UE4 Rendering SourceCode
开始阅读UE4 渲染相关的引擎源码。
源代码目录：
\Source\Runtime\Renderer\
这部分主要记录一些基本的数据类型的代码。
FSceneView
- A projection from scene space into a 2D screen region.
将场景空间转换到屏幕空间的类，直接对应了一个View（一个Camera）。
内部保存了ViewMatrix 和ProjectionMatrix。
一个屏幕上可以用有多个View。
和Camera相关的参数设置等，这里应该就是对应一个Camera。
一些参数，都适合具体摄像机相关的内容：
/** Actual field of view and that desired by the camera originally */
float FOV;
FLinearColor BackgroundColor;
FLinearColor OverlayColor;
/** Color scale multiplier used during post processing */
FLinearColor ColorScale;
/** Maximum number of shadow cascades to render with. */
int32 MaxShadowCascades;
FViewMatrices ViewMatrices;
/** Variables used to determine the view matrix */
FVector ViewLocation;
FRotator ViewRotation;
FQuat BaseHmdOrientation;
FVector BaseHmdLocation;
float WorldToMetersScale;
// normally the same as ViewMatrices unless "r.Shadow.FreezeCamera" is activated
FViewMatrices ShadowViewMatrices;
FViewMatrices
和摄像机相关的矩阵：
ViewMatrix和ProjectionMatrix以及相关的数据和操作：
//构造函数
FViewMatrices()
{
ProjectionMatrix.SetIdentity();
ViewMatrix.SetIdentity();
HMDViewMatrixNoRoll.SetIdentity();
TranslatedViewMatrix.SetIdentity();
TranslatedViewProjectionMatrix.SetIdentity();
InvTranslatedViewProjectionMatrix.SetIdentity();
PreViewTranslation = FVector::ZeroVector;
ViewOrigin = FVector::ZeroVector;
ProjectionScale = FVector2D::ZeroVector;
TemporalAAProjectionJitter = FVector2D::ZeroVector;
ScreenScale = 1.f;
}
FSceneViewFamily
- A set of views into a scene which only have different view transforms and owner actors.
保存所有的FSceneView，对应一个RenderTarget.
TArray<const FSceneView*> Views;
一个FSceneViewFamily当中的物体会渲染到同一个RenderTarget上，类似Unity的多个View。
/** The render target which the views are being rendered to. */
const FRenderTarget* RenderTarget;
要绘制的内容保存在FSceneInterface当中：
/** The scene being viewed. */
FSceneInterface* Scene;
其他和一个视口相关的内容：自动曝光。Gamma矫正、截屏内容等。
/** Gamma correction used when rendering this family. Default is 1.0 */
float GammaCorrection;
/** Editor setting to allow designers to override the automatic expose. 0:Automatic, following indices: -4 .. +4 */
FExposureSettings ExposureSettings;
/**
* Which component of the scene rendering should be output to the final render target.
* If SCS_FinalColorLDR this indicates do nothing.
*/
ESceneCaptureSource SceneCaptureSource;
/** When enabled, the scene capture will composite into the render target instead of overwriting its contents. */
ESceneCaptureCompositeMode SceneCaptureCompositeMode;
FSceneInterface
- An interface to the private scene manager implementation of a scene. Use GetRendererModule().AllocateScene to create.
- The scene
场景和场景管理的接口，这部分没有实现代码只有接口。
把UPrimitiveComponent加入FSceneInterface，这里应该是maintread和renderthread的一个交互位置。
UPrimitiveComponent的增删改查，UPrimitiveComponent应该就是场景当中的渲染对象：
virtual void AddPrimitive(UPrimitiveComponent* Primitive) = 0;
virtual void RemovePrimitive(UPrimitiveComponent* Primitive) = 0;
virtual void ReleasePrimitive(UPrimitiveComponent* Primitive) = 0;
virtual bool GetPreviousLocalToWorld(const FPrimitiveSceneInfo* PrimitiveSceneInfo, FMatrix& OutPreviousLocalToWorld) const { return false; }
灯光相关的管理：
virtual void AddLight(ULightComponent* Light) = 0;
virtual void RemoveLight(ULightComponent* Light) = 0;
virtual void AddInvisibleLight(ULightComponent* Light) = 0;
virtual void SetSkyLight(FSkyLightSceneProxy* Light) = 0;
virtual void DisableSkyLight(FSkyLightSceneProxy* Light) = 0;
Decal、反射探针、雾、风场、SpeedTree、特效等的管理。
从开头声明的类可以看出他管理的内容。
// 渲染相关内容
class AWorldSettings;
class FAtmosphericFogSceneInfo;
class FMaterial;
class FMaterialShaderMap;
class FPrimitiveSceneInfo;
class FRenderResource;
class FRenderTarget;
class FSkyLightSceneProxy;
class FTexture;
class FVertexFactory;
// 场景资源
class UDecalComponent;
class ULightComponent;
class UPlanarReflectionComponent;
class UPrimitiveComponent;
class UReflectionCaptureComponent;
class USkyLightComponent;
class UStaticMeshComponent;
class UTextureCube;
UPrimitiveComponent 略
- PrimitiveComponents are SceneComponents that contain or generate some sort of geometry, generally to be rendered or used as collision data.
- There are several subclasses for the various types of geometry, but the most common by far are the ShapeComponents (Capsule, Sphere, Box), StaticMeshComponent, and SkeletalMeshComponent.
- ShapeComponents generate geometry that is used for collision detection but are not rendered, while StaticMeshComponents and SkeletalMeshComponents contain pre-built geometry that is rendered, but can also be used for collision detection.
描述用于渲染或者碰撞计算的组件，描述多种几何体类型：ShapeComponents 、StaticMeshComponent、SkeletalMeshComponent。
ShapeComponents 主要用于碰撞但是不渲染。
StaticMeshComponents and SkeletalMeshComponents 既可以用于碰撞也可以用于渲染。
FRenderResource
- A rendering resource which is owned by the rendering thread.
渲染线程拥有的资源。
和RHI有关的初始化等内容。
具体的实现包括：
FTexture
- A textures resource.
FTextureReference
- A texture reference resource.
FVertexBuffer
- A vertex buffer resource
FNullColorVertexBuffer
- A vertex buffer with a single color component. This is used on meshes that don’t have a color component to keep from needing a separate vertex factory to handle this case.
FIndexBuffer
- An index buffer resource.
和FrenderResource无关的
FGlobalDynamicVertexBuffer
FGlobalDynamicIndexBuffer
FVertexFactory
- Encapsulates a vertex data source which can be linked into a vertex shader.