[Solved] How to add an alpha mask over the existing Transparent/Cutout/Soft Edge Unlit shader ?

Hi everyone !

I've searched a lot of things on the web but anyone of them fit to my request. Here's my problem :

If the player goes too far on the x axis, it will be out of bounds and will have to retry the level. The purple grid symbolizes the x limit of the level. It is actually a simple plane stuck on a certain x value but follows the y and z positions of the ball. To give the impression that the grid is "infinite", I've attached to my plane a script changing the offset of the texture depending on the y and z positions of the ball. It works fine, but the square shape of the grid is not so aesthetic.

I would prefer having this :


instead of this



The plane with the grid uses the Transparent/Cutout/SoftEdgeUnlit for the following reasons :
- The material.color.a changes depending on the distance between the ball and the grid, making it dissapear if the ball is too far, so I need a material with the "Color" component ;
- Both sides are visible ;
- I need a material which understand the alpha channel of my .png file.

How could I have this result, knowing that the _MainTex (and its own alpha channel) offset depends on another object ?

Thanks for the future answers,

Nhauste

 

multiply alpha channel with another texture's alpha channel.

 

For sure, but how could I add an alpha mask (texture) to the shader I'm using ?

 

You could use this shader:

Code (CSharp):

1. // Unlit alpha-blended shader.
2. // - no lighting
3. // - no lightmap support
4. // - no per-material color
5.  
6. Shader "Unlit/TransparentAlphaMask" {
7. Properties {
8.     _MainTex ("Base (RGB)", 2D) = "white" {}
9.     _AlphaTex ("Alpha mask (R)", 2D) = "white" {}
10. }
11.  
12. SubShader {
13.     Tags {"Queue"="Transparent" "IgnoreProjector"="True" "RenderType"="Transparent"}
14.     LOD 100
15.  
16.     Blend SrcAlpha OneMinusSrcAlpha
17.  
18.     Pass {
19.         CGPROGRAM
20.             #pragma vertex vert
21.             #pragma fragment frag
22.          
23.             #include "UnityCG.cginc"
24.          
25.  
26.             struct appdata_t {
27.                 float4 vertex : POSITION;
28.                 float2 texcoord : TEXCOORD0;
29.             };
30.  
31.             struct v2f {
32.                 float4 vertex : SV_POSITION;
33.                 half2 texcoord : TEXCOORD0;
34.             };
35.  
36.             sampler2D _MainTex;
37.             sampler2D _AlphaTex;
38.          
39.             float4 _MainTex_ST;
40.          
41.             v2f vert (appdata_t v)
42.             {
43.                 v2f o;
44.                 o.vertex = mul(UNITY_MATRIX_MVP, v.vertex);
45.                 o.texcoord = TRANSFORM_TEX(v.texcoord, _MainTex);
46.                 return o;
47.             }
48.          
49.             fixed4 frag (v2f i) : SV_Target
50.             {
51.                 fixed4 col = tex2D(_MainTex, i.texcoord);
52.                 fixed4 col2 = tex2D(_AlphaTex, i.texcoord);
53.              
54.                 return fixed4(col.r, col.g, col.b, col2.r);
55.             }
56.         ENDCG
57.     }
58. }
59.  
60. }

And use a .png file where white is alpha = 1 and black is alpha = 0. So a radial gradient from white to black would do the effect.

 

There is probably an error, when I select your shader in the inspector, I can't add any texture to the "Alpha mask" property. It continues saying "None" (Texture). The console tells me :

Material doesn't have a texture property '_AlphaTex'
UnityEditor.DockArea:OnGUI()

And even with a texture in the Base (RGB), my mesh keeps this annoying pink colour.

 

I checked the Shader, everything seems to be in order here. Here is a screenshot of what I get in Unity :

 

Ok, I tried another time. I've just created a new shader, and I've pasted the code you wrote up there.

Returning back to the editor, I got these two errors. Is really my graphic card a problem ? I have a Nvidia Geforce GT 630M.



Sorry about these questions that could seem absurd, I'm not really good at coding shaders, especially in csharp.

I don't know how will look my grid when I'll manage to use your shader, but I would also need the "Color" property (as I said I change the renderer.material.color.a depending on the distance between the ball and the grid) and an alpha mask directly in the "_MainTex" property (or the squares between the grid lines will be opaque).

NB : I forgot to mention, but as you can see it in my screenshot I'm using the free license of Unity. Could it be a limitation problem ?

 

I've found a solution to my problem.

I modified some things in the Texture Mask Shader available on the web :

Code (CSharp):

1. Shader "Custom/Map Borders" ////////// Shader renamed
2. {
3.    Properties
4.    {
5.       _Color ("Mask Color", Color) = (1, 1, 1, 1) ////////// _Color property added to this shader
6.       _MainTex ("Base (RGB)", 2D) = "white" {}
7.       _Mask ("Culling Mask", 2D) = "white" {}
8.       _Cutoff ("Alpha cutoff", Range (0,1)) = 0.1
9.    }
10.    SubShader
11.    {
12.       Tags {"Queue"="Transparent"}
13.       Cull Off ////////// I added this line to have the both sides of my plane mesh visible
14.       Lighting Off
15.       ZWrite Off
16.       Blend SrcAlpha OneMinusSrcAlpha
17.       AlphaTest GEqual [_Cutoff]
18.       Pass
19.       {
20.          SetTexture [_Mask] {
21.              constantColor [_Color]
22.              Combine texture * constant ////////// The alpha component of the _Color property defines the Culling Mask opacity (depending on the distance between the player and the grid)
23.             }
24.          SetTexture [_MainTex] {combine texture, previous}
25.       }
26.    }
27. }

Now it works fine, here's a fresh new screenshot with my problem solved :

 

Hi, could you please explain further on how you do it? I want to do something similar as well. But I still did not understand about it. Sorry, unity3d newbie here. Thanks.

 

Is there any way to add it to Fx/Water shader? I need to make soft blend edge for water