Unity shader学习之遮罩纹理

什么是遮罩？

遮罩允许我们可以保护某些区域，使它们奂于某些修改。

例如下面的例子，使用遮罩来控制高光反射。

转载请注明出处：http://www.cnblogs.com/jietian331/p/7149182.html

使用的贴图，法线，遮罩纹理如下：

shader如下：

// Upgrade NOTE: replaced 'mul(UNITY_MATRIX_MVP,*)' with 'UnityObjectToClipPos(*)'

Shader "Custom/Mask Texture"

{

    Properties

    {

        _MainTexture("Main Texture", 2D) = "white" {}

        _NormalMap("Normal Map", 2D) = "bump" {}

        _MaskTexture("Mask Texture", 2D) = "white" {}

        _Specular("Specular", Color) = (, , , )

        _Gloss("Gloss", Range(, )) =

    }

    SubShader

    {

        Pass

        {

            Tags

            {

                "LightMode" = "ForwardBase"

            }

            CGPROGRAM

            #pragma vertex vert

            #pragma fragment frag

            #include "UnityCG.cginc"

            #include "Lighting.cginc"

            struct appdata

            {

                float4 vertex : POSITION;

                float4 uv : TEXCOORD0;

                float3 normal : NORMAL;

                float4 tangent : TANGENT;

                float4 color : COLOR;

            };

            struct v2f

            {

                float4 pos : SV_POSITION;

                float4 color : COLOR;

                float4 uv : TEXCOORD0;

                float3 tangentLight : TEXCOORD1;

                float3 tangentView : TEXCOORD2;

            };

            v2f vert(appdata v)

            {

                 v2f o;

                 o.pos = UnityObjectToClipPos(v.vertex);

                 o.uv = v.uv;

                 o.color = v.color;

                 float3 objLightDir = ObjSpaceLightDir(v.vertex);

                 float3 objViewDir = ObjSpaceViewDir(v.vertex);

                 TANGENT_SPACE_ROTATION;

                 o.tangentLight = mul(rotation, objLightDir);

                 o.tangentView = mul(rotation, objViewDir);

                 return o;

            }

            sampler2D _MainTexture;

            sampler2D _NormalMap;

            sampler2D _MaskTexture;

            float4 _Specular;

            float _Gloss;

            fixed4 frag(v2f i) : SV_TARGET

            {

                fixed3 tangentNormal = UnpackNormal(tex2D(_NormalMap, i.uv));

                fixed3 albedo = tex2D(_MainTexture, i.uv).rgb * i.color;

                fixed3 ambient = albedo * UNITY_LIGHTMODEL_AMBIENT.rgb;

                fixed3 diff = albedo * _LightColor0.rgb * max(, dot(tangentNormal, i.tangentLight));

                fixed4 mask = tex2D(_MaskTexture, i.uv);

                fixed3 halfDir = normalize(i.tangentView + i.tangentLight);

                fixed3 spec = _Specular.rgb * _LightColor0.rgb * pow(max(, dot(halfDir, tangentNormal)), _Gloss) * mask.r;

                fixed3 col = ambient + diff + spec;

                return fixed4(col, );

            }

            ENDCG

        }

    }

    Fallback "Specular"

}

使用和不使用遮罩的效果对比图如下：

使用遮罩：

不使用遮罩：

资源如下：

http://files.cnblogs.com/files/jietian331/MaskTexture.rar