Look_At_Cam_Billboard.shader

Shader "Custom/Look_At_Cam_Billboard"
{
    Properties
    {
        _MainTex ("Texture", 2D) = "white" {}
        _Cutoff ("Alpha Cutoff", Range(0,1)) = 0.5
    }
    SubShader
    {
        Tags {
            "RenderType"="TransparentCutout"
            "Queue"="AlphaTest"  // Changed from "Transparent" to "AlphaTest" for cutout
        }
        LOD 100

        Pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            #include "UnityCG.cginc"

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

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

            sampler2D _MainTex;
            float4 _MainTex_ST;
            float _Cutoff;

            v2f vert (appdata v)
            {
                v2f o;

                // Billboard calculation
                float4 origin = mul(unity_ObjectToWorld, float4(0, 0, 0, 1));
                float4 viewOrigin = mul(UNITY_MATRIX_V, origin);

                // Calculate view position
                float4 worldPos = mul(unity_ObjectToWorld, v.vertex);
                float4 viewPos = float4(viewOrigin.xy + (v.vertex.xy * _MainTex_ST.xy), viewOrigin.z, 1.0);
                o.pos = mul(UNITY_MATRIX_P, viewPos);

                o.uv = TRANSFORM_TEX(v.uv, _MainTex);
                return o;
            }

            fixed4 frag (v2f i) : SV_Target
            {
                fixed4 col = tex2D(_MainTex, i.uv);
                clip(col.a - _Cutoff);  // Better than discard
                return col;
            }
            ENDCG
        }
    }
    FallBack "Transparent/Cutout/Diffuse"
}