Shader "Custom/CloudsShader"
{
    Properties
    {
        _MainTex("Texture", 2D) = "white" {}
        _ScrollSpeed("Scroll Speed", Vector) = (0.1, 0.1, 0, 0)
        _Color("Tint Color", Color) = (1,1,1,1)
    }

    SubShader
    {
        Tags { "Queue"="Transparent" "RenderType"="Transparent" }
        Blend One One // Additive blending
        ZWrite Off
        Cull Off

        Pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag

            sampler2D _MainTex;
            float4 _MainTex_ST;
            float4 _ScrollSpeed;
            float4 _Color;

            struct appdata
            {
                float4 vertex : POSITION;
                float2 uv : TEXCOORD0;
            };

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

            v2f vert(appdata v)
            {
                v2f o;
                o.vertex = UnityObjectToClipPos(v.vertex);

                // Scroll UVs over time
                float2 scroll = _ScrollSpeed.xy * _Time.y;
                o.uv = v.uv + scroll;

                return o;
            }

            fixed4 frag(v2f i) : SV_Target
            {
                fixed4 tex = tex2D(_MainTex, i.uv) * _Color;
                return tex;
            }
            ENDCG
        }
    }
    FallBack "Unlit/Transparent"
}