/*
* All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
* its licensors.
*
* For complete copyright and license terms please see the LICENSE at the root of this
* distribution (the "License"). All use of this software is governed by the License,
* or, if provided, by the license below or the license accompanying this file. Do not
* remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
*
*/
// Original file Copyright Crytek GMBH or its affiliates, used under license.

#ifndef __REVERSE_DEPTH_H__
#define __REVERSE_DEPTH_H__

//#include "Cry_Matrix44.h"

struct ReverseDepthHelper
{
    static Matrix44 Convert(const Matrix44& m)
    {
        Matrix44 result = m;
        result.m02 = -m.m02 + m.m03;
        result.m12 = -m.m12 + m.m13;
        result.m22 = -m.m22 + m.m23;
        result.m32 = -m.m32 + m.m33;

        return result;
    }

    static D3DViewPort Convert(const D3DViewPort& vp)
    {
        D3DViewPort result = vp;
        result.MinDepth = 1.0f - vp.MaxDepth;
        result.MaxDepth = 1.0f - vp.MinDepth;

        return result;
    }

    static uint32 ConvertDepthFunc(uint32 nState)
    {
        uint32 nDepthFuncRemapped = nState & GS_DEPTHFUNC_MASK;

        switch (nState & GS_DEPTHFUNC_MASK)
        {
        case GS_DEPTHFUNC_LESS:
            nDepthFuncRemapped = GS_DEPTHFUNC_GREAT;
            break;

        case GS_DEPTHFUNC_LEQUAL:
            nDepthFuncRemapped = GS_DEPTHFUNC_GEQUAL;
            break;

        case GS_DEPTHFUNC_GREAT:
            nDepthFuncRemapped = GS_DEPTHFUNC_LESS;
            break;

        case GS_DEPTHFUNC_GEQUAL:
            nDepthFuncRemapped = GS_DEPTHFUNC_LEQUAL;
            break;
        }

        nState &= ~GS_DEPTHFUNC_MASK;
        nState |= nDepthFuncRemapped;

        return nState;
    }
};

#endif // __REVERSE_DEPTH_H__