Unity CommandBuffer 测试自定义替换渲染

这里做记录用。。。

为了制作其他的一些效果，不得不拿 CommandBuffer 实验一些功能。

这里的替换渲染类似：Camera.RenderWithShader/SetReplacementShader ：Unity - RenderWithShader, SetReplacementShader, ResetReplacementShader 测试

先准备好脚本

Code CSharp

using System;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.Rendering;
using static CmdBuff_ReplacementRender;
// jave.lin 2020.04.13 - CommandBuffer Replace Render
public class CmdReplaceScript : MonoBehaviour
{
    public bool enabledReplace = true;
    public Camera cam;
    public Shader replaceShader;
    private RenderTexture rt;

    [SerializeField] private CmdBuff_ReplacementRender replacementCmdBuff;

    private void Start()
    {
        replacementCmdBuff = new CmdBuff_ReplacementRender(cam, replaceShader);
    }
    private void OnPreRender()
    {
        if (rt == null || rt.width != Screen.width || rt.height != Screen.height)
        {
            if (rt) RenderTexture.ReleaseTemporary(rt);
            rt = RenderTexture.GetTemporary(Screen.width, Screen.height);
            rt.name = "replaceShaderRT";
        }
        if (enabledReplace) replacementCmdBuff.Update(null, CameraEvent.AfterImageEffects);
        else replacementCmdBuff.Clear();
    }

    private void OnDestroy()
    {
        if (rt) RenderTexture.ReleaseTemporary(rt);
        if (replacementCmdBuff != null)
        {
            replacementCmdBuff.Destroy();
            replacementCmdBuff = null;
        }
    }
}
// jave.lin 2020.04.13 - CmdBuff_ReplacementRender
[Serializable]
public class CmdBuff_ReplacementRender
{
    public enum ReplaceType // 替换类型
    {
        CheckType, CheckTypeAndValue, IngoreType_ForAll
    }

    public enum ReplaceTag // 要替换的tag
    {
        CustomType, All
    }

    private static void GetRenders(CmdBuff_ReplacementRender replacement, List replaceList, List sourceList)
    {
        var checkTag = replacement.replaceTag.ToString();
        var checkValue = replacement.replaceType == ReplaceType.CheckTypeAndValue ? replacement.replaceMat.GetTag(checkTag, false) : string.Empty;

        var renderArr = GameObject.FindObjectsOfType();

        if (replacement.replaceType == ReplaceType.IngoreType_ForAll)
        {
            replaceList.AddRange(renderArr);
        }
        else if (replacement.replaceType == ReplaceType.CheckType)
        {
            foreach (var item in renderArr)
            {
                if (!string.IsNullOrEmpty(item.sharedMaterial.GetTag(checkTag, false)))
                {
                    replaceList.Add(item);
                }
                else
                {
                    sourceList.Add(item);
                }
            }
        }
        else if (replacement.replaceType == ReplaceType.CheckTypeAndValue)
        {
            foreach (var item in renderArr)
            {
                if (item.sharedMaterial.GetTag(checkTag, false) == checkValue)
                {
                    replaceList.Add(item);
                }
                else
                {
                    sourceList.Add(item);
                }
            }
        }
    }

    public ReplaceType replaceType;
    public ReplaceTag replaceTag;
    public bool DrawSrcRender = true;

    private Camera cam;
    private CommandBuffer cmdBuff;
    private Shader replaceShader;
    [SerializeField] private Material replaceMat;

    private CameraEvent lastCamEvent;

    [SerializeField] private List replaceList = new List();
    [SerializeField] private List sourceList = new List();

    public CmdBuff_ReplacementRender(Camera cam, Shader replaceShader = null)
    {
        this.cam = cam;
        this.replaceShader = replaceShader;
        this.replaceMat = new Material(this.replaceShader);
    }

    public void Clear()
    {
        if (cmdBuff != null) cmdBuff.Clear();
    }

    public void Update(RenderTexture rt, CameraEvent camEvent)
    {
        if (this.lastCamEvent != camEvent)
        {
            if (cmdBuff != null)
            {
                cam.RemoveCommandBuffer(this.lastCamEvent, cmdBuff);
                cmdBuff.name = $"{camEvent} - Draw Replace";
                cam.AddCommandBuffer(camEvent, cmdBuff);
            }
            this.lastCamEvent = camEvent;
        }
        if (cmdBuff == null)
        {
            cmdBuff = new CommandBuffer();
            cmdBuff.name = $"{this.lastCamEvent} - Draw Replace";
            cam.AddCommandBuffer(this.lastCamEvent, cmdBuff);
        }
        cmdBuff.Clear();
        if (rt) cmdBuff.SetRenderTarget(rt);
        else cmdBuff.SetRenderTarget(cam.targetTexture);
        cmdBuff.ClearRenderTarget(true, true, Color.white);

