Shader Learing(Transparent Shader篇)

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Shader Learing(Transparent Shader篇)

透明物体的写法:
一种是clip,写zwrite,好处是不会排序混乱,坏处是没法blend,即透明度测试,透明度测试不能实现半透,只会删除一些片元,看上去像镂空一些面。(解释:设定一个透明度的值,如a,当物体的透明度>a时,按透明处理,直接舍弃,当透明度<a时,按正常物体处理,及深度测试,深度写入,然后深度值要小的物体就被舍弃掉了,不会渲染,也就是透明物体之后的物体不会被渲染了)。
另一种就是blend,不写zwrite,这时候就完全依赖于排序,即透明度混合。(解释:必须先渲染不透明物体,再渲染透明物体,再进行深度测试,被不透明物体挡住的就不会被渲染,挡住不透明物体的,就能正确进行颜色的混合)。
如果你有一个物体里面的面片互相穿插,可以使用两个pass,一个写深度,另外一个做alpha blending。


渲染顺序Queue:

Background 1000 通常用这个队列渲染需要绘制在背景上的物体
Geometry  2000 默认值;大部分物体在这个队列。不透明的物体也在这里
AlphaTest 2450 需要透明度测试物体使用的队列
Transparent 3000 在Geometry和AlphaTest渲染后,再从后往前渲染。透明度混合物体都该用
Overlay 4000 实现叠加效果[如镜头光晕]。任何需要最后渲染的,用这个。
自定义 用户可以定义任意值,比如"Queue"="Geometry+10"

RenderType[将Shader分类,用于Shader替换]:

Opaque       绝大部分不透明的物体都使用这个
Transparent   绝大部分透明的物体、包括粒子特效都使用这个
TransparentCutout蒙皮透明着色器
Background   天空盒都使用这个
Overlay       GUI/镜头光晕都使用这个

Alpha Blending指令:

Blend Off 关混合
Blend SrcFactor DstFactor
Blend SrcFactor DstFactor, srcFactorA DstFactorA

Blend {code for SrcFactor片元颜色} {code for DstFactor已经在颜色缓冲中的颜色}

resulting RGBA color:
float4 result = SrcFactor * fragment_output + DstFactor * pixel_color;

One                            float4(1.0, 1.0, 1.0, 1.0)
Zero                           float4(0.0, 0.0, 0.0, 0.0)
SrcColor                    fragment_output
SrcAlpha                      fragment_output.aaaa
DstColor                    pixel_color
DstAlpha                    pixel_color.aaaa
OneMinusSrcColor    float4(1.0, 1.0, 1.0, 1.0) - fragment_output
OneMinusSrcAlpha     float4(1.0, 1.0, 1.0, 1.0) - fragment_output.aaaa
OneMinusDstColor    float4(1.0, 1.0, 1.0, 1.0) - pixel_color
OneMinusDstAlpha    float4(1.0, 1.0, 1.0, 1.0) - pixel_color.aaaa

pixel_color.aaaa=float4(pixel_color.a, pixel_color.a, pixel_color.a, pixel_color.a)

Blend SrcAlpha OneMinusSrcAlpha
float4 result = fragment_output.aaaa * fragment_output + (float4(1.0, 1.0, 1.0, 1.0) - fragment_output.aaaa) * pixel_color
Blend One OneMinusSrcAlpha 
float4 result = float4(1.0, 1.0, 1.0, 1.0) * fragment_output + (float4(1.0, 1.0, 1.0, 1.0) - fragment_output.aaaa) * pixel_color
Blend One One
float4 result = float4(1.0, 1.0, 1.0, 1.0) * fragment_output + float4(1.0, 1.0, 1.0, 1.0) * pixel_color


