Unity中URP下实现能量罩（性能优化 和 BRP适配）

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前言

在之前的文章中，我们实现了URP下的能量罩效果。

• Unity中URP下实现能量罩（扭曲流光花纹）

我们在这篇文章中，对其进行性能优化 和 BRP下的适配。

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一、性能优化

1、尽可能减少纹理采样次数

• 我们这里把 能量罩花纹纹理 和 抓屏扭曲纹理 合并成同一个来使用，在效果上没多大变化。但是，可以少使用一次纹理采样。

2、 尽量把 max函数 换成 saturate函数，可以减少一次GPU指令

3、尽可能的把计算移到顶点着色器

• 在片元着色器中计算，需要对片元中的每一个像素进行计算，消耗性能较大

4、变体优化

5、变量放入 常量缓冲区

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二、BuideIn Render Pipeline适配

1、C#脚本开启摄像机深度图

Camera.main.depthTextureMode = DepthTextureMode.Depth;

2、CG语言适配

• 抓屏纹理

GrabPass{“_GrabPass”}

• 引入库修改

#include “UnityCG.cginc”

• 纹理申明

sampler2D _MainTex;
float4 _MainTex_ST;
sampler2D _CameraDepthTexture;
sampler2D _GrabPass;

• 顶点着色器中，顶点坐标系变换需要修改为BRP的方法

v2f vert(appdata v)
{
v2f o = (v2f)0;
o.positionWS = mul(unity_ObjectToWorld,v.positionOS);
o.positionVS = UnityObjectToViewPos(v.positionOS);
o.positionCS = UnityObjectToClipPos(v.positionOS);
o.normalWS = UnityObjectToWorldNormal(v.normalOS);
o.uv.xy = v.uv;
o.uv.zw = TRANSFORM_TEX(v.uv,_MainTex);
return o;
}

• 纹理采样使用 tex2D

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三、最终效果和代码

//流光扭曲花纹
Shader "MyShader/URP/P4_3_7"
{
    Properties
    {
        [Header(MainTex)]
        _MainTex("MainTex",2D) = "white"{}
        [Header(HighLight)]
        _HighLightColor("HighLightColor",Color) = (0,0,0,0)
        _HighLightFade("HighLightFade",Float) = 1.0
        [Header(Fresnel)]
        [PowerSlider(3)]_FresnelIntensity("FresnelIntensity",Range(0,15)) = 1.0
        _FresnelColor("FresnelColor",Color) = (0,0,0,0)
        [Header(Distort)]
        _Tilling("Distort Tilling",Float)=0
        _Distort("Distort",Range(0,1)) = 0.3
    }
    SubShader
    {
        Tags
        {
            //告诉引擎，该Shader只用于 URP 渲染管线
            "RenderPipeline"="UniversalPipeline"
            //渲染类型
            "RenderType"="Transparent"
            //渲染队列
            "Queue"="Transparent"
        }

        Pass
        {
            Blend One One
            ZWrite Off
            Name "Unlit"

            HLSLPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            // Pragmas
            #pragma target 2.0

            // Includes
            #include "Packages/com.unity.render-pipelines.core/ShaderLibrary/Color.hlsl"
            #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"
            #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Input.hlsl"

            CBUFFER_START(UnityPerMaterial)
                half4 _HighLightColor;
                half _HighLightFade;
                half _FresnelIntensity;
                half4 _FresnelColor;
                half _Tilling;
                half _Distort;
                float4 _MainTex_ST;
            CBUFFER_END

            TEXTURE2D(_MainTex);
            SAMPLER(sampler_MainTex);
            TEXTURE2D(_CameraDepthTexture);
            SAMPLER(sampler_CameraDepthTexture);
            TEXTURE2D(_CameraOpaqueTexture);
            SAMPLER(sampler_CameraOpaqueTexture);
            //struct appdata
            //顶点着色器的输入
            struct Attributes
            {
                float3 positionOS : POSITION;
                float2 uv : TEXCOORD0;
                half3 normalOS : NORMAL;
            };

            //struct v2f
            //片元着色器的输入
            struct Varyings
            {
                float4 positionCS : SV_POSITION;
                float4 uv : TEXCOORD0;
                float4 screenPos : TEXCOORD1;
                float3 positionWS : TEXCOORD2;
                float3 positionVS : TEXCOORD3;
                half3 normalWS : TEXCOORD4;
            };

            //v2f vert(Attributes v)
            //顶点着色器
            Varyings vert(Attributes v)
            {
                Varyings o = (Varyings)0;
                o.positionWS = TransformObjectToWorld(v.positionOS);
                o.positionVS = TransformWorldToView(o.positionWS);
                o.positionCS = TransformWViewToHClip(o.positionVS);
                o.screenPos = ComputeScreenPos(o.positionCS);
                o.normalWS = TransformObjectToWorldNormal(v.normalOS);
                o.uv.xy = v.uv;
                o.uv.zw = TRANSFORM_TEX(v.uv, _MainTex);
                return o;
            }

