【Unity】RenderFeature笔记

【Unity】RenderFeature笔记

RenderFeature是在urp中添加的额外渲染pass，并可以将这个pass插入到渲染列队中的任意位置。内置渲染管线中Graphics 的功能需要在RenderFeature里实现,常见的如DrawMesh和Blit

​ 可以实现的效果包括但不限于

1. 后处理，可以编写shader对整个渲染画面进行修改。比如一些全局特效包括：场景描边，地形扫描；

2. 创建网格，通过DrawMesh绘制定义的网格；

3. 渲染画面，将场景渲染到纹理；

4. …

一、RanderFeature简介

1. 创建RanderFeature

在project中Create→Rendering→URPRenderFeature

2.RanderFeature结构

using UnityEngine.Rendering;
using UnityEngine.Rendering.Universal;public class CustomRenderPassFeatureTest : ScriptableRendererFeature
{class CustomRenderPass : ScriptableRenderPass{// 在执行渲染通道之前调用// 创建临时渲染目标纹理。//为Execute提前准备需要的RenderTexture或者其它变量public override void OnCameraSetup(CommandBuffer cmd, ref RenderingData renderingData){}//核心方法，实现这个renderPass的逻辑public override void Execute(ScriptableRenderContext context, ref RenderingData renderingData){}//释放在OnCameraSetup里，声明的变量如TemporaryRenderTexturepublic override void OnCameraCleanup(CommandBuffer cmd) {}}CustomRenderPass m_ScriptablePass;/// <inheritdoc/>public override void Create(){m_ScriptablePass = new CustomRenderPass();//定义渲染的位置m_ScriptablePass.renderPassEvent = RenderPassEvent.AfterRenderingOpaques;}// 这里你可以在渲染器中注入一个或多个渲染通道。//每一帧都执行public override void AddRenderPasses(ScriptableRenderer renderer, ref RenderingData renderingData){//把实例化的CustomRenderPass插入渲染管线renderer.EnqueuePass(m_ScriptablePass);}
}

3.RenderFeatrue使用

在Universal Render Pipeline Asset_Renderer直接Add RenderFeatrue

二、后处理效果

关键词

1、CommandBuffer.Blit

Blit是很常用的后期效果方法，在Build_in中常常是在OnRenderImage里被调用，与urp不同的是，在build_in里是通过Graphics.Blit调用。

Graphics.Blit

常用的接口： Blit(RenderTexturesource, RenderTexture dest, Material mat);

即使用着色器将源纹理复制到目标渲染纹理。

CommandBuffer.Blit

常用的接口：public void Blit (Rendering.RenderTargetIdentifier source, Rendering.RenderTargetIdentifier dest, Material mat);

