Shader实例：高级纹理应用
发表于2018-04-14
使用Shader处理纹理是件简单的事情，不过本篇要和大家介绍的是Shader高级纹理应用。
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);
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（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"
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Properties
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_MainColor("MainColor",color) = (1,1,1,1)
_FresnelScale("FresnelScale(反射系数)",Range(0,1))=0.5
_CubeMap("CubeMap",Cube) = "_Skybox"｛｝
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SubShader
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Tags ｛ "RenderType" = "Opaque" ｝
Pass
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CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#include "UnityCG.cginc"
#include "AutoLight.cginc"
#include "Lighting.cginc"
fixed4 _MainColor;
float _FresnelScale;
samplerCUBE _CubeMap;
struct a2v
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float4 vertex : POSITION;
float4 normal:NORMAL;
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struct v2f
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float4 vertex : SV_POSITION;
float4 worldPos:TEXCOORD1;
float3 worldNormal:TEXCOORD2;
float3 worldViewDir:TEXCOORD3;
float3 worldRefle : TEXCOORD4;
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v2f vert (a2v v)
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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;
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fixed4 frag (v2f i) : SV_Target
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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);
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ENDCG
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（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"
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Properties
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_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"｛｝
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SubShader
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Tags ｛ "RenderType"="Opaque" ｝
Pass
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CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#include "UnityCG.cginc"
#include "AutoLight.cginc"
#include "Lighting.cginc"
struct a2v
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float4 vertex : POSITION;
float4 normal:NORMAL;
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struct v2f
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float4 vertex : SV_POSITION;
float4 worldPos:TEXCOORD0;
float3 worldNormal:TEXCOORD1;
float3 reflectDir:TEXCOORD2;
float3 viewDir:TEXCOORD3;
float3 lightDir:TEXCOORD4;
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fixed4 _Color;
fixed4 _ReflectColor;
float _ReflectAmount;
samplerCUBE _CubeMap;
v2f vert (a2v v)
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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;
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fixed4 frag (v2f i) : SV_Target
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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);
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ENDCG
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（3）折射：
Shader "MyShader/RefractShader"
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Properties
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_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"｛｝
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SubShader
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Tags ｛ "RenderType"="Opaque" ｝
Pass
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CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#include "UnityCG.cginc"
#include "AutoLight.cginc"
#include "Lighting.cginc"
struct a2v
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float4 vertex : POSITION;
float4 normal:NORMAL;
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struct v2f
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float4 vertex : SV_POSITION;
float4 worldPos:TEXCOORD0;
float3 worldNormal:TEXCOORD1;
float3 worldViewDir:TEXCOORD2;
float3 worldRefr:TEXCOORD3;
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fixed4 _Color;
fixed4 _RefractColor;
float _RefractAmount;
float _RefractRatio;
samplerCUBE _CubeMap;
v2f vert (a2v v)
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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;
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fixed4 frag (v2f i) : SV_Target
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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);
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ENDCG
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来自：https://blog.csdn.net/linuxheik/article/details/46128405