/* SPDX-License-Identifier: GPL-2.0-or-later */

/** \file
 * \ingroup imbdds
 */

/*
 * This file is based on a similar file from the NVIDIA texture tools
 * (http://nvidia-texture-tools.googlecode.com/)
 *
 * Original license from NVIDIA follows.
 */

/* Copyright NVIDIA Corporation 2007 -- Ignacio Castano <icastano@nvidia.com>
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use,
 * copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following
 * conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE. */

#include "BLI_utildefines.h"
#undef CLAMP

#include <BlockDXT.h>
#include <DirectDrawSurface.h>
#include <PixelFormat.h>

#include <cmath>   /* sqrt */
#include <cstdio>  /* printf */
#include <cstdlib> /* malloc */
#include <sys/types.h>

/*** declarations ***/

#if !defined(DDS_MAKEFOURCC)
#  define DDS_MAKEFOURCC(ch0, ch1, ch2, ch3) \
    (uint(uint8(ch0)) | (uint(uint8(ch1)) << 8) | (uint(uint8(ch2)) << 16) | \
     (uint(uint8(ch3)) << 24))
#endif

static const uint FOURCC_NVTT = DDS_MAKEFOURCC('N', 'V', 'T', 'T');
static const uint FOURCC_DDS = DDS_MAKEFOURCC('D', 'D', 'S', ' ');
static const uint FOURCC_DXT1 = DDS_MAKEFOURCC('D', 'X', 'T', '1');
static const uint FOURCC_DXT2 = DDS_MAKEFOURCC('D', 'X', 'T', '2');
static const uint FOURCC_DXT3 = DDS_MAKEFOURCC('D', 'X', 'T', '3');
static const uint FOURCC_DXT4 = DDS_MAKEFOURCC('D', 'X', 'T', '4');
static const uint FOURCC_DXT5 = DDS_MAKEFOURCC('D', 'X', 'T', '5');
static const uint FOURCC_RXGB = DDS_MAKEFOURCC('R', 'X', 'G', 'B');
static const uint FOURCC_ATI1 = DDS_MAKEFOURCC('A', 'T', 'I', '1');
static const uint FOURCC_ATI2 = DDS_MAKEFOURCC('A', 'T', 'I', '2');

#if 0 /* Valid but currently unused. */
static const uint FOURCC_A2XY = DDS_MAKEFOURCC('A', '2', 'X', 'Y');
#endif

static const uint FOURCC_DX10 = DDS_MAKEFOURCC('D', 'X', '1', '0');

static const uint FOURCC_UVER = DDS_MAKEFOURCC('U', 'V', 'E', 'R');

/* 32 bit RGB formats. */
static const uint D3DFMT_R8G8B8 = 20;
static const uint D3DFMT_A8R8G8B8 = 21;
static const uint D3DFMT_X8R8G8B8 = 22;
static const uint D3DFMT_R5G6B5 = 23;
static const uint D3DFMT_X1R5G5B5 = 24;
static const uint D3DFMT_A1R5G5B5 = 25;
static const uint D3DFMT_A4R4G4B4 = 26;
static const uint D3DFMT_R3G3B2 = 27;
static const uint D3DFMT_A8 = 28;
static const uint D3DFMT_A8R3G3B2 = 29;
static const uint D3DFMT_X4R4G4B4 = 30;
static const uint D3DFMT_A2B10G10R10 = 31;
static const uint D3DFMT_A8B8G8R8 = 32;
static const uint D3DFMT_X8B8G8R8 = 33;
static const uint D3DFMT_G16R16 = 34;
static const uint D3DFMT_A2R10G10B10 = 35;

#if 0 /* Valid but currently unused. */
static const uint D3DFMT_A16B16G16R16 = 36;
#endif

/* Palette formats. */
#if 0 /* Valid but currently unused. */
static const uint D3DFMT_A8P8 = 40;
static const uint D3DFMT_P8 = 41;
#endif

/* Luminance formats. */
static const uint D3DFMT_L8 = 50;
#if 0 /* Valid but currently unused. */
static const uint D3DFMT_A8L8 = 51;
static const uint D3DFMT_A4L4 = 52;
#endif
static const uint D3DFMT_L16 = 81;

/* Floating point formats */
#if 0 /* Valid but currently unused. */
static const uint D3DFMT_R16F = 111;
static const uint D3DFMT_G16R16F = 112;
static const uint D3DFMT_A16B16G16R16F = 113;
static const uint D3DFMT_R32F = 114;
static const uint D3DFMT_G32R32F = 115;
static const uint D3DFMT_A32B32G32R32F = 116;
#endif

static const uint DDSD_CAPS = 0x00000001U;
static const uint DDSD_PIXELFORMAT = 0x00001000U;
static const uint DDSD_WIDTH = 0x00000004U;
static const uint DDSD_HEIGHT = 0x00000002U;
static const uint DDSD_PITCH = 0x00000008U;
static const uint DDSD_MIPMAPCOUNT = 0x00020000U;
static const uint DDSD_LINEARSIZE = 0x00080000U;
static const uint DDSD_DEPTH = 0x00800000U;

static const uint DDSCAPS_COMPLEX = 0x00000008U;
static const uint DDSCAPS_TEXTURE = 0x00001000U;
static const uint DDSCAPS_MIPMAP = 0x00400000U;
static const uint DDSCAPS2_VOLUME = 0x00200000U;
static const uint DDSCAPS2_CUBEMAP = 0x00000200U;

static const uint DDSCAPS2_CUBEMAP_POSITIVEX = 0x00000400U;
static const uint DDSCAPS2_CUBEMAP_NEGATIVEX = 0x00000800U;
static const uint DDSCAPS2_CUBEMAP_POSITIVEY = 0x00001000U;
static const uint DDSCAPS2_CUBEMAP_NEGATIVEY = 0x00002000U;
static const uint DDSCAPS2_CUBEMAP_POSITIVEZ = 0x00004000U;
static const uint DDSCAPS2_CUBEMAP_NEGATIVEZ = 0x00008000U;
static const uint DDSCAPS2_CUBEMAP_ALL_FACES = 0x0000FC00U;

static const uint DDPF_ALPHAPIXELS = 0x00000001U;
static const uint DDPF_ALPHA = 0x00000002U;
static const uint DDPF_FOURCC = 0x00000004U;
static const uint DDPF_RGB = 0x00000040U;
static const uint DDPF_PALETTEINDEXED1 = 0x00000800U;
static const uint DDPF_PALETTEINDEXED2 = 0x00001000U;
static const uint DDPF_PALETTEINDEXED4 = 0x00000008U;
static const uint DDPF_PALETTEINDEXED8 = 0x00000020U;
static const uint DDPF_LUMINANCE = 0x00020000U;
static const uint DDPF_ALPHAPREMULT = 0x00008000U;

/* Custom NVTT flags. */
static const uint DDPF_NORMAL = 0x80000000U;
static const uint DDPF_SRGB = 0x40000000U;

/* DX10 formats. */
enum DXGI_FORMAT {
  DXGI_FORMAT_UNKNOWN = 0,

  DXGI_FORMAT_R32G32B32A32_TYPELESS = 1,
  DXGI_FORMAT_R32G32B32A32_FLOAT = 2,
  DXGI_FORMAT_R32G32B32A32_UINT = 3,
  DXGI_FORMAT_R32G32B32A32_SINT = 4,

