Need help with gradient shader on sprites with fully transparent pixels.

Hi,

I've been searching around for whole day, trying to understand shaders, but they are fairly complex.

I have this sprite of a spike that looks cracked:

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And when I apply my material with a gradient shader, most of the transparent pixels are filled with the produced color:

​

Here is my shader code:

Code (CSharp):

1. Shader "Unlit/GradientSpriteShader"
2. {
3.         Properties{
4.             [PerRendererData] _MainTex("Sprite Texture", 2D) = "white" {}
5.         _Color("Left Color", Color) = (1,1,1,1)
6.             _Color2("Right Color", Color) = (1,1,1,1)
7.             _Scale("Scale", Float) = 1
8.  
9.         }
10.  
11.             SubShader{
12.             Tags{
13.             "Queue" = "Background"
14.             "IgnoreProjector" = "True"
15.             "RenderType" = "Transparent"
16.             }
17.             LOD 100
18.  
19.             ZWrite On
20.             Blend SrcAlpha OneMinusSrcAlpha
21.  
22.             Pass{
23.             CGPROGRAM
24. #pragma vertex vert
25. #pragma fragment frag
26. #include "UnityCG.cginc"
27.  
28.             fixed4 _Color;
29.         fixed4 _Color2;
30.         fixed  _Scale;
31.  
32.         struct v2f {
33.             float4 pos : SV_POSITION;
34.             fixed4 col : COLOR;
35.         };
36.  
37.         v2f vert(appdata_full v)
38.         {
39.          
40.             v2f o;
41.             o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
42.             o.col = lerp(_Color,_Color2, v.texcoord.x);
43.             return o;
44.         }
45.         float4 frag(v2f i) : COLOR{
46.             float4 c = i.col;
47.             return c;
48.         }
49.  
50.  
51.             ENDCG
52.         }
53.         }
54.  
55. }

Please, can someone explain me what's wrong with the shader?

Here is another example with slightly more details, but not as the original texture:

​

Thanks!


EDIT: Never give up, never back down
http://answers.unity3d.com/questions/1195044/gradient-transparent.html