SpaceEngineersBlueprintEditorInWinUI

namespace SpaceEngineersBlueprintEditor.SpaceEngineersCore;

using SpaceEngineersBlueprintEditor.SpaceEngineersCore.InnerModel;
using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Runtime.InteropServices;

public static class ImageConverter
{
    #region InnerClasses
    [Flags]
    internal enum PixelFormatFlags
    {
        FourCC = 0x00000004, // DDPF_FOURCC
        Rgb = 0x00000040, // DDPF_RGB
        Rgba = 0x00000041, // DDPF_RGB | DDPF_ALPHAPIXELS
        Luminance = 0x00020000, // DDPF_LUMINANCE
        LuminanceAlpha = 0x00020001, // DDPF_LUMINANCE | DDPF_ALPHAPIXELS
        Alpha = 0x00000002, // DDPF_ALPHA
        Pal8 = 0x00000020, // DDPF_PALETTEINDEXED8            
    }

    [Flags]
    internal enum DDSCAPS2 : uint
    {
        DDSCAPS2_CUBEMAP = 0x200,
        DDSCAPS2_CUBEMAP_POSITIVEX = 0x400,
        DDSCAPS2_CUBEMAP_NEGATIVEX = 0x800,
        DDSCAPS2_CUBEMAP_POSITIVEY = 0x1000,
        DDSCAPS2_CUBEMAP_NEGATIVEY = 0x2000,
        DDSCAPS2_CUBEMAP_POSITIVEZ = 0x4000,
        DDSCAPS2_CUBEMAP_NEGATIVEZ = 0x8000,
        DDSCAPS2_VOLUME = 0x200000,
    }

    internal enum DDS_FOURCC : uint
    {
        DXT1 = 0x31545844,
        DXT3 = 0x33545844,
        DXT5 = 0x35545844,
        BC4U = 0x55344342,
        BC4S = 0x53344342,
        ATI2 = 0x32495441,
        BC5S = 0x53354342,
        RGBG = 0x47424752,
        GRGB = 0x42475247,
        DXT2 = 0x32545844,
        DXT4 = 0x34545844,
        UYVY = 0x59565955,
        YUY2 = 0x32595559,
        DX10 = 0x30315844,
    };

    internal enum DXGI_FORMAT : uint
    {
        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,
        DXGI_FORMAT_AYUV = 100,
        DXGI_FORMAT_Y410 = 101,
        DXGI_FORMAT_Y416 = 102,
        DXGI_FORMAT_NV12 = 103,
        DXGI_FORMAT_P010 = 104,
        DXGI_FORMAT_P016 = 105,
        DXGI_FORMAT_420_OPAQUE = 106,
        DXGI_FORMAT_YUY2 = 107,
        DXGI_FORMAT_Y210 = 108,
        DXGI_FORMAT_Y216 = 109,
        DXGI_FORMAT_NV11 = 110,
        DXGI_FORMAT_AI44 = 111,
        DXGI_FORMAT_IA44 = 112,
        DXGI_FORMAT_P8 = 113,
        DXGI_FORMAT_A8P8 = 114,
        DXGI_FORMAT_B4G4R4A4_UNORM = 115,
    };

    internal enum D3D10_RESOURCE_DIMENSION : uint
    {
        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
    };

    [StructLayout(LayoutKind.Sequential)]
    internal struct DDS_PIXELFORMAT
    {
        internal uint dwSize;
        internal uint dwFlags;
        internal uint dwFourCC;
        internal uint dwRGBBitCount;
        internal uint dwRBitMask;
        internal uint dwGBitMask;
        internal uint dwBBitMask;
        internal uint dwABitMask;
    };

    [StructLayout(LayoutKind.Sequential)]
    internal unsafe struct DDS_HEADER
    {
        internal uint dwSize;
        internal uint dwFlags;
        internal uint dwHeight;
        internal uint dwWidth;
        internal uint dwPitchOrLinearSize;
        internal uint dwDepth;
        internal uint dwMipMapCount;
        internal fixed uint dwReserved1[11];
        internal DDS_PIXELFORMAT ddspf;
        internal uint dwCaps;
        internal uint dwCaps2;
        internal uint dwCaps3;
        internal uint dwCaps4;
        internal uint dwReserved2;
        public static readonly int SizeInBytes = Marshal.SizeOf(typeof(DDS_HEADER));
    };