  DXGI_FORMAT_R32G32B32_TYPELESS = 5,
  DXGI_FORMAT_R32G32B32_FLOAT = 6,
  DXGI_FORMAT_R32G32B32_UINT = 7,
  DXGI_FORMAT_R32G32B32_SINT = 8,

  DXGI_FORMAT_R16G16B16A16_TYPELESS = 9,
  DXGI_FORMAT_R16G16B16A16_FLOAT = 10,
  DXGI_FORMAT_R16G16B16A16_UNORM = 11,
  DXGI_FORMAT_R16G16B16A16_UINT = 12,
  DXGI_FORMAT_R16G16B16A16_SNORM = 13,
  DXGI_FORMAT_R16G16B16A16_SINT = 14,

  DXGI_FORMAT_R32G32_TYPELESS = 15,
  DXGI_FORMAT_R32G32_FLOAT = 16,
  DXGI_FORMAT_R32G32_UINT = 17,
  DXGI_FORMAT_R32G32_SINT = 18,

  DXGI_FORMAT_R32G8X24_TYPELESS = 19,
  DXGI_FORMAT_D32_FLOAT_S8X24_UINT = 20,
  DXGI_FORMAT_R32_FLOAT_X8X24_TYPELESS = 21,
  DXGI_FORMAT_X32_TYPELESS_G8X24_UINT = 22,

  DXGI_FORMAT_R10G10B10A2_TYPELESS = 23,
  DXGI_FORMAT_R10G10B10A2_UNORM = 24,
  DXGI_FORMAT_R10G10B10A2_UINT = 25,

  DXGI_FORMAT_R11G11B10_FLOAT = 26,

  DXGI_FORMAT_R8G8B8A8_TYPELESS = 27,
  DXGI_FORMAT_R8G8B8A8_UNORM = 28,
  DXGI_FORMAT_R8G8B8A8_UNORM_SRGB = 29,
  DXGI_FORMAT_R8G8B8A8_UINT = 30,
  DXGI_FORMAT_R8G8B8A8_SNORM = 31,
  DXGI_FORMAT_R8G8B8A8_SINT = 32,

  DXGI_FORMAT_R16G16_TYPELESS = 33,
  DXGI_FORMAT_R16G16_FLOAT = 34,
  DXGI_FORMAT_R16G16_UNORM = 35,
  DXGI_FORMAT_R16G16_UINT = 36,
  DXGI_FORMAT_R16G16_SNORM = 37,
  DXGI_FORMAT_R16G16_SINT = 38,

  DXGI_FORMAT_R32_TYPELESS = 39,
  DXGI_FORMAT_D32_FLOAT = 40,
  DXGI_FORMAT_R32_FLOAT = 41,
  DXGI_FORMAT_R32_UINT = 42,
  DXGI_FORMAT_R32_SINT = 43,

  DXGI_FORMAT_R24G8_TYPELESS = 44,
  DXGI_FORMAT_D24_UNORM_S8_UINT = 45,
  DXGI_FORMAT_R24_UNORM_X8_TYPELESS = 46,
  DXGI_FORMAT_X24_TYPELESS_G8_UINT = 47,

  DXGI_FORMAT_R8G8_TYPELESS = 48,
  DXGI_FORMAT_R8G8_UNORM = 49,
  DXGI_FORMAT_R8G8_UINT = 50,
  DXGI_FORMAT_R8G8_SNORM = 51,
  DXGI_FORMAT_R8G8_SINT = 52,

  DXGI_FORMAT_R16_TYPELESS = 53,
  DXGI_FORMAT_R16_FLOAT = 54,
  DXGI_FORMAT_D16_UNORM = 55,
  DXGI_FORMAT_R16_UNORM = 56,
  DXGI_FORMAT_R16_UINT = 57,
  DXGI_FORMAT_R16_SNORM = 58,
  DXGI_FORMAT_R16_SINT = 59,

  DXGI_FORMAT_R8_TYPELESS = 60,
  DXGI_FORMAT_R8_UNORM = 61,
  DXGI_FORMAT_R8_UINT = 62,
  DXGI_FORMAT_R8_SNORM = 63,
  DXGI_FORMAT_R8_SINT = 64,
  DXGI_FORMAT_A8_UNORM = 65,

  DXGI_FORMAT_R1_UNORM = 66,

  DXGI_FORMAT_R9G9B9E5_SHAREDEXP = 67,

  DXGI_FORMAT_R8G8_B8G8_UNORM = 68,
  DXGI_FORMAT_G8R8_G8B8_UNORM = 69,

  DXGI_FORMAT_BC1_TYPELESS = 70,
  DXGI_FORMAT_BC1_UNORM = 71,
  DXGI_FORMAT_BC1_UNORM_SRGB = 72,

  DXGI_FORMAT_BC2_TYPELESS = 73,
  DXGI_FORMAT_BC2_UNORM = 74,
  DXGI_FORMAT_BC2_UNORM_SRGB = 75,

  DXGI_FORMAT_BC3_TYPELESS = 76,
  DXGI_FORMAT_BC3_UNORM = 77,
  DXGI_FORMAT_BC3_UNORM_SRGB = 78,

  DXGI_FORMAT_BC4_TYPELESS = 79,
  DXGI_FORMAT_BC4_UNORM = 80,
  DXGI_FORMAT_BC4_SNORM = 81,

  DXGI_FORMAT_BC5_TYPELESS = 82,
  DXGI_FORMAT_BC5_UNORM = 83,
  DXGI_FORMAT_BC5_SNORM = 84,

  DXGI_FORMAT_B5G6R5_UNORM = 85,
  DXGI_FORMAT_B5G5R5A1_UNORM = 86,
  DXGI_FORMAT_B8G8R8A8_UNORM = 87,
  DXGI_FORMAT_B8G8R8X8_UNORM = 88,

  DXGI_FORMAT_R10G10B10_XR_BIAS_A2_UNORM = 89,
  DXGI_FORMAT_B8G8R8A8_TYPELESS = 90,
  DXGI_FORMAT_B8G8R8A8_UNORM_SRGB = 91,
  DXGI_FORMAT_B8G8R8X8_TYPELESS = 92,
  DXGI_FORMAT_B8G8R8X8_UNORM_SRGB = 93,

  DXGI_FORMAT_BC6H_TYPELESS = 94,
  DXGI_FORMAT_BC6H_UF16 = 95,
  DXGI_FORMAT_BC6H_SF16 = 96,

  DXGI_FORMAT_BC7_TYPELESS = 97,
  DXGI_FORMAT_BC7_UNORM = 98,
  DXGI_FORMAT_BC7_UNORM_SRGB = 99,
};

enum D3D10_RESOURCE_DIMENSION {
  D3D10_RESOURCE_DIMENSION_UNKNOWN = 0,
  D3D10_RESOURCE_DIMENSION_BUFFER = 1,
  D3D10_RESOURCE_DIMENSION_TEXTURE1D = 2,
  D3D10_RESOURCE_DIMENSION_TEXTURE2D = 3,
  D3D10_RESOURCE_DIMENSION_TEXTURE3D = 4,
};

static const char *getDxgiFormatString(DXGI_FORMAT dxgiFormat)
{
#define CASE(format) \
  case DXGI_FORMAT_##format: \
    return #format
  switch (dxgiFormat) {
    CASE(UNKNOWN);

