//--------------------------------------------------------------------------------------
// File: DDSTextureLoader.cpp
//
// Function for loading a DDS texture and creating a Direct3D 11 runtime resource for it
//
// Note these functions are useful as a light-weight runtime loader for DDS files. For
// a full-featured DDS file reader, writer, and texture processing pipeline see
// the 'Texconv' sample and the 'DirectXTex' library.
//
// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF
// ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
// THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
// PARTICULAR PURPOSE.
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//
// http://go.microsoft.com/fwlink/?LinkId=248926
// http://go.microsoft.com/fwlink/?LinkId=248929
//--------------------------------------------------------------------------------------

#include <dxgiformat.h>
#include <assert.h>
#include <algorithm>
#include <memory>

#include "DDSTextureLoader.h"

#if (_WIN32_WINNT >= 0x0602 /*_WIN32_WINNT_WIN8*/) && !defined(DXGI_1_2_FORMATS)
#define DXGI_1_2_FORMATS
#endif

//--------------------------------------------------------------------------------------
// Macros
//--------------------------------------------------------------------------------------
#ifndef MAKEFOURCC
    #define MAKEFOURCC(ch0, ch1, ch2, ch3)                              \
                ((uint32_t)(uint8_t)(ch0) | ((uint32_t)(uint8_t)(ch1) << 8) |       \
                ((uint32_t)(uint8_t)(ch2) << 16) | ((uint32_t)(uint8_t)(ch3) << 24 ))
#endif /* defined(MAKEFOURCC) */

//--------------------------------------------------------------------------------------
// DDS file structure definitions
//
// See DDS.h in the 'Texconv' sample and the 'DirectXTex' library
//--------------------------------------------------------------------------------------
#pragma pack(push,1)

#define DDS_MAGIC 0x20534444 // "DDS "

struct DDS_PIXELFORMAT
{
    uint32_t    size;
    uint32_t    flags;
    uint32_t    fourCC;
    uint32_t    RGBBitCount;
    uint32_t    RBitMask;
    uint32_t    GBitMask;
    uint32_t    BBitMask;
    uint32_t    ABitMask;
};

#define DDS_FOURCC      0x00000004  // DDPF_FOURCC
#define DDS_RGB         0x00000040  // DDPF_RGB
#define DDS_RGBA        0x00000041  // DDPF_RGB | DDPF_ALPHAPIXELS
#define DDS_LUMINANCE   0x00020000  // DDPF_LUMINANCE
#define DDS_LUMINANCEA  0x00020001  // DDPF_LUMINANCE | DDPF_ALPHAPIXELS
#define DDS_ALPHA       0x00000002  // DDPF_ALPHA
#define DDS_PAL8        0x00000020  // DDPF_PALETTEINDEXED8

#define DDS_HEADER_FLAGS_TEXTURE        0x00001007  // DDSD_CAPS | DDSD_HEIGHT | DDSD_WIDTH | DDSD_PIXELFORMAT 
#define DDS_HEADER_FLAGS_MIPMAP         0x00020000  // DDSD_MIPMAPCOUNT
#define DDS_HEADER_FLAGS_VOLUME         0x00800000  // DDSD_DEPTH
#define DDS_HEADER_FLAGS_PITCH          0x00000008  // DDSD_PITCH
#define DDS_HEADER_FLAGS_LINEARSIZE     0x00080000  // DDSD_LINEARSIZE

#define DDS_HEIGHT 0x00000002 // DDSD_HEIGHT
#define DDS_WIDTH  0x00000004 // DDSD_WIDTH

#define DDS_SURFACE_FLAGS_TEXTURE 0x00001000 // DDSCAPS_TEXTURE
#define DDS_SURFACE_FLAGS_MIPMAP  0x00400008 // DDSCAPS_COMPLEX | DDSCAPS_MIPMAP
#define DDS_SURFACE_FLAGS_CUBEMAP 0x00000008 // DDSCAPS_COMPLEX

#define DDS_CUBEMAP_POSITIVEX 0x00000600 // DDSCAPS2_CUBEMAP | DDSCAPS2_CUBEMAP_POSITIVEX
#define DDS_CUBEMAP_NEGATIVEX 0x00000a00 // DDSCAPS2_CUBEMAP | DDSCAPS2_CUBEMAP_NEGATIVEX
#define DDS_CUBEMAP_POSITIVEY 0x00001200 // DDSCAPS2_CUBEMAP | DDSCAPS2_CUBEMAP_POSITIVEY
#define DDS_CUBEMAP_NEGATIVEY 0x00002200 // DDSCAPS2_CUBEMAP | DDSCAPS2_CUBEMAP_NEGATIVEY
#define DDS_CUBEMAP_POSITIVEZ 0x00004200 // DDSCAPS2_CUBEMAP | DDSCAPS2_CUBEMAP_POSITIVEZ
#define DDS_CUBEMAP_NEGATIVEZ 0x00008200 // DDSCAPS2_CUBEMAP | DDSCAPS2_CUBEMAP_NEGATIVEZ

#define DDS_CUBEMAP_ALLFACES ( DDS_CUBEMAP_POSITIVEX | DDS_CUBEMAP_NEGATIVEX |\
                               DDS_CUBEMAP_POSITIVEY | DDS_CUBEMAP_NEGATIVEY |\
                               DDS_CUBEMAP_POSITIVEZ | DDS_CUBEMAP_NEGATIVEZ )

#define DDS_CUBEMAP 0x00000200 // DDSCAPS2_CUBEMAP

#define DDS_FLAGS_VOLUME 0x00200000 // DDSCAPS2_VOLUME

typedef struct
{
    uint32_t        size;
    uint32_t        flags;
    uint32_t        height;
    uint32_t        width;
    uint32_t        pitchOrLinearSize;
    uint32_t        depth; // only if DDS_HEADER_FLAGS_VOLUME is set in flags
    uint32_t        mipMapCount;
    uint32_t        reserved1[11];
    DDS_PIXELFORMAT ddspf;
    uint32_t        caps;
    uint32_t        caps2;
    uint32_t        caps3;
    uint32_t        caps4;
    uint32_t        reserved2;
} DDS_HEADER;

typedef struct
{
    DXGI_FORMAT     dxgiFormat;
    uint32_t        resourceDimension;
    uint32_t        miscFlag; // see D3D11_RESOURCE_MISC_FLAG
    uint32_t        arraySize;
    uint32_t        reserved;
} DDS_HEADER_DXT10;

#pragma pack(pop)

//---------------------------------------------------------------------------------
struct handle_closer { void operator()(HANDLE h) { if (h) CloseHandle(h); } };

typedef public std::unique_ptr<void, handle_closer> ScopedHandle;

inline HANDLE safe_handle( HANDLE h ) { return (h == INVALID_HANDLE_VALUE) ? 0 : h; }