    [StructLayout(LayoutKind.Sequential)]
    internal struct DDS_HEADER_DXT10
    {
        internal DXGI_FORMAT dxgiFormat;
        internal D3D10_RESOURCE_DIMENSION resourceDimension;
        internal uint miscFlag;
        internal uint arraySize;
        internal uint miscFlags2;
        public static readonly int SizeInBytes = Marshal.SizeOf(typeof(DDS_HEADER_DXT10));
    };
    #endregion

    private static T MarshalTo<T>(byte[] buffer)
    {
        IntPtr intPtr = Marshal.AllocHGlobal(buffer.Length);
        Marshal.Copy(buffer, 0, intPtr, buffer.Length);
        var record = (T)Marshal.PtrToStructure(intPtr, typeof(T));
        Marshal.FreeHGlobal(intPtr);
        return record;
    }

    public static byte[]? TextureToRgbaBuffer(Stream stream, int depth, ref int width, ref int height, bool ignoreAlpha = false)
    {
        var pixelBuffer = ReadTextureFile(stream, depth, ref width, ref height, out var fourCC, out var dxgiFormat);
        if (pixelBuffer == null)
            return null;
        try
        {
            using var imageStream = new MemoryStream(pixelBuffer);
            byte[] pixelColors = fourCC switch
            {
                (uint)DDS_FOURCC.DXT1 => DxtUtil.DecompressDxt1(imageStream, width, height),
                (uint)DDS_FOURCC.DXT3 => DxtUtil.DecompressDxt3(imageStream, width, height),
                _ => DxtUtil.DecompressDxt5(imageStream, width, height, dxgiFormat),
            };
            var pixelRgba = new byte[pixelColors.Length];
            for (var i = 0; i < pixelColors.Length; i += 4)
            {
                pixelRgba[i + 0] = pixelColors[i + 2];
                pixelRgba[i + 1] = pixelColors[i + 1];
                pixelRgba[i + 2] = pixelColors[i + 0];
                pixelRgba[i + 3] = ignoreAlpha ? (byte)0xff : pixelColors[i + 3];
            }
            return pixelRgba;
        }
        catch
        {
            return null;
        }
    }

    private static byte[]? ReadTextureFile(Stream stream, int depth, ref int width, ref int height, out uint fourCC, out DXGI_FORMAT dxgiFormat)
    {
        dxgiFormat = DXGI_FORMAT.DXGI_FORMAT_UNKNOWN;
        fourCC = 0;
        if (stream is null)
            return null;
        var reader = new BinaryReader(stream);
        try
        {
            var magicNumber = reader.ReadUInt32();
            if (magicNumber != 0x20534444)
            {
                fourCC = 0;
                return null;
            }
            var header = MarshalTo<DDS_HEADER>(reader.ReadBytes(DDS_HEADER.SizeInBytes));
            fourCC = header.ddspf.dwFourCC;
            var slices = 1;
            if (((DDSCAPS2)header.dwCaps2 & DDSCAPS2.DDSCAPS2_CUBEMAP) != 0)
                slices = 6;
            uint bytesPerPixel = header.dwPitchOrLinearSize / (header.dwWidth * header.dwHeight);
            var c = header.dwCaps2;
            var mipCount = (int)header.dwMipMapCount;
            if (mipCount == 0)
                mipCount = 1;
            if (header.ddspf.dwFlags == (uint)PixelFormatFlags.FourCC && fourCC == (uint)DDS_FOURCC.DX10)
            {
                DDS_HEADER_DXT10 dx10Header = MarshalTo<DDS_HEADER_DXT10>(reader.ReadBytes(DDS_HEADER_DXT10.SizeInBytes));
                dxgiFormat = dx10Header.dxgiFormat;

