Resolved Glow filter over color mask [Solved with custom blur node]

I need something that will inflate/blur/glow the edges of any white shape over a black background in an unlit shader.

Edit: Made some progress on a gaussian blur implementation in a custom node, however I can't figure out the proper syntax to sample a texture from there. Although I do need the blur to function on the output of a color mask not the original texture. Can it be done with nodes?


Edit #2:
Created a custom blur node, doesn't operate on a color input like I originally wanted but I can just put it before my color mask. Here is the code:

Inputs:
MainTex = Texture2D
state = Sampler2D
uv = Vector2
magnitude = vector1

Code (CSharp):

1.    
2. col = MainTex.Sample(state, uv);
3.         col += MainTex.Sample(state, float2(uv.x + (magnitude * 2), uv.y - (magnitude * 2)));
4.         col += MainTex.Sample(state, float2(uv.x + (magnitude * 1), uv.y - (magnitude * 2)));
5.         col += MainTex.Sample(state, float2(uv.x, uv.y - (magnitude * 2)));
6.         col += MainTex.Sample(state, float2(uv.x + (magnitude * 1), uv.y - (magnitude * 2)));
7.         col += MainTex.Sample(state, float2(uv.x + (magnitude * 2), uv.y - (magnitude * 2)));
8.  
9.         col += MainTex.Sample(state, float2(uv.x + (magnitude * 2), uv.y - (magnitude * 1)));
10.         col += MainTex.Sample(state, float2(uv.x + (magnitude * 1), uv.y - (magnitude * 1)));
11.         col += MainTex.Sample(state, float2(uv.x, uv.y - (magnitude * 1)));
12.         col += MainTex.Sample(state, float2(uv.x + (magnitude * 1), uv.y - (magnitude * 1)));
13.         col += MainTex.Sample(state, float2(uv.x + (magnitude * 2), uv.y - (magnitude * 1)));
14.  
15.         col += MainTex.Sample(state, float2(uv.x + (magnitude * 2), uv.y));
16.         col += MainTex.Sample(state, float2(uv.x + (magnitude * 1), uv.y));
17.         col += MainTex.Sample(state, float2(uv.x + (magnitude * 1), uv.y));
18.         col += MainTex.Sample(state, float2(uv.x + (magnitude * 2), uv.y));
19.  
20.         col += MainTex.Sample(state, float2(uv.x + (magnitude * 2), uv.y + (magnitude * 1)));
21.         col += MainTex.Sample(state, float2(uv.x + (magnitude * 1), uv.y + (magnitude * 1)));
22.         col += MainTex.Sample(state, float2(uv.x, uv.y + (magnitude * 1)));
23.         col += MainTex.Sample(state, float2(uv.x + (magnitude * 1), uv.y + (magnitude * 1)));
24.         col += MainTex.Sample(state, float2(uv.x + (magnitude * 2), uv.y + (magnitude * 1)));
25.  
26.         col += MainTex.Sample(state, float2(uv.x + (magnitude * 2), uv.y + (magnitude * 2)));
27.         col += MainTex.Sample(state, float2(uv.x + (magnitude * 1), uv.y + (magnitude * 2)));
28.         col += MainTex.Sample(state, float2(uv.x, uv.y + (magnitude * 2)));
29.         col += MainTex.Sample(state, float2(uv.x + (magnitude * 1), uv.y + (magnitude * 2)));
30.         col += MainTex.Sample(state, float2(uv.x + (magnitude * 2), uv.y + (magnitude * 2)));
31.  
32.         col /= 25; // normalize

Outputs:
col = Vector4