//VideoViewWidget.h
...
UCLASS()
class AGORAVIDEOCALL_API UVideoViewWidget : public UUserWidget
{
GENERATED_BODY()
public:
...
void NativeConstruct() override;
...
};
//VideoViewWidget.cpp
void UVideoViewWidget::NativeConstruct()
{
Super::NativeConstruct();
Width = 640;
Height = 360;
RenderTargetTexture = UTexture2D::CreateTransient(Width, Height, PF_R8G8B8A8);
RenderTargetTexture->UpdateResource();
BufferSize = Width * Height * 4;
Buffer = new uint8[BufferSize];
for (uint32 i = 0; i < Width * Height; ++i)
{
Buffer[i * 4 + 0] = 0x32;
Buffer[i * 4 + 1] = 0x32;
Buffer[i * 4 + 2] = 0x32;
Buffer[i * 4 + 3] = 0xFF;
}
UpdateTextureRegion = new FUpdateTextureRegion2D(0, 0, 0, 0, Width, Height);
RenderTargetTexture->UpdateTextureRegions(0, 1, UpdateTextureRegion, Width * 4, (uint32)4, Buffer);
Brush.SetResourceObject(RenderTargetTexture);
RenderTargetImage->SetBrush(Brush);
}
覆盖 NativeDestruct() 方法
//VideoViewWidget.h
...
UCLASS()
class AGORAVIDEOCALL_API UVideoViewWidget : public UUserWidget
{
GENERATED_BODY()
public:
...
void NativeDestruct() override;
...
};
//VideoViewWidget.cpp
void UVideoViewWidget::NativeDestruct()
{
Super::NativeDestruct();
delete[] Buffer;
delete UpdateTextureRegion;
}
覆盖 NativeTick() 方法
如果UpdateTextureRegion Width或Height不等于memember的Width Height值，我们需要重新创建RenderTargetTexture以支持更新的值，并像Native Construct成员一样重复初始化。否则只需用Buffer调用UpdateTextureRegions。
//VideoViewWidget.h
...
UCLASS()
class AGORAVIDEOCALL_API UVideoViewWidget : public UUserWidget
{
GENERATED_BODY()
public:
...
void NativeTick(const FGeometry& MyGeometry, float DeltaTime) override;
...
};
//VideoViewWidget.cpp
void UVideoViewWidget::NativeTick(const FGeometry& MyGeometry, float DeltaTime)
{
Super::NativeTick(MyGeometry, DeltaTime);
FScopeLock lock(&Mutex);
if (UpdateTextureRegion->Width != Width ||
UpdateTextureRegion->Height != Height)
{
auto NewUpdateTextureRegion = new FUpdateTextureRegion2D(0, 0, 0, 0, Width, Height);
auto NewRenderTargetTexture = UTexture2D::CreateTransient(Width, Height, PF_R8G8B8A8);
NewRenderTargetTexture->UpdateResource();
NewRenderTargetTexture->UpdateTextureRegions(0, 1, NewUpdateTextureRegion, Width * 4, (uint32)4, Buffer);
Brush.SetResourceObject(NewRenderTargetTexture);
RenderTargetImage->SetBrush(Brush);
//UClass's such as UTexture2D are automatically garbage collected when there is no hard pointer references made to that object.
//So if you just leave it and don't reference it elsewhere then it will be destroyed automatically.
FUpdateTextureRegion2D* TmpUpdateTextureRegion = UpdateTextureRegion;
RenderTargetTexture = NewRenderTargetTexture;
UpdateTextureRegion = NewUpdateTextureRegion;
delete TmpUpdateTextureRegion;
return;
}
RenderTargetTexture->UpdateTextureRegions(0, 1, UpdateTextureRegion, Width * 4, (uint32)4, Buffer);
}
