel shader compilation. * This class contains an interface to enqueue and retreive asynchronous shader jobs, and manages a FShaderCompileThreadRunnable. */class FShaderCompilingManager{

void FShaderCompilingManager::ProcessAsyncResults(bool bLimitExecutionTime, bool bBlockOnGlobalShaderCompletion){if (bAllowAsynchronousShaderCompiling){Thread->CheckHealth();{const double StartTime = FPlatformTime::Seconds();// Block on global shaders before checking for shader maps to finalize// So if we block on global shaders for a long time, we will get a chance to finalize all the non-global shader maps completed during that time.if (bBlockOnGlobalShaderCompletion){TArray<int32> ShaderMapId;ShaderMapId.Add(GlobalShaderMapId);// Block until the global shader map jobs are completeGShaderCompilingManager->BlockOnShaderMapCompletion(ShaderMapId, PendingFinalizeShaderMaps);}int32 NumCompilingShaderMaps = 0;{// Lock CompileQueueSection so we can access the input and output queuesFScopeLock Lock(&CompileQueueSection);if (!bBlockOnGlobalShaderCompletion){bCompilingDuringGame = true;}TArray<int32> ShaderMapsToRemove;for (TMap<int32, FShaderMapCompileResults>::TIterator It(ShaderMapJobs); It; ++It){const FShaderMapCompileResults& Results = It.Value();if (GetNumTotalJobs(Results.FinishedJobs) == Results.NumJobsQueued){PendingFinalizeShaderMaps.Add(It.Key(), FShaderMapFinalizeResults(Results));ShaderMapsToRemove.Add(It.Key());}}for (int32 RemoveIndex = 0; RemoveIndex < ShaderMapsToRemove.Num(); RemoveIndex++){ShaderMapJobs.Remove(ShaderMapsToRemove[RemoveIndex]);}NumCompilingShaderMaps = ShaderMapJobs.Num();}int32 NumPendingShaderMaps = PendingFinalizeShaderMaps.Num();if (PendingFinalizeShaderMaps.Num() > 0){bool bRetry = false;do {bRetry = HandlePotentialRetryOnError(PendingFinalizeShaderMaps);} while (bRetry);const float TimeBudget = bLimitExecutionTime ? ProcessGameThreadTargetTime : FLT_MAX;ProcessCompiledShaderMaps(PendingFinalizeShaderMaps, TimeBudget);check(bLimitExecutionTime || PendingFinalizeShaderMaps.Num() == 0);}if (bBlockOnGlobalShaderCompletion){check(PendingFinalizeShaderMaps.Num() == 0);if (NumPendingShaderMaps - PendingFinalizeShaderMaps.Num() > 0){UE_LOG(LogShaders, Warning, TEXT("Blocking ProcessAsyncResults for %.1fs, processed %u shader maps, %u being compiled"), (float)(FPlatformTime::Seconds() - StartTime),NumPendingShaderMaps - PendingFinalizeShaderMaps.Num(), NumCompilingShaderMaps);}}else if (NumPendingShaderMaps - PendingFinalizeShaderMaps.Num() > 0){UE_LOG(LogShaders, Log, TEXT("Completed %u async shader maps, %u more pending, %u being compiled"), NumPendingShaderMaps - PendingFinalizeShaderMaps.Num(), PendingFinalizeShaderMaps.Num(),NumCompilingShaderMaps);}}}else{check(CompileQueue.Num() == 0);}}

中间可以看到ProcessCompiledShaderMaps，明显是编译完成Shader后会执行的代码。