//--------------------------------------------------------------------------------------
static HRESULT LoadTextureDataFromFile( _In_z_ const wchar_t* fileName,
                                        std::unique_ptr<uint8_t[]>& ddsData,
                                        DDS_HEADER** header,
                                        uint8_t** bitData,
                                        size_t* bitSize
                                      )
{
    if (!header || !bitData || !bitSize)
    {
        return E_POINTER;
    }

    // open the file
#if (_WIN32_WINNT >= 0x0602 /*_WIN32_WINNT_WIN8*/)
    ScopedHandle hFile( safe_handle( CreateFile2( fileName,
                                                  GENERIC_READ,
                                                  FILE_SHARE_READ,
                                                  OPEN_EXISTING,
                                                  nullptr ) ) );
#else
    ScopedHandle hFile( safe_handle( CreateFileW( fileName,
                                                  GENERIC_READ,
                                                  FILE_SHARE_READ,
                                                  nullptr,
                                                  OPEN_EXISTING,
                                                  FILE_ATTRIBUTE_NORMAL,
                                                  nullptr ) ) );
#endif

    if ( !hFile )
    {
        return HRESULT_FROM_WIN32( GetLastError() );
    }

    // Get the file size
    LARGE_INTEGER FileSize = { 0 };

#if (_WIN32_WINNT >= _WIN32_WINNT_VISTA)
    FILE_STANDARD_INFO fileInfo;
    if ( !GetFileInformationByHandleEx( hFile.get(), FileStandardInfo, &fileInfo, sizeof(fileInfo) ) )
    {
        return HRESULT_FROM_WIN32( GetLastError() );
    }
    FileSize = fileInfo.EndOfFile;
#else
    GetFileSizeEx( hFile.get(), &FileSize );
#endif

    // File is too big for 32-bit allocation, so reject read
    if (FileSize.HighPart > 0)
    {
        return E_FAIL;
    }

    // Need at least enough data to fill the header and magic number to be a valid DDS
    if (FileSize.LowPart < ( sizeof(DDS_HEADER) + sizeof(uint32_t) ) )
    {
        return E_FAIL;
    }

    // create enough space for the file data
    ddsData.reset( new uint8_t[ FileSize.LowPart ] );
    if (!ddsData )
    {
        return E_OUTOFMEMORY;
    }

    // read the data in
    DWORD BytesRead = 0;
    if (!ReadFile( hFile.get(),
                   ddsData.get(),
                   FileSize.LowPart,
                   &BytesRead,
                   nullptr
                 ))
    {
        return HRESULT_FROM_WIN32( GetLastError() );
    }

    if (BytesRead < FileSize.LowPart)
    {
        return E_FAIL;
    }

    // DDS files always start with the same magic number ("DDS ")
    uint32_t dwMagicNumber = *( const uint32_t* )( ddsData.get() );
    if (dwMagicNumber != DDS_MAGIC)
    {
        return E_FAIL;
    }

    DDS_HEADER* hdr = reinterpret_cast<DDS_HEADER*>( ddsData.get() + sizeof( uint32_t ) );

    // Verify header to validate DDS file
    if (hdr->size != sizeof(DDS_HEADER) ||
        hdr->ddspf.size != sizeof(DDS_PIXELFORMAT))
    {
        return E_FAIL;
    }

    // Check for DX10 extension
    bool bDXT10Header = false;
    if ((hdr->ddspf.flags & DDS_FOURCC) &&
        (MAKEFOURCC( 'D', 'X', '1', '0' ) == hdr->ddspf.fourCC))
    {
        // Must be long enough for both headers and magic value
        if (FileSize.LowPart < ( sizeof(DDS_HEADER) + sizeof(uint32_t) + sizeof(DDS_HEADER_DXT10) ) )
        {
            return E_FAIL;
        }

        bDXT10Header = true;
    }

    // setup the pointers in the process request
    *header = hdr;
    ptrdiff_t offset = sizeof( uint32_t ) + sizeof( DDS_HEADER )
                       + (bDXT10Header ? sizeof( DDS_HEADER_DXT10 ) : 0);
    *bitData = ddsData.get() + offset;
    *bitSize = FileSize.LowPart - offset;

    return S_OK;
}


//--------------------------------------------------------------------------------------
// Return the BPP for a particular format
//--------------------------------------------------------------------------------------
static size_t BitsPerPixel( _In_ DXGI_FORMAT fmt )
{
    switch( fmt )
    {
    case DXGI_FORMAT_R32G32B32A32_TYPELESS:
    case DXGI_FORMAT_R32G32B32A32_FLOAT:
    case DXGI_FORMAT_R32G32B32A32_UINT:
    case DXGI_FORMAT_R32G32B32A32_SINT:
        return 128;

    case DXGI_FORMAT_R32G32B32_TYPELESS:
    case DXGI_FORMAT_R32G32B32_FLOAT:
    case DXGI_FORMAT_R32G32B32_UINT:
    case DXGI_FORMAT_R32G32B32_SINT:
        return 96;

    case DXGI_FORMAT_R16G16B16A16_TYPELESS:
    case DXGI_FORMAT_R16G16B16A16_FLOAT:
    case DXGI_FORMAT_R16G16B16A16_UNORM:
    case DXGI_FORMAT_R16G16B16A16_UINT:
    case DXGI_FORMAT_R16G16B16A16_SNORM:
    case DXGI_FORMAT_R16G16B16A16_SINT:
    case DXGI_FORMAT_R32G32_TYPELESS:
    case DXGI_FORMAT_R32G32_FLOAT:
    case DXGI_FORMAT_R32G32_UINT:
    case DXGI_FORMAT_R32G32_SINT:
    case DXGI_FORMAT_R32G8X24_TYPELESS:
    case DXGI_FORMAT_D32_FLOAT_S8X24_UINT:
    case DXGI_FORMAT_R32_FLOAT_X8X24_TYPELESS:
    case DXGI_FORMAT_X32_TYPELESS_G8X24_UINT:
        return 64;