这与 Graphics.Blit相似 - 主要用于从一个（渲染）纹理复制到其他纹理，可能使用自定义着色器；

源纹理或渲染目标将作为“_MainTex”属性传递给材质。

在shader中，_MainTex对应的是source，最后retrun对应的是dest

2、RenderTargetIdentifier

渲染目标标识符，标识 CommandBuffer的 RenderTexture；

使用 CommandBuffer.GetTemporaryRT 创建的具有名称的临时渲染纹理；

ScriptableRenderPass中有colorAttachment和depthAttachment是可以直接使用；

RenderTargetHandle.CameraTarget.Identifier()可以得到当前的渲染标识符

renderingData.cameraData.renderer.cameraColorTarget 也可以得到当前的渲染标识符

简单实现

实现脚本

using UnityEngine;
using UnityEngine.Rendering;
using UnityEngine.Rendering.Universal;public class CustomRenderPassFeatureTest : ScriptableRendererFeature
{//结构说明class CustomRenderPass : ScriptableRenderPass{// 在执行渲染通道之前调用// 创建临时渲染目标纹理。//为Execute提前准备需要的RenderTexture或者其它变量public override void OnCameraSetup(CommandBuffer cmd, ref RenderingData renderingData) {}//核心方法，实现这个renderPass的逻辑public override void Execute(ScriptableRenderContext context, ref RenderingData renderingData){}//释放在OnCameraSetup里，声明的变量如TemporaryRenderTexturepublic override void OnCameraCleanup(CommandBuffer cmd){}}//后处理效果class CustomRenderShaderPostPass : ScriptableRenderPass{  //定义渲染材质，通过Create方法赋值public Material _Material;public override void Execute(ScriptableRenderContext context, ref RenderingData renderingData){//创建一个CommandBufferCommandBuffer cmd = CommandBufferPool.Get("ShowShader");//这里有一个疑问，渲染标识符不管怎么传都不影响结果cmd.Blit(colorAttachment, RenderTargetHandle.CameraTarget.Identifier(), _Material);//执行CommandBuffercontext.ExecuteCommandBuffer(cmd);//回收CommandBufferCommandBufferPool.Release(cmd);}}CustomRenderShaderPostPass m_ScriptablePassPost;public Shader shader;/// <inheritdoc/>public override void Create(){m_ScriptablePassPost = new CustomRenderShaderPostPass();//通过创建一个渲染材质m_ScriptablePassPost._Material = new Material(shader);//定义渲染的位置m_ScriptablePassPost.renderPassEvent = RenderPassEvent.AfterRenderingOpaques;}// 这里你可以在渲染器中注入一个或多个渲染通道。//每一帧都执行public override void AddRenderPasses(ScriptableRenderer renderer, ref RenderingData renderingData){//把实例化的CustomRenderPass插入渲染管线renderer.EnqueuePass(m_ScriptablePassPost);}
}

1.实现饱和度和对比度调整

用shaderGraph实现

用shader实现

Shader "Unlit/SaturationContrastShader"
{SubShader{Pass{ZTest Always ZWrite OffCGPROGRAM#pragma vertex vert_img  // 使用内置的vert_img顶点着色器#pragma fragment frag#include "UnityCG.cginc"sampler2D _CameraColorTexture; //饱和度fixed3   Saturation_float(float3 In, float Saturation){float luma = dot(In, float3(0.2126729, 0.7151522, 0.0721750));return luma.xxx + Saturation.xxx * (In - luma.xxx);}//对比度fixed3  Contrast_float(float3 In, float Contrast){float midpoint = pow(0.5, 2.2);return (In - midpoint) * Contrast + midpoint;}fixed4 frag (v2f_img i) : SV_Target{fixed4 col = tex2D(_CameraColorTexture, i.uv);fixed3  Saturation =  Saturation_float(col, 5);fixed3  Contrast = Saturation_float(Saturation, 5);return fixed4(Contrast.x, Contrast.y, Contrast.z,0.1);}ENDCG}}FallBack Off
