Help with Custom Terrain AddPass Shader

I've been adventuring myself in scripting shaders for unity, followed some tutorials, made some on my own and finally tried to adventure into making a terrain shader.

So I've looked into this tutorial :
https://alastaira.wordpress.com/2013/12/07/custom-unity-terrain-material-shaders/

Looked the builtin shaders...

And found this article on Gamasutra:
http://www.gamasutra.com/blogs/Andr...196339/Advanced_Terrain_Texture_Splatting.php

And tried to make a new terrain shader.
But I'm having trouble with the AddPass shader, it's not working. Tried a lot of things and still didn't work. It seems like it's falling back and when I remove the fallback it just paints all the textures from the first pass all mixed up.

Here's a screenshot:


Is there a way to fix these so I can have more than 4 textures in my terrain?

Here are the shaders (did not apply normal maps yet):
FirstPass shader:

Code (CSharp):

1. Shader "Raed Wulf/Terrain/BlendTexture" {
2.     Properties{
3.         //control splat map
4.         [HideInInspector] _Control("Control (RGBA)", 2D) = "red" {}
5.  
6.         //textures Alpha is height
7.         [HideInInspector] _Splat3("Layer 3 (A)", 2D) = "white" {}
8.         [HideInInspector] _Splat2("Layer 2 (B)", 2D) = "white" {}
9.         [HideInInspector] _Splat1("Layer 1 (G)", 2D) = "white" {}
10.         [HideInInspector] _Splat0("Layer 0 (R)", 2D) = "white" {}
11.  
12.         //normal maps
13.         [HideInInspector] _Normal3("Normal 3 (A)", 2D) = "bump" {}
14.         [HideInInspector] _Normal2("Normal 2 (B)", 2D) = "bump" {}
15.         [HideInInspector] _Normal1("Normal 1 (G)", 2D) = "bump" {}
16.         [HideInInspector] _Normal0("Normal 0 (R)", 2D) = "bump" {}
17.  
18.         // used in fallback on old cards & base map
19.         [HideInInspector] _MainTex("BaseMap (RGB)", 2D) = "white" {}
20.         [HideInInspector] _Color("Main Color", Color) = (1,1,1,1)
21.     }
22.  
23.     SubShader{
24.         Tags{
25.             "SplatCount" = "4"
26.             "Queue" = "Geometry-100"
27.             "RenderType" = "Opaque"
28.         }
29.  
30.         CGPROGRAM
31.         #pragma surface surf Lambert exclude_path:forward
32.         #pragma multi_compile_fog
33.         #pragma target 3.0
34.         // needs more than 8 texcoords
35.         #pragma exclude_renderers gles
36.         #include "UnityPBSLighting.cginc"
37.  
38.         // Access the Shaderlab properties
39.         uniform sampler2D _Control;
40.         uniform sampler2D _Splat0,_Splat1,_Splat2,_Splat3;
41.    
42.  
43.         // Surface shader input structure
44.         struct Input {
45.             float2 uv_Control : TEXCOORD0;
46.             float2 uv_Splat0 : TEXCOORD1;
47.             float2 uv_Splat1 : TEXCOORD2;
48.             float2 uv_Splat2 : TEXCOORD3;
49.             float2 uv_Splat3 : TEXCOORD4;
50.         };
51.  
52.         float4 blend(float4 texA, float aA, float4 texB, float aB)
53.         {
54.  
55.             float depth = 0.1;
56.             float ma = max(texA.a + aA, texB.a + aB) - depth;
57.  
58.             float b1 = max(texA.a + aA - ma, 0.0);
59.             float b2 = max(texB.a + aB - ma, 0.0);
60.  
61.             return (texA * b1 + texB * b2) / (b1 + b2);
62.  
63.         }
64.  
65.        
66.         // Surface Shader function
67.         void surf(Input IN, inout SurfaceOutput o) {
68.             fixed4 tex0 = tex2D(_Splat0, IN.uv_Splat0);
69.             fixed4 tex1 = tex2D(_Splat1, IN.uv_Splat1);
70.             fixed4 tex2 = tex2D(_Splat2, IN.uv_Splat2);
71.             fixed4 tex3 = tex2D(_Splat3, IN.uv_Splat3);
72.  
73.             fixed4 splat_control = tex2D(_Control, IN.uv_Control);
74.             fixed4 col;
75.  
76.             col = blend(tex0, splat_control.r, tex1, splat_control.g);
77.             col = blend(col, splat_control.r + splat_control.g, tex2, splat_control.b);
78.             col = blend(col, splat_control.r + splat_control.g + splat_control.b, tex3, splat_control.a);
79.  
80.             o.Albedo = col.rgb;
81.             o.Alpha = col.a;        
82.  
83.         }
84.         ENDCG
85.     }
86.  
87.         Dependency "AddPassShader" = "Hidden/Raed Wulf/Terrain/BlendTexture-AddPass"
88.         Dependency "BaseMapShader" = "Diffuse"
89.  
90.         Fallback "Nature/Terrain/Diffuse"
91. }

