Question by K-16Games · Jul 22, 2018 at 05:21 AM · shader texture transparency alpha flow

Add transparency to this shader?

I have a basic shader that uses a flow map to distort an image over time, following a few tutorials I found. I'd like to add transparency, or find a way to use a texture with transparency on this shader to create layers of clouds or water. Nothing fancy. Is there a way to modify this script without breaking it?

 Shader "Plexus/BasicFlowMap" {
     Properties {
         _MainTex ("Base (RGB)", 2D) = "white" {}
         _FlowMap ("Flow Map", 2D) = "grey" {}
         _Speed ("Speed", Range(-1, 1)) = 0.2
     }
  
     SubShader {
         Pass {
             Tags { "RenderType"="Opaque" }
        
             CGPROGRAM
             #pragma vertex vert keepalpha
             #pragma fragment frag
             #include "UnityCG.cginc"
  
             struct v2f {
                 float4 pos : SV_POSITION;
                 fixed2 uv : TEXCOORD0;
             };
  
             sampler2D _MainTex;
             sampler2D _FlowMap;
             fixed _Speed;
  
             fixed4 _MainTex_ST;
  
             v2f vert(appdata_base IN) {
                 v2f o;
                 o.pos = UnityObjectToClipPos(IN.vertex);
                 o.uv = TRANSFORM_TEX(IN.texcoord, _MainTex);
                 return o;
             }
        
             fixed4 frag(v2f v) : COLOR {
                 fixed4 c;
                 half3 flowVal = (tex2D(_FlowMap, v.uv) * 2 - 1) * _Speed;
  
                 float dif1 = frac(_Time.y * 0.25 + 0.5);
                 float dif2 = frac(_Time.y * 0.25);
  
                 half lerpVal = abs((0.5 - dif1)/0.5);
  
                 half4 col1 = tex2D(_MainTex, v.uv - flowVal.xy * dif1);
                 half4 col2 = tex2D(_MainTex, v.uv - flowVal.xy * dif2);
  
                 c = lerp(col1, col2, lerpVal);
                 return c;
             }
  
             ENDCG
         }
     }
     FallBack "Diffuse"
 }

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