}

使用前

使用后

三、创建网格

关键词

1、CommandBuffer.DrawMesh

常用的接口：DrawMesh(Mesh mesh, Matrix4x4 matrix, Material material);

这个接口相对简单，传入mesh，变换矩阵，和材质

简单实现

这里接着上一个CustomRenderPassFeatureTest写，同时实现后处理和网格创建

using UnityEngine;
using UnityEngine.Rendering;
using UnityEngine.Rendering.Universal;public class CustomRenderPassFeatureTest : ScriptableRendererFeature
{//结构说明class CustomRenderPass : ScriptableRenderPass{// 在执行渲染通道之前调用// 创建临时渲染目标纹理。//为Execute提前准备需要的RenderTexture或者其它变量public override void OnCameraSetup(CommandBuffer cmd, ref RenderingData renderingData) {}//核心方法，实现这个renderPass的逻辑public override void Execute(ScriptableRenderContext context, ref RenderingData renderingData){}//释放在OnCameraSetup里，声明的变量如TemporaryRenderTexturepublic override void OnCameraCleanup(CommandBuffer cmd){}}//后处理效果class CustomRenderShaderPostPass : ScriptableRenderPass{  //定义渲染材质，通过Create方法赋值public Material _Material;public override void Execute(ScriptableRenderContext context, ref RenderingData renderingData){//创建一个CommandBufferCommandBuffer cmd = CommandBufferPool.Get("ShowShader");//这里有一个疑问，渲染标识符不管怎么传都不影响结果cmd.Blit(colorAttachment, RenderTargetHandle.CameraTarget.Identifier(), _Material);//执行CommandBuffercontext.ExecuteCommandBuffer(cmd);//回收CommandBufferCommandBufferPool.Release(cmd);}}//绘制网格class CustomRenderPassCreateMesh : ScriptableRenderPass{public Material _Material;public override void Execute(ScriptableRenderContext context, ref RenderingData renderingData){CommandBuffer cmd = CommandBufferPool.Get("CreateMesh");cmd.DrawMesh(CreateMesh(), Matrix4x4.identity, _Material);//这里和后处理一样的操作context.ExecuteCommandBuffer(cmd);CommandBufferPool.Release(cmd);}//创建网格Mesh CreateMesh(){Mesh mesh = new Mesh();mesh.vertices = new Vector3[4] { new Vector3(1, 1, 1), new Vector3(-1, 1, 1), new Vector3(-1, 1, -1), new Vector3(1, 1, -1) };int[] indices = new int[8] { 0, 1, 1, 2, 2, 3, 3, 0 };//创建简单的线网格mesh.SetIndices(indices, MeshTopology.Lines, 0);return mesh;}}CustomRenderShaderPostPass m_ScriptablePassPost;CustomRenderPassCreateMesh m_ScriptablePassCreateMesh;public Shader shaderPost;public Shader shaderMesh;/// <inheritdoc/>public override void Create(){m_ScriptablePassPost = new CustomRenderShaderPostPass();//通过创建一个渲染材质m_ScriptablePassPost._Material = new Material(shaderPost);//定义渲染的位置m_ScriptablePassPost.renderPassEvent = RenderPassEvent.AfterRendering;m_ScriptablePassCreateMesh = new CustomRenderPassCreateMesh();m_ScriptablePassCreateMesh._Material = new Material(shaderMesh);m_ScriptablePassCreateMesh.renderPassEvent = RenderPassEvent.AfterRenderingOpaques;}// 这里你可以在渲染器中注入一个或多个渲染通道。//每一帧都执行public override void AddRenderPasses(ScriptableRenderer renderer, ref RenderingData renderingData){//把实例化的CustomRenderPass插入渲染管线renderer.EnqueuePass(m_ScriptablePassPost);renderer.EnqueuePass(m_ScriptablePassCreateMesh);}
}