        replaceList.Clear();
        sourceList.Clear();
        // 如果GetRenders处理了：
        // - Camera.cullMask 的筛选
        // - Renderer.sortingLayerID 的排序
        // - Material.queueID 的排序
        // - 等等其他相关的排序，那么就和Camera.RenderWithShader或是SetReplacementShader差不多了
        GetRenders(this, replaceList, sourceList);
        if (DrawSrcRender)
        {
            foreach (var r in sourceList)
            {
                cmdBuff.DrawRenderer(r, r.sharedMaterial);
            }
        }
        foreach (var r in replaceList)
        {
            cmdBuff.DrawRenderer(r, replaceMat);
        }
    }
    public void Destroy()
    {
        if (cmdBuff != null && cam != null)
        {
            cam.RemoveCommandBuffer(this.lastCamEvent, cmdBuff);
            cmdBuff = null;
            cam = null;
        }
        if (replaceList != null)
        {
            replaceList.Clear();
            replaceList = null;
        }
    }
}

Shader Common.cginc

// jave.lin 2020.04.13
#include "UnityCG.cginc"
#include"Lighting.cginc"
struct appdata {
    float4 vertex : POSITION;
    float3 normal : NORMAL;
};
struct v2f {
    float4 vertex : SV_POSITION;
    float3 worldNormal : TEXCOORD0;
    float3 worldPos : TEXCOORD1;
};
fixed4 _MainColor;
fixed4 _XRayColor;
fixed4 _XRayRimColor;
v2f vert (appdata v) {
    v2f o;
    o.vertex = UnityObjectToClipPos(v.vertex);
    o.worldNormal = UnityObjectToWorldNormal(v.normal);
    o.worldPos = mul(unity_ObjectToWorld, v.vertex);
    return o;
}
fixed4 frag_common(v2f i, fixed4 tintColor) {
    i.worldNormal = normalize(i.worldNormal);
    //viewDir后面高光用
    half3 viewDir = normalize(_WorldSpaceCameraPos.xyz - i.worldPos);
    half3 lightDir = normalize(_WorldSpaceLightPos0.xyz);
    // ambient
    fixed3 ambient = UNITY_LIGHTMODEL_AMBIENT.rgb;
    // diffuse
    fixed LdotN = dot(lightDir, i.worldNormal);
    fixed diffuse = max(0, LdotN);
    // specular
    fixed specular = 0;
    if (LdotN > 0) {
        half3 hDir = normalize(viewDir + lightDir);
        fixed HdotN = max(0, dot(hDir, i.worldNormal));
        specular = pow(HdotN, 64);
    }
    fixed4 combinedCol = 0;
    combinedCol.xyz = ambient + 
            diffuse * _LightColor0.rgb * tintColor.rgb +
            specular * _LightColor0.rgb;
    combinedCol.a = tintColor.a;
    return combinedCol;
}
fixed4 frag (v2f i) : SV_Target {
    return frag_common(i, _MainColor);
}
fixed4 frag_replace (v2f i) : SV_Target {
    return frag_common(i, _XRayColor);
}
fixed4 frag_xray (v2f i) : SV_Target {

    fixed4 result = frag_common(i, _XRayColor);
    // rim
    half3 viewDir = normalize(_WorldSpaceCameraPos.xyz - i.worldPos);
    float VdotN = 1 - max(0, dot(i.worldNormal, viewDir));
    result.xyz = lerp(result.xyz, _XRayRimColor.rgb, VdotN);

    return result;
}
fixed4 frag_replace1(v2f i ) : SV_Target {
    return frag_common(i, lerp(_MainColor, _XRayColor, abs(sin(_Time.w))));
}