AlphaTest

Shader "Custom/023_AlphaTest" {Properties     {        _MainTex ("Base (RGB)", 2D) = "white" {}        _NormalMap("NormalMap",2D) = "Bump"{}        _SpecColor("SpecularColor",Color) = (1,1,1,1)        _Shininess("Shininess",Float) = 10_Cutoff ("Alpha Cutoff", Range(0, 1)) = 0.5    }    SubShader     {Tags {"Queue"="AlphaTest" "IgnoreProjector"="True" "RenderType"="TransparentCutout"}        Pass        {            Tags { "LightMode"="ForwardBase" }            CGPROGRAM            #pragma vertex vert            #pragma fragment frag            #include "UnityCG.cginc"            uniform sampler2D _MainTex;            uniform sampler2D _NormalMap;            uniform float4 _SpecColor;//控制凸起程度            uniform float _Shininess;            uniform float4 _LightColor0;fixed _Cutoff;            struct VertexOutput             {                float4 pos:SV_POSITION;                float2 uv:TEXCOORD0;                float3 lightDir:TEXCOORD1;                float3 viewDir:TEXCOORD2;            };            VertexOutput vert(appdata_tan v)            {                VertexOutput o;                o.pos = mul(UNITY_MATRIX_MVP,v.vertex);                o.uv = v.texcoord.xy;//得到Object2TangentMatrix矩阵//这四行代码可以使用Unity定义的一个宏TANGENT_SPACE_ROTATION来代替                float3 normal = v.normal;                float3 tangent = v.tangent;                float3 binormal= cross(v.normal,v.tangent.xyz) * v.tangent.w;//tangent.w决定第三个坐标轴,值为正负1                float3x3 Object2TangentMatrix = float3x3(tangent,binormal,normal);//之所以变换到切线空间,是为了减少片段着色器的计算量                o.lightDir = mul(Object2TangentMatrix,ObjSpaceLightDir(v.vertex));                o.viewDir = mul(Object2TangentMatrix,ObjSpaceViewDir(v.vertex));                return o;            }            float4 frag(VertexOutput input):COLOR            {                float3 lightDir = normalize(input.lightDir);                float3 viewDir = normalize(input.viewDir);                float4 encodedNormal = tex2D(_NormalMap,input.uv);//法线[-1,1],颜色[0,1]                float3 normal = float3(2.0*encodedNormal.ag - 1,0.0);//保证normal为正                normal.z = sqrt(1 - dot(normal,normal));                float4 texColor = tex2D(_MainTex,input.uv);clip (texColor.a -_Cutoff*0.2);                float3 ambient = texColor.rgb * UNITY_LIGHTMODEL_AMBIENT.rgb;                float3 diffuseReflection = texColor.rgb * _LightColor0.rgb * max(0,dot(normal,lightDir));                float facing;                if(dot(normal,lightDir)<0)                {                    facing = 0;                }                else                {                    facing = 1;                }                float3 specularRelection = _SpecColor.rgb * _LightColor0.rgb * facing * pow(max(0,dot(reflect(-lightDir,normal),viewDir)),_Shininess);                return float4(ambient + diffuseReflection + specularRelection,1);            }            ENDCG        }    }     FallBack "Diffuse"}
效果图如下:


AlphaBlend

//AlphaBlendShader "Custom/024_AlphaBlend" {Properties     {        _MainTex ("Base (RGB)", 2D) = "white" {}        _NormalMap("NormalMap",2D) = "Bump"{}        _SpecColor("SpecularColor",Color) = (1,1,1,1)        _Shininess("Shininess",Float) = 10_AlphaScale ("Alpha Scale", Range(0, 1)) = 1    }    SubShader     {Tags {"Queue"="AlphaTest" "IgnoreProjector"="True" "RenderType"="TransparentCutout"}        Pass        {            Tags { "LightMode"="ForwardBase" }ZWrite OffBlend SrcAlpha OneMinusSrcAlpha//float4 result = fragment_output.aaaa * fragment_output + (float4(1.0, 1.0, 1.0, 1.0) - fragment_output.aaaa) * pixel_color            CGPROGRAM            #pragma vertex vert            #pragma fragment frag            #include "UnityCG.cginc"            uniform sampler2D _MainTex;            uniform sampler2D _NormalMap;            uniform float4 _SpecColor;//控制凸起程度            uniform float _Shininess;            uniform float4 _LightColor0;fixed _AlphaScale;            struct VertexOutput             {                float4 pos:SV_POSITION;                float2 uv:TEXCOORD0;                float3 lightDir:TEXCOORD1;                float3 viewDir:TEXCOORD2;            };            VertexOutput vert(appdata_tan v)            {                VertexOutput o;                o.pos = mul(UNITY_MATRIX_MVP,v.vertex);                o.uv = v.texcoord.xy;//得到Object2TangentMatrix矩阵//这四行代码可以使用Unity定义的一个宏TANGENT_SPACE_ROTATION来代替                float3 normal = v.normal;                float3 tangent = v.tangent;                float3 binormal= cross(v.normal,v.tangent.xyz) * v.tangent.w;//tangent.w决定第三个坐标轴,值为正负1                float3x3 Object2TangentMatrix = float3x3(tangent,binormal,normal);//之所以变换到切线空间,是为了减少片段着色器的计算量                o.lightDir = mul(Object2TangentMatrix,ObjSpaceLightDir(v.vertex));                o.viewDir = mul(Object2TangentMatrix,ObjSpaceViewDir(v.vertex));                return o;            }            float4 frag(VertexOutput input):COLOR            {                float3 lightDir = normalize(input.lightDir);                float3 viewDir = normalize(input.viewDir);                float4 encodedNormal = tex2D(_NormalMap,input.uv);//法线[-1,1],颜色[0,1]                float3 normal = float3(2.0*encodedNormal.ag - 1,0.0);//保证normal为正                normal.z = sqrt(1 - dot(normal,normal));                float4 texColor = tex2D(_MainTex,input.uv);//clip (texColor.a -_Cutoff*0.2);                float3 ambient = texColor.rgb * UNITY_LIGHTMODEL_AMBIENT.rgb;                float3 diffuseReflection = texColor.rgb * _LightColor0.rgb * max(0,dot(normal,lightDir));                float facing;                if(dot(normal,lightDir)<0)                {                    facing = 0;                }                else                {                    facing = 1;                }                float3 specularRelection = _SpecColor.rgb * _LightColor0.rgb * facing * pow(max(0,dot(reflect(-lightDir,normal),viewDir)),_Shininess);                return float4(ambient + diffuseReflection + specularRelection,min(1,texColor.a*_AlphaScale*50));            }            ENDCG        }    }     FallBack "Diffuse"}
效果图如下:


One Pass ZWrite,Next Pass AlphaBlend

Shader "Custom/025_AlphaBlendZWrite" {Properties     {        _MainTex ("Base (RGB)", 2D) = "white" {}        _NormalMap("NormalMap",2D) = "Bump"{}        _SpecColor("SpecularColor",Color) = (1,1,1,1)        _Shininess("Shininess",Float) = 10_AlphaScale ("Alpha Scale", Range(0, 1)) = 1    }    SubShader     {Tags {"Queue"="AlphaTest" "IgnoreProjector"="True" "RenderType"="TransparentCutout"}Pass {ZWrite OnColorMask 0 //该pass不写入任何颜色通道}        Pass        {            Tags { "LightMode"="ForwardBase" }ZWrite OffBlend SrcAlpha OneMinusSrcAlpha            CGPROGRAM            #pragma vertex vert            #pragma fragment frag            #include "UnityCG.cginc"            uniform sampler2D _MainTex;            uniform sampler2D _NormalMap;            uniform float4 _SpecColor;//控制凸起程度            uniform float _Shininess;            uniform float4 _LightColor0;fixed _AlphaScale;            struct VertexOutput             {                float4 pos:SV_POSITION;                float2 uv:TEXCOORD0;                float3 lightDir:TEXCOORD1;                float3 viewDir:TEXCOORD2;            };            VertexOutput vert(appdata_tan v)            {                VertexOutput o;                o.pos = mul(UNITY_MATRIX_MVP,v.vertex);                o.uv = v.texcoord.xy;//得到Object2TangentMatrix矩阵//这四行代码可以使用Unity定义的一个宏TANGENT_SPACE_ROTATION来代替                float3 normal = v.normal;                float3 tangent = v.tangent;                float3 binormal= cross(v.normal,v.tangent.xyz) * v.tangent.w;//tangent.w决定第三个坐标轴,值为正负1                float3x3 Object2TangentMatrix = float3x3(tangent,binormal,normal);//之所以变换到切线空间,是为了减少片段着色器的计算量                o.lightDir = mul(Object2TangentMatrix,ObjSpaceLightDir(v.vertex));                o.viewDir = mul(Object2TangentMatrix,ObjSpaceViewDir(v.vertex));                return o;            }            float4 frag(VertexOutput input):COLOR            {                float3 lightDir = normalize(input.lightDir);                float3 viewDir = normalize(input.viewDir);                float4 encodedNormal = tex2D(_NormalMap,input.uv);//法线[-1,1],颜色[0,1]                float3 normal = float3(2.0*encodedNormal.ag - 1,0.0);//保证normal为正                normal.z = sqrt(1 - dot(normal,normal));                float4 texColor = tex2D(_MainTex,input.uv);//clip (texColor.a -_Cutoff*0.2);                float3 ambient = texColor.rgb * UNITY_LIGHTMODEL_AMBIENT.rgb;                float3 diffuseReflection = texColor.rgb * _LightColor0.rgb * max(0,dot(normal,lightDir));                float facing;                if(dot(normal,lightDir)<0)                {                    facing = 0;                }                else                {                    facing = 1;                }                float3 specularRelection = _SpecColor.rgb * _LightColor0.rgb * facing * pow(max(0,dot(reflect(-lightDir,normal),viewDir)),_Shininess);                return float4(ambient + diffuseReflection + specularRelection,min(1,texColor.a*_AlphaScale*50));            }            ENDCG        }    }     FallBack "Diffuse"}
效果图如下:


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