﻿Shader "SnapshotProHDRP/Mosaic"
{
    HLSLINCLUDE

    #pragma target 4.5
    #pragma only_renderers d3d11 ps4 xboxone vulkan metal switch

    #include "Packages/com.unity.render-pipelines.core/ShaderLibrary/Common.hlsl"
    #include "Packages/com.unity.render-pipelines.core/ShaderLibrary/Color.hlsl"
    #include "Packages/com.unity.render-pipelines.high-definition/Runtime/ShaderLibrary/ShaderVariables.hlsl"
    #include "Packages/com.unity.render-pipelines.high-definition/Runtime/PostProcessing/Shaders/FXAA.hlsl"
    #include "Packages/com.unity.render-pipelines.high-definition/Runtime/PostProcessing/Shaders/RTUpscale.hlsl"

    struct Attributes
    {
        uint vertexID : SV_VertexID;
        UNITY_VERTEX_INPUT_INSTANCE_ID
    };

    struct Varyings
    {
        float4 positionCS : SV_POSITION;
        float2 texcoord   : TEXCOORD0;
        UNITY_VERTEX_OUTPUT_STEREO
    };

    Varyings Vert(Attributes input)
    {
        Varyings output;
        UNITY_SETUP_INSTANCE_ID(input);
        UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(output);
        output.positionCS = GetFullScreenTriangleVertexPosition(input.vertexID);
        output.texcoord = GetFullScreenTriangleTexCoord(input.vertexID);
        return output;
    }

    // List of properties to control your post process effect
    TEXTURE2D_X(_InputTexture);
	sampler2D _OverlayTex;
	float4 _OverlayColor;
	int _XTileCount;
	int _YTileCount;

    float4 CustomPostProcess(Varyings input) : SV_Target
    {
        UNITY_SETUP_STEREO_EYE_INDEX_POST_VERTEX(input);

        uint2 positionSS = input.texcoord * _ScreenSize.xy;
		float4 tex = LOAD_TEXTURE2D_X(_InputTexture, positionSS);

		float2 overlayUV = input.texcoord * float2(_XTileCount, _YTileCount);
		float4 overlayCol = tex2D(_OverlayTex, overlayUV) * _OverlayColor;

		return lerp(tex, overlayCol, overlayCol.a);
    }

    ENDHLSL

    SubShader
    {
		Pass
		{
			Name "Mosaic"

			ZWrite Off
			ZTest Always
			Blend Off
			Cull Off

			HLSLPROGRAM
				#pragma fragment CustomPostProcess
				#pragma vertex Vert
			ENDHLSL
		}
    }
    Fallback Off
}