    CASE(R32G32B32A32_TYPELESS);
    CASE(R32G32B32A32_FLOAT);
    CASE(R32G32B32A32_UINT);
    CASE(R32G32B32A32_SINT);

    CASE(R32G32B32_TYPELESS);
    CASE(R32G32B32_FLOAT);
    CASE(R32G32B32_UINT);
    CASE(R32G32B32_SINT);

    CASE(R16G16B16A16_TYPELESS);
    CASE(R16G16B16A16_FLOAT);
    CASE(R16G16B16A16_UNORM);
    CASE(R16G16B16A16_UINT);
    CASE(R16G16B16A16_SNORM);
    CASE(R16G16B16A16_SINT);

    CASE(R32G32_TYPELESS);
    CASE(R32G32_FLOAT);
    CASE(R32G32_UINT);
    CASE(R32G32_SINT);

    CASE(R32G8X24_TYPELESS);
    CASE(D32_FLOAT_S8X24_UINT);
    CASE(R32_FLOAT_X8X24_TYPELESS);
    CASE(X32_TYPELESS_G8X24_UINT);

    CASE(R10G10B10A2_TYPELESS);
    CASE(R10G10B10A2_UNORM);
    CASE(R10G10B10A2_UINT);

    CASE(R11G11B10_FLOAT);

    CASE(R8G8B8A8_TYPELESS);
    CASE(R8G8B8A8_UNORM);
    CASE(R8G8B8A8_UNORM_SRGB);
    CASE(R8G8B8A8_UINT);
    CASE(R8G8B8A8_SNORM);
    CASE(R8G8B8A8_SINT);

    CASE(R16G16_TYPELESS);
    CASE(R16G16_FLOAT);
    CASE(R16G16_UNORM);
    CASE(R16G16_UINT);
    CASE(R16G16_SNORM);
    CASE(R16G16_SINT);

    CASE(R32_TYPELESS);
    CASE(D32_FLOAT);
    CASE(R32_FLOAT);
    CASE(R32_UINT);
    CASE(R32_SINT);

    CASE(R24G8_TYPELESS);
    CASE(D24_UNORM_S8_UINT);
    CASE(R24_UNORM_X8_TYPELESS);
    CASE(X24_TYPELESS_G8_UINT);

    CASE(R8G8_TYPELESS);
    CASE(R8G8_UNORM);
    CASE(R8G8_UINT);
    CASE(R8G8_SNORM);
    CASE(R8G8_SINT);

    CASE(R16_TYPELESS);
    CASE(R16_FLOAT);
    CASE(D16_UNORM);
    CASE(R16_UNORM);
    CASE(R16_UINT);
    CASE(R16_SNORM);
    CASE(R16_SINT);

    CASE(R8_TYPELESS);
    CASE(R8_UNORM);
    CASE(R8_UINT);
    CASE(R8_SNORM);
    CASE(R8_SINT);
    CASE(A8_UNORM);

    CASE(R1_UNORM);

    CASE(R9G9B9E5_SHAREDEXP);

    CASE(R8G8_B8G8_UNORM);
    CASE(G8R8_G8B8_UNORM);

    CASE(BC1_TYPELESS);
    CASE(BC1_UNORM);
    CASE(BC1_UNORM_SRGB);

    CASE(BC2_TYPELESS);
    CASE(BC2_UNORM);
    CASE(BC2_UNORM_SRGB);

    CASE(BC3_TYPELESS);
    CASE(BC3_UNORM);
    CASE(BC3_UNORM_SRGB);

    CASE(BC4_TYPELESS);
    CASE(BC4_UNORM);
    CASE(BC4_SNORM);

    CASE(BC5_TYPELESS);
    CASE(BC5_UNORM);
    CASE(BC5_SNORM);

    CASE(B5G6R5_UNORM);
    CASE(B5G5R5A1_UNORM);
    CASE(B8G8R8A8_UNORM);
    CASE(B8G8R8X8_UNORM);

    default:
      return "UNKNOWN";
  }
#undef CASE
}

static const char *getD3d10ResourceDimensionString(D3D10_RESOURCE_DIMENSION resourceDimension)
{
  switch (resourceDimension) {
    default:
    case D3D10_RESOURCE_DIMENSION_UNKNOWN:
      return "UNKNOWN";
    case D3D10_RESOURCE_DIMENSION_BUFFER:
      return "BUFFER";
    case D3D10_RESOURCE_DIMENSION_TEXTURE1D:
      return "TEXTURE1D";
    case D3D10_RESOURCE_DIMENSION_TEXTURE2D:
      return "TEXTURE2D";
    case D3D10_RESOURCE_DIMENSION_TEXTURE3D:
      return "TEXTURE3D";
  }
}

/*** implementation ***/

void mem_read(Stream &mem, DDSPixelFormat &pf)
{
  mem_read(mem, pf.size);
  mem_read(mem, pf.flags);
  mem_read(mem, pf.fourcc);
  mem_read(mem, pf.bitcount);
  mem_read(mem, pf.rmask);
  mem_read(mem, pf.gmask);
  mem_read(mem, pf.bmask);
  mem_read(mem, pf.amask);
}

void mem_read(Stream &mem, DDSCaps &caps)
{
  mem_read(mem, caps.caps1);
  mem_read(mem, caps.caps2);
  mem_read(mem, caps.caps3);
  mem_read(mem, caps.caps4);
}

void mem_read(Stream &mem, DDSHeader10 &header)
{
  mem_read(mem, header.dxgiFormat);
  mem_read(mem, header.resourceDimension);
  mem_read(mem, header.miscFlag);
  mem_read(mem, header.arraySize);
  mem_read(mem, header.reserved);
}

void mem_read(Stream &mem, DDSHeader &header)
{
  mem_read(mem, header.fourcc);
  mem_read(mem, header.size);
  mem_read(mem, header.flags);
  mem_read(mem, header.height);
  mem_read(mem, header.width);
  mem_read(mem, header.pitch);
  mem_read(mem, header.depth);
  mem_read(mem, header.mipmapcount);
  for (uint i = 0; i < 11; i++) {
    mem_read(mem, header.reserved[i]);
  }
  mem_read(mem, header.pf);
  mem_read(mem, header.caps);
  mem_read(mem, header.notused);

  if (header.hasDX10Header()) {
    mem_read(mem, header.header10);
  }
}

namespace {
struct FormatDescriptor {
  uint format;
  uint bitcount;
  uint rmask;
  uint gmask;
  uint bmask;
  uint amask;
};

