Systems

ComponentSystemBase、SystemBase、ISystemBase、SystemState、Update

继承关系

• ComponentSystemBase
  • SystemBase
  • JobComponentSystem
  • ComponentSystem
    • EntityPatcherBlobAssetSystem
    • RetainBlobAssetSystem
    • ComponentSystemGroup
      • InitializationSystemGroup
      • FixedStepSimulationSystemGroup
      • LateSimulationSystemGroup
      • SimulationSystemGroup
      • PresentationSystemGroup
    • EntityCommandBufferSystem
      • BeginInitializationEntityCommandBufferSystem
      • EndInitializationEntityCommandBufferSystem
      • BeginFixedStepSimulationEntityCommandBufferSystem
      • EndFixedStepSimulationEntityCommandBufferSystem
      • BeginSimulationEntityCommandBufferSystem
      • EndSimulationEntityCommandBufferSystem
      • BeginPresentationEntityCommandBufferSystem

生命周期

1.Create

• OnCreateForCompiler(); 被调用于CreateInstance，被调用于 World.CreateSystemInternal
• OnCreate 被调用于CreateInstance，被调用于 World.CreateSystemInternal

internal void CreateInstance(World world)
{
    m_StatePtr = SystemState.Allocate();
    m_StatePtr->InitManaged(world, GetType());

    OnBeforeCreateInternal(world);
    try
    {
        OnCreateForCompiler();
        OnCreate();
    }
    catch
    {
        OnBeforeDestroyInternal();
        OnAfterDestroyInternal();
        throw;
    }
}

2.OnDestroy

3. Update (主要)

• ComponentSystem.Update

public sealed override void Update()
{
    var state = CheckedState();
#if ENABLE_PROFILER
    using (state->m_ProfilerMarker.Auto())
#endif

    {
        state->BeforeUpdateResetRunTracker();

        if (Enabled && ShouldRunSystem())
        {
            if (!state->m_PreviouslyEnabled)
            {
                state->m_PreviouslyEnabled = true;
                OnStartRunning();
            }

            BeforeOnUpdate();

            var oldExecutingSystem = ms_ExecutingSystem;
            ms_ExecutingSystem = this;

            try
            {
                OnUpdate();
            }
            finally
            {
                ms_ExecutingSystem = oldExecutingSystem;
                AfterOnUpdate();
            }
        }
        else if (state->m_PreviouslyEnabled)
        {
            state->m_PreviouslyEnabled = false;
            OnStopRunningInternal();
        }
    }
}

• JobComponentSystem.Update

public sealed override void Update()
{
    var state = CheckedState();

#if ENABLE_PROFILER
    using (state->m_ProfilerMarker.Auto())
#endif
    {
        if (Enabled && ShouldRunSystem())
        {
            if (!state->m_PreviouslyEnabled)
            {
                state->m_PreviouslyEnabled = true;
                OnStartRunning();
            }

            var inputJob = BeforeOnUpdate();
            JobHandle outputJob = new JobHandle();

            var oldExecutingSystem = ms_ExecutingSystem;
            ms_ExecutingSystem = this;
            try
            {
                outputJob = OnUpdate(inputJob);
            }
            catch
            {
                ms_ExecutingSystem = oldExecutingSystem;

                AfterOnUpdate(outputJob, false);
                throw;
            }

            ms_ExecutingSystem = oldExecutingSystem;

            AfterOnUpdate(outputJob, true);
        }
        else if (state->m_PreviouslyEnabled)
        {
            state->m_PreviouslyEnabled = false;
            OnStopRunning();
        }
    }
}

• SystemBase

public sealed override void Update()
{
    var state = CheckedState();

#if ENABLE_PROFILER
    using (state->m_ProfilerMarker.Auto())
#endif
    {
        state->BeforeUpdateResetRunTracker();

        if (Enabled && ShouldRunSystem())
        {
            if (!state->m_PreviouslyEnabled)
            {
                state->m_PreviouslyEnabled = true;
                OnStartRunning();
            }

            state->BeforeOnUpdate();

            var oldExecutingSystem = ms_ExecutingSystem;
            ms_ExecutingSystem = this;
            try
            {
                OnUpdate();
            }
            catch
            {
                ms_ExecutingSystem = oldExecutingSystem;

                state->AfterOnUpdate();

#if ENABLE_UNITY_COLLECTIONS_CHECKS
                var hasSafetyError = false;
                var details = default(SystemDependencySafetyUtility.SafetyErrorDetails);
                state->CheckSafety(ref details, ref hasSafetyError);
#endif

                throw;
            }

            ms_ExecutingSystem = oldExecutingSystem;

            state->AfterOnUpdate();

#if ENABLE_UNITY_COLLECTIONS_CHECKS
            {
                var hasSafetyError = false;
                var details = default(SystemDependencySafetyUtility.SafetyErrorDetails);
                state->CheckSafety(ref details, ref hasSafetyError);
                if (hasSafetyError)
                {
                    throw new InvalidOperationException(details.FormatToString(GetType()));
                }
            }
#endif
        }
        else if (state->m_PreviouslyEnabled)
        {
            state->m_PreviouslyEnabled = false;
            OnStopRunning();
        }
    }
}

包含重要对象

• SystemState

其他分组属性

UpdateInGroup

UpdateAfter

UpdateBefore