[游戏开发]ZoomBlur 聚焦模糊效果Shader（URP）

?修改自这篇文章【Unity】UniversalRPでカスタムポストプロセスを作る【ZoomBlur】 - Qiita

?1. VolumeEditor，用于在UnityVolume中控制自己写的后处理效果

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


[System.Serializable, VolumeComponentMenu("Dejavu/ZoomBlur")]
public class ZoomBlurVolume : VolumeComponent, IPostProcessComponent
{
    [Range(0f, 100f), Tooltip("强度")]
    public FloatParameter focusPower = new FloatParameter(0f);

    [Range(0, 10), Tooltip("模糊层数")]
    public IntParameter focusDetail = new IntParameter(5);

    [Tooltip("聚焦焦点")]
    public Vector2Parameter focusScreenPosition = new Vector2Parameter(Vector2.zero);


    public bool IsActive() => focusPower.value > 0f;

    public bool IsTileCompatible() => false;
}

2. RenderFeature和RenderPass

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

public class ZoomBlurRenderFeature : ScriptableRendererFeature
{
    ZoomBlurPass zoomBlurPass;

    public override void Create()
    {
        zoomBlurPass = new ZoomBlurPass(RenderPassEvent.BeforeRenderingPostProcessing);
    }

    public override void AddRenderPasses(ScriptableRenderer renderer, ref RenderingData renderingData)
    {
        zoomBlurPass.Setup(renderer.cameraColorTarget);
        renderer.EnqueuePass(zoomBlurPass);
    }
}

public class ZoomBlurPass : ScriptableRenderPass
{
    static readonly string k_RenderTag = "Render ZoomBlur Effects";
    static readonly int MainTexId = Shader.PropertyToID("_MainTex");
    static readonly int TempTargetId = Shader.PropertyToID("_TempTargetZoomBlur");
    static readonly int FocusPowerId = Shader.PropertyToID("_FocusPower");
    static readonly int FocusDetailId = Shader.PropertyToID("_FocusDetail");
    static readonly int FocusScreenPositionId = Shader.PropertyToID("_FocusScreenPosition");
    ZoomBlurVolume zoomBlur;
    Material zoomBlurMaterial;
    RenderTargetIdentifier currentTarget;

    public ZoomBlurPass(RenderPassEvent evt)
    {
        renderPassEvent = evt;
        var shader = Shader.Find("PostEffect/ZoomBlur");
        if (shader == null)
        {
            Debug.LogError("Shader not found.");
            return;
        }
        zoomBlurMaterial = CoreUtils.CreateEngineMaterial(shader);
    }

    public override void Execute(ScriptableRenderContext context, ref RenderingData renderingData)
    {
        if (zoomBlurMaterial == null)
        {
            Debug.LogError("Material not created.");
            return;
        }

        if (!renderingData.cameraData.postProcessEnabled) return;

        var stack = VolumeManager.instance.stack;
        zoomBlur = stack.GetComponent<ZoomBlurVolume >();
        if (zoomBlur == null) { return; }
        if (!zoomBlur.IsActive()) { return; }
        var cmd = CommandBufferPool.Get(k_RenderTag);
        Render(cmd, ref renderingData);
        context.ExecuteCommandBuffer(cmd);
        CommandBufferPool.Release(cmd);
    }

    public void Setup(in RenderTargetIdentifier currentTarget)
    {
        this.currentTarget = currentTarget;
    }

    void Render(CommandBuffer cmd, ref RenderingData renderingData)
    {
        ref var cameraData = ref renderingData.cameraData;
        var source = currentTarget;
        int destination = TempTargetId;

        var w = cameraData.camera.scaledPixelWidth;
        var h = cameraData.camera.scaledPixelHeight;
        zoomBlurMaterial.SetFloat(FocusPowerId, zoomBlur.focusPower.value);
        zoomBlurMaterial.SetInt(FocusDetailId, zoomBlur.focusDetail.value);
        zoomBlurMaterial.SetVector(FocusScreenPositionId, zoomBlur.focusScreenPosition.value);

        int shaderPass = 0;
        cmd.SetGlobalTexture(MainTexId, source);
        cmd.GetTemporaryRT(destination, w, h, 0, FilterMode.Point, RenderTextureFormat.Default);
        cmd.Blit(source, destination);
        cmd.Blit(destination, source, zoomBlurMaterial, shaderPass);
    }
}

?3.Shader

Shader "PostEffect/ZoomBlur"
{
    Properties
    {
        _MainTex("Texture", 2D) = "white" {}
    }

        SubShader
    {
        Cull Off ZWrite Off ZTest Always
        Tags { "RenderPipeline" = "UniversalPipeline"}
        Pass
        {
            CGPROGRAM
                #pragma vertex Vert
                #pragma fragment Frag

                sampler2D _MainTex;
                float2 _FocusScreenPosition;
                float _FocusPower;
                int _FocusDetail;
                int _ReferenceResolutionX;

                struct appdata
                {
                    float4 vertex : POSITION;
                    float2 uv : TEXCOORD0;
                };

                struct v2f
                {
                    float2 uv : TEXCOORD0;
                    float4 vertex : SV_POSITION;
                };

                v2f Vert(appdata v)
                {
                    v2f o;
                    o.vertex = UnityObjectToClipPos(v.vertex);
                    o.uv = v.uv;
                    return o;
                }

                float4 Frag(v2f i) : SV_Target
                {
                    //_FocusScreenPosition 范围是(-width/2,-height/2) 到( width/2, height/2) ，（0,0）变换到屏幕中心为（_ScreenParams.xy / 2）
                    float2 focusPos = _FocusScreenPosition + _ScreenParams.xy / 2;
                    float2 uv = i.uv;
                    //根据屏幕坐标计算UV
                    float2 focusPosUV = (focusPos / _ScreenParams.xy);
                    //计算像素点距离中心焦点的UV差，以中心点乘系数外扩
                    uv = uv - focusPosUV;
                    float4 outColor = float4(0, 0, 0, 1);
                    //多层模糊
                    for (int i = 0; i < _FocusDetail; i++) {
                        //计算模糊的强度，也就是UV的偏移强度
                        float power = 1.0 - _FocusPower/1000 * float(i);
                        //以中心点乘系数外扩
                        outColor.rgb += tex2D(_MainTex , uv * power + focusPosUV).rgb;
                    }
                    outColor.rgb *= 1.0 / float(_FocusDetail);
                    return outColor;
                }
            ENDCG
        }
    }
}

工程示例链接：git@github.com:Dejavu0709/StudyForShader.git? 中的ZoomBlure文件夹