const FormatDescriptor s_d3dFormats[] = {
    {D3DFMT_R8G8B8, 24, 0xFF0000, 0xFF00, 0xFF, 0},
    {D3DFMT_A8R8G8B8, 32, 0xFF0000, 0xFF00, 0xFF, 0xFF000000}, /* DXGI_FORMAT_B8G8R8A8_UNORM */
    {D3DFMT_X8R8G8B8, 32, 0xFF0000, 0xFF00, 0xFF, 0},          /* DXGI_FORMAT_B8G8R8X8_UNORM */
    {D3DFMT_R5G6B5, 16, 0xF800, 0x7E0, 0x1F, 0},               /* DXGI_FORMAT_B5G6R5_UNORM */
    {D3DFMT_X1R5G5B5, 16, 0x7C00, 0x3E0, 0x1F, 0},
    {D3DFMT_A1R5G5B5, 16, 0x7C00, 0x3E0, 0x1F, 0x8000}, /* DXGI_FORMAT_B5G5R5A1_UNORM */
    {D3DFMT_A4R4G4B4, 16, 0xF00, 0xF0, 0xF, 0xF000},
    {D3DFMT_R3G3B2, 8, 0xE0, 0x1C, 0x3, 0},
    {D3DFMT_A8, 8, 0, 0, 0, 8}, /* DXGI_FORMAT_A8_UNORM */
    {D3DFMT_A8R3G3B2, 16, 0xE0, 0x1C, 0x3, 0xFF00},
    {D3DFMT_X4R4G4B4, 16, 0xF00, 0xF0, 0xF, 0},
    {D3DFMT_A2B10G10R10, 32, 0x3FF, 0xFFC00, 0x3FF00000, 0xC0000000}, /* DXGI_FORMAT_R10G10B10A2 */
    {D3DFMT_A8B8G8R8, 32, 0xFF, 0xFF00, 0xFF0000, 0xFF000000}, /* DXGI_FORMAT_R8G8B8A8_UNORM */
    {D3DFMT_X8B8G8R8, 32, 0xFF, 0xFF00, 0xFF0000, 0},
    {D3DFMT_G16R16, 32, 0xFFFF, 0xFFFF0000, 0, 0}, /* DXGI_FORMAT_R16G16_UNORM */
    {D3DFMT_A2R10G10B10, 32, 0x3FF00000, 0xFFC00, 0x3FF, 0xC0000000},
    {D3DFMT_A2B10G10R10, 32, 0x3FF, 0xFFC00, 0x3FF00000, 0xC0000000},

    {D3DFMT_L8, 8, 8, 0, 0, 0},    /* DXGI_FORMAT_R8_UNORM */
    {D3DFMT_L16, 16, 16, 0, 0, 0}, /* DXGI_FORMAT_R16_UNORM */
};

const uint s_d3dFormatCount = sizeof(s_d3dFormats) / sizeof(s_d3dFormats[0]);

} /* namespace */

static uint findD3D9Format(uint bitcount, uint rmask, uint gmask, uint bmask, uint amask)
{
  for (int i = 0; i < s_d3dFormatCount; i++) {
    if (s_d3dFormats[i].bitcount == bitcount && s_d3dFormats[i].rmask == rmask &&
        s_d3dFormats[i].gmask == gmask && s_d3dFormats[i].bmask == bmask &&
        s_d3dFormats[i].amask == amask) {
      return s_d3dFormats[i].format;
    }
  }

  return 0;
}

DDSHeader::DDSHeader()
{
  this->fourcc = FOURCC_DDS;
  this->size = 124;
  this->flags = (DDSD_CAPS | DDSD_PIXELFORMAT);
  this->height = 0;
  this->width = 0;
  this->pitch = 0;
  this->depth = 0;
  this->mipmapcount = 0;
  for (uint i = 0; i < 11; i++) {
    this->reserved[i] = 0;
  }

  /* Store version information on the reserved header attributes. */
  this->reserved[9] = FOURCC_NVTT;
  this->reserved[10] = (2 << 16) | (1 << 8) | (0); /* major.minor.revision */

  this->pf.size = 32;
  this->pf.flags = 0;
  this->pf.fourcc = 0;
  this->pf.bitcount = 0;
  this->pf.rmask = 0;
  this->pf.gmask = 0;
  this->pf.bmask = 0;
  this->pf.amask = 0;
  this->caps.caps1 = DDSCAPS_TEXTURE;
  this->caps.caps2 = 0;
  this->caps.caps3 = 0;
  this->caps.caps4 = 0;
  this->notused = 0;

  this->header10.dxgiFormat = DXGI_FORMAT_UNKNOWN;
  this->header10.resourceDimension = D3D10_RESOURCE_DIMENSION_UNKNOWN;
  this->header10.miscFlag = 0;
  this->header10.arraySize = 0;
  this->header10.reserved = 0;
}

void DDSHeader::setWidth(uint w)
{
  this->flags |= DDSD_WIDTH;
  this->width = w;
}

void DDSHeader::setHeight(uint h)
{
  this->flags |= DDSD_HEIGHT;
  this->height = h;
}

void DDSHeader::setDepth(uint d)
{
  this->flags |= DDSD_DEPTH;
  this->depth = d;
}

void DDSHeader::setMipmapCount(uint count)
{
  if (ELEM(count, 0, 1)) {
    this->flags &= ~DDSD_MIPMAPCOUNT;
    this->mipmapcount = 1;

    if (this->caps.caps2 == 0) {
      this->caps.caps1 = DDSCAPS_TEXTURE;
    }
    else {
      this->caps.caps1 = DDSCAPS_TEXTURE | DDSCAPS_COMPLEX;
    }
  }
  else {
    this->flags |= DDSD_MIPMAPCOUNT;
    this->mipmapcount = count;

    this->caps.caps1 |= DDSCAPS_COMPLEX | DDSCAPS_MIPMAP;
  }
}

void DDSHeader::setTexture2D()
{
  this->header10.resourceDimension = D3D10_RESOURCE_DIMENSION_TEXTURE2D;
  this->header10.arraySize = 1;
}

void DDSHeader::setTexture3D()
{
  this->caps.caps2 = DDSCAPS2_VOLUME;

  this->header10.resourceDimension = D3D10_RESOURCE_DIMENSION_TEXTURE3D;
  this->header10.arraySize = 1;
}

void DDSHeader::setTextureCube()
{
  this->caps.caps1 |= DDSCAPS_COMPLEX;
  this->caps.caps2 = DDSCAPS2_CUBEMAP | DDSCAPS2_CUBEMAP_ALL_FACES;

  this->header10.resourceDimension = D3D10_RESOURCE_DIMENSION_TEXTURE2D;
  this->header10.arraySize = 6;
}

void DDSHeader::setLinearSize(uint size)
{
  this->flags &= ~DDSD_PITCH;
  this->flags |= DDSD_LINEARSIZE;
  this->pitch = size;
}

void DDSHeader::setPitch(uint pitch)
{
  this->flags &= ~DDSD_LINEARSIZE;
  this->flags |= DDSD_PITCH;
  this->pitch = pitch;
}

void DDSHeader::setFourCC(uint8 c0, uint8 c1, uint8 c2, uint8 c3)
{
  /* set fourcc pixel format. */
  this->pf.flags = DDPF_FOURCC;
  this->pf.fourcc = DDS_MAKEFOURCC(c0, c1, c2, c3);

  this->pf.bitcount = 0;
  this->pf.rmask = 0;
  this->pf.gmask = 0;
  this->pf.bmask = 0;
  this->pf.amask = 0;
}

void DDSHeader::setFormatCode(uint32 code)
{
  /* set fourcc pixel format. */
  this->pf.flags = DDPF_FOURCC;
  this->pf.fourcc = code;

