Double Sided *Material*

Hi everyone!

I really need to be able to create a double sided material.

For example one face (two tris, 1 poly) that shows the material on the reverse side of it.

I know alot of people have enquired about this, but i really can't afford to physically have the reverse side as part of the geometry.

My actual question is, does unity support this type of material option and if so does it need to be scripted in or is there a prefab or a shader that someone has made that is able to do it

Any info regarding this would be amazing!

Many thanks

 

This has been asked and answered many times...a search will easily find the solution.

--Eric

 

Hi eric

Thank you for your insightful response, maybe if i had spent time making four thousand and something posts i may recall a vague reference to it, but unfortunately i have just the two posts for now.

I have looked alot using the search and all i can find is information from people that don't really seem to actually know the answer to my specific question and just describe physically making another polygon mirrored fr the solution to a two sided *material*.

i.e.

"I know alot of people have enquired about this, but i really can't afford to physically have the reverse side as part of the geometry."

if you can find a post relating to the material settings i need to use that can answer my question, you may receive a gold star.

or

you may not

either way don't make condescending posts for the sake of it, its slightly immature, and will waste a lot of your time. Much appreciated.

But to anyone else that may be able to help, i would love some constructive feedback it will help alot as i really can not find any information relating to this and i felt posting a more specific question would be more efficient.

Many thanks

Kind regards

 

Hi Muriac,

Thank you very very much! ill look into that then, i wasn't sure on what avenue to approach on this. But this will really help.

Thanks so much!

 

My post was not condescending, it was factual. If you do a search on "double-sided", you get many relevant results. This is to your benefit, since you would have instantly gotten your answer without having to wait for a reply. Please refrain from reading negative intent into posts where there isn't any.

--Eric

 

I don't think Eric's response was inappropriate -- this really has been asked before. And that comes up through searching.

 

Here am I, a complete newb, having to answer such a popular question, shame on you!!! jk
here is my code for a DoubleSided Shader mate. Not like the ones Eric posted, this one is for any model, lighted or not:

Code (csharp):

1. Shader "DoubleSided" {
2.     Properties {
3.         _Color ("Main Color", Color) = (1,1,1,1)
4.         _MainTex ("Base (RGB)", 2D) = "white" {}
5.         //_BumpMap ("Bump (RGB) Illumin (A)", 2D) = "bump" {}
6.     }
7.     SubShader {    
8.         //UsePass "Self-Illumin/VertexLit/BASE"
9.         //UsePass "Bumped Diffuse/PPL"
10.        
11.         // Ambient pass
12.         Pass {
13.         Name "BASE"
14.         Tags {"LightMode" = "PixelOrNone"}
15.         Color [_PPLAmbient]
16.         SetTexture [_BumpMap] {
17.             constantColor (.5,.5,.5)
18.             combine constant lerp (texture) previous
19.             }
20.         SetTexture [_MainTex] {
21.             constantColor [_Color]
22.             Combine texture * previous DOUBLE, texture*constant
23.             }
24.         }
25.    
26.     // Vertex lights
27.     Pass {
28.         Name "BASE"
29.         Tags {"LightMode" = "Vertex"}
30.         Material {
31.             Diffuse [_Color]
32.             Emission [_PPLAmbient]
33.             Shininess [_Shininess]
34.             Specular [_SpecColor]
35.             }
36.         SeparateSpecular On
37.         Lighting On
38.         Cull Off
39.         SetTexture [_BumpMap] {
40.             constantColor (.5,.5,.5)
41.             combine constant lerp (texture) previous
42.             }
43.         SetTexture [_MainTex] {
44.             Combine texture * previous DOUBLE, texture*primary
45.             }
46.         }
47.     }
48.     FallBack "Diffuse", 1
49. }

[/code]

 

Thanks guys

 

This gets asked/answered so often, i think it's worth Unity looking into providing this functionality with the standard assets package.

 

PS: What part of that shader code actually renders it double-sided?

I wish more shader source had comments in them; I feel lost trying to figure it out.

 

...SeparateSpecular On
Lighting On
Cull Off
...

Just the cull off part

 

Wow, so you can take any shader with Cull off, remove that line, and you get double-sided?

Seems like comments in the default shader code could cut down this problem being asked/answered so often.

 

Actually, is not taking that line off. It is more like:
Cull On //Don't render "inner" faces
Cull Off // Render double-sided

 

It would be EXTREMELY helpful to have a simple "on/off" button next to the shader for this function...

This is giving me shades of TGEA nauseum.

