/*
 * Copyright (c) Contributors to the Open 3D Engine Project.
 * For complete copyright and license terms please see the LICENSE at the root of this distribution.
 *
 * SPDX-License-Identifier: Apache-2.0 OR MIT
 *
 */

#include <Atom/Features/SrgSemantics.azsli>

#include <Atom/Features/PostProcessing/FullscreenPixelInfo.azsli>
#include <Atom/Features/PostProcessing/PostProcessUtil.azsli>
#include <Atom/Features/PostProcessing/FullscreenVertexInfo.azsli>
#include <Atom/Features/PostProcessing/FullscreenVertexUtil.azsli>

struct VSOutputBlendingWeightCalculation
{
    float4 m_position : SV_Position;
    float2 m_texCoord : TEXCOORD0;
    float2 m_pixcoord : TEXCOORD1;
    float4 m_offset[3] : TEXCOORD2;
};

ShaderResourceGroup PassSrg : SRG_PerPass_WithFallback
{
    Texture2D<float4> m_framebuffer;
    Texture2D<float4> m_areaTexture;
    Texture2D<float4> m_searchTexture;

    // Information for render target.
    // x = 1.0 / width
    // y = 1.0 / height
    // z = width
    // w = height
    float4 m_renderTargetMetrics;
    // How many steps to be used in horizontal/vertical search process. For details please check comment related to SMAA_MAX_SEARCH_STEPS in SMAA.azsli.
    int m_maxSearchSteps;
    // How many steps to be used in diagonal search process. For details please check comment related to SMAA_MAX_SEARCH_STEPS_DIAG in SMAA.azsli.
    int m_maxSearchStepsDiagonal;
    // This is a tweak value for the sharp corner feature. For details please check comment related to SMAA_CORNER_ROUNDING in SMAA.azsli.
    int m_cornerRounding;

    Sampler LinearSampler
    {
        MinFilter = Linear;
        MagFilter = Linear;
        MipFilter = Linear;
        AddressU = Clamp;
        AddressV = Clamp;
        AddressW = Clamp;
    };
    Sampler PointSampler
    {
        MinFilter = Point;
        MagFilter = Point;
        MipFilter = Point;
        AddressU = Clamp;
        AddressV = Clamp;
        AddressW = Clamp;
    };
}

// Option shader variable to enable diagonal edge detection feature. This option value is used instead of SMAA_DISABLE_DIAG_DETECTION define in SMAA.azsli.
option bool o_enableDiagonalDetectionFeature = true;
// Option shader variable to enable corner detection feature. This option value will be used instead of SMAA_DISABLE_CORNER_DETECTION define in SMAA.azsli.
option bool o_enableCornerDetectionFeature = true;

// This macro being defined before being included in SMAA.azsli, we can control which function is enabled in SMAA.azsli.
// This macro is intended to enable the blending weight calculation functions only.
#define ATOM_SMAA_BLENDING_WEIGHT_CALCULATION_PASS_IMPLEMENTATION_ENABLE

// Defining the elements below before including SMAA.azsli as they'll be used in it.
// - PassSrg SRG to be used for the blending weight calculation implementation.
// - The option shader variables to be used for the blending weight calculation implementation.
#include "SMAA.azsli"

VSOutputBlendingWeightCalculation MainVS(VSInput input)
{
    VSOutputBlendingWeightCalculation OUT;
    
    float4 posTex = GetVertexPositionAndTexCoords(input.m_vertexID);
    
    OUT.m_texCoord = float2(posTex.z, posTex.w);
    OUT.m_position = float4(posTex.x, posTex.y, 0.0, 1.0);
    
    SMAABlendingWeightCalculationVS(OUT.m_texCoord, OUT.m_pixcoord, OUT.m_offset);

    return OUT;
}

PSOutput MainPS(VSOutputBlendingWeightCalculation IN)
{
    PSOutput OUT;
    
    OUT.m_color = SMAABlendingWeightCalculationPS(IN.m_texCoord, IN.m_pixcoord, IN.m_offset, PassSrg::m_framebuffer, PassSrg::m_areaTexture, PassSrg::m_searchTexture, float4(0.0, 0.0, 0.0, 0.0));

    return OUT;
}