Unity shader学习之屏幕后期处理效果之边缘检测

边缘检测的原理是利用一些边缘检测算子对图像进行卷积操作。

转载请注明出处：http://www.cnblogs.com/jietian331/p/7232707.html

例如：

代码如下：

 using UnityEngine;

 public class EdgeDetectRenderer : PostEffectRenderer

 {

     [SerializeField]

     Color m_edgeColor;

     protected override void OnRenderImage(RenderTexture src, RenderTexture dest)

     {

         base.Mat.SetColor("_EdgeColor", m_edgeColor);

         base.OnRenderImage(src, dest);

     }

     protected override string ShaderName

     {

         get { return "Custom/Edge Detect"; }

     }

 }

EdgeDetectRenderer

shader如下：

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

 Shader "Custom/Edge Detect"

 {

     Properties

     {

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

         _EdgeColor("Edge Color", Color) = (,,,)

     }

     SubShader

     {

         Pass

         {

             Cull Off

             ZWrite Off

             ZTest Always

             CGPROGRAM

             #pragma vertex vert

             #pragma fragment frag

             sampler2D _MainTex;

             float4 _MainTex_TexelSize;

             uniform fixed4 _EdgeColor;

             struct appdata

             {

                 float4 vertex : POSITION;

                 float2 uv : TEXCOORD0;

             };

             struct v2f

             {

                 float4 pos : SV_POSITION;

                 half2 uv[] : TEXCOORD0;

             };

             v2f vert(appdata v)

             {

                 v2f o;

                 o.pos = UnityObjectToClipPos(v.vertex);

                 o.uv[] = v.uv + _MainTex_TexelSize.xy * half2(-, );

                 o.uv[] = v.uv + _MainTex_TexelSize.xy * half2(, );

                 o.uv[] = v.uv + _MainTex_TexelSize.xy * half2(, );

                 o.uv[] = v.uv + _MainTex_TexelSize.xy * half2(-, );

                 o.uv[] = v.uv + _MainTex_TexelSize.xy * half2(, );

                 o.uv[] = v.uv + _MainTex_TexelSize.xy * half2(, );

                 o.uv[] = v.uv + _MainTex_TexelSize.xy * half2(-, -);

                 o.uv[] = v.uv + _MainTex_TexelSize.xy * half2(, -);

                 o.uv[] = v.uv + _MainTex_TexelSize.xy * half2(, -);

                 return o;

             }

             float luminance(float3 color)

             {

                 return dot(fixed3(0.2125, 0.7154, 0.0721), color);

             }

             half sober(half2 uvs[])

             {

                 half gx[] = {    -, , ,

                                 -, , ,

                                 -, , };

                 half gy[] = {    -, -, -,

                                 , , ,

                                 , , };

                 float edgeX = ;

                 float edgeY = ;

                 for(int i = ; i < ; i++)

                 {

                     fixed3 c = tex2D(_MainTex, uvs[i]).rgb;

                     float l = luminance(c);

                     edgeX += l * gx[i];

                     edgeY += l * gy[i];

                 }

                 return abs(edgeX) + abs(edgeY);

             }

             fixed4 frag(v2f i) : SV_TARGET

             {

                 half edge = sober(i.uv);

                 fixed4 tex = tex2D(_MainTex, i.uv[]);

                 return lerp(tex, _EdgeColor, edge);

             }

             ENDCG

         }

     }

     Fallback Off

 }

效果如下：

巴特西

Unity shader学习之屏幕后期处理效果之边缘检测

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