    case DXGI_FORMAT_R10G10B10A2_TYPELESS:
    case DXGI_FORMAT_R10G10B10A2_UNORM:
    case DXGI_FORMAT_R10G10B10A2_UINT:
    case DXGI_FORMAT_R11G11B10_FLOAT:
    case DXGI_FORMAT_R8G8B8A8_TYPELESS:
    case DXGI_FORMAT_R8G8B8A8_UNORM:
    case DXGI_FORMAT_R8G8B8A8_UNORM_SRGB:
    case DXGI_FORMAT_R8G8B8A8_UINT:
    case DXGI_FORMAT_R8G8B8A8_SNORM:
    case DXGI_FORMAT_R8G8B8A8_SINT:
    case DXGI_FORMAT_R16G16_TYPELESS:
    case DXGI_FORMAT_R16G16_FLOAT:
    case DXGI_FORMAT_R16G16_UNORM:
    case DXGI_FORMAT_R16G16_UINT:
    case DXGI_FORMAT_R16G16_SNORM:
    case DXGI_FORMAT_R16G16_SINT:
    case DXGI_FORMAT_R32_TYPELESS:
    case DXGI_FORMAT_D32_FLOAT:
    case DXGI_FORMAT_R32_FLOAT:
    case DXGI_FORMAT_R32_UINT:
    case DXGI_FORMAT_R32_SINT:
    case DXGI_FORMAT_R24G8_TYPELESS:
    case DXGI_FORMAT_D24_UNORM_S8_UINT:
    case DXGI_FORMAT_R24_UNORM_X8_TYPELESS:
    case DXGI_FORMAT_X24_TYPELESS_G8_UINT:
    case DXGI_FORMAT_R9G9B9E5_SHAREDEXP:
    case DXGI_FORMAT_R8G8_B8G8_UNORM:
    case DXGI_FORMAT_G8R8_G8B8_UNORM:
    case DXGI_FORMAT_B8G8R8A8_UNORM:
    case DXGI_FORMAT_B8G8R8X8_UNORM:
    case DXGI_FORMAT_R10G10B10_XR_BIAS_A2_UNORM:
    case DXGI_FORMAT_B8G8R8A8_TYPELESS:
    case DXGI_FORMAT_B8G8R8A8_UNORM_SRGB:
    case DXGI_FORMAT_B8G8R8X8_TYPELESS:
    case DXGI_FORMAT_B8G8R8X8_UNORM_SRGB:
        return 32;

    case DXGI_FORMAT_R8G8_TYPELESS:
    case DXGI_FORMAT_R8G8_UNORM:
    case DXGI_FORMAT_R8G8_UINT:
    case DXGI_FORMAT_R8G8_SNORM:
    case DXGI_FORMAT_R8G8_SINT:
    case DXGI_FORMAT_R16_TYPELESS:
    case DXGI_FORMAT_R16_FLOAT:
    case DXGI_FORMAT_D16_UNORM:
    case DXGI_FORMAT_R16_UNORM:
    case DXGI_FORMAT_R16_UINT:
    case DXGI_FORMAT_R16_SNORM:
    case DXGI_FORMAT_R16_SINT:
    case DXGI_FORMAT_B5G6R5_UNORM:
    case DXGI_FORMAT_B5G5R5A1_UNORM:

#ifdef DXGI_1_2_FORMATS
    case DXGI_FORMAT_B4G4R4A4_UNORM:
#endif
        return 16;

    case DXGI_FORMAT_R8_TYPELESS:
    case DXGI_FORMAT_R8_UNORM:
    case DXGI_FORMAT_R8_UINT:
    case DXGI_FORMAT_R8_SNORM:
    case DXGI_FORMAT_R8_SINT:
    case DXGI_FORMAT_A8_UNORM:
        return 8;

    case DXGI_FORMAT_R1_UNORM:
        return 1;

    case DXGI_FORMAT_BC1_TYPELESS:
    case DXGI_FORMAT_BC1_UNORM:
    case DXGI_FORMAT_BC1_UNORM_SRGB:
    case DXGI_FORMAT_BC4_TYPELESS:
    case DXGI_FORMAT_BC4_UNORM:
    case DXGI_FORMAT_BC4_SNORM:
        return 4;

    case DXGI_FORMAT_BC2_TYPELESS:
    case DXGI_FORMAT_BC2_UNORM:
    case DXGI_FORMAT_BC2_UNORM_SRGB:
    case DXGI_FORMAT_BC3_TYPELESS:
    case DXGI_FORMAT_BC3_UNORM:
    case DXGI_FORMAT_BC3_UNORM_SRGB:
    case DXGI_FORMAT_BC5_TYPELESS:
    case DXGI_FORMAT_BC5_UNORM:
    case DXGI_FORMAT_BC5_SNORM:
    case DXGI_FORMAT_BC6H_TYPELESS:
    case DXGI_FORMAT_BC6H_UF16:
    case DXGI_FORMAT_BC6H_SF16:
    case DXGI_FORMAT_BC7_TYPELESS:
    case DXGI_FORMAT_BC7_UNORM:
    case DXGI_FORMAT_BC7_UNORM_SRGB:
        return 8;

    default:
        return 0;
    }
}


//--------------------------------------------------------------------------------------
// Get surface information for a particular format
//--------------------------------------------------------------------------------------
static void GetSurfaceInfo( _In_ size_t width,
                            _In_ size_t height,
                            _In_ DXGI_FORMAT fmt,
                            _Out_opt_ size_t* outNumBytes,
                            _Out_opt_ size_t* outRowBytes,
                            _Out_opt_ size_t* outNumRows )
{
    size_t numBytes = 0;
    size_t rowBytes = 0;
    size_t numRows = 0;

    bool bc = false;
    bool packed  = false;
    size_t bcnumBytesPerBlock = 0;
    switch (fmt)
    {
    case DXGI_FORMAT_BC1_TYPELESS:
    case DXGI_FORMAT_BC1_UNORM:
    case DXGI_FORMAT_BC1_UNORM_SRGB:
    case DXGI_FORMAT_BC4_TYPELESS:
    case DXGI_FORMAT_BC4_UNORM:
    case DXGI_FORMAT_BC4_SNORM:
        bc=true;
        bcnumBytesPerBlock = 8;
        break;

    case DXGI_FORMAT_BC2_TYPELESS:
    case DXGI_FORMAT_BC2_UNORM:
    case DXGI_FORMAT_BC2_UNORM_SRGB:
    case DXGI_FORMAT_BC3_TYPELESS:
    case DXGI_FORMAT_BC3_UNORM:
    case DXGI_FORMAT_BC3_UNORM_SRGB:
    case DXGI_FORMAT_BC5_TYPELESS:
    case DXGI_FORMAT_BC5_UNORM:
    case DXGI_FORMAT_BC5_SNORM:
    case DXGI_FORMAT_BC6H_TYPELESS:
    case DXGI_FORMAT_BC6H_UF16:
    case DXGI_FORMAT_BC6H_SF16:
    case DXGI_FORMAT_BC7_TYPELESS:
    case DXGI_FORMAT_BC7_UNORM:
    case DXGI_FORMAT_BC7_UNORM_SRGB:
        bc = true;
        bcnumBytesPerBlock = 16;
        break;

    case DXGI_FORMAT_R8G8_B8G8_UNORM:
    case DXGI_FORMAT_G8R8_G8B8_UNORM:
        packed = true;
        break;
    }

    if (bc)
    {
        size_t numBlocksWide = 0;
        if (width > 0)
        {
            numBlocksWide = std::max<size_t>( 1, (width + 3) / 4 );
        }
        size_t numBlocksHigh = 0;
        if (height > 0)
        {
            numBlocksHigh = std::max<size_t>( 1, (height + 3) / 4 );
        }
        rowBytes = numBlocksWide * bcnumBytesPerBlock;
        numRows = numBlocksHigh;
    }
    else if (packed)
    {
        rowBytes = ( ( width + 1 ) >> 1 ) * 4;
        numRows = height;
    }
    else
    {
        size_t bpp = BitsPerPixel( fmt );
        rowBytes = ( width * bpp + 7 ) / 8; // round up to nearest byte
        numRows = height;
    }

    numBytes = rowBytes * numRows;
    if (outNumBytes)
    {
        *outNumBytes = numBytes;
    }
    if (outRowBytes)
    {
        *outRowBytes = rowBytes;
    }
    if (outNumRows)
    {
        *outNumRows = numRows;
    }
}


