Starting to move data loader to its own package

Signed-off-by: Hans Kokx <hans.d.kokx@gmail.com>

packages/wolf_3d_data/lib/src/classes/level.dart

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+import 'matrix.dart';
+
+typedef Level = Matrix<int>;

packages/wolf_3d_data/lib/src/classes/matrix.dart

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+typedef Matrix<T> = List<List<T>>;

packages/wolf_3d_data/lib/src/classes/sprite.dart

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+import 'matrix.dart';
+
+typedef Sprite = Matrix<int>;

packages/wolf_3d_data/lib/src/vswap_parser.dart

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+import 'dart:typed_data';
+
+import 'classes/sprite.dart';
+
+class VswapParser {
+  /// Extracts the 64x64 wall textures from VSWAP.WL1
+  static List<Sprite> parseWalls(ByteData vswap) {
+    // 1. Read Header
+    int chunks = vswap.getUint16(0, Endian.little);
+    int spriteStart = vswap.getUint16(2, Endian.little);
+    // int soundStart = vswap.getUint16(4, Endian.little); // We don't need this yet
+
+    // 2. Read Offsets (Where does each chunk start in the file?)
+    List<int> offsets = [];
+    for (int i = 0; i < spriteStart; i++) {
+      offsets.add(vswap.getUint32(6 + (i * 4), Endian.little));
+    }
+
+    // 3. Extract the Wall Textures
+    List<Sprite> textures = [];
+
+    // Walls are chunks 0 through (spriteStart - 1)
+    for (int i = 0; i < spriteStart; i++) {
+      int offset = offsets[i];
+      if (offset == 0) continue; // Empty chunk
+
+      // Walls are always exactly 64x64 pixels (4096 bytes)
+      // Note: Wolf3D stores pixels in COLUMN-MAJOR order (Top to bottom, then left to right)
+      Sprite texture = List.generate(64, (_) => List.filled(64, 0));
+
+      for (int x = 0; x < 64; x++) {
+        for (int y = 0; y < 64; y++) {
+          int byteIndex = offset + (x * 64) + y;
+          texture[x][y] = vswap.getUint8(byteIndex);
+        }
+      }
+      textures.add(texture);
+    }
+
+    return textures;
+  }
+
+  /// Extracts the compiled scaled sprites from VSWAP.WL1
+  static List<Sprite> parseSprites(ByteData vswap) {
+    int chunks = vswap.getUint16(0, Endian.little);
+    int spriteStart = vswap.getUint16(2, Endian.little);
+    int soundStart = vswap.getUint16(4, Endian.little);
+
+    List<int> offsets = [];
+    for (int i = 0; i < chunks; i++) {
+      offsets.add(vswap.getUint32(6 + (i * 4), Endian.little));
+    }
+
+    List<Sprite> sprites = [];
+
+    // Sprites are located between the walls and the sounds
+    for (int i = spriteStart; i < soundStart; i++) {
+      int offset = offsets[i];
+      if (offset == 0) continue; // Some chunks are empty placeholders
+
+      // Initialize the 64x64 grid with 255 (The Magenta Transparency Color!)
+      Sprite sprite = List.generate(64, (_) => List.filled(64, 255));
+
+      int leftPix = vswap.getUint16(offset, Endian.little);
+      int rightPix = vswap.getUint16(offset + 2, Endian.little);
+
+      // Read the offsets for each vertical column of the sprite
+      List<int> colOffsets = [];
+      for (int x = leftPix; x <= rightPix; x++) {
+        colOffsets.add(
+          vswap.getUint16(offset + 4 + ((x - leftPix) * 2), Endian.little),
+        );
+      }
+
+      for (int x = leftPix; x <= rightPix; x++) {
+        int colOffset = colOffsets[x - leftPix];
+        if (colOffset == 0) continue;
+
+        int cmdOffset = offset + colOffset;
+
+        // Execute the column drawing commands
+        while (true) {
+          int endY = vswap.getUint16(cmdOffset, Endian.little);
+          if (endY == 0) break; // 0 marks the end of the column
+          endY ~/= 2; // Wolf3D stores Y coordinates multiplied by 2
+
+          int pixelOfs = vswap.getUint16(cmdOffset + 2, Endian.little);
+
+          int startY = vswap.getUint16(cmdOffset + 4, Endian.little);
+          startY ~/= 2;
+
+          for (int y = startY; y < endY; y++) {
+            // The Carmack 286 Hack: pixelOfs + y gives the exact byte address!
+            sprite[x][y] = vswap.getUint8(offset + pixelOfs + y);
+          }
+          cmdOffset += 6; // Move to the next 6-byte instruction
+        }
+      }
+      sprites.add(sprite);
+    }
+    return sprites;
+  }
+
+  /// Extracts digitized sound effects (PCM Audio) from VSWAP.WL1
+  static List<Uint8List> parseSounds(ByteData vswap) {
+    int chunks = vswap.getUint16(0, Endian.little);
+    int soundStart = vswap.getUint16(4, Endian.little);
+
+    List<int> offsets = [];
+    List<int> lengths = [];
+
+    // Offsets are 32-bit integers starting at byte 6
+    for (int i = 0; i < chunks; i++) {
+      offsets.add(vswap.getUint32(6 + (i * 4), Endian.little));
+    }
+
+    // Lengths are 16-bit integers immediately following the offset array
+    int lengthStart = 6 + (chunks * 4);
+    for (int i = 0; i < chunks; i++) {
+      lengths.add(vswap.getUint16(lengthStart + (i * 2), Endian.little));
+    }
+
+    List<Uint8List> sounds = [];
+
+    // Sounds start after the sprites and go to the end of the chunks
+    for (int i = soundStart; i < chunks; i++) {
+      int offset = offsets[i];
+      int length = lengths[i];
+
+      if (offset == 0 || length == 0) {
+        sounds.add(Uint8List(0)); // Empty placeholder
+        continue;
+      }
+
+      // Extract the raw 8-bit PCM audio bytes
+      final soundData = vswap.buffer.asUint8List(offset, length);
+      sounds.add(soundData);
+    }
+
+    return sounds;
+  }
+}

packages/wolf_3d_data/lib/wolf_3d_data.dart

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+/// Support for doing something awesome.
+///
+/// More dartdocs go here.
+library;
+
+export 'src/classes/level.dart' show Level;
+export 'src/classes/sprite.dart' show Sprite;
+export 'src/vswap_parser.dart' show VswapParser;