虚幻4 Slate主线程

来源：互联网发布：淘宝上的海外专营店编辑：程序博客网时间：2024/05/17 23:31

总控制：

Engine_Updating\Engine\Source\Runtime\Slate\Private\Framework\Application\SlateApplication.cpp

void FSlateApplication::PrivateDrawWindows( TSharedPtr<SWindow> DrawOnlyThisWindow ){<span style="color:#ff0000;">DrawWindowAndChildren(CurrentWindow, DrawWindowArgs);</span>

{<span style="color:#ff0000;"></span>SLATE_CYCLE_COUNTER_SCOPE(GSlateRendererDrawWindows);<span style="color:#ff0000;">Renderer->DrawWindows( DrawWindowArgs.OutDrawBuffer );</span>}}

第一个，主线程装配所有的这一帧的UI的数据，保存在DrawWindowArgs.OutDrawBuffer里面，

然后最后调用到第二个红色的地方，用来想渲染线程发送Task。在发送task之前，会调用batcher，先把可以batch的batch到一起。

下面是装配函数:

\Engine\Source\Runtime\Slate\Private\Framework\Application\SlateApplication.cpp

void FSlateApplication::DrawWindowAndChildren( const TSharedRef<SWindow>& WindowToDraw, FDrawWindowArgs& DrawWindowArgs ){// Only draw visible windowsif( WindowToDraw->IsVisible() && !WindowToDraw->IsWindowMinimized() ){SLATE_CYCLE_COUNTER_SCOPE_CUSTOM(GSlateDrawWindowAndChildren, WindowToDraw->GetCreatedInLocation());// Switch to the appropriate world for drawingFScopedSwitchWorldHack SwitchWorld( WindowToDraw );//FPlatformMisc::BeginNamedEvent(FColor::Magenta, "Slate::DrawPrep");<span style="color:#ff0000;">FSlateWindowElementList& WindowElementList = DrawWindowArgs.OutDrawBuffer.AddWindowElementList( WindowToDraw );</span>//FPlatformMisc::EndNamedEvent();// Drawing is done in window space, so null out the positions and keep the size.FGeometry WindowGeometry = WindowToDraw->GetWindowGeometryInWindow();int32 MaxLayerId = 0;{//FPlatformMisc::BeginNamedEvent(FColor::Magenta, "Slate::ClearHitTestGrid");WindowToDraw->GetHittestGrid()->ClearGridForNewFrame( VirtualDesktopRect );//FPlatformMisc::EndNamedEvent();FPlatformMisc::BeginNamedEvent(FColor::Magenta, "Slate::DrawWindow");<span style="color:#ff0000;">MaxLayerId = WindowToDraw->PaintWindow(FPaintArgs(WindowToDraw.Get(), *WindowToDraw->GetHittestGrid(), WindowToDraw->GetPositionInScreen(), GetCurrentTime(), GetDeltaTime()),WindowGeometry, WindowToDraw->GetClippingRectangleInWindow(),WindowElementList,0,FWidgetStyle(),WindowToDraw->IsEnabled() );</span>

第一个红色代码，清掉上一帧的历史数据，班会一个空的buffer，

第二个红色的代码，递归调用，遍历树形结构，向WindowElementList里面填数据。

0 0