//--------------------------------------------------------------------------------------
#define ISBITMASK( r,g,b,a ) ( ddpf.RBitMask == r && ddpf.GBitMask == g && ddpf.BBitMask == b && ddpf.ABitMask == a )

static DXGI_FORMAT GetDXGIFormat( const DDS_PIXELFORMAT& ddpf )
{
    if (ddpf.flags & DDS_RGB)
    {
        // Note that sRGB formats are written using the "DX10" extended header

        switch (ddpf.RGBBitCount)
        {
        case 32:
            if (ISBITMASK(0x000000ff,0x0000ff00,0x00ff0000,0xff000000))
            {
                return DXGI_FORMAT_R8G8B8A8_UNORM;
            }

            if (ISBITMASK(0x00ff0000,0x0000ff00,0x000000ff,0xff000000))
            {
                return DXGI_FORMAT_B8G8R8A8_UNORM;
            }

            if (ISBITMASK(0x00ff0000,0x0000ff00,0x000000ff,0x00000000))
            {
                return DXGI_FORMAT_B8G8R8X8_UNORM;
            }

            // No DXGI format maps to ISBITMASK(0x000000ff,0x0000ff00,0x00ff0000,0x00000000) aka D3DFMT_X8B8G8R8

            // Note that many common DDS reader/writers (including D3DX) swap the
            // the RED/BLUE masks for 10:10:10:2 formats. We assumme
            // below that the 'backwards' header mask is being used since it is most
            // likely written by D3DX. The more robust solution is to use the 'DX10'
            // header extension and specify the DXGI_FORMAT_R10G10B10A2_UNORM format directly

            // For 'correct' writers, this should be 0x000003ff,0x000ffc00,0x3ff00000 for RGB data
            if (ISBITMASK(0x3ff00000,0x000ffc00,0x000003ff,0xc0000000))
            {
                return DXGI_FORMAT_R10G10B10A2_UNORM;
            }

            // No DXGI format maps to ISBITMASK(0x000003ff,0x000ffc00,0x3ff00000,0xc0000000) aka D3DFMT_A2R10G10B10

            if (ISBITMASK(0x0000ffff,0xffff0000,0x00000000,0x00000000))
            {
                return DXGI_FORMAT_R16G16_UNORM;
            }

            if (ISBITMASK(0xffffffff,0x00000000,0x00000000,0x00000000))
            {
                // Only 32-bit color channel format in D3D9 was R32F
                return DXGI_FORMAT_R32_FLOAT; // D3DX writes this out as a FourCC of 114
            }
            break;

        case 24:
            // No 24bpp DXGI formats aka D3DFMT_R8G8B8
            break;

        case 16:
            if (ISBITMASK(0x7c00,0x03e0,0x001f,0x8000))
            {
                return DXGI_FORMAT_B5G5R5A1_UNORM;
            }
            if (ISBITMASK(0xf800,0x07e0,0x001f,0x0000))
            {
                return DXGI_FORMAT_B5G6R5_UNORM;
            }

            // No DXGI format maps to ISBITMASK(0x7c00,0x03e0,0x001f,0x0000) aka D3DFMT_X1R5G5B5

#ifdef DXGI_1_2_FORMATS
            if (ISBITMASK(0x0f00,0x00f0,0x000f,0xf000))
            {
                return DXGI_FORMAT_B4G4R4A4_UNORM;
            }

            // No DXGI format maps to ISBITMASK(0x0f00,0x00f0,0x000f,0x0000) aka D3DFMT_X4R4G4B4
#endif

            // No 3:3:2, 3:3:2:8, or paletted DXGI formats aka D3DFMT_A8R3G3B2, D3DFMT_R3G3B2, D3DFMT_P8, D3DFMT_A8P8, etc.
            break;
        }
    }
    else if (ddpf.flags & DDS_LUMINANCE)
    {
        if (8 == ddpf.RGBBitCount)
        {
            if (ISBITMASK(0x000000ff,0x00000000,0x00000000,0x00000000))
            {
                return DXGI_FORMAT_R8_UNORM; // D3DX10/11 writes this out as DX10 extension
            }

            // No DXGI format maps to ISBITMASK(0x0f,0x00,0x00,0xf0) aka D3DFMT_A4L4
        }

        if (16 == ddpf.RGBBitCount)
        {
            if (ISBITMASK(0x0000ffff,0x00000000,0x00000000,0x00000000))
            {
                return DXGI_FORMAT_R16_UNORM; // D3DX10/11 writes this out as DX10 extension
            }
            if (ISBITMASK(0x000000ff,0x00000000,0x00000000,0x0000ff00))
            {
                return DXGI_FORMAT_R8G8_UNORM; // D3DX10/11 writes this out as DX10 extension
            }
        }
    }
    else if (ddpf.flags & DDS_ALPHA)
    {
        if (8 == ddpf.RGBBitCount)
        {
            return DXGI_FORMAT_A8_UNORM;
        }
    }
    else if (ddpf.flags & DDS_FOURCC)
    {
        if (MAKEFOURCC( 'D', 'X', 'T', '1' ) == ddpf.fourCC)
        {
            return DXGI_FORMAT_BC1_UNORM;
        }
        if (MAKEFOURCC( 'D', 'X', 'T', '3' ) == ddpf.fourCC)
        {
            return DXGI_FORMAT_BC2_UNORM;
        }
        if (MAKEFOURCC( 'D', 'X', 'T', '5' ) == ddpf.fourCC)
        {
            return DXGI_FORMAT_BC3_UNORM;
        }

