Shader实例：高级纹理应用

Shader实例：高级纹理应用

首先说下CubeMap的几种制作方式：

第一种方法：就是提供一张具有特殊布局的纹理（如：立方体展开贴图交叉布局，全景布局等）用的时候把Texture Type设置成Cubemap（优点：这种方法可以对纹理数据进行压缩，而且可以支持边缘修正，光滑反射和HDR等功能）；

第二种方法：先创建一个CubeMap，然后赋予6张贴图；

第三种方法：

这种方法比较灵活，就是利用Camera的RenderToCubeMap方法动态创建了，脚本要放在Editor文件夹下，因为是在编辑环境下执行：

using System.Collections;using System.Collections.Generic;using UnityEngine;using UnityEditor;public class SourceCubeMap : MonoBehaviour {    public Cubemap cubeMap;    public Transform RenderPos;   [MenuItem("Component/ExecuteRender")]static void ExecuteRender() {                   GameObject go = new GameObject("SourceCubeMap");            go.AddComponent<Camera>();            go.transform.position = GameObject.Find("Cube (2)").gameObject.transform.position;//获取具有反射效果对象的位置            go.GetComponent<Camera>().RenderToCubemap(Resources.Load("CubeMap") as Cubemap); //渲染立方体纹理            DestroyImmediate(go);}}

（1）菲涅尔反射：

运用公式：

Schlick菲涅尔近似等式:F(v,n)=F0+(1-F0)pow(1-cos(v.n));

直接看代码：

Shader "MyShader/FresnelReflection"{Properties{_MainColor("MainColor",color) = (1,1,1,1)_FresnelScale("FresnelScale(反射系数)",Range(0,1))=0.5_CubeMap("CubeMap",Cube) = "_Skybox"{}}SubShader{Tags { "RenderType" = "Opaque" }Pass{CGPROGRAM#pragma vertex vert#pragma fragment frag#include "UnityCG.cginc"#include "AutoLight.cginc"#include "Lighting.cginc"fixed4 _MainColor;        float _FresnelScale;       samplerCUBE _CubeMap;struct a2v{float4 vertex : POSITION;float4 normal:NORMAL;};struct v2f{float4 vertex : SV_POSITION;float4 worldPos:TEXCOORD1;float3 worldNormal:TEXCOORD2;float3 worldViewDir:TEXCOORD3;    float3 worldRefle : TEXCOORD4;};v2f vert (a2v v){v2f o;o.vertex = UnityObjectToClipPos(v.vertex);o.worldPos = mul(unity_ObjectToWorld,v.vertex);o.worldNormal = UnityObjectToWorldNormal(v.normal);o.worldViewDir = UnityWorldSpaceViewDir(o.worldPos);o.worldRefle = reflect(-o.worldViewDir,o.worldNormal);TRANSFER_SHADOW(o); //顶点着色器中使用此内置宏//计算阴影纹理坐标后传递给片元着色器；return o;}fixed4 frag (v2f i) : SV_Target{fixed3 worldNor = normalize(i.worldNormal);   fixed3 worldLightDir = normalize(UnityWorldSpaceLightDir(i.worldPos));   fixed3 worldViewDir = normalize(i.worldViewDir);   fixed3 ambient = UNITY_LIGHTMODEL_AMBIENT.xyz;   UNITY_LIGHT_ATTENUATION(atten,i,i.worldPos);    //内置宏，计算阴影和光照衰减；   fixed3 reflection = texCUBE(_CubeMap,i.worldRefle).rgb;   fixed fresnel = _FresnelScale + (1 - _FresnelScale)*pow(1 - dot(worldViewDir, worldNor), 5);   //Schlick菲涅尔近似等式:F(v,n)=F0+(1-F0)pow(1-cos(v.n));   //F0是反射系数，用于控制菲涅尔反射的强度，V是视角方向，n是表面法线；   fixed3 diffuse = _LightColor0.rgb*_MainColor.rgb*max(0, dot(worldLightDir, worldNor));   fixed3 color = ambient + lerp(diffuse, reflection, saturate(fresnel))*atten;   return fixed4(color,1);}ENDCG}}}