            //fixed4 frag(v2f i) : SV_TARGET
            //片元着色器
            half4 frag(Varyings i) : SV_TARGET
            {
                half4 col = 0;
                //深度图
                //float2 uv = i.screenPos.xy / i.screenPos.w;
                float2 uv = i.positionCS.xy / _ScreenParams.xy;
                half4 cameraDepthTex = SAMPLE_TEXTURE2D(_CameraDepthTexture, sampler_CameraDepthTexture, uv);
                half depthTex = LinearEyeDepth(cameraDepthTex.r, _ZBufferParams);
                half4 highLight = depthTex + i.positionVS.z;
                highLight = pow(saturate(highLight), _HighLightFade);
                highLight = 1 - highLight;
                highLight *= _HighLightColor;
                col += saturate(highLight);

                //fresnel外发光
                //pow(max(0,dot(N,V)),Intensity)
                half3 N = i.normalWS;
                half3 V = normalize(_WorldSpaceCameraPos - i.positionWS);
                half NdotV = dot(N, V);
                half4 fresnel = pow(abs(1 - saturate(NdotV)), _FresnelIntensity);
                fresnel *= _FresnelColor;
                col += fresnel;
                //能量罩花纹
                float4 mainTex = SAMPLE_TEXTURE2D(_MainTex, sampler_MainTex, i.uv.zw + float2(0,_Time.x));
                col += mainTex * 0.1;

                //流光
                half flowMask = frac(i.uv.y * _Tilling + _Time.y);
                col *= flowMask;

                //抓屏流光扭曲
                float2 distortUV = lerp(uv, mainTex.rr, _Distort);
                half4 opaqueTex = SAMPLE_TEXTURE2D(_CameraOpaqueTexture, sampler_CameraOpaqueTexture, distortUV);

                half4 distort = opaqueTex;

                col *= distort;
                return col;
            }
            ENDHLSL
        }
    }

    SubShader
    {
        Tags
        {
            //渲染类型
            "RenderType"="Transparent"
            //渲染队列
            "Queue"="Transparent"
        }

        GrabPass
        {
            "_GrabPass"
        }

        Pass
        {
            Blend One One
            ZWrite Off


            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            // Pragmas
            #pragma target 2.0

            // Includes
            #include "UnityCG.cginc"

            half4 _HighLightColor;
            half _HighLightFade;
            half _FresnelIntensity;
            half4 _FresnelColor;
            half _Tilling;
            half _Distort;

            sampler2D _MainTex;
            float4 _MainTex_ST;
            sampler2D _CameraDepthTexture;
            sampler2D _GrabPass;


            struct appdata
            {
                float3 positionOS : POSITION;
                float2 uv : TEXCOORD0;
                half3 normalOS : NORMAL;
            };

            //struct v2f
            //片元着色器的输入
            struct v2f
            {
                float4 positionCS : SV_POSITION;
                float4 uv : TEXCOORD0;
                float3 positionWS : TEXCOORD2;
                float3 positionVS : TEXCOORD3;
                half3 normalWS : TEXCOORD4;
            };

            //v2f vert(appdata v)
            //顶点着色器
            v2f vert(appdata v)
            {
                v2f o = (v2f)0;
                o.positionWS = mul(unity_ObjectToWorld, v.positionOS);
                o.positionVS = UnityObjectToViewPos(v.positionOS);
                o.positionCS = UnityObjectToClipPos(v.positionOS);
                o.normalWS = UnityObjectToWorldNormal(v.normalOS);
                o.uv.xy = v.uv;
                o.uv.zw = TRANSFORM_TEX(v.uv, _MainTex);
                return o;
            }

            //fixed4 frag(v2f i) : SV_TARGET
            //片元着色器
            half4 frag(v2f i) : SV_TARGET
            {
                half4 col = 0;
                //深度图
                //float2 uv = i.screenPos.xy / i.screenPos.w;
                float2 uv = i.positionCS.xy / _ScreenParams.xy;
                half4 cameraDepthTex = tex2D(_CameraDepthTexture, uv);
                half depthTex = LinearEyeDepth(cameraDepthTex);
                half4 highLight = depthTex + i.positionVS.z;
                highLight = pow(saturate(highLight), _HighLightFade);
                highLight = 1 - highLight;
                highLight *= _HighLightColor;
                col += saturate(highLight);

                //fresnel外发光
                //pow(max(0,dot(N,V)),Intensity)
                half3 N = i.normalWS;
                half3 V = normalize(_WorldSpaceCameraPos - i.positionWS);
                half NdotV = dot(N, V);
                half4 fresnel = pow(abs(1 - saturate(NdotV)), _FresnelIntensity);
                fresnel *= _FresnelColor;
                col += fresnel;
                //能量罩花纹
                float4 mainTex = tex2D(_MainTex, i.uv.zw + float2(0, _Time.x));
                col += mainTex * 0.1;

                //流光
                half flowMask = frac(i.uv.y * _Tilling + _Time.y);
                col *= flowMask;

                //抓屏流光扭曲
                float2 distortUV = lerp(uv, mainTex.rr, _Distort);
                half4 opaqueTex = tex2D(_GrabPass, distortUV);

                half4 distort = opaqueTex;

                col *= distort;
                return col;
            }
            ENDCG
        }
    }
}