UE4-笔记-通用功能实现逻辑/材质例子

UGameViewportClient记一些自己实现的通用功能的例子.备查

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Q.保持场景Actor相对于Screen的像素缩放比（例如Gizmos组件）:

ref:参考UE源码的UnrealWidgetRender.cpp 里的Render_Rotate函数实现：

如源码,第一步需要获得的是当前相机位的ViewMatrix 的视口矩阵

方式一：

直接重写UGameViewportClient::Draw 截获FSceneView Instance实现.(同Gizmos逻辑)

方式二:

从指定相机获取Info并计算相关Matrix

    UCameraComponent * _Camera = nullptr; /* your camera component */
    
    FMinimalViewInfo info;
    _Camera->GetCameraView(DeltaTime,info);
    FMatrix _ViewMatrix;
    FMatrix _ProjectionMatrix;
    FMatrix _ViewProjectionMatrix;
    UGameplayStatics::GetViewProjectionMatrix(info,_ViewMatrix, _ProjectionMatrix, _ViewProjectionMatrix);
    FVector2D _size; 
    GEngine->GameViewport->GetViewportSize(_size);
    float Scale = _ProjectionMatrix.TransformFVector4(this->GetActorLocation()).W * (4.0f / _size.X / _ProjectionMatrix.M[0][0]);
    FVector scaleV(Scale);

Q.双击模拟（应用于二段跳/双击W加速跑等）:

推荐用C++实现的，BP不好维护搜索定位=_,=

BP:

宏实现:

C++实现:

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.h文件：

UENUM(BlueprintType)
enum class EM_ClickType : uint8
{
    EM_FisrtClick    UMETA(DisplayName = "FisrtClick"),
    EM_DoubleClick    UMETA(DisplayName = "DoubleClick")
};

UCLASS()
class UBPLibrary_CommonDemonstrate : public UBlueprintFunctionLibrary
{
    GENERATED_BODY()
public:
    UFUNCTION(BlueprintCallable)
        static EM_ClickType DoubleClick();
};

cpp文件：

EM_ClickType UCppBPLibrary_CommonDemonstrate::DoubleClick()
{
    static bool bReadyOnce = false;
    if (bReadyOnce)
    {
        bReadyOnce = false;
        return  EM_ClickType::EM_DoubleClick;// double click
    }
    else
    {
        bReadyOnce = true;
        TFuture<void> future = Async<void>(EAsyncExecution::TaskGraph, [=]
        {
            FPlatformProcess::Sleep(0.25);
            if (bReadyOnce)
            {
                bReadyOnce = false;
                return;
            }
        });

        return  EM_ClickType::EM_FisrtClick; // first click
    }
}