Shader "Custom/DepthSpriteNoShear"
{
    Properties
    {
        _MainTex ("Sprite Texture", 2D) = "white" {}
        _Color ("Tint Color", Color) = (1,1,1,1)
        _Tilt ("Tilt Angle (Degrees)", Float) = 50.0
    }
    SubShader
    {
        // Render in the Geometry queue for proper depth testing.
        Tags { "Queue"="Geometry" "RenderType"="Opaque" }
        LOD 100

        Pass
        {
            // Ensure the sprite writes depth and is double-sided.
            ZWrite On
            Cull Off

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

            sampler2D _MainTex;
            fixed4 _Color;
            float _Tilt;

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

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

            /// <summary>
            /// Vertex shader applies a shear transformation to achieve the tilt.
            /// It assumes that the mesh is a quad centered at the origin.
            /// </summary>
            v2f vert(appdata v)
            {
                v2f o;
                // Convert the tilt angle from degrees to radians.
                float tiltRadians = radians(_Tilt);
                // Apply a shear: offset the x coordinate proportional to the y coordinate.
                // This simulates a perspective deformation that gives the sprite a 50° angled appearance.
                // It assumes the quad is defined with local vertex coordinates (e.g., from -0.5 to 0.5).
                v.vertex.z += v.vertex.y * tan(tiltRadians);
                o.vertex = UnityObjectToClipPos(v.vertex);
                o.uv = v.uv;
                return o;
            }

            fixed4 frag(v2f i) : SV_Target
            {
                fixed4 texColor = tex2D(_MainTex, i.uv) * _Color;
                // Clip pixels with very low alpha for proper transparency.
                clip(texColor.a - 0.01);
                return texColor;
            }
            ENDCG
        }
    }
    FallBack "Diffuse"
}