  this->pf.bitcount = 0;
  this->pf.rmask = 0;
  this->pf.gmask = 0;
  this->pf.bmask = 0;
  this->pf.amask = 0;
}

void DDSHeader::setSwizzleCode(uint8 c0, uint8 c1, uint8 c2, uint8 c3)
{
  this->pf.bitcount = DDS_MAKEFOURCC(c0, c1, c2, c3);
}

void DDSHeader::setPixelFormat(uint bitcount, uint rmask, uint gmask, uint bmask, uint amask)
{
  /* Make sure the masks are correct. */
  if ((rmask & gmask) || (rmask & bmask) || (rmask & amask) || (gmask & bmask) ||
      (gmask & amask) || (bmask & amask)) {
    printf("DDS: bad RGBA masks, pixel format not set\n");
    return;
  }

  if (rmask != 0 || gmask != 0 || bmask != 0) {
    if (gmask == 0 && bmask == 0) {
      this->pf.flags = DDPF_LUMINANCE;
    }
    else {
      this->pf.flags = DDPF_RGB;
    }

    if (amask != 0) {
      this->pf.flags |= DDPF_ALPHAPIXELS;
    }
  }
  else if (amask != 0) {
    this->pf.flags |= DDPF_ALPHA;
  }

  if (bitcount == 0) {
    /* Compute bit count from the masks. */
    uint total = rmask | gmask | bmask | amask;
    while (total != 0) {
      bitcount++;
      total >>= 1;
    }
  }

  /* D3DX functions do not like this: */
  this->pf.fourcc = 0;  // findD3D9Format(bitcount, rmask, gmask, bmask, amask);
#if 0
  if (this->pf.fourcc) {
    this->pf.flags |= DDPF_FOURCC;
  }
#endif

  if (!(bitcount > 0 && bitcount <= 32)) {
    printf("DDS: bad bit count, pixel format not set\n");
    return;
  }
  this->pf.bitcount = bitcount;
  this->pf.rmask = rmask;
  this->pf.gmask = gmask;
  this->pf.bmask = bmask;
  this->pf.amask = amask;
}

void DDSHeader::setDX10Format(uint format)
{
  // this->pf.flags = 0;
  this->pf.fourcc = FOURCC_DX10;
  this->header10.dxgiFormat = format;
}

void DDSHeader::setNormalFlag(bool b)
{
  if (b) {
    this->pf.flags |= DDPF_NORMAL;
  }
  else {
    this->pf.flags &= ~DDPF_NORMAL;
  }
}

void DDSHeader::setSrgbFlag(bool b)
{
  if (b) {
    this->pf.flags |= DDPF_SRGB;
  }
  else {
    this->pf.flags &= ~DDPF_SRGB;
  }
}

void DDSHeader::setHasAlphaFlag(bool b)
{
  if (b) {
    this->pf.flags |= DDPF_ALPHAPIXELS;
  }
  else {
    this->pf.flags &= ~DDPF_ALPHAPIXELS;
  }
}

void DDSHeader::setUserVersion(int version)
{
  this->reserved[7] = FOURCC_UVER;
  this->reserved[8] = version;
}

#if 0
void DDSHeader::swapBytes()
{
  this->fourcc = POSH_LittleU32(this->fourcc);
  this->size = POSH_LittleU32(this->size);
  this->flags = POSH_LittleU32(this->flags);
  this->height = POSH_LittleU32(this->height);
  this->width = POSH_LittleU32(this->width);
  this->pitch = POSH_LittleU32(this->pitch);
  this->depth = POSH_LittleU32(this->depth);
  this->mipmapcount = POSH_LittleU32(this->mipmapcount);

  for (int i = 0; i < 11; i++) {
    this->reserved[i] = POSH_LittleU32(this->reserved[i]);
  }

  this->pf.size = POSH_LittleU32(this->pf.size);
  this->pf.flags = POSH_LittleU32(this->pf.flags);
  this->pf.fourcc = POSH_LittleU32(this->pf.fourcc);
  this->pf.bitcount = POSH_LittleU32(this->pf.bitcount);
  this->pf.rmask = POSH_LittleU32(this->pf.rmask);
  this->pf.gmask = POSH_LittleU32(this->pf.gmask);
  this->pf.bmask = POSH_LittleU32(this->pf.bmask);
  this->pf.amask = POSH_LittleU32(this->pf.amask);
  this->caps.caps1 = POSH_LittleU32(this->caps.caps1);
  this->caps.caps2 = POSH_LittleU32(this->caps.caps2);
  this->caps.caps3 = POSH_LittleU32(this->caps.caps3);
  this->caps.caps4 = POSH_LittleU32(this->caps.caps4);
  this->notused = POSH_LittleU32(this->notused);

  this->header10.dxgiFormat = POSH_LittleU32(this->header10.dxgiFormat);
  this->header10.resourceDimension = POSH_LittleU32(this->header10.resourceDimension);
  this->header10.miscFlag = POSH_LittleU32(this->header10.miscFlag);
  this->header10.arraySize = POSH_LittleU32(this->header10.arraySize);
  this->header10.reserved = POSH_LittleU32(this->header10.reserved);
}
#endif

bool DDSHeader::hasDX10Header() const
{
  return this->pf.fourcc == FOURCC_DX10;
}

uint DDSHeader::signature() const
{
  return this->reserved[9];
}

uint DDSHeader::toolVersion() const
{
  return this->reserved[10];
}

uint DDSHeader::userVersion() const
{
  if (this->reserved[7] == FOURCC_UVER) {
    return this->reserved[8];
  }
  return 0;
}

bool DDSHeader::isNormalMap() const
{
  return (pf.flags & DDPF_NORMAL) != 0;
}

bool DDSHeader::isSrgb() const
{
  return (pf.flags & DDPF_SRGB) != 0;
}

bool DDSHeader::hasAlpha() const
{
  return (pf.flags & DDPF_ALPHAPIXELS) != 0;
}

uint DDSHeader::d3d9Format() const
{
  if (pf.flags & DDPF_FOURCC) {
    return pf.fourcc;
  }

  return findD3D9Format(pf.bitcount, pf.rmask, pf.gmask, pf.bmask, pf.amask);
}

DirectDrawSurface::DirectDrawSurface(unsigned char *mem, uint size) : stream(mem, size), header()
{
  mem_read(stream, header);