        // While pre-mulitplied alpha isn't directly supported by the DXGI formats,
        // they are basically the same as these BC formats so they can be mapped
        if (MAKEFOURCC( 'D', 'X', 'T', '2' ) == ddpf.fourCC)
        {
            return DXGI_FORMAT_BC2_UNORM;
        }
        if (MAKEFOURCC( 'D', 'X', 'T', '4' ) == ddpf.fourCC)
        {
            return DXGI_FORMAT_BC3_UNORM;
        }

        if (MAKEFOURCC( 'A', 'T', 'I', '1' ) == ddpf.fourCC)
        {
            return DXGI_FORMAT_BC4_UNORM;
        }
        if (MAKEFOURCC( 'B', 'C', '4', 'U' ) == ddpf.fourCC)
        {
            return DXGI_FORMAT_BC4_UNORM;
        }
        if (MAKEFOURCC( 'B', 'C', '4', 'S' ) == ddpf.fourCC)
        {
            return DXGI_FORMAT_BC4_SNORM;
        }

        if (MAKEFOURCC( 'A', 'T', 'I', '2' ) == ddpf.fourCC)
        {
            return DXGI_FORMAT_BC5_UNORM;
        }
        if (MAKEFOURCC( 'B', 'C', '5', 'U' ) == ddpf.fourCC)
        {
            return DXGI_FORMAT_BC5_UNORM;
        }
        if (MAKEFOURCC( 'B', 'C', '5', 'S' ) == ddpf.fourCC)
        {
            return DXGI_FORMAT_BC5_SNORM;
        }

        // BC6H and BC7 are written using the "DX10" extended header

        if (MAKEFOURCC( 'R', 'G', 'B', 'G' ) == ddpf.fourCC)
        {
            return DXGI_FORMAT_R8G8_B8G8_UNORM;
        }
        if (MAKEFOURCC( 'G', 'R', 'G', 'B' ) == ddpf.fourCC)
        {
            return DXGI_FORMAT_G8R8_G8B8_UNORM;
        }

        // Check for D3DFORMAT enums being set here
        switch( ddpf.fourCC )
        {
        case 36: // D3DFMT_A16B16G16R16
            return DXGI_FORMAT_R16G16B16A16_UNORM;

        case 110: // D3DFMT_Q16W16V16U16
            return DXGI_FORMAT_R16G16B16A16_SNORM;

        case 111: // D3DFMT_R16F
            return DXGI_FORMAT_R16_FLOAT;

        case 112: // D3DFMT_G16R16F
            return DXGI_FORMAT_R16G16_FLOAT;

        case 113: // D3DFMT_A16B16G16R16F
            return DXGI_FORMAT_R16G16B16A16_FLOAT;

        case 114: // D3DFMT_R32F
            return DXGI_FORMAT_R32_FLOAT;

        case 115: // D3DFMT_G32R32F
            return DXGI_FORMAT_R32G32_FLOAT;

        case 116: // D3DFMT_A32B32G32R32F
            return DXGI_FORMAT_R32G32B32A32_FLOAT;
        }
    }

    return DXGI_FORMAT_UNKNOWN;
}


//--------------------------------------------------------------------------------------
static HRESULT FillInitData( _In_ size_t width,
                             _In_ size_t height,
                             _In_ size_t depth,
                             _In_ size_t mipCount,
                             _In_ size_t arraySize,
                             _In_ DXGI_FORMAT format,
                             _In_ size_t maxsize,
                             _In_ size_t bitSize,
                             _In_reads_bytes_(bitSize) const uint8_t* bitData,
                             _Out_ size_t& twidth,
                             _Out_ size_t& theight,
                             _Out_ size_t& tdepth,
                             _Out_ size_t& skipMip,
                             _Out_writes_(mipCount*arraySize) D3D11_SUBRESOURCE_DATA* initData )
{
    if ( !bitData || !initData )
        return E_POINTER;

    skipMip = 0;
    twidth = 0;
    theight = 0;
    tdepth = 0;

    size_t NumBytes = 0;
    size_t RowBytes = 0;
    size_t NumRows = 0;
    const uint8_t* pSrcBits = bitData;
    const uint8_t* pEndBits = bitData + bitSize;

    size_t index = 0;
    for( size_t j = 0; j < arraySize; j++ )
    {
        size_t w = width;
        size_t h = height;
        size_t d = depth;
        for( size_t i = 0; i < mipCount; i++ )
        {
            GetSurfaceInfo( w,
                            h,
                            format,
                            &NumBytes,
                            &RowBytes,
                            &NumRows
                          );

            if ( (mipCount <= 1) || !maxsize || (w <= maxsize && h <= maxsize && d <= maxsize) )
            {
                if ( !twidth )
                {
                    twidth = w;
                    theight = h;
                    tdepth = d;
                }

                initData[index].pSysMem = ( const void* )pSrcBits;
                initData[index].SysMemPitch = static_cast<UINT>( RowBytes );
                initData[index].SysMemSlicePitch = static_cast<UINT>( NumBytes );
                ++index;
            }
            else
                ++skipMip;

            if (pSrcBits + (NumBytes*d) > pEndBits)
            {
                return HRESULT_FROM_WIN32( ERROR_HANDLE_EOF );
            }
  
            pSrcBits += NumBytes * d;

            w = w >> 1;
            h = h >> 1;
            d = d >> 1;
            if (w == 0)
            {
                w = 1;
            }
            if (h == 0)
            {
                h = 1;
            }
            if (d == 0)
            {
                d = 1;
            }
        }
    }

    return (index > 0) ? S_OK : E_FAIL;
}


//--------------------------------------------------------------------------------------
static HRESULT CreateD3DResources( _In_ ID3D11Device* d3dDevice,
                                   _In_ uint32_t resDim,
                                   _In_ size_t width,
                                   _In_ size_t height,
                                   _In_ size_t depth,
                                   _In_ size_t mipCount,
                                   _In_ size_t arraySize,
                                   _In_ DXGI_FORMAT format,
                                   _In_ bool isCubeMap,
                                   _In_reads_(mipCount*arraySize) D3D11_SUBRESOURCE_DATA* initData,
                                   _Out_opt_ ID3D11Resource** texture,
                                   _Out_opt_ ID3D11ShaderResourceView** textureView )
{
    if ( !d3dDevice || !initData )
        return E_POINTER;

    HRESULT hr = E_FAIL;

    switch ( resDim ) 
    {
        case D3D11_RESOURCE_DIMENSION_TEXTURE1D:
            {
                D3D11_TEXTURE1D_DESC desc;
                desc.Width = static_cast<UINT>( width ); 
                desc.MipLevels = static_cast<UINT>( mipCount );
                desc.ArraySize = static_cast<UINT>( arraySize );
                desc.Format = format;
                desc.Usage = D3D11_USAGE_DEFAULT;
                desc.BindFlags = D3D11_BIND_SHADER_RESOURCE;
                desc.CPUAccessFlags = 0;
                desc.MiscFlags = 0;

                ID3D11Texture1D* tex = nullptr;
                hr = d3dDevice->CreateTexture1D( &desc,
                                                 initData,
                                                 &tex
                                               );
                if (SUCCEEDED( hr ) && tex != 0)
                {
                    if (textureView != 0)
                    {
                        D3D11_SHADER_RESOURCE_VIEW_DESC SRVDesc;
                        memset( &SRVDesc, 0, sizeof( SRVDesc ) );
                        SRVDesc.Format = format;

