Unity Shader突出显示重叠 [英] Unity Shader highlighting overlaps
问题描述
我正在尝试编写一个统一的着色器，以突出显示网格的重叠片段.它应该适用于一个重叠的对象以及多个对象.
I am trying to write a shader for unity that will highlight the overlapping fragments of meshes. It should work for one object overlapping itself as well as multiple objects.
结果应该看起来像是附加的图像.
The result should look like an attached image.
首先，我尝试通过碰撞检测来完成此操作，但我认为最好的方法是编写着色器.
First I tried to accomplish this with collision detection but I think that the best way is writing a shader.
我对着色器不是很熟悉，所以如果有人可以帮助我，我将不胜感激.
I'm not very familiar with shaders so if anyone could help me I would be grateful.
我认为可以通过使用此处的模板着色器来完成 http://docs .unity3d.com/Manual/SL-Stencil.html 但是此着色器仅渲染两个对象的交集而不渲染整个对象.
I think that it can be done by using stencil shaders like here http://docs.unity3d.com/Manual/SL-Stencil.html but this shaders only render intersection of two objects without rendering whole object.
I also found shader based on Depth (https://chrismflynn.wordpress.com/2012/09/06/fun-with-shaders-and-the-depth-buffer/) but this also work on two objects and doesn't work on one mesh that overlap itself
关于@Zze注释以及有关两个Pass的想法，我现在有两个着色器.当一个拥有一个着色器而另一个拥有第二个着色器时，它可以在两个对象上工作.
Regarding @Zze comment with idea about two Pass I have now two shaders. And it works on two objects when one have one shader and other have second one.
也许有人可以帮助我如何将其组合为一个着色器，该着色器在重叠的对象中也可以使用?
Maybe any one can help me how to combine it into one shader that will work also in object that will overlap itself?
ShaderOne
ShaderOne
Shader "Custom/ShaderOne"
{
SubShader {
Tags { "RenderType"="Opaque" "Queue"="Geometry"}
Pass {
Stencil {
Ref 2
Comp always
Pass keep
Fail decrWrap
ZFail keep
}
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
struct appdata {
float4 vertex : POSITION;
};
struct v2f {
float4 pos : SV_POSITION;
};
v2f vert(appdata v) {
v2f o;
o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
return o;
}
half4 frag(v2f i) : SV_Target {
return half4(0,1,0,1);
}
ENDCG
}
Pass {
Stencil {
Ref 2
Comp equal
}
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
struct appdata {
float4 vertex : POSITION;
};
struct v2f {
float4 pos : SV_POSITION;
};
v2f vert(appdata v) {
v2f o;
o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
return o;
}
half4 frag(v2f i) : SV_Target {
return half4(0,0,1,1);
}
ENDCG
}
}
}
ShaderTwo
ShaderTwo
Shader "Custom/ShaderTwo"
{
SubShader {
Tags { "RenderType"="Opaque" "Queue"="Geometry"}
Pass {
Stencil {
Ref 2
Comp always
Pass replace
ZFail keep
}
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
struct appdata {
float4 vertex : POSITION;
};
struct v2f {
float4 pos : SV_POSITION;
};
v2f vert(appdata v) {
v2f o;
o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
return o;
}
half4 frag(v2f i) : SV_Target {
return half4(1,0,0,1);
}
ENDCG
}
}
}
结果看起来像一个附加的图像
The result looks like an attached image
推荐答案
可以通过Stencil缓冲区和一次两遍着色器解决此问题. 这个想法是这样的:
This problem can be solved with help of Stencil buffer and one, two-pass shader. The idea is the following:
- 第一次通过会将模板缓冲区中的值与0进行比较.在两种情况下(通过/失败)，都将增加缓冲区中的值.
- 第二遍将模板缓冲区中的值与1进行比较.如果参考值1小于，则我们将通过并突出显示重叠的像素.
您可能希望添加更多与第二遍相同的遍，但具有不同的参考值以突出显示重叠两次，三次等的区域.
You might want to add more passes that are the same as the second, but with different reference value to highlight regions that overlaps two times, three times, etc.
在Unity的shaderlab符号中，应该是这样的:
In Unity's shaderlab notation, it should be something like that:
Pass
{
Stencil {
Ref 0
Comp Equal
Pass IncrSat
Fail IncrSat
}
// Shader for not overlapping regions goes here.
}
Pass
{
Stencil {
Ref 1
Comp Less
}
// Shader for one-time overlapping regions goes here.
}
Pass
{
Stencil {
Ref 2
Comp Less
}
// Shader for two-time overlapping regions goes here.
}
示例:
着色器:
Shader "Unlit/Stencil"
{
Properties
{
_MainTex ("Texture", 2D) = "white" {}
}
SubShader
{
Tags { "RenderType"="Opaque" }
LOD 100
Pass
{
Stencil {
Ref 0
Comp Equal
Pass IncrSat
Fail IncrSat
}
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#include "UnityCG.cginc"
struct appdata
{
float4 vertex : POSITION;
};
struct v2f
{
float4 vertex : SV_POSITION;
};
v2f vert (appdata v)
{
v2f o;
o.vertex = mul(UNITY_MATRIX_MVP, v.vertex);
return o;
}
fixed4 frag (v2f i) : SV_Target
{
fixed4 col = fixed4(0.0, 0.0, 1.0, 1.0);
return col;
}
ENDCG
}
Pass
{
Stencil {
Ref 1
Comp Less
}
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#include "UnityCG.cginc"
struct appdata
{
float4 vertex : POSITION;
};
struct v2f
{
float4 vertex : SV_POSITION;
};
v2f vert (appdata v)
{
v2f o;
o.vertex = mul(UNITY_MATRIX_MVP, v.vertex);
return o;
}
fixed4 frag (v2f i) : SV_Target
{
fixed4 col = fixed4(1.0, 1.0, 0.0, 1.0);
return col;
}
ENDCG
}
Pass
{
Stencil {
Ref 2
Comp Less
}
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#include "UnityCG.cginc"
struct appdata
{
float4 vertex : POSITION;
};
struct v2f
{
float4 vertex : SV_POSITION;
};
v2f vert (appdata v)
{
v2f o;
o.vertex = mul(UNITY_MATRIX_MVP, v.vertex);
return o;
}
fixed4 frag (v2f i) : SV_Target
{
fixed4 col = fixed4(1.0, 0.0, 0.0, 1.0);
return col;
}
ENDCG
}
}
}
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