  /* Some ATI2 compressed normal maps do not have their
   * normal flag set, so force it here (the original nvtt don't do
   * this, but the decompressor has a -forcenormal flag). */
  if (header.pf.fourcc == FOURCC_ATI2) {
    header.setNormalFlag(true);
  }
}

bool DirectDrawSurface::isValid() const
{
  if (header.fourcc != FOURCC_DDS || header.size != 124) {
    return false;
  }

  const uint required = (DDSD_WIDTH | DDSD_HEIGHT /*|DDSD_CAPS|DDSD_PIXELFORMAT*/);
  if ((header.flags & required) != required) {
    return false;
  }

  if (header.pf.size != 32) {
    return false;
  }

  /* in some files DDSCAPS_TEXTURE is missing: silently ignore */
#if 0
  if (!(header.caps.caps1 & DDSCAPS_TEXTURE)) {
    return false;
  }
#endif

  return true;
}

bool DirectDrawSurface::isSupported() const
{
  if (header.hasDX10Header()) {
    if (ELEM(header.header10.dxgiFormat,
             DXGI_FORMAT_BC1_UNORM,
             DXGI_FORMAT_BC2_UNORM,
             DXGI_FORMAT_BC3_UNORM,
             DXGI_FORMAT_BC4_UNORM,
             DXGI_FORMAT_BC5_UNORM)) {
      return true;
    }

    return false;
  }

  if (header.pf.flags & DDPF_FOURCC) {
    if (!ELEM(header.pf.fourcc,
              FOURCC_DXT1,
              FOURCC_DXT2,
              FOURCC_DXT3,
              FOURCC_DXT4,
              FOURCC_DXT5,
              FOURCC_RXGB,
              FOURCC_ATI1,
              FOURCC_ATI2)) {
      /* Unknown fourcc code. */
      return false;
    }
  }
  else if ((header.pf.flags & DDPF_RGB) || (header.pf.flags & DDPF_LUMINANCE)) {
    /* All RGB and luminance formats are supported now. */
  }
  else {
    return false;
  }

  if (isTextureCube() &&
      (header.caps.caps2 & DDSCAPS2_CUBEMAP_ALL_FACES) != DDSCAPS2_CUBEMAP_ALL_FACES) {
    /* Cubemaps must contain all faces. */
    return false;
  }

  if (isTexture3D()) {
    /* @@ 3D textures not supported yet. */
    return false;
  }

  return true;
}

bool DirectDrawSurface::hasAlpha() const
{
  if (header.hasDX10Header()) {
    /* TODO: Update hasAlpha to handle all DX10 formats. */
    return header.header10.dxgiFormat == DXGI_FORMAT_BC1_UNORM ||
           header.header10.dxgiFormat == DXGI_FORMAT_BC2_UNORM ||
           header.header10.dxgiFormat == DXGI_FORMAT_BC3_UNORM;
  }

  if (header.pf.flags & DDPF_RGB) {
    return header.pf.amask != 0;
  }
  if (header.pf.flags & DDPF_FOURCC) {
    if (header.pf.fourcc == FOURCC_RXGB || header.pf.fourcc == FOURCC_ATI1 ||
        header.pf.fourcc == FOURCC_ATI2 || header.pf.flags & DDPF_NORMAL) {
      return false;
    }

    /* @@ Here we could check the ALPHA_PIXELS flag, but nobody sets it. (except us?) */
    return true;
  }

  return false;
}

uint DirectDrawSurface::mipmapCount() const
{
  if (header.flags & DDSD_MIPMAPCOUNT) {
    return header.mipmapcount;
  }

  return 1;
}

uint DirectDrawSurface::fourCC() const
{
  return header.pf.fourcc;
}

uint DirectDrawSurface::width() const
{
  if (header.flags & DDSD_WIDTH) {
    return header.width;
  }

  return 1;
}

uint DirectDrawSurface::height() const
{
  if (header.flags & DDSD_HEIGHT) {
    return header.height;
  }

  return 1;
}

uint DirectDrawSurface::depth() const
{
  if (header.flags & DDSD_DEPTH) {
    return header.depth;
  }

  return 1;
}

bool DirectDrawSurface::isTexture1D() const
{
  if (header.hasDX10Header()) {
    return header.header10.resourceDimension == D3D10_RESOURCE_DIMENSION_TEXTURE1D;
  }
  return false;
}

bool DirectDrawSurface::isTexture2D() const
{
  if (header.hasDX10Header()) {
    return header.header10.resourceDimension == D3D10_RESOURCE_DIMENSION_TEXTURE2D;
  }

  return !isTexture3D() && !isTextureCube();
}

bool DirectDrawSurface::isTexture3D() const
{
  if (header.hasDX10Header()) {
    return header.header10.resourceDimension == D3D10_RESOURCE_DIMENSION_TEXTURE3D;
  }

  return (header.caps.caps2 & DDSCAPS2_VOLUME) != 0;
}

bool DirectDrawSurface::isTextureCube() const
{
  return (header.caps.caps2 & DDSCAPS2_CUBEMAP) != 0;
}

void DirectDrawSurface::setNormalFlag(bool b)
{
  header.setNormalFlag(b);
}

void DirectDrawSurface::setHasAlphaFlag(bool b)
{
  header.setHasAlphaFlag(b);
}

void DirectDrawSurface::setUserVersion(int version)
{
  header.setUserVersion(version);
}

void DirectDrawSurface::mipmap(Image *img, uint face, uint mipmap)
{
  stream.seek(offset(face, mipmap));

  uint w = width();
  uint h = height();

  /* Compute width and height. */
  for (uint m = 0; m < mipmap; m++) {
    w = MAX(1U, w / 2);
    h = MAX(1U, h / 2);
  }

  img->allocate(w, h);

  if (hasAlpha()) {
    img->setFormat(Image::Format_ARGB);
  }
  else {
    img->setFormat(Image::Format_RGB);
  }

  if (header.hasDX10Header()) {
    /* So far only block formats supported. */
    readBlockImage(img);
  }
  else {
    if (header.pf.flags & DDPF_RGB) {
      readLinearImage(img);
    }
    else if (header.pf.flags & DDPF_FOURCC) {
      readBlockImage(img);
    }
  }
}

void *DirectDrawSurface::readData(uint &rsize)
{
  uint header_size = 128;  // sizeof(DDSHeader);
  if (header.hasDX10Header()) {
    header_size += 20;  // sizeof(DDSHeader10);
  }

  uint size = stream.size - header_size;
  rsize = size;

  unsigned char *data = (unsigned char *)malloc(sizeof(*data) * size);

  stream.seek(header_size);
  mem_read(stream, data, size);

  if (stream.failed) {
    free(data);
    data = nullptr;
    rsize = 0;
  }

  /* Maybe check if size == rsize? assert() isn't in this scope. */

  return data;
}

void DirectDrawSurface::readLinearImage(Image *img)
{

  const uint w = img->width();
  const uint h = img->height();

  uint rshift, rsize;
  PixelFormat::maskShiftAndSize(header.pf.rmask, &rshift, &rsize);

  uint gshift, gsize;
  PixelFormat::maskShiftAndSize(header.pf.gmask, &gshift, &gsize);

  uint bshift, bsize;
  PixelFormat::maskShiftAndSize(header.pf.bmask, &bshift, &bsize);

  uint ashift, asize;
  PixelFormat::maskShiftAndSize(header.pf.amask, &ashift, &asize);

  uint byteCount = (header.pf.bitcount + 7) / 8;

  if (byteCount > 4) {
    /* just in case... we could have segfaults later on if byteCount > 4 */
    printf("DDS: bitcount too large");
    return;
  }

  /* Read linear RGB images. */
  for (uint y = 0; y < h; y++) {
    for (uint x = 0; x < w; x++) {
      uint c = 0;
      mem_read(stream, (unsigned char *)(&c), byteCount);