AddPass Shader:

Code (CSharp):

1. Shader "Hidden/Raed Wulf/Terrain/BlendTexture-AddPass" {
2.     Properties{
3.         //control splat map
4.         [HideInInspector] _Control("Control (RGBA)", 2D) = "red" {}
5.  
6.         //textures Alpha is height
7.         [HideInInspector] _Splat3("Layer 3 (A)", 2D) = "white" {}
8.         [HideInInspector] _Splat2("Layer 2 (B)", 2D) = "white" {}
9.         [HideInInspector] _Splat1("Layer 1 (G)", 2D) = "white" {}
10.         [HideInInspector] _Splat0("Layer 0 (R)", 2D) = "white" {}
11.  
12.         //normal maps
13.         [HideInInspector] _Normal3("Normal 3 (A)", 2D) = "bump" {}
14.         [HideInInspector] _Normal2("Normal 2 (B)", 2D) = "bump" {}
15.         [HideInInspector] _Normal1("Normal 1 (G)", 2D) = "bump" {}
16.         [HideInInspector] _Normal0("Normal 0 (R)", 2D) = "bump" {}
17.  
18.         // used in fallback on old cards & base map
19.         [HideInInspector] _MainTex("BaseMap (RGB)", 2D) = "white" {}
20.         [HideInInspector] _Color("Main Color", Color) = (1,1,1,1)
21.    
22.     }
23.  
24.     SubShader{
25.         Tags{
26.             "SplatCount" = "4"
27.             "Queue" = "Geometry-99"
28.             "IgnoreProjector" = "True"
29.             "RenderType" = "Opaque"
30.         }
31.  
32.         CGPROGRAM
33.         #pragma surface surf Lambert exclude_path:forward decal:add
34.         #pragma multi_compile_fog
35.         #pragma target 3.0
36.         // needs more than 8 texcoords
37.         #pragma exclude_renderers gles
38.         #include "UnityPBSLighting.cginc"
39.    
40.         // Access the Shaderlab properties
41.         uniform sampler2D _Control;
42.         uniform sampler2D _Splat0,_Splat1,_Splat2,_Splat3;
43.  
44.         // Surface shader input structure
45.         struct Input {
46.             float2 uv_Control : TEXCOORD0;
47.             float2 uv_Splat0 : TEXCOORD1;
48.             float2 uv_Splat1 : TEXCOORD2;
49.             float2 uv_Splat2 : TEXCOORD3;
50.             float2 uv_Splat3 : TEXCOORD4;
51.         };
52.  
53.         float4 blend(float4 texA, float aA, float4 texB, float aB)
54.         {
55.  
56.             float depth = 0.1;
57.             float ma = max(texA.a + aA, texB.a + aB) - depth;
58.  
59.             float b1 = max(texA.a + aA - ma, 0.0);
60.             float b2 = max(texB.a + aB - ma, 0.0);
61.  
62.             return (texA * b1 + texB * b2) / (b1 + b2);
63.  
64.         }
65.  
66.        
67.         // Surface Shader function
68.         void surf(Input IN, inout SurfaceOutput o) {
69.             fixed4 tex0 = tex2D(_Splat0, IN.uv_Splat0);
70.             fixed4 tex1 = tex2D(_Splat1, IN.uv_Splat1);
71.             fixed4 tex2 = tex2D(_Splat2, IN.uv_Splat2);
72.             fixed4 tex3 = tex2D(_Splat3, IN.uv_Splat3);
73.  
74.             fixed4 splat_control = tex2D(_Control, IN.uv_Control);
75.             fixed4 col;
76.  
77.             col = blend(tex0, splat_control.r, tex1, splat_control.g);
78.             col = blend(col, splat_control.r + splat_control.g, tex2, splat_control.b);
79.             col = blend(col, splat_control.r + splat_control.g + splat_control.b, tex3, splat_control.a);
80.  
81.             o.Albedo = col.rgb;
82.             o.Alpha = 0.0;
83.                    
84.         }
85.         ENDCG
86.     }
87.  
88.         Fallback "Hidden/TerrainEngine/Splatmap/Diffuse-AddPass"
89.         //Fallback off
90. }

Thanks in Advanced!

 

addpass will blend firstpass pixel alpha
you can change this line:
o.Alpha = 0.0;
to:
o.Alpha=dot(float4(tex0.a,tex1.a,tex2.a,tex3.a),splat_control);
good luck!