Opacity in Unity Shader - unity3d

Question

I´m trying to make a shader which simulates a warp speed effect, and i think is almost done, only need to know what should i change in the code to make the tunnel effect completely opaque and not see anything behind the tunnel effect.
I have added an alpha slider to see if i can control opacity but still the same result at the end.
Code is here:
Shader "Warp Tunnel Distortion Opaque" {
Properties {
_TintColor ("Tint Color", Color) = (0.5,0.5,0.5,0.5)
_Speed("UV Speed", Float) = 1.0
_WiggleX("_WiggleX", Float) = 1.0
_WiggleY("_WiggleY", Float) = 1.0
_WiggleDist("Wiggle distance", Float) = 1.0
_Offset("Vertex offset", float) = 0
_TintColor("Tint", Color) = (1.0, 1.0, 1.0, 1.0)
_MainTex("Distortion map", 2D) = "" {}
_Dist("Distortion ammount", Float) = 10.0
}
Category {
Tags { "Queue"="Geometry" "RenderType"="Opaque" }
Cull Back Lighting Off ZWrite Off
Fog { Color (0,0,0,0) }
ZTest LEqual
SubShader {
GrabPass {
Name "BASE"
Tags { "LightMode" = "Always" }
}
Pass {
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#pragma multi_compile_particles
#include "UnityCG.cginc"
sampler2D _MainTex;
fixed4 _TintColor;
struct appdata_t {
float4 vertex : POSITION;
fixed4 color : COLOR;
float2 texcoord : TEXCOORD0;
float4 normal : NORMAL;
};
struct v2f {
float4 vertex : SV_POSITION;
fixed4 color : COLOR;
float2 texcoord : TEXCOORD0;
float4 posWorld : TEXCOORD1;
float4 uvgrab : TEXCOORD2;
float4 projPos : TEXCOORD3;
};
float4 _MainTex_ST;
float _Speed;
float _WiggleX, _WiggleY, _WiggleDist;
float _Offset;
float _Dist;
sampler2D _CameraDepthTexture;
float _InvFade;
sampler2D _GrabTexture;
float4 _GrabTexture_TexelSize;
v2f vert (appdata_t v)
{
v2f o;
o.posWorld = mul(unity_ObjectToWorld, v.vertex);
v.vertex.xyz += normalize(v.normal.xyz) * _Offset;
o.vertex = UnityObjectToClipPos(v.vertex);
o.vertex.x += sin(_Time.y * _WiggleX) * _WiggleDist;
o.vertex.y -= sin(_Time.y * _WiggleY) * _WiggleDist;
o.color = v.color;
o.texcoord = TRANSFORM_TEX(v.texcoord,_MainTex);
o.projPos = ComputeScreenPos (o.vertex);
COMPUTE_EYEDEPTH(o.projPos.z);
#if UNITY_UV_STARTS_AT_TOP
float scale = -1.0;
#else
float scale = 1.0;
#endif
o.uvgrab.xy = (float2(o.vertex.x, o.vertex.y*scale) + o.vertex.w) * 0.5;
o.uvgrab.zw = o.vertex.zw;
return o;
}
fixed4 frag (v2f i) : SV_Target
{
i.texcoord.y += _Time.x * _Speed;
float4 packedTex = tex2D(_MainTex, i.texcoord);
float local1 = packedTex.z * 2.4;
float2 local2 = packedTex.rg * 2.25;
packedTex.rg = local1 * local2;
half2 bump = UnpackNormal(packedTex).rg;
float2 offset = bump * _Dist * _GrabTexture_TexelSize.xy;
i.uvgrab.xy = offset * i.uvgrab.z + i.uvgrab.xy;
half4 col = tex2Dproj( _GrabTexture, UNITY_PROJ_COORD(i.uvgrab));
return col;
}
ENDCG
}
}
}
}
Thank you in advance.

Answer 1

Well if you want it completely opaque, that's easy.
Right before the return statement, just add:
col.a = 1;
If you want it to actually care about the alpha slider in the input color, then do this:
col.a = _TintColor.a;
In the first case, _TintColor isn't used at all (there are no other references to it besides its declaration, of which there are 2 at the top (you should remove one of them) and one inside the CGprogram block which links the first one to a property that can be used within the CGprogram).
If you actually want to tint things, you'll have to multiply the _TintColor with the computed color coming from the texture and effect. There are multiple ways of doing it, for example:
col.r *= _TintColor.r;
col.g *= _TintColor.g;
col.b *= _TintColor.b;
How you want to handle it is up to you.