Shader problem: Transparency removed with Opacity changes

Unity Engine
,
1

Hello! I am trying to make a shader that takes in 2 textures and blends them together, and then the final output needs to have opacity as a variable. To that end, I have gotten it all worked out, EXCEPT, whenever one of the inputs has transparency, the opacity element removes the transparency and replaces it with this:8218011--1073043--upload_2022-6-19_16-40-50.png

my code so far:

Shader "Custom/TonyShader2D"
{
    Properties
    {
        _MainTex ("Albedo (RGB)", 2D) = "white" {}
        _OffTex ("Other Texture", 2D) = "white" {}
        _Strength ("Blend Strength Between Textures", Range(0,1)) = 1
        _Opacity ("Opacity", Range(0,1)) = 0.0
    }
    SubShader
    {
        Tags { "Queue"="Transparent"  "RenderType"="Transparent" }

         Blend SrcAlpha OneMinusSrcAlpha
        Pass
        {
        CGPROGRAM

        #pragma vertex vert
        #pragma fragment frag
       
        #include "UnityCG.cginc"


        sampler2D _MainTex;
        sampler2D _OffTex;

        half _Opacity;
        half _Strength;

        float4 _MainTex_ST;
        float4 _OffTex_ST;

        struct Input
        {
            float2 uv_MainTex;
            float2 uv_OffTex;
        };


            struct v2f
            {
                float4 vertex : SV_POSITION;
                float2 uv : TEXCOORD0;
                float2  uv2 : TEXCOORD1;
            };

            v2f vert(appdata_base v)
            {
                v2f o;
                o.vertex = UnityObjectToClipPos(v.vertex);
                o.uv = TRANSFORM_TEX (v.texcoord, _MainTex);
                o.uv2 = TRANSFORM_TEX (v.texcoord, _OffTex);
                return o;
            }


        //void surf (Input IN, inout SurfaceOutputStandard o)
        float4 frag(v2f i) : SV_Target
        {
            fixed4 c = tex2D (_MainTex, i.uv);
            //c.a= _Opacity;
            fixed4 c2 = tex2D (_OffTex, i.uv2);
            //c2.a= _Opacity;
            fixed4 c3 = lerp (c, c2, _Strength);
            c3.a= _Opacity;
            return c3;
        }
        ENDCG
    }
}}

Any Ideas?

2

This is to be expected: you’re throwing away your texture’s alpha channel and entirely replacing with your _Opacity value.

c3.a = _Opacity;

You should multiply (modulate) your alpha channel by _Opacity instead:

c3.a *= _Opacity;
3

Thank you!!