                        if (arraySize > 1)
                        {
                            SRVDesc.ViewDimension = D3D11_SRV_DIMENSION_TEXTURE1DARRAY;
                            SRVDesc.Texture1DArray.MipLevels = desc.MipLevels;
                            SRVDesc.Texture1DArray.ArraySize = static_cast<UINT>( arraySize );
                        }
                        else
                        {
                            SRVDesc.ViewDimension = D3D11_SRV_DIMENSION_TEXTURE1D;
                            SRVDesc.Texture1D.MipLevels = desc.MipLevels;
                        }

                        hr = d3dDevice->CreateShaderResourceView( tex,
                                                                  &SRVDesc,
                                                                  textureView
                                                                );
                        if ( FAILED(hr) )
                        {
                            tex->Release();
                            return hr;
                        }
                    }

                    if (texture != 0)
                    {
                        *texture = tex;
                    }
                    else
                    {
#if defined(DEBUG) || defined(PROFILE)
                        tex->SetPrivateData( WKPDID_D3DDebugObjectName,
                                             sizeof("DDSTextureLoader")-1,
                                             "DDSTextureLoader" );
#endif
                        tex->Release();
                    }
                }
            }
           break;

        case D3D11_RESOURCE_DIMENSION_TEXTURE2D:
            {
                D3D11_TEXTURE2D_DESC desc;
                desc.Width = static_cast<UINT>( width );
                desc.Height = static_cast<UINT>( height );
                desc.MipLevels = static_cast<UINT>( mipCount );
                desc.ArraySize = static_cast<UINT>( arraySize );
                desc.Format = format;
                desc.SampleDesc.Count = 1;
                desc.SampleDesc.Quality = 0;
                desc.Usage = D3D11_USAGE_DEFAULT;
                desc.BindFlags = D3D11_BIND_SHADER_RESOURCE;
                desc.CPUAccessFlags = 0;
                desc.MiscFlags = (isCubeMap) ? D3D11_RESOURCE_MISC_TEXTURECUBE : 0;

                ID3D11Texture2D* tex = nullptr;
                hr = d3dDevice->CreateTexture2D( &desc,
                                                 initData,
                                                 &tex
                                               );
                if (SUCCEEDED( hr ) && tex != 0)
                {
                    if (textureView != 0)
                    {
                        D3D11_SHADER_RESOURCE_VIEW_DESC SRVDesc;
                        memset( &SRVDesc, 0, sizeof( SRVDesc ) );
                        SRVDesc.Format = format;

                        if (isCubeMap)
                        {
                            if (arraySize > 6)
                            {
                                SRVDesc.ViewDimension = D3D11_SRV_DIMENSION_TEXTURECUBEARRAY;
                                SRVDesc.TextureCubeArray.MipLevels = desc.MipLevels;

                                // Earlier we set arraySize to (NumCubes * 6)
                                SRVDesc.TextureCubeArray.NumCubes = static_cast<UINT>( arraySize / 6 );
                            }
                            else
                            {
                                SRVDesc.ViewDimension = D3D11_SRV_DIMENSION_TEXTURECUBE;
                                SRVDesc.TextureCube.MipLevels = desc.MipLevels;
                            }
                        }
                        else if (arraySize > 1)
                        {
                            SRVDesc.ViewDimension = D3D11_SRV_DIMENSION_TEXTURE2DARRAY;
                            SRVDesc.Texture2DArray.MipLevels = desc.MipLevels;
                            SRVDesc.Texture2DArray.ArraySize = static_cast<UINT>( arraySize );
                        }
                        else
                        {
                            SRVDesc.ViewDimension = D3D11_SRV_DIMENSION_TEXTURE2D;
                            SRVDesc.Texture2D.MipLevels = desc.MipLevels;
                        }

                        hr = d3dDevice->CreateShaderResourceView( tex,
                                                                  &SRVDesc,
                                                                  textureView
                                                                );
                        if ( FAILED(hr) )
                        {
                            tex->Release();
                            return hr;
                        }
                    }

                    if (texture != 0)
                    {
                        *texture = tex;
                    }
                    else
                    {
#if defined(DEBUG) || defined(PROFILE)
                        tex->SetPrivateData( WKPDID_D3DDebugObjectName,
                                             sizeof("DDSTextureLoader")-1,
                                             "DDSTextureLoader"
                                           );
#endif
                        tex->Release();
                    }
                }
            }
            break;

        case D3D11_RESOURCE_DIMENSION_TEXTURE3D:
            {
                D3D11_TEXTURE3D_DESC desc;
                desc.Width = static_cast<UINT>( width );
                desc.Height = static_cast<UINT>( height );
                desc.Depth = static_cast<UINT>( depth );
                desc.MipLevels = static_cast<UINT>( mipCount );
                desc.Format = format;
                desc.Usage = D3D11_USAGE_DEFAULT;
                desc.BindFlags = D3D11_BIND_SHADER_RESOURCE;
                desc.CPUAccessFlags = 0;
                desc.MiscFlags = 0;

                ID3D11Texture3D* tex = nullptr;
                hr = d3dDevice->CreateTexture3D( &desc,
                                                 initData,
                                                 &tex
                                               );
                if (SUCCEEDED( hr ) && tex != 0)
                {
                    if (textureView != 0)
                    {
                        D3D11_SHADER_RESOURCE_VIEW_DESC SRVDesc;
                        memset( &SRVDesc, 0, sizeof( SRVDesc ) );
                        SRVDesc.Format = format;
                        SRVDesc.ViewDimension = D3D11_SRV_DIMENSION_TEXTURE3D;
                        SRVDesc.Texture3D.MipLevels = desc.MipLevels;

                        hr = d3dDevice->CreateShaderResourceView( tex,
                                                                  &SRVDesc,
                                                                  textureView
                                                                );
                        if ( FAILED(hr) )
                        {
                            tex->Release();
                            return hr;
                        }
                    }

                    if (texture != 0)
                    {
                        *texture = tex;
                    }
                    else
                    {
#if defined(DEBUG) || defined(PROFILE)
                        tex->SetPrivateData( WKPDID_D3DDebugObjectName,
                                             sizeof("DDSTextureLoader")-1,
                                             "DDSTextureLoader" );
#endif
                        tex->Release();
                    }
                }
            }
            break; 
    }

    return hr;
}


//--------------------------------------------------------------------------------------
static HRESULT CreateTextureFromDDS( _In_ ID3D11Device* d3dDevice,
                                     _In_ const DDS_HEADER* header,
                                     _In_reads_bytes_(bitSize) const uint8_t* bitData,
                                     _In_ size_t bitSize,
                                     _Out_opt_ ID3D11Resource** texture,
                                     _Out_opt_ ID3D11ShaderResourceView** textureView,
                                     _In_ size_t maxsize )
{
    HRESULT hr = S_OK;

