Unity-URP代码架构

protected override void Render(ScriptableRenderContext renderContext, Camera[]cameras)
{
    Render(renderContext, new List<Camera>(cameras));
}

protected override void Render(ScriptableRenderContext renderContext, Camera[] cameras)
{
     //1.准备全局设置的数据
     //2.SortCamera摄像机排序
     //3.RenderSingleCamera渲染单个摄像机
}

public static void RenderSingleCamera(ScriptableRenderContext context, Camera camera)
{
    //1.InitializeCameraData()   使用摄像机上挂的UniversalAdditionalCameraData数据对摄像机设置进行配置
    //2.使用SciptableRenderer进行摄像机绘制，URP里是UniversalRenderer，它继承于ScriptableRenderer。后面有讲解。    
}

public UniversalRenderPipeline(UniversalRenderPipelineAsset asset)
{
    //管线的创建
}

public struct RenderingData
{
    public CullingResults cullResults;
    public CameraData cameraData;
    public LightData lightData;
    public ShadowData shadowData;
    public PostProcessingData postProcessingData;
    public bool supportsDynamicBatching;
    public PerObjectData perObjectData;

    /// <summary>
    /// True if post-processing effect is enabled while rendering the camera stack.
    /// </summary>
    public bool postProcessingEnabled;
}
public struct LightData
{
    public int mainLightIndex;
    public int additionalLightsCount;
    public int maxPerObjectAdditionalLightsCount;
    public NativeArray<VisibleLight> visibleLights;
    internal NativeArray<int> originalIndices;
    public bool shadeAdditionalLightsPerVertex;
    public bool supportsMixedLighting;
    public bool reflectionProbeBoxProjection;
    public bool reflectionProbeBlending;
    public bool supportsLightLayers;

    /// <summary>
    /// True if additional lights enabled.
    /// </summary>
    public bool supportsAdditionalLights;
}
其他结构...

internal static class ShaderPropertyId
{  
    public static readonly int time = Shader.PropertyToID("_Time");
    public static readonly int sinTime = Shader.PropertyToID("_SinTime");
    public static readonly int cosTime = Shader.PropertyToID("_CosTime");
    public static readonly int deltaTime = Shader.PropertyToID("unity_DeltaTime");
    public static readonly int timeParameters = Shader.PropertyToID("_TimeParameters");
    public static readonly int viewMatrix = Shader.PropertyToID("unity_MatrixV");
    public static readonly int projectionMatrix = Shader.PropertyToID("glstate_matrix_projection");
    public static readonly int viewAndProjectionMatrix = Shader.PropertyToID("unity_MatrixVP");
    ...其他
}

public static class ShaderKeywordStrings
{
    public static readonly string MainLightShadows = "_MAIN_LIGHT_SHADOWS";
    public static readonly string MainLightShadowCascades = "_MAIN_LIGHT_SHADOWS_CASCADE";
    public static readonly string MainLightShadowScreen = "_MAIN_LIGHT_SHADOWS_SCREEN";
    public static readonly string CastingPunctualLightShadow = "_CASTING_PUNCTUAL_LIGHT_SHADOW"; 
   ...其他
 }

renderPassEvent  //pass的渲染event

Configure()  //called by the renderer before executing the render pass.

OnCameraSetup()  //called by the renderer before rendering a camera.

OnCameraCleanup(CommandBuffer cmd) //Called on finish rendering a camera

Execute(ScriptableRenderContext context, ref RenderingData renderingData);  //Pass的真正内容

CreateDrawingSettings()  //创建一个DrawSettings对象，控制一些settings

public abstract partial class ScriptableRenderer : IDisposable
{
    设置摄像机矩阵
    void SetCameraMatrices()

    设置每个摄像机的渲染变量，比如worldCameraPos、screenParams、ZBufferParams等
     void SetPerCameraShaderVariables()

     UniversalRenderPipeline绘制摄像机中间去调。执行各个RenderPass的Execute()
     void Execute()

     管理renderfeature的list
     List<ScriptableRenderFeature> renderfeatures

     管理开启的RenderPass队列
     List<ScriptableRenderPass> m_ActiveRenderPassQueue
 
     ...
}

 public sealed class UniversalRenderer : ScriptableRenderer
{
        DepthOnlyPass m_DepthPrepass;
        DepthNormalOnlyPass m_DepthNormalPrepass;
        CopyDepthPass m_PrimedDepthCopyPass;
        MotionVectorRenderPass m_MotionVectorPass;
        MainLightShadowCasterPass m_MainLightShadowCasterPass;
        AdditionalLightsShadowCasterPass m_AdditionalLightsShadowCasterPass;
        GBufferPass m_GBufferPass;
        CopyDepthPass m_GBufferCopyDepthPass;
        TileDepthRangePass m_TileDepthRangePass;
        TileDepthRangePass m_TileDepthRangeExtraPass; // TODO use subpass API to hide this pass
        DeferredPass m_DeferredPass;
        DrawObjectsPass m_RenderOpaqueForwardOnlyPass;
        DrawObjectsPass m_RenderOpaqueForwardPass;
        DrawSkyboxPass m_DrawSkyboxPass;
        CopyDepthPass m_CopyDepthPass;
        CopyColorPass m_CopyColorPass;
        TransparentSettingsPass m_TransparentSettingsPass;
        DrawObjectsPass m_RenderTransparentForwardPass;
        InvokeOnRenderObjectCallbackPass m_OnRenderObjectCallbackPass;
        FinalBlitPass m_FinalBlitPass;
        CapturePass m_CapturePass;
        ...
}

IsActive : 控制Feature是否生效

public abstract  void Create();   //做RenderPass的构造和初始化

public abstract void AddRenderPasses(ScriptableRenderer renderer, ref RenderingDatarenderingData); // 将RenderPass加入渲染队列

public abstract void OnCameraPreCull(); //在camera剔除之前执行

Dispose();  //销毁资源