（2）普通反射：

//反射原理：通过入射光线得方向和表面法线方向计算反射方向（reflect函数）
//再利用反射方向对立方体纹理采样即可

Shader "MyShader/ReflectionShader"{Properties{_Color("MainColor",color) = (1,1,1,1)_ReflectColor("ReflectColor",color) = (1,1,1,1)//反射颜色_ReflectAmount("Reflect Amount",Range(0,1)) = 0.5 //反射程度_CubeMap("Reflect Map",Cube) = "_Skybox"{}}SubShader{Tags { "RenderType"="Opaque" }Pass{CGPROGRAM#pragma vertex vert#pragma fragment frag#include "UnityCG.cginc"#include "AutoLight.cginc"#include "Lighting.cginc"struct a2v{float4 vertex : POSITION;float4 normal:NORMAL;};struct v2f{float4 vertex : SV_POSITION;float4 worldPos:TEXCOORD0;float3 worldNormal:TEXCOORD1;float3 reflectDir:TEXCOORD2;float3 viewDir:TEXCOORD3;float3 lightDir:TEXCOORD4;};fixed4 _Color;fixed4 _ReflectColor;float _ReflectAmount;samplerCUBE _CubeMap;v2f vert (a2v v){v2f o;o.vertex = UnityObjectToClipPos(v.vertex);o.worldPos = mul(unity_ObjectToWorld, v.vertex);o.worldNormal = UnityObjectToWorldNormal(v.normal);o.lightDir = normalize(UnityWorldSpaceLightDir(o.worldPos));o.viewDir = UnityWorldSpaceViewDir(o.worldPos);o.reflectDir = reflect(-o.viewDir, o.worldNormal);TRANSFER_SHADOW(o);return o;}fixed4 frag (v2f i) : SV_Target{fixed3 worldNor = normalize(i.worldNormal);fixed3 viewDir = normalize(i.viewDir);fixed3 lightDir = normalize(i.lightDir);fixed3 ambient = UNITY_LIGHTMODEL_AMBIENT.xyz;fixed3 diffuse = _Color.rgb*_LightColor0.rgb*max(0, dot(worldNor, lightDir));fixed3 reflection = texCUBE(_CubeMap, i.reflectDir).rgb*_ReflectColor.rgb;UNITY_LIGHT_ATTENUATION(atten,i,i.worldPos);fixed3 color = ambient + lerp(diffuse, reflection, _ReflectAmount)*atten;return fixed4(color,1);}ENDCG}}}

（3）折射：

Shader "MyShader/RefractShader"{Properties{_Color("MainColor",color) = (1,1,1,1)_RefractColor("RefractColor",color) = (1,1,1,1)_RefractAmount("RefractAmount",Range(0,1)) = 0.5_RefractRatio("Refract Ratio",Range(0.1,1)) = 0.5_CubeMap("Refract CubeMap",Cube) = "_Skybox"{}}SubShader{Tags { "RenderType"="Opaque" }Pass{CGPROGRAM#pragma vertex vert#pragma fragment frag#include "UnityCG.cginc"#include "AutoLight.cginc"#include "Lighting.cginc"struct a2v{float4 vertex : POSITION;float4 normal:NORMAL;};struct v2f{float4 vertex : SV_POSITION;float4 worldPos:TEXCOORD0;float3 worldNormal:TEXCOORD1;float3 worldViewDir:TEXCOORD2;float3 worldRefr:TEXCOORD3;};fixed4 _Color;fixed4 _RefractColor;float _RefractAmount;float _RefractRatio;samplerCUBE _CubeMap;v2f vert (a2v v){v2f o;o.vertex = UnityObjectToClipPos(v.vertex);o.worldPos = mul(unity_ObjectToWorld, v.vertex);o.worldNormal = UnityObjectToWorldNormal(v.normal);o.worldViewDir = UnityWorldSpaceViewDir(o.worldPos);o.worldRefr = refract(-normalize(o.worldViewDir),normalize(o.worldNormal), _RefractRatio);TRANSFER_SHADOW(o);return o;}fixed4 frag (v2f i) : SV_Target{fixed3 worldNor = normalize(i.worldNormal);    fixed3 lightDir = normalize(UnityWorldSpaceLightDir(i.worldPos));;fixed3 ambient = UNITY_LIGHTMODEL_AMBIENT.xyz;fixed3 diffuse = _LightColor0.rgb*_Color.rgb*max(0, dot(worldNor, lightDir));UNITY_LIGHT_ATTENUATION(atten,i,i.worldPos);fixed3 refract = texCUBE(_CubeMap, i.worldRefr).rgb*_RefractColor.rgb;fixed3 color = ambient + lerp(diffuse,refract, _RefractAmount)*atten;return fixed4(color,1);}ENDCG}}}