分享一下我老師大神的人工智慧教程！零基礎，通俗易懂！http://blog.csdn.net/jiangjunshow

也歡迎大家轉載本篇文章。分享知識，造福人民，實現我們中華民族偉大復興！

筆者介紹：姜雪偉，IT公司技術合夥人，IT高階講師，CSDN社群專家，特邀編輯，暢銷書作者，國家專利發明人，已出版書籍：《手把手教你架構3D遊戲引擎》電子工業出版社 和《Unity3D實戰核心技術詳解》電子工業出版社等書籍

在遊戲開發中尤其對於角色的材質渲染一直是被遊戲開發者所看重，也成為衡量遊戲品質的一個指標，關於渲染就需要考慮到Shader程式設計，Shader主要是對模型的頂點和模型的材質圖片做處理，下面告訴讀者如何去編寫Shader。

在公司，策劃需求提出用Unity3D引擎實現角色材質高光、法線效果。策劃需求提出後，美術首先用PS和MAX工具將模型製作出來，MAX中有自身帶的Shader，它可以完整的實現高光、法線效果，這也是程式編寫和除錯Shader時的參照依據，程式是參照MAX中的效果去除錯，程式實現的效果只能無限接近MAX工具製作的效果。Unity5.4以上版本也有自己的高光法線Shader，但是在使用時效果並不理想，不如自己去實現一下。在這裡首先需要提供三張貼圖：Diffuse(原圖)，Specular(高光)，Normal(法線)。

接下來就需要對其進行Shader程式設計實現，為了讓美術除錯方便，在這裡我們使用了控制面板。首先實現一個繼承於Materal類的編輯器指令碼，將其放到Editor資料夾下面，內容如下所示：

using System.Collections.Generic;using UnityEngine;using UnityEditor;using System.Linq;using System.Text.RegularExpressions;public abstract class CustomMaterialEditor :
 
 MaterialEditor{ public class FeatureEditor {  // The name the toggle will have in the inspector.  public string InspectorName;  // We will look for properties that contain this word, and hide them if we're not enabled.  public string InspectorPropertyHideTag;  // The keyword that the shader uses when this feature is enabled or disabled.  public string ShaderKeywordEnabled;  public string ShaderKeywordDisabled;  // The current state of this feature.  public bool Enabled;  public FeatureEditor(string InspectorName, string InspectorPropertyHideTag, string ShaderKeywordEnabled, string ShaderKeywordDisabled)  {   this.InspectorName = InspectorName;   this.InspectorPropertyHideTag = InspectorPropertyHideTag;   this.ShaderKeywordEnabled = ShaderKeywordEnabled;   this.ShaderKeywordDisabled = ShaderKeywordDisabled;   this.Enabled = false;  } } // A list of all the toggles that we have in this material editor. protected List<FeatureEditor> Toggles = new List<FeatureEditor>(); // This function will be implemented in derived classes, and used to populate the list of toggles. protected abstract void CreateToggleList();  public override void OnInspectorGUI () {  // if we are not visible... return  if (!isVisible)   return;  // Get the current keywords from the material  Material targetMat = target as Material;  string[] oldKeyWords = targetMat.shaderKeywords;  // Populate our list of toggles  //Toggles.Clear();  Toggles = new List<FeatureEditor>();  CreateToggleList();  // Update each toggle to enabled if it's enabled keyword is present. If it's enabled keyword is missing, we assume it's disabled.  for(int i = 0; i < Toggles.Count; i++)  {   Toggles[i].Enabled = oldKeyWords.Contains (Toggles[i].ShaderKeywordEnabled);  }  // Begin listening for changes in GUI, so we don't waste time re-applying settings that haven't changed.  EditorGUI.BeginChangeCheck();  serializedObject.Update ();  var theShader = serializedObject.FindProperty ("m_Shader");  if (isVisible && !theShader.hasMultipleDifferentValues && theShader.objectReferenceValue != null)  {   float controlSize = 64;   EditorGUIUtility.labelWidth = Screen.width - controlSize - 20;   EditorGUIUtility.fieldWidth = controlSize;   Shader shader = theShader.objectReferenceValue as Shader;   EditorGUI.BeginChangeCheck();   // Draw Non-toggleable values   for (int i = 0; i < ShaderUtil.GetPropertyCount(shader); i++)   {    ShaderPropertyImpl(shader, i, null);   }   // Draw toggles, then their values.   for (int s = 0; s < Toggles.Count; s++)   {    EditorGUILayout.Separator();    Toggles[s].Enabled = EditorGUILayout.BeginToggleGroup(Toggles[s].InspectorName, Toggles[s].Enabled);    if (Toggles[s].Enabled)    {     for (int i = 0; i < ShaderUtil.GetPropertyCount(shader); i++)     {      ShaderPropertyImpl(shader, i, Toggles[s]);     }    }    EditorGUILayout.EndToggleGroup();   }   if (EditorGUI.EndChangeCheck())    PropertiesChanged ();  }  // If changes have been made, then apply them.  if (EditorGUI.EndChangeCheck())  {   // New list of key words.   List<string> newKeyWords = new List<string>();   // If true, add the enabled keyword (ending with _ON), if false, add the disabled keyword(ending with _OFF).   for(int i = 0; i < Toggles.Count; i++)   {    newKeyWords.Add(Toggles[i].Enabled ? Toggles[i].ShaderKeywordEnabled : Toggles[i].ShaderKeywordDisabled);   }   // Send the new list of keywords to the material, this will define what version of the shader to use.   targetMat.shaderKeywords = newKeyWords.ToArray ();   EditorUtility.SetDirty (targetMat);  } } // This runs once for every property in our shader. private void ShaderPropertyImpl(Shader shader, int propertyIndex, FeatureEditor currentToggle) {  string propertyDescription = ShaderUtil.GetPropertyDescription(shader, propertyIndex);  // If current toggle is null, we only want to show properties that aren't already "owned" by a toggle,  // so if it is owned by another toggle, then return.  if (currentToggle == null)  {   for (int i = 0; i < Toggles.Count; i++)   {    if (Regex.IsMatch(propertyDescription, Toggles[i].InspectorPropertyHideTag , RegexOptions.IgnoreCase))    {     return;    }   }  }  // Only draw if we the current property is owned by the current toggle.  else if (!Regex.IsMatch(propertyDescription, currentToggle.InspectorPropertyHideTag , RegexOptions.IgnoreCase))  {   return;  }  // If we've gotten to this point, draw the shader property regulairly.  ShaderProperty(shader,propertyIndex); }}

