Unity Shader实现素描风格的渲染

Shader "Hatching" 
{
 Properties {
 _Color ("Color Tint", Color) = (1, 1, 1, 1)//颜色
 _TileFactor ("Tile Factor", Float) = 1//纹理的平铺系数，数值越大素描线条越密
 _Outline ("Outline", Range(0, 1)) = 0.1
 _Hatch0 ("Hatch 0", 2D) = "white" {}
 _Hatch1 ("Hatch 1", 2D) = "white" {}
 _Hatch2 ("Hatch 2", 2D) = "white" {}
 _Hatch3 ("Hatch 3", 2D) = "white" {}
 _Hatch4 ("Hatch 4", 2D) = "white" {}
 _Hatch5 ("Hatch 5", 2D) = "white" {}//对应的6张素描纹理
 }
 
 SubShader {
 Tags { "RenderType"="Opaque" "Queue"="Geometry"}
 
 
 Pass {
 Tags { "LightMode"="ForwardBase" }
 
 CGPROGRAM
 
 #pragma vertex vert
 #pragma fragment frag 
 
 #pragma multi_compile_fwdbase
 
 #include "UnityCG.cginc"
 #include "Lighting.cginc"
 #include "AutoLight.cginc"
 #include "UnityShaderVariables.cginc"
 
 fixed4 _Color;
 float _TileFactor;
 sampler2D _Hatch0;
 sampler2D _Hatch1;
 sampler2D _Hatch2;
 sampler2D _Hatch3;
 sampler2D _Hatch4;
 sampler2D _Hatch5;
 
 struct a2v {
 float4 vertex : POSITION;
 float4 tangent : TANGENT; 
 float3 normal : NORMAL; 
 float2 texcoord : TEXCOORD0; 
 };
 
 struct v2f {
 float4 pos : SV_POSITION;
 float2 uv : TEXCOORD0;
 fixed3 hatchWeights0 : TEXCOORD1;//
 fixed3 hatchWeights1 : TEXCOORD2;// 6个混合权重，存在两个fixed3变量中
 float3 worldPos : TEXCOORD3;
 SHADOW_COORDS(4)
 };
 
 v2f vert(a2v v) {
 v2f o;
 
 o.pos = UnityObjectToClipPos(v.vertex);
 
 o.uv = v.texcoord.xy * _TileFactor;
 
 fixed3 worldLightDir = normalize(WorldSpaceLightDir(v.vertex));
 fixed3 worldNormal = UnityObjectToWorldNormal(v.normal);
 fixed diff = max(0, dot(worldLightDir, worldNormal));//漫反射系数
 
 o.hatchWeights0 = fixed3(0, 0, 0);
 o.hatchWeights1 = fixed3(0, 0, 0);
 
 float hatchFactor = diff * 7.0;//把diff缩放到[0,7]范围
 
 //纯白
 if (hatchFactor > 6.0) 
 {
 
 } else if (hatchFactor > 5.0) {
  o.hatchWeights0.x = hatchFactor - 5.0;
 } else if (hatchFactor > 4.0) {
  o.hatchWeights0.x = hatchFactor - 4.0;
  o.hatchWeights0.y = 1.0 - o.hatchWeights0.x;
 } else if (hatchFactor > 3.0) {
  o.hatchWeights0.y = hatchFactor - 3.0;
  o.hatchWeights0.z = 1.0 - o.hatchWeights0.y;
 } else if (hatchFactor > 2.0) {
  o.hatchWeights0.z = hatchFactor - 2.0;
  o.hatchWeights1.x = 1.0 - o.hatchWeights0.z;
 } else if (hatchFactor > 1.0) {
  o.hatchWeights1.x = hatchFactor - 1.0;
  o.hatchWeights1.y = 1.0 - o.hatchWeights1.x;
 } else {
  o.hatchWeights1.y = hatchFactor;
  o.hatchWeights1.z = 1.0 - o.hatchWeights1.y;
 }
 
 o.worldPos = mul(unity_ObjectToWorld, v.vertex).xyz;
 
 TRANSFER_SHADOW(o);
 
 return o; 
 }
 
 fixed4 frag(v2f i) : SV_Target 
 { //根据相应的权重进行采样
 fixed4 hatchTex0 = tex2D(_Hatch0, i.uv) * i.hatchWeights0.x;
 fixed4 hatchTex1 = tex2D(_Hatch1, i.uv) * i.hatchWeights0.y;
 fixed4 hatchTex2 = tex2D(_Hatch2, i.uv) * i.hatchWeights0.z;
 fixed4 hatchTex3 = tex2D(_Hatch3, i.uv) * i.hatchWeights1.x;
 fixed4 hatchTex4 = tex2D(_Hatch4, i.uv) * i.hatchWeights1.y;
 fixed4 hatchTex5 = tex2D(_Hatch5, i.uv) * i.hatchWeights1.z;
 fixed4 whiteColor = fixed4(1, 1, 1, 1) * (1 - i.hatchWeights0.x - i.hatchWeights0.y - i.hatchWeights0.z - 
  i.hatchWeights1.x - i.hatchWeights1.y - i.hatchWeights1.z);
 
 fixed4 hatchColor = hatchTex0 + hatchTex1 + hatchTex2 + hatchTex3 + hatchTex4 + hatchTex5 + whiteColor;
 
 UNITY_LIGHT_ATTENUATION(atten, i, i.worldPos);
  
 return fixed4(hatchColor.rgb * _Color.rgb * atten, 1.0);
 }
 
 ENDCG
 }
 }
 FallBack "Diffuse"
}