Shader "Custom/HitboxVisualizer"
{
    Properties
    {
        [HDR] _BaseColor ("Color", Color) = (1, 0, 0, 0.7)
        _BorderWidth ("Border Width", Range(0.005, 0.15)) = 0.035
    }

    SubShader
    {
        Tags 
        { 
            "RenderType" = "Transparent" 
            "Queue" = "Transparent+200" 
            "RenderPipeline" = "UniversalPipeline"
        }

        Pass
        {
            Name "HitboxPass"
            Blend SrcAlpha OneMinusSrcAlpha
            ZWrite Off
            Cull Off
            ZTest LEqual

            HLSLPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            #pragma multi_compile_instancing

            #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"

            struct Attributes
            {
                float4 positionOS : POSITION;
                float2 uv         : TEXCOORD0;
                UNITY_VERTEX_INPUT_INSTANCE_ID
            };

            struct Varyings
            {
                float4 positionCS : SV_POSITION;
                float2 uv         : TEXCOORD0;
                UNITY_VERTEX_INPUT_INSTANCE_ID
            };

            CBUFFER_START(UnityPerMaterial)
                float _BorderWidth;
            CBUFFER_END

            UNITY_INSTANCING_BUFFER_START(Props)
                UNITY_DEFINE_INSTANCED_PROP(float4, _BaseColor)
            UNITY_INSTANCING_BUFFER_END(Props)

            Varyings vert(Attributes input)
            {
                Varyings output = (Varyings)0;
                UNITY_SETUP_INSTANCE_ID(input);
                UNITY_TRANSFER_INSTANCE_ID(input, output);

                output.positionCS = TransformObjectToHClip(input.positionOS.xyz);
                output.uv = input.uv;
                return output;
            }

            half4 frag(Varyings input) : SV_Target
            {
                UNITY_SETUP_INSTANCE_ID(input);
                half4 baseColor = UNITY_ACCESS_INSTANCED_PROP(Props, _BaseColor);

                // Дистанция до края полигона (грани куба)
                float2 dist = min(input.uv, 1.0 - input.uv);
                float edgeDist = min(dist.x, dist.y);

                // 1.0 если пиксель на краю грани, иначе 0.0
                float isEdge = step(edgeDist, _BorderWidth);

                half4 finalColor = baseColor;
                // Внутри объема цвет прозрачный, на гранях — яркий и четкий
                finalColor.a = lerp(baseColor.a * 0.25, saturate(baseColor.a * 1.5), isEdge);
                finalColor.rgb = lerp(baseColor.rgb, baseColor.rgb * 1.3, isEdge);

                return finalColor;
            }
            ENDHLSL
        }
    }
    FallBack Off
}