// Copyright 2019-Present LexLiu. All Rights Reserved.
#include "LGUIPostProcessVertexShader.usf"
#include "/Engine/Public/Platform.ush"

static float _Offset[3] =
{
    0.0,
	1.3846153846,
	3.2307692308
};

static float _Weight[3] =
{
    0.2270270270,
	0.3162162162,
	0.0702702703
};
Texture2D _MainTex;
SamplerState _MainTexSampler;
float2 _BlurStrength;
#if USE_STRENGTH_TEXTURE
Texture2D _StrengthTex;
SamplerState _StrengthTexSampler;
#endif

float4 GaussianBlurPS(SimpleVSToPS input) : SV_Target0
{
#if USE_STRENGTH_TEXTURE
    float strength = _StrengthTex.Sample(_StrengthTexSampler, input.uv).r;
#endif
    float4 color = _MainTex.Sample(_MainTexSampler, input.uv) * _Weight[0];
    for (int i = 1; i < 3; i++)
    {
        float2 uvOffset = _Offset[i] * _BlurStrength;
#if USE_STRENGTH_TEXTURE
        uvOffset *= strength;
#endif
        color += _MainTex.Sample(_MainTexSampler, input.uv + uvOffset) * _Weight[i];
        color += _MainTex.Sample(_MainTexSampler, input.uv - uvOffset) * _Weight[i];
    }
    return color;
}