unreal-engine4 - 如何在 UE4 中动态渲染四边形？

Question

answers.unrealengine.com 上对此有一些手动的答案，但它们似乎缺乏任何细节或示例。

具体来说，如果你想实现一组在 3d 游戏世界中渲染的动态纹理四边形，你会怎么做？

对于用例，请考虑使用Spriter动画的 2dish 侧滚动条。从 XML 加载 2D 动画很容易，但是如何在场景中动态渲染这组 2D 纹理、旋转和缩放的四边形？

score 4 · Accepted Answer

您面临的问题是生成网格还是获得正确的方向？（即正交投影，面向相机）

生成网格很容易，可以通过蓝图或代码来完成。

在蓝图中，您将设置某些先决条件，然后根据条件选择生成 Actor。实际的编码解决方案看起来大致相同。

如果是关于方向，那么这个答案将对您有所帮助，在 UnrealEngine 论坛上找到：

https://answers.unrealengine.com/questions/62126/how-do-i-render-a-dynamic-mesh-with-orthographic-p.html

编辑：

经过大量的头发拉动和文档冲浪，这是使事情正常进行的代码。

ADynamicMeshSpawner::ADynamicMeshSpawner()
{
     // Set this actor to call Tick() every frame.  You can turn this off to improve performance if you don't need it.
     PrimaryActorTick.bCanEverTick = true;

    // Using a SphereComponent is not particularly necessary or relevant, but the cube refused to spawn without a root component to attach to, or so I surmise. Yay Unreal. =/
    USphereComponent* CubeComponent = CreateDefaultSubobject<USphereComponent>(TEXT("RootComponent"));
    RootComponent = CubeComponent;
    CubeComponent->InitSphereRadius(40.0f);
    CubeComponent->SetCollisionProfileName(TEXT("Pawn"));

    // Create and position a mesh component so we can see where our cube is
    UStaticMeshComponent* CubeVisual = CreateDefaultSubobject<UStaticMeshComponent>(TEXT("VisualRepresentation"));
    CubeVisual->AttachTo(RootComponent);
    static ConstructorHelpers::FObjectFinder<UStaticMesh> SphereVisualAsset(TEXT("StaticMesh'/Game/StarterContent/Shapes/Shape_Cube.Shape_Cube'"));
    if (SphereVisualAsset.Succeeded())
    {
        CubeVisual->SetStaticMesh(SphereVisualAsset.Object);
        CubeVisual->SetRelativeLocation(FVector(-200.0f, 0.0f, 100.0f));
        CubeVisual->SetWorldScale3D(FVector(2.0f));
    }
    // Create a material to be applied on the StaticMeshComponent
    static ConstructorHelpers::FObjectFinder<UMaterial> Material(TEXT("Material'/Game/StarterContent/Materials/M_Tech_Hex_Tile_Pulse.M_Tech_Hex_Tile_Pulse'"));

    if (Material.Object != NULL)
    {
        TheMaterial = (UMaterial*)Material.Object;
    }

    CubeVisual->SetMaterial(0, TheMaterial);
}

头文件如下所示：

UCLASS()
class MYPROJECT_API ADynamicMeshSpawner : public AActor
{
    GENERATED_BODY()

public: 
    // Sets default values for this actor's properties
    ADynamicMeshSpawner();

    // Called when the game starts or when spawned
    virtual void BeginPlay() override;

    // Called every frame
    virtual void Tick( float DeltaSeconds ) override;
    // Pointer to the material that needs to be used
    UMaterial* TheMaterial;
};

编辑器中的最终输出如下所示：