Trying to mod shader to work with particle color over time

Hello,
Preface: I know nothing about shaders.

However, I have this shader that came from an asset pack that I like, but it doesn't work with the particle color over time module. Some research says that the color must be _Color and it must be a vertex color (whatever that means), I've tried to modify the shader to match the examples to no avail, could anyone take a quick peek and let me know what exactly needs to change to get the color over time working? Much appreciated!

Code (CSharp):

1. // Upgrade NOTE: replaced 'mul(UNITY_MATRIX_MVP,*)' with 'UnityObjectToClipPos(*)'
2.  
3. // Upgrade NOTE: replaced '_Object2World' with 'unity_ObjectToWorld'
4. // Upgrade NOTE: replaced '_World2Object' with 'unity_WorldToObject'
5.  
6. Shader "FORGE3D/Billboard Nebula Custom"
7. {
8.     Properties
9.     {
10.         _CoronaNoise("Texture", 2D) = "black" {}
11.         _Color("Color", Color) = (0.5,0.5,0.5,0.5)
12.         _EdgeMaskFalloff("Edge Mask Falloff", float) = 0
13.         _EdgeMaskPower("Edge Mask Power", float) = 0
14.         _MinFadeStart("Min Fade Start", float) = 0
15.         _MinFadeEnd("Min Fade End", float) = 0
16.         _MaxFadeStart("Max Fade Start", float) = 0
17.         _MaxFadeEnd("Max Fade End", float) = 0
18.     }
19.  
20.     Category
21.     {
22.    
23.        
24.        
25.            
26.         Tags { "Queue"="Transparent" "IgnoreProjector"="True" "RenderType"="Transparent" }
27.         Blend One One
28.         AlphaTest Greater .01
29.         ColorMask RGB
30.         Cull Off Lighting Off ZWrite Off Fog { Color (0,0,0,0) }
31.         // Tags { "RenderType"="Opaque" }
32.         SubShader {  
33.  
34.         // Disable Dynamic Batching
35.         //Pass{}
36.  
37.         Pass {
38.  
39.             CGPROGRAM
40.              #pragma vertex vert
41.             #pragma fragment frag
42.           //  #pragma only_renderers opengl d3d9 d3d11
43.             #pragma glsl
44.          //   #pragma target 3.0
45.             #pragma multi_compile_particles
46.             #include "UnityCG.cginc"
47.            
48.            
49.  
50.             float4 _Color;
51.  
52.             float _EdgeMaskFalloff, _EdgeMaskPower;
53.             float _MinFadeStart, _MinFadeEnd;
54.             float _MaxFadeStart, _MaxFadeEnd;
55.  
56.             sampler2D _CoronaNoise;
57.  
58.        
59.  
60.             struct VertexInput
61.             {
62.                 float4 vertex : POSITION;
63.                 float3 normal : NORMAL;  
64.                 float2 texcoord0 : TEXCOORD0;
65.             };
66.  
67.             struct VertexOutput
68.             {                  
69.                 float4 pos : POSITION;
70.                 float4 posWorld : TEXCOORD0;
71.                 float3 normalDir : TEXCOORD1;            
72.                 float2 uv : TEXCOORD2;  
73.             };
74.  
75.             VertexOutput vert (VertexInput v)
76.             {
77.                 VertexOutput o;
78.                    o.normalDir = mul(float4(v.normal,0), unity_WorldToObject).xyz;              
79.                 o.posWorld = mul(unity_ObjectToWorld, v.vertex);
80.                 o.pos = UnityObjectToClipPos(v.vertex);
81.                 o.uv = v.texcoord0;
82.        
83.            
84.                 return o;
85.             }
86.  
87.        
88.  
89.          
90.  
91.  
92.             float4 frag(VertexOutput i) : COLOR
93.             {
94.                
95.                 float3 finalColor = tex2D(_CoronaNoise, i.uv.xy);
96.  
97.                 float3 viewDirection = normalize(_WorldSpaceCameraPos.xyz - i.posWorld.xyz);
98.                 float viewDot = abs(dot(viewDirection, normalize(i.normalDir)));          
99.                 viewDot = pow(viewDot, _EdgeMaskFalloff) * _EdgeMaskPower;
100.                 viewDot = clamp(viewDot, 0 ,1);
101.  
102.                 float dist = distance(_WorldSpaceCameraPos.xyz, i.posWorld.xyz);
103.                 float MinFade = saturate((_MinFadeEnd - dist) / (_MinFadeStart -_MinFadeEnd));
104.                 float MaxFade = saturate((_MaxFadeEnd - dist) / (_MaxFadeEnd - _MaxFadeStart));
105.  
106.                
107.                 return float4(saturate(pow(finalColor * viewDot *_Color, 1.3) * 1.5 * MaxFade * MinFade), 1);
108.  
109.            
110.             }
111.  
112.             ENDCG  
113.         }
114.     }    
115.      
116. }
117. }
118.  

 

Your Vertex structs don't contain any color information. You need to assign the vertex color from the mesh to a variable in your VertexOutput struct and then do something with it in the frag.

_Color is just a color property on your material, it won't have anything to do with vertex color.