Unity shader学习之渐变纹理

渐变纹理，及使用纹理来存储漫反射光照的结果，这种技术在游戏《军团要塞2》中流行起来，它也是由Valve公司（提出半兰伯特光照技术的公司）提出来的，他们使用这种技术来渲染游戏中具有插画风格的角色。

如使用下图作为渐变纹理：

转载请注明出处：http://www.cnblogs.com/jietian331/p/7133212.html

shader如下：

 Shader "Custom/Ramp texture"
 {
     Properties
     {
         _RampTex("Ramp texture", 2D) = "white"
         _Gloss("Gloss", float) =
     }

     SubShader
     {
         Pass
         {
             Tags
             {
                 "LightMode" = "ForwardBase"
             }

             CGPROGRAM
             #pragma vertex vert
             #pragma fragment frag

             #include "UnityCG.cginc"
             #include "Lighting.cginc"

             struct v2f
             {
                 float4 pos : SV_POSITION;
                 float4 worldPos : TEXCOORD0;
                 float3 worldNormal : TEXCOORD1;
             };

             v2f vert(appdata_base v)
             {
                 v2f o;
                 o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
                 o.worldPos = mul(unity_ObjectToWorld, v.vertex);
                 o.worldNormal = normalize(UnityObjectToWorldNormal(v.normal));
                 return o;
             }

             sampler2D _RampTex;
             float _Gloss;

             float4 frag(v2f i) : SV_TARGET
             {
                 float3 worldLightDir = normalize(UnityWorldSpaceLightDir(i.worldPos));
                 float3 worldViewDir = normalize(UnityWorldSpaceViewDir(i.worldPos));

                 float halfLambert = dot(worldLightDir, i.worldNormal) * 0.5 + 0.5;
                 float3 diff = _LightColor0.rgb * tex2D(_RampTex, float2(halfLambert, halfLambert));

                 float3 halfDir = normalize(worldLightDir + worldViewDir);
                 float3 spec = _LightColor0.rgb * pow(saturate(dot(halfDir, i.worldNormal)), _Gloss);

                 float3 col = spec + diff + UNITY_LIGHTMODEL_AMBIENT.rgb;

                 return float4(col.rgb ,);
             }

             ENDCG
         }
     }

     fallback "Diffuse"
 }

效果如下：

资源如下：

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