上面是我們自己實現的可以作為父類使用，其實就是做了一個介面封裝，下面程式碼是自己定義的為我們自己的Shader指令碼操作寫的幾個開關。如下所示：

using System.Collections.Generic;using UnityEngine;using UnityEditor; public class EditorInspector : CustomMaterialEditor{    protected override void CreateToggleList()    {        Toggles.Add(new FeatureEditor("Normal Enabled","normal","NORMALMAP_ON","NORMALMAP_OFF"));        Toggles.Add(new FeatureEditor("Specular Enabled","specular","SPECULAR_ON","SPECULAR_OFF"));        Toggles.Add(new FeatureEditor("Fresnel Enabled","fresnel","FRESNEL_ON","FRESNEL_OFF"));        Toggles.Add(new FeatureEditor("Rim Light Enabled","rim","RIMLIGHT_ON","RIMLIGHT_OFF"));    }} 

相對來說比較簡單，它只是做了幾個Toggle作為Shader指令碼中的控制。將上述兩個檔案拖放到Editor資料夾下面。

  下面才開始真正的Shader編寫工作，在這裡我們使用了SurfaceOutput作為我們的輸出結構體，SurfaceOutput簡單地描述了surface的屬性（  properties of the surface ），如反射率顏色（albedo color）、法線（normal）、散射（emission）、鏡面反射（specularity ）等。首先定義一個輸入結構體如下所示：

struct Input        {            float2 uv_DiffuseMap;            #if SPECULAR_ON            float2 uv_SpecMap;            #endif            #if NORMALMAP_ON            float2 uv_NormalMap;            #endif            #if FRESNEL_ON || RIMLIGHT_ON            float3 viewDir;            #endif        }; 

結構體中包含 Diffuse貼圖的uv座標uv_DiffuseMap，高光的uv座標uv_SpecMap，法線的uv座標uv_NormalMap，另外還定義了一個方向值viewDir。接下來就是實現主函式surf了，對於高光法線的渲染就在這裡面了，它呼叫了大量的CG庫函式，如下所示：

 void surf (Input IN, inout SurfaceOutput o)        {              float3 TexData = tex2D(_DiffuseMap, IN.uv_DiffuseMap);            float3 _BlendColor =  _TintColor.rgb * _TintColorMultiply;                         o.Albedo.rgb = _Brightness * lerp(TexData, _TintColor.rgb, _TintColorMultiply) ;                         #if SPECULAR_ON            o.Specular = _Gloss;            o.Gloss = max(_SpecAdd + _SpecularMultiply, 1.0) * tex2D (_SpecMap, IN.uv_SpecMap);            //o.Emission = _Gloss * tex2D (_SpecMap, IN.uv_SpecMap);            #endif            #if NORMALMAP_ON            o.Normal = UnpackNormal(tex2D(_NormalMap, IN.uv_NormalMap));            #endif                     #if FRESNEL_ON && SPECULAR_ON || RIMLIGHT_ON            float facing = saturate(1.0 - max(dot(normalize(IN.viewDir), normalize(o.Normal)), 0.0));                 #if FRESNEL_ON && SPECULAR_ON                float fresnel = max(_FresnelBias + (1.0-_FresnelBias) * pow(facing, _FresnelPower), 0);                fresnel = fresnel * o.Specular * _FresnelMultiply;                o.Gloss *= 1+fresnel;                #endif                        #if RIMLIGHT_ON                float rim = max(_RimBias + (1.0-_RimBias) * pow(facing, _RimPower), 0);                rim = rim * o.Specular * _RimMultiply;                o.Albedo *= 1+rim;                #endif            #endif                 } 

