Unity Shader實現素描效果

本文例項為大家分享了Unity Shader實現素描效果的具體程式碼，供大家參考，具體內容如下
這是樂樂大佬書裡的非真實渲染，其中的演演算法還是挺有意思的，感興趣的小夥伴可以試一試。
素描效果基本原理：先將物體進行描邊畫出輪廓，計算物體的漫反射部分，漫反射越暗表明顏色越暗，然後根據漫反射的值來設定取樣貼圖的權重。
取樣貼圖：
shader部分：
Shader "Unlit/Sketch" { Properties { _Color("Color",Color) = (1,1,1,1) //貼圖平鋪係數 _TileFactor("TileFactor", Range(0, 10)) = 1 _Hatch0("Hatch0",2D)="white"{} _Hatch1("Hatch1",2D) = "white"{} _Hatch2("Hatch2",2D) = "white"{} _Hatch3("Hatch3",2D) = "white"{} _Hatch4("Hatch4",2D) = "white"{} _Hatch5("Hatch5",2D) = "white"{} //描邊係數 _OutlineFactor("OutlineFactor",Range(0.0,0.1))=0.01 } SubShader { Tags{ "Queue" = "Transparent" } //描邊使用兩個Pass，第一個pass沿法線擠出一點，只輸出描邊的顏色 Pass { //剔除正面，只渲染背面 Cull Front //關閉深度寫入 ZWrite Off //控制深度偏移，描邊pass遠離相機一些，防止與正常pass穿插 Offset 1,1 CGPROGRAM #include "UnityCG.cginc" #pragma vertex vert #pragma fragment frag float _OutlineFactor; struct v2f { float4 pos : SV_POSITION; }; v2f vert(appdata_full v) { v2f o; o.pos = UnityObjectToClipPos(v.vertex); //將法線方向轉換到視空間 float3 vnormal = mul((float3x3)UNITY_MATRIX_IT_MV, v.normal); //將視空間法線xy座標轉化到投影空間 float2 offset = TransformViewToProjection(vnormal.xy); //在最終投影階段輸出進行偏移操作 o.pos.xy += offset * _OutlineFactor; return o; } fixed4 frag(v2f i) : SV_Target { return float4(0,0,0,1); } ENDCG } Pass { CGPROGRAM #include "UnityCG.cginc" #include "Lighting.cginc" //使用陰影需新增 #include "AutoLight.cginc" #pragma vertex vert #pragma fragment frag //使主要平行光產生陰影 #pragma multi_compile_fwdbase float4 _Color; float _TileFactor; sampler2D _Hatch0; sampler2D _Hatch1; sampler2D _Hatch2; sampler2D _Hatch3; sampler2D _Hatch4; sampler2D _Hatch5; struct v2f { float2 uv : TEXCOORD0; float4 vertex : SV_POSITION; //6張依次加深的貼圖 float3 hatchWeights0:TEXCOORD1; float3 hatchWeights1:TEXCOORD2; //宣告陰影 SHADOW_COORDS(4) float3 worldPos:TEXCOORD3; }; v2f vert (appdata_full v) { v2f o; o.vertex = UnityObjectToClipPos(v.vertex); //平鋪係數越大，顯示的貼圖越密集 o.uv = v.texcoord* _TileFactor; float3 worldLightDir = normalize(WorldSpaceLightDir(v.vertex)); float3 worldNormal = UnityObjectToWorldNormal(v.normal); //漫反射 float diffuse = max(0, dot(worldLightDir, worldNormal)); o.worldPos = mul(unity_ObjectToWorld, v.vertex).xyz ; //六張圖片的權重 o.hatchWeights0 = float3(0, 0, 0); o.hatchWeights1 = float3(0, 0, 0); //根據漫反射值計算權重，漫反射越暗，線條越密集 float hatchFactor = diffuse * 7.0; 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; } //把計算的陰影傳到fragment中 TRANSFER_SHADOW(o); return o; } fixed4 frag (v2f i) : SV_Target { float4 hatchTex0 = tex2D(_Hatch0, i.uv) * i.hatchWeights0.x; float4 hatchTex1 = tex2D(_Hatch1, i.uv) * i.hatchWeights0.y; float4 hatchTex2 = tex2D(_Hatch2, i.uv) * i.hatchWeights0.z; float4 hatchTex3 = tex2D(_Hatch3, i.uv) * i.hatchWeights1.x; float4 hatchTex4 = tex2D(_Hatch4, i.uv) * i.hatchWeights1.y; float4 hatchTex5 = tex2D(_Hatch5, i.uv) * i.hatchWeights1.z; //漫反射暗色部分權重越大，白色越少 float4 whiteColor = float4(1, 1, 1, 1)*(1 - i.hatchWeights0.x - i.hatchWeights0.y - i.hatchWeights0.z - i.hatchWeights1.x - i.hatchWeights1.y - i.hatchWeights1.z); float4 hatchColor = hatchTex0 + hatchTex1 + hatchTex2 + hatchTex3 + hatchTex4 + hatchTex5+ whiteColor; //使物體接受陰影 UNITY_LIGHT_ATTENUATION(atten, i, i.worldPos); return float4(hatchColor.rgb*_Color.rgb*atten, 1.0); } ENDCG } } }