      Color32 pixel(0, 0, 0, 0xFF);
      pixel.r = PixelFormat::convert((c & header.pf.rmask) >> rshift, rsize, 8);
      pixel.g = PixelFormat::convert((c & header.pf.gmask) >> gshift, gsize, 8);
      pixel.b = PixelFormat::convert((c & header.pf.bmask) >> bshift, bsize, 8);
      pixel.a = PixelFormat::convert((c & header.pf.amask) >> ashift, asize, 8);

      img->pixel(x, y) = pixel;
    }
  }
}

void DirectDrawSurface::readBlockImage(Image *img)
{

  const uint w = img->width();
  const uint h = img->height();

  const uint bw = (w + 3) / 4;
  const uint bh = (h + 3) / 4;

  for (uint by = 0; by < bh; by++) {
    for (uint bx = 0; bx < bw; bx++) {
      ColorBlock block;

      /* Read color block. */
      readBlock(&block);

      /* Write color block. */
      for (uint y = 0; y < MIN(4U, h - 4 * by); y++) {
        for (uint x = 0; x < MIN(4U, w - 4 * bx); x++) {
          img->pixel(4 * bx + x, 4 * by + y) = block.color(x, y);
        }
      }
    }
  }
}

static Color32 buildNormal(uint8 x, uint8 y)
{
  float nx = 2 * (x / 255.0f) - 1;
  float ny = 2 * (y / 255.0f) - 1;
  float nz = 0.0f;
  if (1 - nx * nx - ny * ny > 0) {
    nz = sqrt(1 - nx * nx - ny * ny);
  }
  uint8 z = CLAMP(int(255.0f * (nz + 1) / 2.0f), 0, 255);

  return Color32(x, y, z);
}

void DirectDrawSurface::readBlock(ColorBlock *rgba)
{
  uint fourcc = header.pf.fourcc;

  /* Map DX10 block formats to fourcc codes. */
  if (header.hasDX10Header()) {
    if (header.header10.dxgiFormat == DXGI_FORMAT_BC1_UNORM) {
      fourcc = FOURCC_DXT1;
    }
    if (header.header10.dxgiFormat == DXGI_FORMAT_BC2_UNORM) {
      fourcc = FOURCC_DXT3;
    }
    if (header.header10.dxgiFormat == DXGI_FORMAT_BC3_UNORM) {
      fourcc = FOURCC_DXT5;
    }
    if (header.header10.dxgiFormat == DXGI_FORMAT_BC4_UNORM) {
      fourcc = FOURCC_ATI1;
    }
    if (header.header10.dxgiFormat == DXGI_FORMAT_BC5_UNORM) {
      fourcc = FOURCC_ATI2;
    }
  }

  if (fourcc == FOURCC_DXT1) {
    BlockDXT1 block;
    mem_read(stream, block);
    block.decodeBlock(rgba);
  }
  else if (fourcc == FOURCC_DXT2 || header.pf.fourcc == FOURCC_DXT3) {
    BlockDXT3 block;
    mem_read(stream, block);
    block.decodeBlock(rgba);
  }
  else if (fourcc == FOURCC_DXT4 || header.pf.fourcc == FOURCC_DXT5 ||
           header.pf.fourcc == FOURCC_RXGB) {
    BlockDXT5 block;
    mem_read(stream, block);
    block.decodeBlock(rgba);

    if (fourcc == FOURCC_RXGB) {
      /* Swap R & A. */
      for (int i = 0; i < 16; i++) {
        Color32 &c = rgba->color(i);
        uint tmp = c.r;
        c.r = c.a;
        c.a = tmp;
      }
    }
  }
  else if (fourcc == FOURCC_ATI1) {
    BlockATI1 block;
    mem_read(stream, block);
    block.decodeBlock(rgba);
  }
  else if (fourcc == FOURCC_ATI2) {
    BlockATI2 block;
    mem_read(stream, block);
    block.decodeBlock(rgba);
  }

  /* If normal flag set, convert to normal. */
  if (header.pf.flags & DDPF_NORMAL) {
    if (fourcc == FOURCC_ATI2) {
      for (int i = 0; i < 16; i++) {
        Color32 &c = rgba->color(i);
        c = buildNormal(c.r, c.g);
      }
    }
    else if (fourcc == FOURCC_DXT5) {
      for (int i = 0; i < 16; i++) {
        Color32 &c = rgba->color(i);
        c = buildNormal(c.a, c.g);
      }
    }
  }
}

uint DirectDrawSurface::blockSize() const
{
  switch (header.pf.fourcc) {
    case FOURCC_DXT1:
    case FOURCC_ATI1:
      return 8;
    case FOURCC_DXT2:
    case FOURCC_DXT3:
    case FOURCC_DXT4:
    case FOURCC_DXT5:
    case FOURCC_RXGB:
    case FOURCC_ATI2:
      return 16;
    case FOURCC_DX10:
      switch (header.header10.dxgiFormat) {
        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 8;
        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:
          return 16;
      }
  }

  /* Not a block image. */
  return 0;
}

uint DirectDrawSurface::mipmapSize(uint mipmap) const
{
  uint w = width();
  uint h = height();
  uint d = depth();

  for (uint m = 0; m < mipmap; m++) {
    w = MAX(1U, w / 2);
    h = MAX(1U, h / 2);
    d = MAX(1U, d / 2);
  }

  if (header.pf.flags & DDPF_FOURCC) {
    /* @@ How are 3D textures aligned? */
    w = (w + 3) / 4;
    h = (h + 3) / 4;
    return blockSize() * w * h;
  }
  if (header.pf.flags & DDPF_RGB || (header.pf.flags & DDPF_LUMINANCE)) {
    /* Assuming 8 bit alignment, which is the same D3DX expects. */
    uint pitch = computePitch(w, header.pf.bitcount, 8);

    return pitch * h * d;
  }

  printf("DDS: mipmap format not supported\n");
  return 0;
}

uint DirectDrawSurface::faceSize() const
{
  const uint count = mipmapCount();
  uint size = 0;

  for (uint m = 0; m < count; m++) {
    size += mipmapSize(m);
  }

  return size;
}

uint DirectDrawSurface::offset(const uint face, const uint mipmap)
{
  uint size = 128;  // sizeof(DDSHeader);

  if (header.hasDX10Header()) {
    size += 20;  // sizeof(DDSHeader10);
  }

  if (face != 0) {
    size += face * faceSize();
  }

  for (uint m = 0; m < mipmap; m++) {
    size += mipmapSize(m);
  }

  return size;
}

void DirectDrawSurface::printInfo() const
{
  printf("Flags: 0x%.8X\n", header.flags);
  if (header.flags & DDSD_CAPS) {
    printf("\tDDSD_CAPS\n");
  }
  if (header.flags & DDSD_PIXELFORMAT) {
    printf("\tDDSD_PIXELFORMAT\n");
  }
  if (header.flags & DDSD_WIDTH) {
    printf("\tDDSD_WIDTH\n");
  }
  if (header.flags & DDSD_HEIGHT) {
    printf("\tDDSD_HEIGHT\n");
  }
  if (header.flags & DDSD_DEPTH) {
    printf("\tDDSD_DEPTH\n");
  }
  if (header.flags & DDSD_PITCH) {
    printf("\tDDSD_PITCH\n");
  }
  if (header.flags & DDSD_LINEARSIZE) {
    printf("\tDDSD_LINEARSIZE\n");
  }
  if (header.flags & DDSD_MIPMAPCOUNT) {
    printf("\tDDSD_MIPMAPCOUNT\n");
  }

