85 lines
2.7 KiB
Markdown
85 lines
2.7 KiB
Markdown
|
# LatentCallbackTarget
|
|||
|
|
|
|||
|
|
- **功能描述：** 用在FLatentActionInfo::CallbackTarget属性上，告诉蓝图VM在哪个对象上调用函数。
|
|||
|
|
- **使用位置：** UPROPERTY
|
|||
|
|
- **元数据类型：** bool
|
|||
|
|
- **关联项：** [Latent](Latent.md)
|
|||
|
|
- **常用程度：** ★
|
|||
|
|
|
|||
|
|
用在FLatentActionInfo::CallbackTarget属性上，告诉蓝图VM在哪个对象上调用函数。
|
|||
|
|
|
|||
|
|
```cpp
|
|||
|
|
USTRUCT(BlueprintInternalUseOnly)
|
|||
|
|
struct FLatentActionInfo
|
|||
|
|
{
|
|||
|
|
GENERATED_USTRUCT_BODY()
|
|||
|
|
|
|||
|
|
/** Object to execute the function on. */
|
|||
|
|
UPROPERTY(meta=(LatentCallbackTarget = true))
|
|||
|
|
TObjectPtr<UObject> CallbackTarget;
|
|||
|
|
|
|||
|
|
//...
|
|||
|
|
};
|
|||
|
|
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
## 源码里作用的地方：
|
|||
|
|
|
|||
|
|
```cpp
|
|||
|
|
void EmitLatentInfoTerm(FBPTerminal* Term, FProperty* LatentInfoProperty, FBlueprintCompiledStatement* TargetLabel)
|
|||
|
|
{
|
|||
|
|
// Special case of the struct property emitter. Needs to emit a linkage property for fixup
|
|||
|
|
FStructProperty* StructProperty = CastFieldChecked<FStructProperty>(LatentInfoProperty);
|
|||
|
|
check(StructProperty->Struct == LatentInfoStruct);
|
|||
|
|
|
|||
|
|
int32 StructSize = LatentInfoStruct->GetStructureSize();
|
|||
|
|
uint8* StructData = (uint8*)FMemory_Alloca(StructSize);
|
|||
|
|
StructProperty->InitializeValue(StructData);
|
|||
|
|
|
|||
|
|
// Assume that any errors on the import of the name string have been caught in the function call generation
|
|||
|
|
StructProperty->ImportText_Direct(*Term->Name, StructData, NULL, 0, GLog);
|
|||
|
|
|
|||
|
|
Writer << EX_StructConst;
|
|||
|
|
Writer << LatentInfoStruct;
|
|||
|
|
Writer << StructSize;
|
|||
|
|
|
|||
|
|
checkSlow(Schema);
|
|||
|
|
for (FProperty* Prop = LatentInfoStruct->PropertyLink; Prop; Prop = Prop->PropertyLinkNext)
|
|||
|
|
{
|
|||
|
|
if (TargetLabel && Prop->GetBoolMetaData(FBlueprintMetadata::MD_NeedsLatentFixup))
|
|||
|
|
{
|
|||
|
|
// Emit the literal and queue a fixup to correct it once the address is known
|
|||
|
|
Writer << EX_SkipOffsetConst;
|
|||
|
|
CodeSkipSizeType PatchUpNeededAtOffset = Writer.EmitPlaceholderSkip();
|
|||
|
|
JumpTargetFixupMap.Add(PatchUpNeededAtOffset, FCodeSkipInfo(FCodeSkipInfo::Fixup, TargetLabel));
|
|||
|
|
}
|
|||
|
|
else if (Prop->GetBoolMetaData(FBlueprintMetadata::MD_LatentCallbackTarget))
|
|||
|
|
{
|
|||
|
|
FBPTerminal CallbackTargetTerm;
|
|||
|
|
CallbackTargetTerm.bIsLiteral = true;
|
|||
|
|
CallbackTargetTerm.Type.PinSubCategory = UEdGraphSchema_K2::PN_Self;
|
|||
|
|
EmitTermExpr(&CallbackTargetTerm, Prop);
|
|||
|
|
}
|
|||
|
|
else
|
|||
|
|
{
|
|||
|
|
// Create a new term for each property, and serialize it out
|
|||
|
|
FBPTerminal NewTerm;
|
|||
|
|
if(Schema->ConvertPropertyToPinType(Prop, NewTerm.Type))
|
|||
|
|
{
|
|||
|
|
NewTerm.bIsLiteral = true;
|
|||
|
|
Prop->ExportText_InContainer(0, NewTerm.Name, StructData, StructData, NULL, PPF_None);
|
|||
|
|
|
|||
|
|
EmitTermExpr(&NewTerm, Prop);
|
|||
|
|
}
|
|||
|
|
else
|
|||
|
|
{
|
|||
|
|
// Do nothing for unsupported/unhandled property types. This will leave the value unchanged from its constructed default.
|
|||
|
|
Writer << EX_Nothing;
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
Writer << EX_EndStructConst;
|
|||
|
|
}
|
|||
|
|
```
|