problem with using color in fragment shader

HI all! Could you help me with my question about shaders? I trying write vertex fragment shader. If use i.color in fragment shader, my shader looks just white, but if i use _Color. Shader works correctly.

Code (CSharp):

1. Shader "custom/green"
2. {
3.     Properties
4.     {
5.         _Color ("Color", Color) = (1,1,1,1)
6.         _MainTex ("Color Texture", 2D) = "white" {}
7.     }
8.     SubShader
9.     {
10.         Tags
11.         {
12.             "Queue"="Transparent"
13.             "IgnoreProjector"="True"
14.             "RenderType"="Transparent"
15.             "PreviewType"="Plane"
16.             "CanUseSpriteAtlas"="True"
17.         }
18.  
19.         Cull Off
20.         Lighting Off
21.         ZWrite Off
22.         Blend One OneMinusSrcAlpha
23.         Pass
24.         {
25.             CGPROGRAM
26.             #pragma vertex vert
27.             #pragma fragment frag
28.  
29.  
30.             #include "UnityCG.cginc"
31.  
32.             struct appdata
33.             {
34.                 float4 vertex : POSITION;
35.                 float2 uv : TEXCOORD0;
36.                 float4 color : COLOR0;
37.             };
38.  
39.             struct v2f
40.             {
41.                 float4 vertex : SV_POSITION;
42.                 float2 uv : TEXCOORD0;
43.                 float4 color : COLOR0;
44.             };
45.            
46.             float4 _Color;
47.             sampler2D _MainTex;
48.             float4 _MainTex_ST;
49.  
50.             v2f vert (appdata v)
51.             {
52.                 v2f o;
53.                 o.vertex = UnityObjectToClipPos(v.vertex);              
54.                 o.uv = TRANSFORM_TEX(v.uv, _MainTex);
55.                 o.color = v.color;
56.                 return o;
57.             }
58.  
59.             fixed4 frag (v2f i) : SV_Target
60.             {
61.                 fixed4 col_tex = tex2D(_MainTex, i.uv);
62.                 // fixed4 col = i.color; // not work
63.                 fixed4 col = _Color; // work!
64.                 return col;
65.             }
66.             ENDCG
67.         }
68.     }
69. }

 

_Color

is the name of the color property that you see on the material.

i.color

is the value passed to the fragment shader from the vertex shader, which the vertex shader got from the mesh’s vertex color data. If you don’t have any color data set on your mesh (either colored in an external program, via a custom script, or some kind of vertex painting tool you’re using in the editor) then it’ll default to white.

 

thank you! I understood