33 lines
1.1 KiB
Markdown
33 lines
1.1 KiB
Markdown
# NiagaraClearEachFrame
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- **功能描述：** ScriptStruct /Script/Niagara.NiagaraSpawnInfo
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- **使用位置：** USTRUCT
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- **引擎模块：** Niagara
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- **元数据类型：** bool
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- **常用程度：** 0
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指定某结构的数据在Niagara后续每一帧不应该读取，只作为初始数据。
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当前只用在FNiagaraSpawnInfo上，仅仅内部用。
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## 源码例子：
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```cpp
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/** Data controlling the spawning of particles */
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USTRUCT(BlueprintType, meta = (DisplayName = "Spawn Info", NiagaraClearEachFrame = "true"))
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struct FNiagaraSpawnInfo
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{
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}
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```
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## 原理：
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```cpp
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// If the NiagaraClearEachFrame value is set on the data set, we don't bother reading it in each frame as we know that it is is invalid. However,
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// this is only used for the base data set. Other reads are potentially from events and are therefore perfectly valid.
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if (DataSetIndex == 0 && Var.GetType().GetScriptStruct() != nullptr && Var.GetType().GetScriptStruct()->GetMetaData(TEXT("NiagaraClearEachFrame")).Equals(TEXT("true"), ESearchCase::IgnoreCase))
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{
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Fmt = VariableName + TEXT("{0} = {4};\n");
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}
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```
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