自定义 Post-processing V2 Stack

2019-7-28

LWRP 中使用的是 Post-processing V2 Stack，而以前常用的 OnRenderImage 来处理后处理特效也变得失效了。如果要扩展自己的后处理效果，需要换种方式。这里就放一个模板，可以在此基础上进行扩展。

C# 代码（ImageEffectTemplatePP.cs）

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.Rendering.PostProcessing;
using System;

#if UNITY_EDITOR
using UnityEditor.Rendering.PostProcessing;
#endif

[Serializable]
[PostProcess(typeof(ImageEffectTemplatePPRenderer), PostProcessEvent.BeforeStack, "Custom/ImageEffectTemplate")]
public class ImageEffectTemplatePP : PostProcessEffectSettings
{
    [Range(0.0f, 2.0f), Tooltip("Lighting")]
    public FloatParameter m_lighting = new FloatParameter { value = 1f };
}

public sealed class ImageEffectTemplatePPRenderer : PostProcessEffectRenderer<ImageEffectTemplatePP>
{
    Shader m_shader = Shader.Find("Hidden/ImageEffectTemplate");

    public override void Render(PostProcessRenderContext iContext)
    {
        if (m_shader == null)
            return;

        var sheet = iContext.propertySheets.Get(m_shader);
        sheet.properties.SetFloat("_Lighting", settings.m_lighting.value);
        iContext.command.BlitFullscreenTriangle(iContext.source, iContext.destination, sheet, 0);
    }
}

#if UNITY_EDITOR
[PostProcessEditor(typeof(ImageEffectTemplatePP))]
public class ImageEffectTemplatePPEditor : PostProcessEffectEditor<ImageEffectTemplatePP>
{
    SerializedParameterOverride m_lighting;

    public override void OnEnable()
    {
        base.OnEnable();

        m_lighting = FindParameterOverride(x => x.m_lighting);
    }

    public override void OnInspectorGUI()
    {
        base.OnInspectorGUI();

        PropertyField(m_lighting);
    }
}
#endif

Shader 代码（ImageEffectTemplate.shader）

Shader "Hidden/ImageEffectTemplate"
{
    HLSLINCLUDE

    #include "Packages/com.unity.postprocessing/PostProcessing/Shaders/StdLib.hlsl"

    TEXTURE2D_SAMPLER2D(_MainTex, sampler_MainTex);

    uniform float _Lighting;

    float4 Frag(VaryingsDefault i) : SV_TARGET
    {
        float4 color = SAMPLE_TEXTURE2D(_MainTex, sampler_MainTex, i.texcoord);
        color.rgb = (1 - color.rgb) * _Lighting;
        return color;
    }

    ENDHLSL

    SubShader
    {
        Cull Off ZWrite Off ZTest Always

        Pass
        {
            HLSLPROGRAM
                #pragma vertex VertDefault
                #pragma fragment Frag
            ENDHLSL
        }
    }
}

将代码复制到项目中，就可以在 Post Process Volume 上看到自定义的 ImageEffectTemplate 了。