                uint dwPitchOrLinearSize;
                switch (dx10Header.dxgiFormat)
                {
                    case DXGI_FORMAT.DXGI_FORMAT_BC1_TYPELESS:
                    case DXGI_FORMAT.DXGI_FORMAT_BC1_UNORM:
                    case DXGI_FORMAT.DXGI_FORMAT_BC1_UNORM_SRGB:
                    case DXGI_FORMAT.DXGI_FORMAT_BC2_TYPELESS:
                    case DXGI_FORMAT.DXGI_FORMAT_BC2_UNORM:
                    case DXGI_FORMAT.DXGI_FORMAT_BC2_UNORM_SRGB:
                    case DXGI_FORMAT.DXGI_FORMAT_BC3_TYPELESS:
                    case DXGI_FORMAT.DXGI_FORMAT_BC3_UNORM:
                    case DXGI_FORMAT.DXGI_FORMAT_BC3_UNORM_SRGB:
                    case DXGI_FORMAT.DXGI_FORMAT_BC4_TYPELESS:
                    case DXGI_FORMAT.DXGI_FORMAT_BC4_UNORM:
                    case DXGI_FORMAT.DXGI_FORMAT_BC4_SNORM:
                    case DXGI_FORMAT.DXGI_FORMAT_BC5_TYPELESS:
                    case DXGI_FORMAT.DXGI_FORMAT_BC5_UNORM:
                    case DXGI_FORMAT.DXGI_FORMAT_BC5_SNORM:
                    case DXGI_FORMAT.DXGI_FORMAT_BC6H_TYPELESS:
                    case DXGI_FORMAT.DXGI_FORMAT_BC6H_UF16:
                    case DXGI_FORMAT.DXGI_FORMAT_BC6H_SF16:
                    case DXGI_FORMAT.DXGI_FORMAT_BC7_TYPELESS:
                    case DXGI_FORMAT.DXGI_FORMAT_BC7_UNORM:
                    case DXGI_FORMAT.DXGI_FORMAT_BC7_UNORM_SRGB:
                        uint blockSize = 8;
                        dwPitchOrLinearSize = Math.Max(1, ((header.dwWidth + 3) / 4)) * blockSize;
                        break;
                    case DXGI_FORMAT.DXGI_FORMAT_R8G8_B8G8_UNORM:
                    case DXGI_FORMAT.DXGI_FORMAT_G8R8_G8B8_UNORM:
                        dwPitchOrLinearSize = ((header.dwWidth + 1) >> 1) * 4;
                        break;
                    default:
                        bytesPerPixel = header.ddspf.dwSize;
                        dwPitchOrLinearSize = (header.dwWidth * bytesPerPixel + 7) / 8;
                        break;
                }
            }
            if (bytesPerPixel == 0)
            {
                width = (int)header.dwWidth;
                height = (int)header.dwHeight;
                int size = (int)(reader.BaseStream.Length - reader.BaseStream.Position);
                return reader.ReadBytes(size);
            }
            for (var slice = 0; slice < slices; slice++)
            {
                uint w = header.dwWidth == 0 ? 1 : header.dwWidth;
                uint h = header.dwHeight == 0 ? 1 : header.dwHeight;
                for (var map = 0; map < mipCount; map++)
                {
                    var size = (int)(bytesPerPixel * w * h);
                    if (depth == slice && ((width <= 0 && height <= 0) || (w == width && h == height)))
                    {
                        width = (int)w;
                        height = (int)h;
                        return reader.ReadBytes(size);
                    }
                    else
                    {
                        if (stream.CanSeek)
                            reader.BaseStream.Seek(size, SeekOrigin.Current);
                        else
                            for (int i = 0; i < size; i++)
                                reader.BaseStream.ReadByte();
                    }
                    w >>= 1;
                    h >>= 1;
                    if (w == 0) w = 1;
                    if (h == 0) h = 1;
                }
                reader.BaseStream.Seek(27, SeekOrigin.Current);
            }
            return null;
        }
        catch
        {
            fourCC = 0;
            return null;
        }
    }
}