    size_t width = header->width;
    size_t height = header->height;
    size_t depth = header->depth;

    uint32_t resDim = D3D11_RESOURCE_DIMENSION_UNKNOWN;
    size_t arraySize = 1;
    DXGI_FORMAT format = DXGI_FORMAT_UNKNOWN;
    bool isCubeMap = false;

    size_t mipCount = header->mipMapCount;
    if (0 == mipCount)
    {
        mipCount = 1;
    }

    if ((header->ddspf.flags & DDS_FOURCC) &&
        (MAKEFOURCC( 'D', 'X', '1', '0' ) == header->ddspf.fourCC ))
    {
        const DDS_HEADER_DXT10* d3d10ext = reinterpret_cast<const DDS_HEADER_DXT10*>( (const char*)header + sizeof(DDS_HEADER) );

        arraySize = d3d10ext->arraySize;
        if (arraySize == 0)
        {
           return HRESULT_FROM_WIN32( ERROR_INVALID_DATA );
        }

        if (BitsPerPixel( d3d10ext->dxgiFormat ) == 0)
        {
            return HRESULT_FROM_WIN32( ERROR_NOT_SUPPORTED );
        }
           
        format = d3d10ext->dxgiFormat;

        switch ( d3d10ext->resourceDimension )
        {
        case D3D11_RESOURCE_DIMENSION_TEXTURE1D:
            // D3DX writes 1D textures with a fixed Height of 1
            if ((header->flags & DDS_HEIGHT) && height != 1)
            {
                return HRESULT_FROM_WIN32( ERROR_INVALID_DATA );
            }
            height = depth = 1;
            break;

        case D3D11_RESOURCE_DIMENSION_TEXTURE2D:
            if (d3d10ext->miscFlag & D3D11_RESOURCE_MISC_TEXTURECUBE)
            {
                arraySize *= 6;
                isCubeMap = true;
            }
            depth = 1;
            break;

        case D3D11_RESOURCE_DIMENSION_TEXTURE3D:
            if (!(header->flags & DDS_HEADER_FLAGS_VOLUME))
            {
                return HRESULT_FROM_WIN32( ERROR_INVALID_DATA );
            }

            if (arraySize > 1)
            {
                return HRESULT_FROM_WIN32( ERROR_NOT_SUPPORTED );
            }
            break;

        default:
            return HRESULT_FROM_WIN32( ERROR_NOT_SUPPORTED );
        }

        resDim = d3d10ext->resourceDimension;
    }
    else
    {
        format = GetDXGIFormat( header->ddspf );

        if (format == DXGI_FORMAT_UNKNOWN)
        {
           return HRESULT_FROM_WIN32( ERROR_NOT_SUPPORTED );
        }

        if (header->flags & DDS_HEADER_FLAGS_VOLUME)
        {
            resDim = D3D11_RESOURCE_DIMENSION_TEXTURE3D;
        }
        else 
        {
            if (header->caps2 & DDS_CUBEMAP)
            {
                // We require all six faces to be defined
                if ((header->caps2 & DDS_CUBEMAP_ALLFACES ) != DDS_CUBEMAP_ALLFACES)
                {
                    return HRESULT_FROM_WIN32( ERROR_NOT_SUPPORTED );
                }

                arraySize = 6;
                isCubeMap = true;
            }

            depth = 1;
            resDim = D3D11_RESOURCE_DIMENSION_TEXTURE2D;

            // Note there's no way for a legacy Direct3D 9 DDS to express a '1D' texture
        }

        assert( BitsPerPixel( format ) != 0 );
    }

    // Bound sizes (for security purposes we don't trust DDS file metadata larger than the D3D 11.x hardware requirements)
    if (mipCount > D3D11_REQ_MIP_LEVELS)
    {
        return HRESULT_FROM_WIN32( ERROR_NOT_SUPPORTED );
    }

    switch ( resDim )
    {
        case D3D11_RESOURCE_DIMENSION_TEXTURE1D:
            if ((arraySize > D3D11_REQ_TEXTURE1D_ARRAY_AXIS_DIMENSION) ||
                (width > D3D11_REQ_TEXTURE1D_U_DIMENSION) )
            {
                return HRESULT_FROM_WIN32( ERROR_NOT_SUPPORTED );
            }
            break;

        case D3D11_RESOURCE_DIMENSION_TEXTURE2D:
            if (isCubeMap)
            {
                // This is the right bound because we set arraySize to (NumCubes*6) above
                if ((arraySize > D3D11_REQ_TEXTURE2D_ARRAY_AXIS_DIMENSION) ||
                    (width > D3D11_REQ_TEXTURECUBE_DIMENSION) ||
                    (height > D3D11_REQ_TEXTURECUBE_DIMENSION))
                {
                    return HRESULT_FROM_WIN32( ERROR_NOT_SUPPORTED );
                }
            }
            else if ((arraySize > D3D11_REQ_TEXTURE2D_ARRAY_AXIS_DIMENSION) ||
                     (width > D3D11_REQ_TEXTURE2D_U_OR_V_DIMENSION) ||
                     (height > D3D11_REQ_TEXTURE2D_U_OR_V_DIMENSION))
            {
                return HRESULT_FROM_WIN32( ERROR_NOT_SUPPORTED );
            }
            break;

        case D3D11_RESOURCE_DIMENSION_TEXTURE3D:
            if ((arraySize > 1) ||
                (width > D3D11_REQ_TEXTURE3D_U_V_OR_W_DIMENSION) ||
                (height > D3D11_REQ_TEXTURE3D_U_V_OR_W_DIMENSION) ||
                (depth > D3D11_REQ_TEXTURE3D_U_V_OR_W_DIMENSION) )
            {
                return HRESULT_FROM_WIN32( ERROR_NOT_SUPPORTED );
            }
            break;
    }

