URP后处理(三)——Volume 控制后处理参数

将后处理参数添加到 Volume 中，如果后处理不需要通过Volume 动态控制，可以不用，

参考代码以及注释：

其中MaterialParameter 是Volume 没有自带的材质类型，需要手动封装不存在的参数类型

using System;
using System.Threading.Tasks;
using UnityEngine;
using UnityEngine.Rendering;
using UnityEngine.Rendering.Universal;

public class MyVolume : VolumeComponent, IPostProcessComponent
{
    
    
    //需要封装参数
    public MaterialParameter Material = new MaterialParameter(null, false);
    //需要封装参数
    public ColorParameter BlendColor = new ColorParameter(Color.white);

    public bool IsActive()
    {
    
    
        if (Material.overrideState == false)//如果材质没有被勾选，则不激活
        {
    
    
            return false;
        }

        return true;
    }

    public bool IsTileCompatible()
    {
    
    
        return true;
    }
}


[Serializable]
public sealed class MaterialParameter : VolumeParameter<Material>
{
    
    
    //没有自带的Material 封装，手动封装参数
    public MaterialParameter(Material value, bool overrideState = false)
        : base(value, overrideState)
    {
    
    
    }
}

MaterialParameter 修改，不需要从Render Feature 面板获取参数，改为从VolumeManager 获取

using UnityEngine;
using UnityEngine.Rendering;
using UnityEngine.Rendering.Universal;

public class MyVolumeFeature : ScriptableRendererFeature
{
    
    
    public Material Material; //UniversalRenderPipelineAsset_Renderer 面板，设置材质
    public Color BlendColor;
    private MyVolumeFeaturePass myPass;
   
    public override void Create()
    {
    
    
        myPass = new MyVolumeFeaturePass();
    }
	
    public override void AddRenderPasses(ScriptableRenderer renderer, ref RenderingData renderingData)
    {
    
    
        renderer.EnqueuePass(myPass);
        myPass.SetValue(renderer.cameraColorTarget, Material,BlendColor); //传递给Pass 处理
    }
}

public class MyVolumeFeaturePass : ScriptableRenderPass
{
    
    
    private Material Material;
    private RenderTargetIdentifier source;
    private Color color;//接受面板颜色
    public override void Execute(ScriptableRenderContext context, ref RenderingData renderingData)
    {
    
    
         MyVolume Volume = VolumeManager.instance.stack.GetComponent<MyVolume>();
         
         if (!Volume.IsActive())//没激活Volume 则不后处理
         {
    
    
             return;
         }
        //执行后处理
        //设置要混合的材质参数，从Volume 获取
        Material = Volume.Material.value;
        Material.SetColor("_Color",Volume.BlendColor.value);
        
        CommandBuffer cmd = CommandBufferPool.Get();
        //source  //源图像
        var dec = renderingData.cameraData.cameraTargetDescriptor; //目标图像
        RenderTargetHandle tempTargetHandle=new RenderTargetHandle();
        cmd.GetTemporaryRT(tempTargetHandle.id, dec);
       
        cmd.Blit(source, tempTargetHandle.Identifier(), Material);
        //核心命令CommandBuffer
        cmd.Blit(tempTargetHandle.Identifier(), source); //相当于 Graphics.Blit

        context.ExecuteCommandBuffer(cmd);
        CommandBufferPool.Release(cmd);
    }
  
    public void SetValue(RenderTargetIdentifier source, Material material, Color blendColor)
    {
    
    
        Material = material; //接受面板材质
        this.source = source;
        color = blendColor;
    }
}

最终效果：与自带的Volume 叠加

UI 没有被MyVolume 后处理,因为没有设置后处理时机

myPass.renderPassEvent = RenderPassEvent.AfterRenderingTransparents;