 

Ow, I never actually coded for it to be only back sided or fof, so I didn't know, sorry...

 

your shader light's direction was wrong.

 

excuse to all,
how to install shader?? :?

 

ok installed :wink:
but no speculat light!! :cry:

 

damn eric pwned you

 

Sorry Daniel, you might be able to help, I think I'm getting the same thing. I modelled a garden umbrella but the underside of the cover was missing in unity. When I use your double sided shader, Unity draws both sides but the underside of the umbrella is lit brightly with the shadows on the top of the umbrella. How do I change the direction of the lighting or is it something else I'm doing wrong?

 

In reply to Eric5h5:
This thread IS the top result on google if you search for "double sided shader unity." I felt I should let you know that. Telling people to "do a search" is useless advice. I came to this thread through a search, so if you can't offer good information, refrain from replying next time.

 

@bkgamer

Congratulations on bumping up a long-dead thread with a useless comment on someone who has answered over *thousands* of questions on both these forums and UA, very classy. At this moment Eric has over 13500 posts where this one could be considered as unhelpful (but correct) critique, you have four posts on this forum where one just made me waste my time on a rant..

 

This thread has a bunch of good links thanks to Charles Hinshaw's post on the first page. Not to mention, looking through the first 10 results of your Google search, most of them are completely relevant and get you good answers. So I can't honestly see what you're complaining about...looks like "do a search" was great advice in this case.

--Eric

 

Guys. I,ve googled a lot and tested a lot. Please, help me to write

"Cull Off" and using two one sided materials (one with "Cull Back" and another "Cull Front") is not suitable because of incorrect lighting.
I need "bumped diffuse doublesided" shader.

 

I cannot use mesh with doubled polygons because it create problems with cloth simulation. Using 2 materials with "Cull Back" and "Cull Front" still has problem with lighting on inner side.

 

Well, thank you, it's almost what I need. But still has some problems - lighting not looking as correct as suppose to be (sometimes it's looks like translucent), maybe I really need "shadow support".
I will be much appreciated if you show me how to fix it.

 

Thats is a problem

 

Well, I found this helpers in *.cginc file, but I still cannot understand how can I implement it.
I'm game-logic programmer, but had to work with shaders, it's very difficult for me.
Am I first who really need 2sided shader with correct lighting?

 

I didn't find vertexlit.shader source in Unity installation, so I googled i little and found http://code.google.com/p/syphon-imp...SyphonShaders/AlphaTest-VertexLit.shader?r=39

So, as I can see, I need to use this lines of code? (there is late night right now, so I'll try it tommorow at work)

Code (csharp):

1.     // Pass to render object as a shadow caster
2.     Pass {
3.         Name "Caster"
4.         Tags { "LightMode" = "ShadowCaster" }
5.         Offset 1, 1
6.        
7.         Fog {Mode Off}
8.         ZWrite On ZTest Less Cull Off
9.  
10. CGPROGRAM
11. #pragma vertex vert
12. #pragma fragment frag
13. #pragma multi_compile_shadowcaster
14. #pragma fragmentoption ARB_precision_hint_fastest
15. #include "UnityCG.cginc"
16.  
17. struct v2f {
18.     V2F_SHADOW_CASTER;
19.     float2  uv : TEXCOORD1;
20. };
21.  
22. uniform float4 _MainTex_ST;
23.  
24. v2f vert( appdata_base v )
25. {
26.     v2f o;
27.     TRANSFER_SHADOW_CASTER(o)
28.     o.uv = TRANSFORM_TEX(v.texcoord, _MainTex);
29.     return o;
30. }
31.  
32. uniform sampler2D _MainTex;
33. uniform float _Cutoff;
34. uniform float4 _Color;
35.  
36. float4 frag( v2f i ) : COLOR
37. {
38.     half4 texcol = tex2D( _MainTex, i.uv );
39.     clip( texcol.a*_Color.a - _Cutoff );
40.    
41.     SHADOW_CASTER_FRAGMENT(i)
42. }
43. ENDCG
44.  
45.     }
46.    
47.     // Pass to render object as a shadow collector
48.     Pass {
49.         Name "ShadowCollector"
50.         Tags { "LightMode" = "ShadowCollector" }
51.        
52.         Fog {Mode Off}
53.         ZWrite On ZTest Less
54.  
55. CGPROGRAM
56. #pragma vertex vert
57. #pragma fragment frag
58. #pragma fragmentoption ARB_precision_hint_fastest
59. #pragma multi_compile_shadowcollector
60.  
61. #define SHADOW_COLLECTOR_PASS
62. #include "UnityCG.cginc"
63.  
64. struct v2f {
65.     V2F_SHADOW_COLLECTOR;
66.     float2  uv : TEXCOORD5;
67. };
68.  
69. uniform float4 _MainTex_ST;
70.  
71. v2f vert (appdata_base v)
72. {
73.     v2f o;
74.     TRANSFER_SHADOW_COLLECTOR(o)
75.     o.uv = TRANSFORM_TEX(v.texcoord, _MainTex);
76.     return o;
77. }
78.  
79. uniform sampler2D _MainTex;
80. uniform float _Cutoff;
81. uniform float4 _Color;
82.  
83. half4 frag (v2f i) : COLOR
84. {
85.     half4 texcol = tex2D( _MainTex, i.uv );
86.     clip( texcol.a*_Color.a - _Cutoff );
87.    
88.     SHADOW_COLLECTOR_FRAGMENT(i)
89. }
90. ENDCG
91.  
92.     }

