parse PAL file

PalLib/PalFile.cs

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+using SixLabors.ImageSharp;
+using SixLabors.ImageSharp.PixelFormats;
+
+namespace PalLib;
+
+/// <summary>
+/// PAL файл по сути это indexed текстура (1024 байт - 256 цветов lookup + 4 байта "Ipol" и затем 256x256 индексов в lookup)
+/// </summary>
+public class PalFile
+{
+    public required string FileName { get; set; }
+    
+    /// <summary>
+    /// 256 цветов lookup (1024 байт)
+    /// </summary>
+    public required byte[] Palette { get; set; }
+    
+    /// <summary>
+    /// 256x256 индексов в lookup
+    /// </summary>
+    public required byte[] Indices { get; set; }
+
+    public void SaveAsPng(string outputPath)
+    {
+        const int width = 256;
+        const int height = 256;
+
+        var rgbaBytes = new byte[width * height * 4];
+
+        for (int i = 0; i < Indices.Length; i++)
+        {
+            var index = Indices[i];
+            
+            // Palette is 256 colors * 4 bytes (ARGB usually, based on TexmLib)
+            // TexmLib: r = lookup[i*4+0], g = lookup[i*4+1], b = lookup[i*4+2], a = lookup[i*4+3]
+            // Assuming same format here.
+            
+            // since PAL is likely directx related, the format is is likely BGRA
+
+            var b = Palette[index * 4 + 0];
+            var g = Palette[index * 4 + 1];
+            var r = Palette[index * 4 + 2];
+            var a = Palette[index * 4 + 3]; // Alpha? Or is it unused/padding? TexmLib sets alpha to 255 manually for indexed.
+
+            rgbaBytes[i * 4 + 0] = r;
+            rgbaBytes[i * 4 + 1] = g;
+            rgbaBytes[i * 4 + 2] = b;
+            rgbaBytes[i * 4 + 3] = 255; 
+        }
+
+        using var image = Image.LoadPixelData<Rgba32>(rgbaBytes, width, height);
+        image.SaveAsPng(outputPath);
+    }
+}

PalLib/PalLib.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+
+    <ItemGroup>
+        <PackageReference Include="SixLabors.ImageSharp"/>
+    </ItemGroup>
+
+</Project>

PalLib/PalParser.cs

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+using System.Text;
+
+namespace PalLib;
+
+public class PalParser
+{
+    public static PalFile ReadFromStream(Stream stream, string filename)
+    {
+        // Expected size: 1024 (palette) + 4 ("Ipol") + 65536 (indices) = 66564
+        if (stream.Length != 66564)
+        {
+            throw new InvalidDataException($"Invalid PAL file size. Expected 66564 bytes, got {stream.Length}.");
+        }
+
+        var palette = new byte[1024];
+        stream.ReadExactly(palette, 0, 1024);
+
+        var signatureBytes = new byte[4];
+        stream.ReadExactly(signatureBytes, 0, 4);
+        var signature = Encoding.ASCII.GetString(signatureBytes);
+
+        if (signature != "Ipol")
+        {
+            throw new InvalidDataException($"Invalid PAL file signature. Expected 'Ipol', got '{signature}'.");
+        }
+
+        var indices = new byte[65536];
+        stream.ReadExactly(indices, 0, 65536);
+
+        return new PalFile
+        {
+            FileName = filename,
+            Palette = palette,
+            Indices = indices
+        };
+    }
+}