o3de/Gems/Atom/Feature/Common/Assets/Shaders/PostProcessing/DepthToLinearDepth.azsl

/*
 * 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 <viewsrg.srgi>

#include <Atom/Features/PostProcessing/FullscreenVertex.azsli>

ShaderResourceGroup PassSrg : SRG_PerPass
{
    // D32_FLOAT_S8X24_UINT (Format:15) depthStencil texture
    Texture2D<float2> m_depthStencil;
    Sampler PointSampler
    {
        MinFilter = Point;
        MagFilter = Point;
        MipFilter = Point;
        AddressU = Clamp;
        AddressV = Clamp;
        AddressW = Clamp;
    };
}

struct PSOutput
{
    float m_linearDepth : SV_Target0;
};

PSOutput MainPS(VSOutput IN)
{
    PSOutput OUT;

    float zDepth = PassSrg::m_depthStencil.Sample(PassSrg::PointSampler, IN.m_texCoord).r;
    float linearDepth = 
        abs(((ViewSrg::GetFarZTimesNearZ()) / (ViewSrg::GetFarZMinusNearZ() * zDepth - ViewSrg::GetFarZ()))); 

    OUT.m_linearDepth = linearDepth;
    return OUT;
}