Unity Shader学习笔记

Posted 2021-09-10 一吟流曲年殇

 在Unity5.2及以上版本中，Unity一共提供了4中UnityShader模板供我们选择，分别是：UnlitShader、SurfaceShader、ImageEffectShader、ComputeShader。

    SurfaceShader：会产生一个包含了标准光照模型的表面着色器模板，代码如下：

 

Shader "Custom/SurfaceShader" {

Properties {
    _Color ("Color", Color) = (1,1,1,1)
    _MainTex ("Albedo (RGB)", 2D) = "white" {}
    _Glossiness ("Smoothness", Range(0,1)) = 0.5
    _Metallic ("Metallic", Range(0,1)) = 0.0
}
SubShader {
    Tags { "RenderType"="Opaque" }
    LOD 200
    
    CGPROGRAM
    // Physically based Standard lighting model, and enable shadows on all light types
    #pragma surface surf Standard fullforwardshadows

    // Use shader model 3.0 target, to get nicer looking lighting
    #pragma target 3.0

    sampler2D _MainTex;

    struct Input {
        float2 uv_MainTex;
    };

    half _Glossiness;
    half _Metallic;
    fixed4 _Color;

    void surf (Input IN, inout SurfaceOutputStandard o) {
        // Albedo comes from a texture tinted by color
        fixed4 c = tex2D (_MainTex, IN.uv_MainTex) * _Color;
        o.Albedo = c.rgb;
        // Metallic and smoothness come from slider variables
        o.Metallic = _Metallic;
        o.Smoothness = _Glossiness;
        o.Alpha = c.a;
    }
    ENDCG
} 
FallBack "Diffuse"

}
Unlit Shader 会产生一个不包含光照（但包含雾效）的基本顶点/片元着色器，代码如下：

Shader "Unlit/UnlitShader"
{

Properties
{
    _MainTex ("Texture", 2D) = "white" {}
}
SubShader
{
    Tags { "RenderType"="Opaque" }
    LOD 100

    Pass
    {
        CGPROGRAM
        #pragma vertex vert
        #pragma fragment frag
        // make fog work
        #pragma multi_compile_fog
        
        #include "UnityCG.cginc"

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

        struct v2f
        {
            float2 uv : TEXCOORD0;
            UNITY_FOG_COORDS(1)
            float4 vertex : SV_POSITION;
        };

        sampler2D _MainTex;
        float4 _MainTex_ST;
        
        v2f vert (appdata v)
        {
            v2f o;
            o.vertex = mul(UNITY_MATRIX_MVP, v.vertex);
            o.uv = TRANSFORM_TEX(v.uv, _MainTex);
            UNITY_TRANSFER_FOG(o,o.vertex);
            return o;
        }
        
        fixed4 frag (v2f i) : SV_Target
        {
            // sample the texture
            fixed4 col = tex2D(_MainTex, i.uv);
            // apply fog
            UNITY_APPLY_FOG(i.fogCoord, col);                
            return col;
        }
        ENDCG
    }
}

}

Image Effect Shader 则为我们实现各种屏幕后处理效果提供了一个模板，代码如下：

Shader "Hidden/ImageEffectShader"
{

Properties
{
    _MainTex ("Texture", 2D) = "white" {}
}
SubShader
{
    // No culling or depth
    Cull Off ZWrite Off ZTest Always

    Pass
    {
        CGPROGRAM
        #pragma vertex vert
        #pragma fragment frag
        
        #include "UnityCG.cginc"

        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 = mul(UNITY_MATRIX_MVP, v.vertex);
            o.uv = v.uv;
            return o;
        }
        
        sampler2D _MainTex;

        fixed4 frag (v2f i) : SV_Target
        {
            fixed4 col = tex2D(_MainTex, i.uv);
            // just invert the colors
            col = 1 - col;
            return col;
        }
        ENDCG
    }
}

}
Compute Shader会产生一张特殊的Shader文件，这类Shader旨在利用GPU的并行性来进行一些与常规渲染流水线无关的计算,
与正常着色器类似，Compute着色器是项目中的资源文件，具有* .compute文件扩展名。 它们是用DirectX 11风格的HLSL语言编写的，用最少量的#pragma编译指令来指示哪些函数要编译为计算着色器内核。