# Extraction

**命名空间**: `XCEngine::Rendering`

**类型**: `submodule`

**头文件目录**: `engine/include/XCEngine/Rendering/Extraction/`

**描述**: Rendering 场景提取层，负责把 `Scene` 和 `CameraComponent` 压平成 `RenderSceneData`、`RenderCameraData` 与 `VisibleRenderItem`。

## 概览

`Extraction` 解决的是“场景语义如何转换成渲染语义”。

当前它由两个公开入口组成：

- [RenderSceneExtractor](RenderSceneExtractor/RenderSceneExtractor.md)
- [RenderSceneUtility](RenderSceneUtility/RenderSceneUtility.md)

## 当前职责

- 选择当前应使用的相机
- 提取主方向光和 additional lights
- 遍历场景层级并收集 `VisibleRenderItem`
- 构建 `RenderCameraData`

## 相关文档

- [Rendering](../Rendering.md)
- [FrameData](../FrameData/FrameData.md)
- [Execution](../Execution/Execution.md)
- [Scene Extraction And Builtin Forward Pipeline](../../../_guides/Rendering/Scene-Extraction-And-Builtin-Forward-Pipeline.md)