问题遇到的现象和发生背景
所用模型是人体肝脏器官，但是在改变其透明度时出现遮挡，不能通过人体在各个角度完整看到内部器官的问题
我的解答思路和尝试过的方法
在网上找了很多资料，试了采用两个pass以及双面渲染
两个pass渲染效果好些。如下：
Properties
{
_Color("Main Tint", Color) = (1, 1, 1, 1)
_MainTex("Main Tex", 2D) = "white" {}
_AlphaScale("Alpha Scale", Range(0, 1)) = 1
}
Subshader
{
Tags{"Queue" = "Transparent" "IgnoreProjector" = "False" "RenderType" = "Transparent"}
//第一个pass:计算深度，第二个pass:着色
pass
{
ZWrite On
ColorMask 0
}
pass
{
Tags { "LightMode" = "ForwardBase"}
Zwrite Off
Blend SrcAlpha OneMinusSrcAlpha
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#include "Lighting.cginc"
fixed4 _Color;
sampler2D _MainTex;
float4 _MainTex_ST;
fixed _AlphaScale;
struct a2v
{
float4 vertex : POSITION;
float3 normal : NORMAL;
float4 texcoord : TEXCOORD0;
};
struct v2f
{
float4 pos : SV_POSITION;
float3 worldNormal : TEXCOORD0;
float3 worldPos : TEXCOORD1;
float2 uv : TEXCOORD2;
};
v2f vert(a2v v)
{
v2f o;
o.pos = UnityObjectToClipPos(v.vertex);
o.worldNormal = UnityObjectToWorldNormal(v.normal);
o.worldPos = mul(unity_ObjectToWorld, v.vertex).xyz;
o.uv = TRANSFORM_TEX(v.texcoord, _MainTex);
return o;
}
fixed4 frag(v2f i) : SV_Target
{
fixed3 worldNormal = normalize(i.worldNormal);
fixed3 worldLightDir = normalize(UnityWorldSpaceLightDir(i.worldPos));
fixed4 texColor = tex2D(_MainTex, i.uv);
fixed3 albedo = texColor.rgb * _Color.rgb;
fixed3 ambient = UNITY_LIGHTMODEL_AMBIENT.xyz * albedo;
fixed3 diffuse = _LightColor0.rgb * albedo * max(0, dot(worldNormal, worldLightDir));
return fixed4(ambient + diffuse, texColor.a * _AlphaScale);
}
ENDCG
}
}
双面渲染会出现穿透现象，如下：
Properties
{
_Color("Color Tint", Color) = (1,1,1,1)
_MainTex("Texture", 2D) = "white" {}
_AlphaScale("Alpha Scale", Range(0,1)) = 1
}
SubShader
{
Tags { "Queue" = "Transparent" "IgnoreProjector" = "True" "RenderType" = "Transparent" }
Pass
{
Tags {"LightMode" = "ForwardBase"}
Cull Front
ZWrite off
Blend SrcAlpha OneMinusSrcAlpha
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#include "Lighting.cginc"
struct appdata
{
float4 vertex : POSITION;
float3 normal : NORMAL;
float2 uv : TEXCOORD0;
};
struct v2f
{
float2 uv : TEXCOORD0;
float4 vertex : SV_POSITION;
float3 worldNormal : TEXCOORD1;
float3 worldPos : TEXCOORD2;
};
fixed4 _Color;
sampler2D _MainTex;
float4 _MainTex_ST;
fixed _AlphaScale;
v2f vert(appdata v)
{
v2f o;
o.vertex = UnityObjectToClipPos(v.vertex);
o.uv = TRANSFORM_TEX(v.uv, _MainTex);
o.worldNormal = UnityObjectToWorldNormal(v.normal);
o.worldPos = mul(unity_ObjectToWorld, v.vertex).xyz;
return o;
}
fixed4 frag(v2f i) : SV_Target
{
fixed3 worldNormal = normalize(i.worldNormal);
fixed3 worldLightDir = normalize(UnityWorldSpaceLightDir(i.worldPos));
fixed4 texColor = tex2D(_MainTex, i.uv);
fixed3 albedo = texColor.rgb * _Color.rgb;
fixed3 ambient = UNITY_LIGHTMODEL_AMBIENT.xyz * albedo;
fixed3 diffuse = _LightColor0.rgb * albedo * max(0, dot(worldLightDir, worldNormal));
return fixed4(ambient + diffuse, texColor.a * _AlphaScale);
}
ENDCG
}
Pass
{
Tags {"LightMode" = "ForwardBase"}
Cull Back
ZWrite off
Blend SrcAlpha OneMinusSrcAlpha
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#include "Lighting.cginc"
struct appdata
{
float4 vertex : POSITION;
float3 normal : NORMAL;
float2 uv : TEXCOORD0;
};
struct v2f
{
float2 uv : TEXCOORD0;
float4 vertex : SV_POSITION;
float3 worldNormal : TEXCOORD1;
float3 worldPos : TEXCOORD2;
};
fixed4 _Color;
sampler2D _MainTex;
float4 _MainTex_ST;
fixed _AlphaScale;
v2f vert(appdata v)
{
v2f o;
o.vertex = UnityObjectToClipPos(v.vertex);
o.uv = TRANSFORM_TEX(v.uv, _MainTex);
o.worldNormal = UnityObjectToWorldNormal(v.normal);
o.worldPos = mul(unity_ObjectToWorld, v.vertex).xyz;
return o;
}
fixed4 frag(v2f i) : SV_Target
{
fixed3 worldNormal = normalize(i.worldNormal);
fixed3 worldLightDir = normalize(UnityWorldSpaceLightDir(i.worldPos));
fixed4 texColor = tex2D(_MainTex, i.uv);
fixed3 albedo = texColor.rgb * _Color.rgb;
fixed3 ambient = UNITY_LIGHTMODEL_AMBIENT.xyz * albedo;
fixed3 diffuse = _LightColor0.rgb * albedo * max(0, dot(worldLightDir, worldNormal));
return fixed4(ambient + diffuse, texColor.a * _AlphaScale);
}
ENDCG
}
}
Fallback "Transparent/VertexLit"
我想要达到的结果
复杂模型可以改变透明度，不会出现遮挡问题
已实现此效果
方法教程
推荐使用插件OIT
如下图：
使用方法：
将插件自带代码给相机，并做如下设置，也可以根据自己项目调整
然后把OIT插件里的材质球OIT赋给需要改变透明度的物体
