描邊效果的實現方式有很多種,比如後期處理的方式、修改頂點著色器的方式。
本次描邊效果的實現方式就是使用第二種方法。
實現思路大致如下:
下面進入shader講解:
Properties { _Albedo ("Albedo", 2D) = "white" {} _Specular ("Specular Glossiness(RGB A)", 2D) = "black" {} _Normal ("Normal", 2D) = "bump" {} _AO ("Ambient Occlusion", 2D) = "white" {} _Emission("Emission", 2D) = "black"{}
_OutlineColor ("Outline Color", Color) = (1,0,1,1) _OutlineWidth ("Outline Width", Range(0, 0.1)) = 0.01 }
定義了Unity Specular標準工作流的材質屬性以及描邊的顏色和寬度。
Tags { "RenderType"="Opaque" "Queue" = "Transparent-1"} LOD 200
渲染類型為不透明。
渲染隊列之所以設置為Transparent,是為了避免被天空盒擋住;而最後減1是為了保證是在Transparent之前被渲染。
Pass { ZWrite Off
CGPROGRAM #pragma vertex vert #pragma fragment frag struct appdata { float4 vertex : POSITION; float3 normal : NORMAL; };
struct v2f { float4 vertex : SV_POSITION; };
fixed4 _OutlineColor; fixed _OutlineWidth;
v2f vert(appdata v) { v2f o; v.vertex.xyz += v.normal * _OutlineWidth; o.vertex = UnityObjectToClipPos(v.vertex); return o; }
fixed4 frag(v2f i) : SV_Target { return _OutlineColor; }
ENDCG }
在頂點著色器裏,我們把頂點坐標向著法線方向擴展,通過_OutlineWidth變數控制擴展的距離。
在片元著色器裏,直接返回_OutlineColor變數的顏色,這樣我們就可以看到膨脹之後的純色效果了。
為了避免膨脹之後的效果擋住接下來的正常效果層,我們把這一pass的深度寫入關閉。
CGPROGRAM // Physically based Standard lighting model, and enable shadows on all light types #pragma surface surf StandardSpecular fullforwardshadows // Use shader model 3.0 target, to get nicer looking lighting #pragma target 3.0
struct Input { float2 uv_Albedo; };
sampler2D _Albedo; sampler2D _Specular; sampler2D _Normal; sampler2D _AO; sampler2D _Emission;
// Add instancing support for this shader. You need to check Enable Instancing on materials that use the shader. // See https://docs.unity3d.com/Manual/GPUInstancing.html for more information about instancing. // #pragma instancing_options assumeuniformscaling UNITY_INSTANCING_BUFFER_START(Props) // put more per-instance properties here UNITY_INSTANCING_BUFFER_END(Props)
void surf (Input IN, inout SurfaceOutputStandardSpecular o) { fixed4 c = tex2D (_Albedo, IN.uv_Albedo); o.Albedo = c.rgb; o.Alpha = c.a;
fixed4 specular = tex2D (_Specular, IN.uv_Albedo); o.Specular = specular.rgb; o.Smoothness = specular.a;
o.Normal = UnpackNormal(tex2D (_Normal, IN.uv_Albedo)); o.Occlusion = tex2D (_AO, IN.uv_Albedo); o.Emission = tex2D (_Emission, IN.uv_Albedo); } ENDCG
這一層是完整Specular工作流的表面著色器,我們也可以根據需要使用頂點-片元著色器。
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