下面將Shader的完整程式碼展示如下：

Shader "Custom_Shaders/DNSRender"{    Properties    {        _TintColor ("Color Tint",color) = (1.0,1.0,1.0,1.0)        //Diffuse Sliders        _TintColorMultiply("Color Tint Multiply", Range(0.0, 1.0)) = 0.0        _Brightness ("Diffuse Brightness", Range(0.0, 2.0)) = 1.0        _DiffuseMap ("Diffuse (RGB)", 2D) = "white" {}        _NormalMap ("Normal Map(RGB)", 2D) = "bump" {}        _SpecColor ("Specular Color", Color) = (0.5, 0.5, 0.5, 1)        _SpecularMultiply ("Specular Brightness",float) = 1.0        _SpecAdd ("Specular Boost", float) = 0        _SpecMap ("Specular Map (RGB)", 2D) = "grey" {}        _Gloss ("Specular Glossiness", float) = 0.5        _FresnelPower ("Fresnel Power",float) = 1.0        _FresnelMultiply ("Fresnel Multiply", float) = 0.2        _FresnelBias ("Fresnel Bias", float) = -0.1        _RimPower ("RimLight Power",float) = 1.0        _RimMultiply ("RimLight Multiply", float) = 0.2        _RimBias ("RimLight Bias", float) = 0        _EmissionColor("Emission Color", color) = (1.0,1.0,1.0,1.0)    }    SubShader    {        Tags { "RenderType"="Opaque" }        LOD 300        CGPROGRAM        #pragma surface surf BlinnPhong        #pragma target 3.0        #pragma shader_feature NORMALMAP_ON NORMALMAP_OFF        #pragma shader_feature SPECULAR_ON SPECULAR_OFF        #pragma shader_feature FRESNEL_ON FRESNEL_OFF        #pragma shader_feature RIMLIGHT_ON RIMLIGHT_OFF        float3 _TintColor;        float _TintColorMultiply;        float _Brightness;        sampler2D _DiffuseMap;        sampler2D _NormalMap;            sampler2D _SpecMap;        float _SpecularMultiply;        float _SpecAdd;        float _Gloss;        float _FresnelPower;        float _FresnelMultiply;        float _FresnelBias;        float _RimPower;        float _RimMultiply;        float _RimBias;        float3 _EmissionColor;        struct Input        {            float2 uv_DiffuseMap;            #if SPECULAR_ON            float2 uv_SpecMap;            #endif            #if NORMALMAP_ON            float2 uv_NormalMap;            #endif            #if FRESNEL_ON || RIMLIGHT_ON            float3 viewDir;            #endif        };         void surf (Input IN, inout SurfaceOutput o)        {              float3 TexData = tex2D(_DiffuseMap, IN.uv_DiffuseMap);            float3 _BlendColor =  _TintColor.rgb * _TintColorMultiply;                o.Albedo.rgb = _Brightness * lerp(TexData, _TintColor.rgb, _TintColorMultiply) ;                #if SPECULAR_ON            o.Specular = _Gloss;            o.Gloss = max(_SpecAdd + _SpecularMultiply, 1.0) * tex2D (_SpecMap, IN.uv_SpecMap);            //o.Emission = _Gloss * tex2D (_SpecMap, IN.uv_SpecMap);            #endif            #if NORMALMAP_ON            o.Normal = UnpackNormal(tex2D(_NormalMap, IN.uv_NormalMap));            #endif                     #if FRESNEL_ON && SPECULAR_ON || RIMLIGHT_ON            float facing = saturate(1.0 - max(dot(normalize(IN.viewDir), normalize(o.Normal)), 0.0));                 #if FRESNEL_ON && SPECULAR_ON                float fresnel = max(_FresnelBias + (1.0-_FresnelBias) * pow(facing, _FresnelPower), 0);                fresnel = fresnel * o.Specular * _FresnelMultiply;                o.Gloss *= 1+fresnel;                #endif                        #if RIMLIGHT_ON                float rim = max(_RimBias + (1.0-_RimBias) * pow(facing, _RimPower), 0);                rim = rim * o.Specular * _RimMultiply;                o.Albedo *= 1+rim;                #endif            #endif                 }        ENDCG    }    CustomEditor "EditorInspector"} 

將Shader掛接到材質球上效果如下：

最終展示效果如下所示：

給我老師的人工智慧教程打call！http://blog.csdn.net/jiangjunshow