Tools for Extracting Terraria 1.4 Tmod.

Extract-TMOD.cs

using System.IO.Compression;
using System.Text;
using System.Security.Cryptography;
using Microsoft.Xna.Framework.Graphics;

class Program {

    static void Main( string[] _ ) => new Program().MainProc();

    private void MainProc() {
        var outRootDirectory = @"C:\Temp";

        var tmodFiles = new string[] {
            @"C:\Program Files (x86)\Steam\steamapps\workshop\content\1281930\2824688072\2022.6\CalamityMod.tmod",
            //@"C:\Program Files (x86)\Steam\steamapps\workshop\content\1281930\2824688266\2022.6\CalamityModMusic.tmod",
            //@"C:\Program Files (x86)\Steam\steamapps\workshop\content\1281930\2563309347\2022.7\MagicStorage.tmod",
            //@"C:\Program Files (x86)\Steam\steamapps\workshop\content\1281930\2563851005\2022.6\WMITF.tmod",
            //@"C:\Program Files (x86)\Steam\steamapps\workshop\content\1281930\2565540604\2022.7\AutoTrash.tmod",
        };

        foreach( var tmodFile in tmodFiles ) {
            this.ExtractTmod( tmodFile, outRootDirectory );
        }
    }

    private void ExtractTmod( string tmodFile, string outRootDirectory ) {

        using var stream = File.OpenRead( tmodFile );
        using var reader = new BinaryReader( stream );

        if( Encoding.ASCII.GetString( reader.ReadBytes( 4 ) ) != "TMOD" ) {
            throw new Exception( "Magic Header != \"TMOD\"" );
        }
        var ModLoaderVersion = new Version( reader.ReadString() );
        var hash = reader.ReadBytes( 20 );
        var Signature = reader.ReadBytes( 256 );
        reader.ReadInt32();

        var pos = stream.Position;
        if( !SHA1.Create().ComputeHash( stream ).SequenceEqual( hash ) ) {
            throw new Exception( "ModLoader Load Error : Hash Mismatch Corrupted" );
        }
        stream.Position = pos;

        var modName = reader.ReadString();
        var modVersion = new Version( reader.ReadString() );
        var fileCount = reader.ReadInt32();

        Console.WriteLine( $"modName: {modName}\nmodVersion: {modVersion}\nfileCount: {fileCount}" );

        var outTopDirectory = Path.Combine( outRootDirectory, Path.GetFileNameWithoutExtension( tmodFile ) );

        var files = new List<(string Name, int Offset, int Length, int CompressedLength)>();

        var offset = 0;
        for( int i = 0; i < fileCount; i++ ) {
            var name = reader.ReadString();
            var length = reader.ReadInt32();
            var compressedLength = reader.ReadInt32();
            files.Add( (name, offset, length, compressedLength) );
            offset += compressedLength;
        }

        var dataStartPos = (int)stream.Position;
        for( var i = 0; i < files.Count; i++ ) {
            var f = files[i];
            var dataOffset = f.Offset + dataStartPos;

            Console.WriteLine( $"[{i,4}] {f.Name}" );

            byte[] data;
            if( f.Length != f.CompressedLength ) {
                //圧縮されている
                data = new byte[f.CompressedLength];
                stream.Position = dataOffset;
                stream.Read( data, 0, data.Length );

                using var ms = new MemoryStream( data );
                using var ds = new DeflateStream( ms, CompressionMode.Decompress );
                using var decompressMs = new MemoryStream();

                ds.CopyTo( decompressMs );
                decompressMs.Position = 0;

                data = decompressMs.ToArray();
            }
            else {
                //圧縮されていない
                data = new byte[f.Length];
                stream.Position = dataOffset;
                stream.Read( data, 0, data.Length );
            }

            var outFile = Path.Combine( outTopDirectory, f.Name );
            var outDirectory = Path.GetDirectoryName( outFile );
            Directory.CreateDirectory( outDirectory );

            using var outStream = new FileStream( outFile, FileMode.OpenOrCreate, FileAccess.Write );
            using var outWriter = new BinaryWriter( outStream );
            outWriter.Write( data );

            if( outFile.EndsWith( ".rawimg" ) ) {
                var imgFile = Path.ChangeExtension( outFile, ".png" );
                this.SaveAsPng( data, imgFile );
            }
        }
    }

    /// <summary>
    /// save .rawimg file to PNG.
    /// </summary>
    /// <param name="data">.rawimg binary data</param>
    /// <param name="pngFile">PNG filename</param>
    /// <remarks>require FNA.dll, FNA3D.dll & SDL2.dll.</remarks>
    private unsafe void SaveAsPng( byte[] data, string pngFile ) {
        using var ms = new MemoryStream( data );
        using var reader = new BinaryReader( ms );

        var formatVersion = reader.ReadInt32();
        if( formatVersion != 1 ) {
            throw new Exception( "Unknown RawImg Format Version: " + formatVersion );
        }
        var width = reader.ReadInt32();
        var height = reader.ReadInt32();
        var imgData = reader.ReadBytes( width * height * 4 );

        fixed( byte* pixels = &imgData[0] ) {
            using var outStream = new FileStream( pngFile, FileMode.Create );
            FNA3D.WritePNGStream( outStream, width, height, width, height, (IntPtr)((void*)pixels) );
        }
        imgData = null;
    }
}