实现效果

知识点：RenderPassEvent控制渲染的顺序，上图我们可以看到，创建的线是可以被模型遮挡和遮挡模型的。但是如果把m_ScriptablePassCreateMesh.renderPassEvent=RenderPassEvent.AfterRendering 就会发现线完全遮挡模型，即线最后渲染

四、渲染画面到图片

关键词

1、GetTemporaryRT

获取临时渲染纹理

可使用给定参数创建临时渲染纹理，并使用 nameID 将其设置为全局着色器属性。使用 Shader.PropertyToID创建整数名称。

2、Shader.PropertyToID

获取着色器属性名称的唯一标识符。

static string RtName = "_TestRT";
static int RT_ID = Shader.PropertyToID(RtName);

简单实现

同样接着上一个CustomRenderPassFeatureTest写，同时实现后处理和网格创建

using UnityEngine;
using UnityEngine.Rendering;
using UnityEngine.Rendering.Universal;public class CustomRenderPassFeatureTest : ScriptableRendererFeature
{//结构说明class CustomRenderPass : ScriptableRenderPass{// 在执行渲染通道之前调用// 创建临时渲染目标纹理。//为Execute提前准备需要的RenderTexture或者其它变量public override void OnCameraSetup(CommandBuffer cmd, ref RenderingData renderingData) {}//核心方法，实现这个renderPass的逻辑public override void Execute(ScriptableRenderContext context, ref RenderingData renderingData){}//释放在OnCameraSetup里，声明的变量如TemporaryRenderTexturepublic override void OnCameraCleanup(CommandBuffer cmd){}}//后处理效果class CustomRenderShaderPostPass : ScriptableRenderPass{  //定义渲染材质，通过Create方法赋值public Material _Material;public override void Execute(ScriptableRenderContext context, ref RenderingData renderingData){//创建一个CommandBufferCommandBuffer cmd = CommandBufferPool.Get("ShowShader");//这里有一个疑问，渲染标识符不管怎么传都不影响结果cmd.Blit(colorAttachment, RenderTargetHandle.CameraTarget.Identifier(), _Material);//执行CommandBuffercontext.ExecuteCommandBuffer(cmd);//回收CommandBufferCommandBufferPool.Release(cmd);}}//创建网格class CustomRenderPassCreateMesh : ScriptableRenderPass{public Material _Material;public override void Execute(ScriptableRenderContext context, ref RenderingData renderingData){CommandBuffer cmd = CommandBufferPool.Get("CreateMesh");cmd.DrawMesh(CreateMesh(), Matrix4x4.identity, _Material);context.ExecuteCommandBuffer(cmd);CommandBufferPool.Release(cmd);}//创建网格Mesh CreateMesh(){Mesh mesh = new Mesh();mesh.vertices = new Vector3[4] { new Vector3(1, 1, 1), new Vector3(-1, 1, 1), new Vector3(-1, 1, -1), new Vector3(1, 1, -1) };int[] indices = new int[8] { 0, 1, 1, 2, 2, 3, 3, 0 };mesh.SetIndices(indices, MeshTopology.Lines, 0);return mesh;}}//渲染画面class CustomRenderPassRT : ScriptableRenderPass{static string RtName = "_TestRT";//获取着色器属性名称的唯一标识符。static int RT_ID = Shader.PropertyToID(RtName);public override void OnCameraSetup(CommandBuffer cmd, ref RenderingData renderingData){//新建一个RenderTextureDescriptorRenderTextureDescriptor textureDescriptor = new RenderTextureDescriptor(1920, 1080, RenderTextureFormat.Default, 0);//获取临时渲染纹理cmd.GetTemporaryRT(RT_ID, textureDescriptor);}public override void Execute(ScriptableRenderContext context, ref RenderingData renderingData){CommandBuffer cmd = CommandBufferPool.Get("ShowRT");//下面三段实现效果一样cmd.Blit(renderingData.cameraData.renderer.cameraColorTarget, RT_ID);// cmd.Blit(RenderTargetHandle.CameraTarget.Identifier(), RT_ID);// cmd.Blit(colorAttachment, RT_ID);context.ExecuteCommandBuffer(cmd);CommandBufferPool.Release(cmd);}public override void OnCameraCleanup(CommandBuffer cmd){cmd.ReleaseTemporaryRT(RT_ID);}}CustomRenderShaderPostPass m_ScriptablePassPost;CustomRenderPassCreateMesh m_ScriptablePassCreateMesh;CustomRenderPassRT m_ScriptablePassRenderTextrue;public Shader shaderPost;public Shader shaderMesh;/// <inheritdoc/>public override void Create(){#region 后处理效果m_ScriptablePassPost = new CustomRenderShaderPostPass();//通过创建一个渲染材质m_ScriptablePassPost._Material = new Material(shaderPost);//定义渲染的位置m_ScriptablePassPost.renderPassEvent = RenderPassEvent.AfterRendering;#endregion#region 创建网格m_ScriptablePassCreateMesh = new CustomRenderPassCreateMesh();m_ScriptablePassCreateMesh._Material = new Material(shaderMesh);m_ScriptablePassCreateMesh.renderPassEvent = RenderPassEvent.AfterRenderingOpaques;#endregion#region 渲染画面m_ScriptablePassRenderTextrue = new CustomRenderPassRT();m_ScriptablePassRenderTextrue.renderPassEvent = RenderPassEvent.AfterRendering;#endregion}// 这里你可以在渲染器中注入一个或多个渲染通道。//每一帧都执行public override void AddRenderPasses(ScriptableRenderer renderer, ref RenderingData renderingData){//把实例化的CustomRenderPass插入渲染管线renderer.EnqueuePass(m_ScriptablePassRenderTextrue);renderer.EnqueuePass(m_ScriptablePassPost);renderer.EnqueuePass(m_ScriptablePassCreateMesh);}
}

五、RenderFeatrue参数赋值

1、VolumeComponent

在Volume中提供Render Feature读取参数数据，通过VolumeManager单列，拿到stack，可以直接取得Volume中的数据。

以修改上文后处理的饱和度和对比度为例

1）创建一个全局的Global Volume

右击Hierarchy面板空白处选择Volume→Global Volume

2）自定义一个VolumeComponent

using UnityEngine.Rendering;public class VolumeComponentTest : VolumeComponent
{public ClampedFloatParameter Saturation = new ClampedFloatParameter(1f, 0, 3);public ClampedFloatParameter Contrast = new ClampedFloatParameter(1f, 0, 3);
}