    // Create the texture
    std::unique_ptr<D3D11_SUBRESOURCE_DATA> initData( new D3D11_SUBRESOURCE_DATA[ mipCount * arraySize ] );
    if ( !initData )
    {
        return E_OUTOFMEMORY;
    }

    size_t skipMip = 0;
    size_t twidth = 0;
    size_t theight = 0;
    size_t tdepth = 0;
    hr = FillInitData( width, height, depth, mipCount, arraySize, format, maxsize, bitSize, bitData,
                       twidth, theight, tdepth, skipMip, initData.get() );

    if ( SUCCEEDED(hr) )
    {
        hr = CreateD3DResources( d3dDevice, resDim, twidth, theight, tdepth, mipCount - skipMip, arraySize, format, isCubeMap, initData.get(), texture, textureView );

        if ( FAILED(hr) && !maxsize && (mipCount > 1) )
        {
            // Retry with a maxsize determined by feature level
            switch( d3dDevice->GetFeatureLevel() )
            {
            case D3D_FEATURE_LEVEL_9_1:
            case D3D_FEATURE_LEVEL_9_2:
                if (isCubeMap)
                {
                    maxsize = 512 /*D3D_FL9_1_REQ_TEXTURECUBE_DIMENSION*/;
                }
                else
                {
                    maxsize = (resDim == D3D11_RESOURCE_DIMENSION_TEXTURE3D)
                              ? 256 /*D3D_FL9_1_REQ_TEXTURE3D_U_V_OR_W_DIMENSION*/
                              : 2048 /*D3D_FL9_1_REQ_TEXTURE2D_U_OR_V_DIMENSION*/;
                }
                break;

            case D3D_FEATURE_LEVEL_9_3:
                maxsize = (resDim == D3D11_RESOURCE_DIMENSION_TEXTURE3D)
                          ? 256 /*D3D_FL9_1_REQ_TEXTURE3D_U_V_OR_W_DIMENSION*/
                          : 4096 /*D3D_FL9_3_REQ_TEXTURE2D_U_OR_V_DIMENSION*/;
                break;

            default: // D3D_FEATURE_LEVEL_10_0 & D3D_FEATURE_LEVEL_10_1
                maxsize = (resDim == D3D11_RESOURCE_DIMENSION_TEXTURE3D)
                          ? 2048 /*D3D10_REQ_TEXTURE3D_U_V_OR_W_DIMENSION*/
                          : 8192 /*D3D10_REQ_TEXTURE2D_U_OR_V_DIMENSION*/;
                break;
            }

            hr = FillInitData( width, height, depth, mipCount, arraySize, format, maxsize, bitSize, bitData,
                               twidth, theight, tdepth, skipMip, initData.get() );
            if ( SUCCEEDED(hr) )
            {
                hr = CreateD3DResources( d3dDevice, resDim, twidth, theight, tdepth, mipCount - skipMip, arraySize, format, isCubeMap, initData.get(), texture, textureView );
            }
        }
    }

    return hr;
}

//--------------------------------------------------------------------------------------
HRESULT CreateDDSTextureFromMemory( _In_ ID3D11Device* d3dDevice,
                                    _In_reads_bytes_(ddsDataSize) const uint8_t* ddsData,
                                    _In_ size_t ddsDataSize,
                                    _Out_opt_ ID3D11Resource** texture,
                                    _Out_opt_ ID3D11ShaderResourceView** textureView,
                                    _In_ size_t maxsize )
{
    if (!d3dDevice || !ddsData || (!texture && !textureView))
    {
        return E_INVALIDARG;
    }

    // Validate DDS file in memory
    if (ddsDataSize < (sizeof(uint32_t) + sizeof(DDS_HEADER)))
    {
        return E_FAIL;
    }

    uint32_t dwMagicNumber = *( const uint32_t* )( ddsData );
    if (dwMagicNumber != DDS_MAGIC)
    {
        return E_FAIL;
    }

    const DDS_HEADER* header = reinterpret_cast<const DDS_HEADER*>( ddsData + sizeof( uint32_t ) );

    // Verify header to validate DDS file
    if (header->size != sizeof(DDS_HEADER) ||
        header->ddspf.size != sizeof(DDS_PIXELFORMAT))
    {
        return E_FAIL;
    }

    // Check for DX10 extension
    bool bDXT10Header = false;
    if ((header->ddspf.flags & DDS_FOURCC) &&
        (MAKEFOURCC( 'D', 'X', '1', '0' ) == header->ddspf.fourCC) )
    {
        // Must be long enough for both headers and magic value
        if (ddsDataSize < (sizeof(DDS_HEADER) + sizeof(uint32_t) + sizeof(DDS_HEADER_DXT10)))
        {
            return E_FAIL;
        }

        bDXT10Header = true;
    }

    ptrdiff_t offset = sizeof( uint32_t )
                       + sizeof( DDS_HEADER )
                       + (bDXT10Header ? sizeof( DDS_HEADER_DXT10 ) : 0);

    HRESULT hr = CreateTextureFromDDS( d3dDevice,
                                       header,
                                       ddsData + offset,
                                       ddsDataSize - offset,
                                       texture,
                                       textureView,
                                       maxsize
                                     );

#if defined(DEBUG) || defined(PROFILE)
    if (texture != 0 && *texture != 0)
    {
        (*texture)->SetPrivateData( WKPDID_D3DDebugObjectName,
                                    sizeof("DDSTextureLoader")-1,
                                    "DDSTextureLoader"
                                  );
    }

    if (textureView != 0 && *textureView != 0)
    {
        (*textureView)->SetPrivateData( WKPDID_D3DDebugObjectName,
                                        sizeof("DDSTextureLoader")-1,
                                        "DDSTextureLoader"
                                      );
    }
#endif

    return hr;
}

//--------------------------------------------------------------------------------------
HRESULT CreateDDSTextureFromFile( _In_ ID3D11Device* d3dDevice,
                                  _In_z_ const wchar_t* fileName,
                                  _Out_opt_ ID3D11Resource** texture,
                                  _Out_opt_ ID3D11ShaderResourceView** textureView,
                                  _In_ size_t maxsize )
{
    if (!d3dDevice || !fileName || (!texture && !textureView))
    {
        return E_INVALIDARG;
    }

    DDS_HEADER* header = nullptr;
    uint8_t* bitData = nullptr;
    size_t bitSize = 0;

    std::unique_ptr<uint8_t[]> ddsData;
    HRESULT hr = LoadTextureDataFromFile( fileName,
                                          ddsData,
                                          &header,
                                          &bitData,
                                          &bitSize
                                        );
    if (FAILED(hr))
    {
        return hr;
    }

    hr = CreateTextureFromDDS( d3dDevice,
                               header,
                               bitData,
                               bitSize,
                               texture,
                               textureView,
                               maxsize
                             );

#if defined(DEBUG) || defined(PROFILE)
    if (texture != 0 || textureView != 0)
    {
        CHAR strFileA[MAX_PATH];
        WideCharToMultiByte( CP_ACP,
                             WC_NO_BEST_FIT_CHARS,
                             fileName,
                             -1,
                             strFileA,
                             MAX_PATH,
                             nullptr,
                             FALSE
                           );
        const CHAR* pstrName = strrchr( strFileA, '\\' );
        if (!pstrName)
        {
            pstrName = strFileA;
        }
        else
        {
            pstrName++;
        }

        if (texture != 0 && *texture != 0)
        {
            (*texture)->SetPrivateData( WKPDID_D3DDebugObjectName,
                                        lstrlenA(pstrName),
                                        pstrName
                                      );
        }

        if (textureView != 0 && *textureView != 0 )
        {
            (*textureView)->SetPrivateData( WKPDID_D3DDebugObjectName,
                                            lstrlenA(pstrName),
                                            pstrName
                                          );
        }
    }
#endif

    return hr;
}
