#ifndef PIXELATE_PASS_INCLUDED
#define PIXELATE_PASS_INCLUDED

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

TEXTURE2D(_SourceTexture);
SAMPLER(sampler_SourceTexture);
float4 _SourceTexture_TexelSize;

float _PixelateStrengthX;
float _PixelateStrengthY;

struct Varyings
{
    float4 positionCS_SS : SV_POSITION;
    float2 screenUV : VAR_SCREEN_UV;
};

Varyings PixelatePassVert(uint vertexID : SV_VertexID)
{
    Varyings output;
    output.positionCS_SS = float4(
        vertexID <= 1 ? -1.0 : 3.0,
        vertexID == 1 ? 3.0 : -1.0,
        0.0, 1.0
    );
    output.screenUV = float2(
        vertexID <= 1 ? 0.0 : 2.0,
        vertexID == 1 ? 2.0 : 0.0
    );
    if (_ProjectionParams.x < 0.0)
    {
        output.screenUV.y = 1.0 - output.screenUV.y;
    }
    return output;
}

half4 PixelatePassFrag(Varyings input) : SV_Target
{
    float2 screenUV = input.screenUV;
    float2 strength = float2(_PixelateStrengthX, _PixelateStrengthY);
    float2 uvScaled = screenUV * strength;
    float2 uvFloor = floor(uvScaled);
    float2 uvCenter = uvFloor + 0.5;
    float2 uvPixelated = uvCenter / strength;

    return SAMPLE_TEXTURE2D(_SourceTexture, sampler_SourceTexture, uvPixelated);
}

#endif