可以在Volume中添加VolumeComponentTest组件

3）在shader中添加控制的参数

这添加了Saturation和Contrast两个控制参数

Shader "Unlit/SaturationContrastShader"
{Properties{_Saturation("Saturation", Range(0, 3)) = 1.0_Contrast("Contrast", Range(0, 3)) = 1.0}SubShader{Pass{ZTest Always ZWrite OffCGPROGRAM#pragma vertex vert_img  // 使用内置的vert_img顶点着色器#pragma fragment frag#include "UnityCG.cginc"float _Saturation;float _Contrast;sampler2D _CameraColorTexture; //饱和度fixed3   Saturation_float(float3 In, float Saturation){float luma = dot(In, float3(0.2126729, 0.7151522, 0.0721750));return luma.xxx + Saturation.xxx * (In - luma.xxx);}//对比度fixed3  Contrast_float(float3 In, float Contrast){float midpoint = pow(0.5, 2.2);return (In - midpoint) * Contrast + midpoint;}fixed4 frag (v2f_img i) : SV_Target{fixed4 col = tex2D(_CameraColorTexture, i.uv);fixed3  Saturation =  Saturation_float(col, _Saturation);fixed3  Contrast = Saturation_float(Saturation, _Contrast);return fixed4(Contrast.x, Contrast.y, Contrast.z,0.1);}ENDCG}}FallBack Off
}

用shaderGraph实现的也是一样的添加两个参数

4）在RenderFeatrue中读取参数

对CustomRenderShaderPostPass修过如下

  class CustomRenderShaderPostPass : ScriptableRenderPass{  //定义渲染材质，通过Create方法赋值public Material _Material;//定义一个VolumeComponentTestVolumeComponentTest volumeComponentTest;public override void Execute(ScriptableRenderContext context, ref RenderingData renderingData){//读取VolumeManager的单列取得stackvar stack = VolumeManager.instance.stack;//为volumeComponentTest赋值volumeComponentTest = stack.GetComponent<VolumeComponentTest>();if (!volumeComponentTest) return;//直接从volumeComponentTest中读取数据_Material.SetFloat("_Saturation", volumeComponentTest.Saturation.value);_Material.SetFloat("_Contrast", volumeComponentTest.Contrast.value);//创建一个CommandBufferCommandBuffer cmd = CommandBufferPool.Get("ShowShader");//这里有一个疑问，渲染标识符不管怎么传都不影响结果cmd.Blit(colorAttachment, RenderTargetHandle.CameraTarget.Identifier(), _Material);//执行CommandBuffercontext.ExecuteCommandBuffer(cmd);//回收CommandBufferCommandBufferPool.Release(cmd);}}

实现效果

2、代码直接赋值

在RenderFeatrue中开放参数，用代码直接赋值

以后处理的饱和度和对比度为例

1）开放参数

在CustomRenderPassFeatureTest和CustomRenderShaderPostPass下分别定义饱和度和对比度，并赋值

public class CustomRenderPassFeatureTest : ScriptableRendererFeature
{//后处理效果class CustomRenderShaderPostPass : ScriptableRenderPass{  //定义渲染材质，通过Create方法赋值public Material _Material;public float _Contrast;public float _Saturation;public override void Execute(ScriptableRenderContext context, ref RenderingData renderingData){_Material.SetFloat("_Saturation", _Saturation);_Material.SetFloat("_Contrast", _Contrast);//创建一个CommandBufferCommandBuffer cmd = CommandBufferPool.Get("ShowShader");//这里有一个疑问，渲染标识符不管怎么传都不影响结果cmd.Blit(colorAttachment, RenderTargetHandle.CameraTarget.Identifier(), _Material);//执行CommandBuffercontext.ExecuteCommandBuffer(cmd);//回收CommandBufferCommandBufferPool.Release(cmd);}}CustomRenderShaderPostPass m_ScriptablePassPost;public Shader shaderPost;public float Saturation;public float Contrast;/// <inheritdoc/>public override void Create(){#region 后处理效果m_ScriptablePassPost = new CustomRenderShaderPostPass();//通过创建一个渲染材质m_ScriptablePassPost._Material = new Material(shaderPost);//将饱和度和对比度赋值给CustomRenderShaderPostPassm_ScriptablePassPost._Contrast = Contrast;m_ScriptablePassPost._Saturation = Saturation;//定义渲染的位置m_ScriptablePassPost.renderPassEvent = RenderPassEvent.AfterRendering;#endregion}// 这里你可以在渲染器中注入一个或多个渲染通道。//每一帧都执行public override void AddRenderPasses(ScriptableRenderer renderer, ref RenderingData renderingData){//把实例化的CustomRenderPass插入渲染管线renderer.EnqueuePass(m_ScriptablePassPost);}
}

2）对参数进行修改

//得到RenderFeatrue    
CustomRenderPassFeatureTest custom=renderData.rendererFeatures.OfType<CustomRenderPassFeatureTest>().FirstOrDefault();
//对值进行修改
custom.Saturation =0;
custom.Contrast =0;
//设置数据
custom.SetParam();