 

Have you tried 3 passes for that cloth?

Cull Front -> Unlit
Cull Back -> Unlit
Cull Off -> Shadow/Light for both sides

 

i used this code for one of my projects
I create JS and paste the code.
But it;s show me that there are some errors..


Image: http://www.flickr.com/photos/76257364@N08/6840919073/

 

i used this code for one of my projects
I create JS and paste the code.
But it;s show me that there are some errors..


Image: http://www.flickr.com/photos/76257364@N08/6840919073/

 

You need to create a shader, this is not javascript.

In the project view, right click and go to 'Create > Shader'.

 

iafter i create the shader how to put it to my object?
Thank you for your help =)

 

You then need to create a new material, and when you have that material selected, change the "Shader" drop down box to the name of the shader that is defined in the code, which in this case would be "DoubleSided".

You can then drag this material onto your object in the scene.

 

This thread is pretty old, but here's another approach. I've been using Unity 4 surface shaders. Create a FrontShader (culls backfaces) and BackShader (culls frontfaces and inverts normals), and corresponding materials. Then apply both materials to the mesh you want double sided. The generated surface shader code deals with lighting, and this also allows you to specify separate textures for the front and back faces - and you can change the lightModel if needed using the surface directive.

FrontSide.shader

Code (csharp):

1. Shader "Custom/FrontSide" {
2.     Properties {
3.         _MainTex ("Base (RGB)", 2D) = "white" {}
4.     }
5.     SubShader {
6.         Tags { "RenderType"="Opaque" }
7.         Cull Back
8.         LOD 200
9.        
10.         CGPROGRAM
11.         #pragma surface surf Lambert
12.  
13.         sampler2D _MainTex;
14.  
15.         struct Input {
16.             float2 uv_MainTex;
17.         };
18.  
19.         void surf(Input IN, inout SurfaceOutput o) {
20.             half4 c = tex2D(_MainTex, IN.uv_MainTex);
21.             o.Albedo = c.rgb;
22.             o.Alpha = c.a;
23.         }
24.         ENDCG
25.     }
26.     FallBack "Diffuse"
27. }
28.  

BackSide.shader

Code (csharp):

1. Shader "Custom/BackSide" {
2.     Properties {
3.         _MainTex ("Base (RGB)", 2D) = "white" {}
4.     }
5.     SubShader {
6.         Tags { "RenderType"="Opaque" }
7.         Cull Front
8.         LOD 200
9.        
10.         CGPROGRAM
11.         #pragma surface surf Lambert vertex:vert
12.  
13.         sampler2D _MainTex;
14.  
15.         struct Input {
16.             float2 uv_MainTex;
17.         };
18.  
19.         void vert (inout appdata_full v, out Input o) {
20.             UNITY_INITIALIZE_OUTPUT(Input, o);
21.             v.normal = -v.normal;
22.         }
23.  
24.         void surf(Input IN, inout SurfaceOutput o) {
25.             half4 c = tex2D(_MainTex, IN.uv_MainTex);
26.             o.Albedo = c.rgb;
27.             o.Alpha = c.a;
28.         }
29.         ENDCG
30.     }
31.     FallBack "Diffuse"
32. }
33.  

 

Except as far as I'm aware you can't apply two materials to one mesh (by which I mean submesh).

You could just split those out into passes and have it in one shader.

 

Well, it seems to work. Mesh Renderer has an array of materials, so you can put both the front and back materials in that array.

Yeah, but you can't use passes with surface shaders since they generate the passes for you. The advantage of surface shaders is they deal with the lighting model etc. for you.