Shader "Hidden/Bansonic/GlobalDistortion"
{
    SubShader
    {
        Tags { "RenderPipeline" = "UniversalPipeline" }
        ZWrite Off
        Cull Off
        ZTest Always

        Pass
        {
            Name "GlobalDistortion"

            HLSLPROGRAM
            #pragma vertex Vert
            #pragma fragment Frag
            #pragma target 4.5

            #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"
            #include "Packages/com.unity.render-pipelines.core/Runtime/Utilities/Blit.hlsl"

            float _DistortionIntensity;
            float _NoiseStrength;
            float _RadialStrength;
            float _NoiseScale;
            float2 _DistortionCenter;
            float _EdgeFade;

            half4 Frag(Varyings input) : SV_Target
            {
                float2 uv = input.texcoord;
                float2 centered = uv - _DistortionCenter;
                float distanceFromCenter = length(centered);
                float2 direction = distanceFromCenter > 0.0001 ? centered / distanceFromCenter : float2(0.0, 0.0);
                float normalizedDistance = saturate(distanceFromCenter * 1.41421356);
                float edgeMask = saturate(1.0 - pow(normalizedDistance, _EdgeFade));

                float t = _Time.y;
                float noiseA = sin((uv.x + t * 0.73) * _NoiseScale) * cos((uv.y - t * 1.13) * (_NoiseScale * 0.87));
                float noiseB = cos((uv.x * 1.31 - t * 0.41) * (_NoiseScale * 0.63)) * sin((uv.y * 1.11 + t * 0.52) * (_NoiseScale * 1.21));

                float2 radialOffset = direction * edgeMask * (_RadialStrength * 0.03) * _DistortionIntensity;
                float2 noiseOffset = float2(noiseA, noiseB) * (_NoiseStrength * 0.015) * _DistortionIntensity;
                float2 sampleUv = uv + radialOffset + noiseOffset;
                sampleUv = clamp(sampleUv, 0.0, 1.0);

                return SAMPLE_TEXTURE2D_X(_BlitTexture, sampler_LinearClamp, sampleUv);
            }
            ENDHLSL
        }
    }
}