A.shader

// jave.lin 2020.04.13
Shader "Custom/A" {
    Properties {
        _MainColor ("Color", Color) = (1,0,0,1)
    }
    SubShader {
        Tags { "CustomType"="A" "All"="1" }
        Pass {
            CGPROGRAM
            #include "Common.cginc"
            #pragma vertex vert
            #pragma fragment frag
            ENDCG
        }
    }
}

B.shader

// jave.lin 2020.04.13
Shader "Custom/B" {
    Properties {
        _MainColor ("Color", Color) = (0,1,0,1)
    }
    SubShader {
        Tags { "CustomType"="B" "All"="1" }
        Pass {
            CGPROGRAM
            #include "Common.cginc"
            #pragma vertex vert
            #pragma fragment frag
            ENDCG
        }
    }
}

C.shader

// jave.lin 2020.04.13
Shader "Custom/C" {
    Properties {
        _MainColor ("Color", Color) = (0,0,1,1)
    }
    SubShader {
        Pass {
            CGPROGRAM
            #include "Common.cginc"
            #pragma vertex vert
            #pragma fragment frag
            ENDCG
        }
    }
}

ReplaceShader.shader

// jave.lin 2020.04.13
Shader "Custom/ReplaceShader" {
    Properties {
        _MainColor ("Color", Color) = (1,1,0,1)
        _XRayColor ("XRayColor", Color) = (0, 1, 1, 0.5)
        _XRayRimColor ("XRayRimColor", Color) = (1, 0, 0, 1)
    }

    SubShader {
        Tags { "CustomType"="B" "All"="1" }
        Blend SrcAlpha OneMinusSrcAlpha
        Pass { // front
            ZWrite Off
            ZTest Greater
            CGPROGRAM
            #include "Common.cginc"
            #pragma vertex vert
            #pragma fragment frag_xray
            ENDCG
        }
        Pass { // front
            ZWrite Off
            CGPROGRAM
            #include "Common.cginc"
            #pragma vertex vert
            #pragma fragment frag_replace
            ENDCG
        }
    }
}

ReplaceShader2.shader

// jave.lin 2020.04.13
Shader "Custom/ReplaceShader2" {
    Properties {
        _MainColor ("Color", Color) = (1,1,0,1)
        _XRayColor ("XRayColor", Color) = (0, 1, 1, 0.5)
        _XRayRimColor ("XRayRimColor", Color) = (1, 0, 0, 1)
    }

    SubShader {
        Tags { "CustomType"="B" "All"="1" }
        Blend SrcAlpha OneMinusSrcAlpha
        Pass { // front
            ZWrite Off
            ZTest Greater
            CGPROGRAM
            #include "Common.cginc"
            #pragma vertex vert
            #pragma fragment frag_xray
            ENDCG
        }
        Pass { // front
            ZWrite Off
            CGPROGRAM
            #include "Common.cginc"
            #pragma vertex vert
            #pragma fragment frag_replace1
            ENDCG
        }
    }
}

运行效果

其中

public enum ReplaceType // 替换类型
{
    CheckType, CheckTypeAndValue, IngoreType_ForAll
}

有三种类型

• CheckType 只要有对应的 tag在，不论之是什么，都可以替换
• CheckTypeAndValue 要有对应tag同时，要需要值与替换shader的是一致才替换
• IngoreType_ForAll 不换检测类似，对所有对象都替换

相比之下，Unity内置的Camera.RenderWithShader接口只能处理 tag 对 value 都相同才能替换。

总结

如果GetRenders处理了：

• Camera.cullMask 的筛选
• Renderer.sortingLayerID 的排序
• Material.queueID 的排序
• 等等其他相关的排序

那么就和Camera.RenderWithShader或是SetReplacementShader差不多了

限制： 想让Renderer指定在其他的Camera下渲染都不行 如：CommandBuffer.DrawRenderer(Renderer, Material);中的Renderer是相对该CommadnBuffer绑定的Camera的变换关系的。

我还想用一个不启用（Active == false）的Camera来作为CommandBuffer的渲染事件来绑定又不可以，因为没有启用（Active == false）的Camera 是不会调用 CameraEvent的。

反正CommandBuffer使用起来还是会有很多限制。

所以，Unity下替换渲染妥妥的还是用回Camera来处理吧。

Project

backup : Unity_CmdBuffReplacementRender_2018.3.0f2

有个更完善的 CmdBuff_ReplacementRender 累，在之前一篇文章：Unity Shader - Custom DirectionalLight ShadowMap 自定义方向光的ShadowMap