texm viewer

2025-06-19 07:59:47 +03:00 · 2024-11-18 23:48:42 +03:00
parent f9f89d9703
commit 08c8d07d91
17 changed files with 403 additions and 227 deletions
--- a/TexmLib/TexmParser.cs
+++ b/TexmLib/TexmParser.cs
@ -0,0 +1,201 @@
+using System.Buffers.Binary;
+using System.Text;
+
+namespace TexmLib;
+
+public class TexmParser
+{
+    public static TexmParseResult ReadFromStream(Stream stream, string file)
+    {
+        if (stream.Length < 32)
+        {
+            return new TexmParseResult(null, "Файл короче 32 байт - точно не текстура");
+        }
+
+        Span<byte> headerBytes = stackalloc byte[32];
+        stream.ReadExactly(headerBytes);
+
+        var texmHeader = headerBytes[0..4];
+
+        var widthBytes = headerBytes[4..8];
+        var heightBytes = headerBytes[8..12];
+        var mipmapCountBytes = headerBytes[12..16];
+        var strideBytes = headerBytes[16..20];
+        var magic1Bytes = headerBytes[20..24];
+        var magic2Bytes = headerBytes[24..28];
+        var formatBytes = headerBytes[28..32];
+
+        var texmAscii = Encoding.ASCII.GetString(texmHeader).Trim('\0');
+        var width = BinaryPrimitives.ReadInt32LittleEndian(widthBytes);
+        var height = BinaryPrimitives.ReadInt32LittleEndian(heightBytes);
+        var mipmapCount = BinaryPrimitives.ReadInt32LittleEndian(mipmapCountBytes);
+        var stride = BinaryPrimitives.ReadInt32LittleEndian(strideBytes);
+        var magic1 = BinaryPrimitives.ReadInt32LittleEndian(magic1Bytes);
+        var magic2 = BinaryPrimitives.ReadInt32LittleEndian(magic2Bytes);
+        var format = BinaryPrimitives.ReadInt32LittleEndian(formatBytes);
+
+        if (texmAscii != "Texm")
+        {
+            return new TexmParseResult(null, "Файл не начинается с Texm");
+        }
+        
+        var textureFile = new TexmFile()
+        {
+            FileName = file
+        };
+
+        var header = new TexmHeader(
+            texmAscii,
+            width,
+            height,
+            mipmapCount,
+            stride,
+            magic1,
+            magic2,
+            format
+        );
+
+        textureFile.Header = header;
+
+        if (format == 0)
+        {
+            // если формат 0, то текстура использует lookup таблицу в первых 1024 байтах (256 разных цветов в формате ARGB 888)
+
+            var lookupColors = new byte[1024];
+            stream.ReadExactly(lookupColors, 0, lookupColors.Length);
+
+            textureFile.LookupColors = lookupColors;
+
+            var mipmapBytesList = ReadMipmapsAsIndexes(
+                stream,
+                mipmapCount,
+                width,
+                height
+            );
+
+            textureFile.MipmapBytes = mipmapBytesList;
+            textureFile.IsIndexed = true;
+        }
+        else
+        {
+            var mipmapBytesList = ReadMipmaps(
+                stream,
+                format.AsStride(),
+                mipmapCount,
+                width,
+                height
+            );
+
+            textureFile.MipmapBytes = mipmapBytesList;
+        }
+
+        if (stream.Position < stream.Length)
+        {
+            // has PAGE data
+            var pageHeader = ReadPage(stream);
+
+            textureFile.Pages = pageHeader;
+        }
+
+        return new TexmParseResult(textureFile);
+    }
+
+    private static PageHeader ReadPage(Stream stream)
+    {
+        Span<byte> pageBytes = stackalloc byte[4];
+
+        stream.ReadExactly(pageBytes);
+
+        var pageHeaderAscii = Encoding.ASCII.GetString(pageBytes);
+
+        stream.ReadExactly(pageBytes);
+
+        var pageCount = BinaryPrimitives.ReadInt32LittleEndian(pageBytes);
+
+        List<PageItem> pageItems = [];
+
+        Span<byte> itemBytes = stackalloc byte[2];
+        for (int i = 0; i < pageCount; i++)
+        {
+            stream.ReadExactly(itemBytes);
+            var x = BinaryPrimitives.ReadInt16LittleEndian(itemBytes);
+            stream.ReadExactly(itemBytes);
+            var pageWidth = BinaryPrimitives.ReadInt16LittleEndian(itemBytes);
+            stream.ReadExactly(itemBytes);
+            var y = BinaryPrimitives.ReadInt16LittleEndian(itemBytes);
+            stream.ReadExactly(itemBytes);
+            var pageHeight = BinaryPrimitives.ReadInt16LittleEndian(itemBytes);
+
+            pageItems.Add(
+                new PageItem(
+                    x,
+                    pageWidth,
+                    y,
+                    pageHeight
+                )
+            );
+        }
+
+        var pageHeader = new PageHeader(pageHeaderAscii, pageCount, pageItems);
+        return pageHeader;
+    }
+
+    private static List<byte[]> ReadMipmaps(Stream stream, int stride, int mipmapCount, int topWidth, int topHeight)
+    {
+        if (stride == 0)
+        {
+            stride = 16;
+        }
+
+        List<int> mipmapByteLengths = [];
+
+        for (int i = 0; i < mipmapCount; i++)
+        {
+            var mipWidth = topWidth / (int) Math.Pow(2, i);
+            var mipHeight = topHeight / (int) Math.Pow(2, i);
+
+            var imageByteLength = mipWidth * mipHeight * (stride / 8);
+            mipmapByteLengths.Add(imageByteLength);
+        }
+
+        List<byte[]> mipmapBytesList = [];
+
+        foreach (var mipmapByteLength in mipmapByteLengths)
+        {
+            var mipmapBuffer = new byte[mipmapByteLength];
+
+            stream.ReadExactly(mipmapBuffer, 0, mipmapByteLength);
+
+            mipmapBytesList.Add(mipmapBuffer);
+        }
+
+        return mipmapBytesList;
+    }
+
+    private static List<byte[]> ReadMipmapsAsIndexes(Stream stream, int mipmapCount, int topWidth, int topHeight)
+    {
+        List<int> mipmapByteLengths = [];
+
+        for (int i = 0; i < mipmapCount; i++)
+        {
+            var mipWidth = topWidth / (int) Math.Pow(2, i);
+            var mipHeight = topHeight / (int) Math.Pow(2, i);
+
+            var imageByteLength = mipWidth * mipHeight;
+            mipmapByteLengths.Add(imageByteLength);
+        }
+
+        List<byte[]> mipmapBytesList = [];
+
+        foreach (var mipmapByteLength in mipmapByteLengths)
+        {
+            var mipmapBuffer = new byte[mipmapByteLength];
+
+            stream.ReadExactly(mipmapBuffer, 0, mipmapByteLength);
+
+            mipmapBytesList.Add(mipmapBuffer);
+        }
+
+        return mipmapBytesList;
+    }
+}