  printf("Height: %u\n", header.height);
  printf("Width: %u\n", header.width);
  printf("Depth: %u\n", header.depth);
  if (header.flags & DDSD_PITCH) {
    printf("Pitch: %u\n", header.pitch);
  }
  else if (header.flags & DDSD_LINEARSIZE) {
    printf("Linear size: %u\n", header.pitch);
  }
  printf("Mipmap count: %u\n", header.mipmapcount);

  printf("Pixel Format:\n");
  printf("\tFlags: 0x%.8X\n", header.pf.flags);
  if (header.pf.flags & DDPF_RGB) {
    printf("\t\tDDPF_RGB\n");
  }
  if (header.pf.flags & DDPF_LUMINANCE) {
    printf("\t\tDDPF_LUMINANCE\n");
  }
  if (header.pf.flags & DDPF_FOURCC) {
    printf("\t\tDDPF_FOURCC\n");
  }
  if (header.pf.flags & DDPF_ALPHAPIXELS) {
    printf("\t\tDDPF_ALPHAPIXELS\n");
  }
  if (header.pf.flags & DDPF_ALPHA) {
    printf("\t\tDDPF_ALPHA\n");
  }
  if (header.pf.flags & DDPF_PALETTEINDEXED1) {
    printf("\t\tDDPF_PALETTEINDEXED1\n");
  }
  if (header.pf.flags & DDPF_PALETTEINDEXED2) {
    printf("\t\tDDPF_PALETTEINDEXED2\n");
  }
  if (header.pf.flags & DDPF_PALETTEINDEXED4) {
    printf("\t\tDDPF_PALETTEINDEXED4\n");
  }
  if (header.pf.flags & DDPF_PALETTEINDEXED8) {
    printf("\t\tDDPF_PALETTEINDEXED8\n");
  }
  if (header.pf.flags & DDPF_ALPHAPREMULT) {
    printf("\t\tDDPF_ALPHAPREMULT\n");
  }
  if (header.pf.flags & DDPF_NORMAL) {
    printf("\t\tDDPF_NORMAL\n");
  }

  if (header.pf.fourcc != 0) {
    /* Display fourcc code even when DDPF_FOURCC flag not set. */
    printf("\tFourCC: '%c%c%c%c' (0x%.8X)\n",
           (int)((header.pf.fourcc >> 0) & 0xFF),
           (int)((header.pf.fourcc >> 8) & 0xFF),
           (int)((header.pf.fourcc >> 16) & 0xFF),
           (int)((header.pf.fourcc >> 24) & 0xFF),
           header.pf.fourcc);
  }

  if ((header.pf.flags & DDPF_FOURCC) && (header.pf.bitcount != 0)) {
    printf("\tSwizzle: '%c%c%c%c' (0x%.8X)\n",
           (int)(header.pf.bitcount >> 0) & 0xFF,
           (int)(header.pf.bitcount >> 8) & 0xFF,
           (int)(header.pf.bitcount >> 16) & 0xFF,
           (int)(header.pf.bitcount >> 24) & 0xFF,
           header.pf.bitcount);
  }
  else {
    printf("\tBit count: %u\n", header.pf.bitcount);
  }

  printf("\tRed mask: 0x%.8X\n", header.pf.rmask);
  printf("\tGreen mask: 0x%.8X\n", header.pf.gmask);
  printf("\tBlue mask: 0x%.8X\n", header.pf.bmask);
  printf("\tAlpha mask: 0x%.8X\n", header.pf.amask);

  printf("Caps:\n");
  printf("\tCaps 1: 0x%.8X\n", header.caps.caps1);
  if (header.caps.caps1 & DDSCAPS_COMPLEX) {
    printf("\t\tDDSCAPS_COMPLEX\n");
  }
  if (header.caps.caps1 & DDSCAPS_TEXTURE) {
    printf("\t\tDDSCAPS_TEXTURE\n");
  }
  if (header.caps.caps1 & DDSCAPS_MIPMAP) {
    printf("\t\tDDSCAPS_MIPMAP\n");
  }

  printf("\tCaps 2: 0x%.8X\n", header.caps.caps2);
  if (header.caps.caps2 & DDSCAPS2_VOLUME) {
    printf("\t\tDDSCAPS2_VOLUME\n");
  }
  else if (header.caps.caps2 & DDSCAPS2_CUBEMAP) {
    printf("\t\tDDSCAPS2_CUBEMAP\n");
    if ((header.caps.caps2 & DDSCAPS2_CUBEMAP_ALL_FACES) == DDSCAPS2_CUBEMAP_ALL_FACES) {
      printf("\t\tDDSCAPS2_CUBEMAP_ALL_FACES\n");
    }
    else {
      if (header.caps.caps2 & DDSCAPS2_CUBEMAP_POSITIVEX) {
        printf("\t\tDDSCAPS2_CUBEMAP_POSITIVEX\n");
      }
      if (header.caps.caps2 & DDSCAPS2_CUBEMAP_NEGATIVEX) {
        printf("\t\tDDSCAPS2_CUBEMAP_NEGATIVEX\n");
      }
      if (header.caps.caps2 & DDSCAPS2_CUBEMAP_POSITIVEY) {
        printf("\t\tDDSCAPS2_CUBEMAP_POSITIVEY\n");
      }
      if (header.caps.caps2 & DDSCAPS2_CUBEMAP_NEGATIVEY) {
        printf("\t\tDDSCAPS2_CUBEMAP_NEGATIVEY\n");
      }
      if (header.caps.caps2 & DDSCAPS2_CUBEMAP_POSITIVEZ) {
        printf("\t\tDDSCAPS2_CUBEMAP_POSITIVEZ\n");
      }
      if (header.caps.caps2 & DDSCAPS2_CUBEMAP_NEGATIVEZ) {
        printf("\t\tDDSCAPS2_CUBEMAP_NEGATIVEZ\n");
      }
    }
  }

  printf("\tCaps 3: 0x%.8X\n", header.caps.caps3);
  printf("\tCaps 4: 0x%.8X\n", header.caps.caps4);

  if (header.hasDX10Header()) {
    printf("DX10 Header:\n");
    printf("\tDXGI Format: %u (%s)\n",
           header.header10.dxgiFormat,
           getDxgiFormatString((DXGI_FORMAT)header.header10.dxgiFormat));
    printf("\tResource dimension: %u (%s)\n",
           header.header10.resourceDimension,
           getD3d10ResourceDimensionString(
               (D3D10_RESOURCE_DIMENSION)header.header10.resourceDimension));
    printf("\tMisc flag: %u\n", header.header10.miscFlag);
    printf("\tArray size: %u\n", header.header10.arraySize);
  }

  if (header.reserved[9] == FOURCC_NVTT) {
    int major = (header.reserved[10] >> 16) & 0xFF;
    int minor = (header.reserved[10] >> 8) & 0xFF;
    int revision = header.reserved[10] & 0xFF;

    printf("Version:\n");
    printf("\tNVIDIA Texture Tools %d.%d.%d\n", major, minor, revision);
  }

  if (header.reserved[7] == FOURCC_UVER) {
    printf("User Version: %u\n", header.reserved[8]);
  }
}
