Working on fixing enemy identification

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

packages/wolf_3d_data/lib/src/wl_parser.dart

@@ -0,0 +1,130 @@
+import 'dart:typed_data';
+
+import 'classes/sprite.dart';
+
+class WLParser {
+  /// Extracts the 64x64 wall textures from VSWAP.WL1
+  static List<Sprite> parseWalls(ByteData vswap) {
+    final header = _VswapHeader(vswap);
+
+    return header.offsets
+        .take(header.spriteStart)
+        .where((offset) => offset != 0) // Skip empty chunks
+        .map((offset) => _parseWallChunk(vswap, offset))
+        .toList();
+  }
+
+  /// Extracts the compiled scaled sprites from VSWAP.WL1
+  static List<Sprite> parseSprites(ByteData vswap) {
+    final header = _VswapHeader(vswap);
+    final sprites = <Sprite>[];
+
+    // Sprites are located between the walls and the sounds
+    for (int i = header.spriteStart; i < header.soundStart; i++) {
+      int offset = header.offsets[i];
+      if (offset != 0) {
+        sprites.add(_parseSingleSprite(vswap, offset));
+      }
+    }
+
+    return sprites;
+  }
+
+  /// Extracts digitized sound effects (PCM Audio) from VSWAP.WL1
+  static List<Uint8List> parseSounds(ByteData vswap) {
+    final header = _VswapHeader(vswap);
+    final lengthStart = 6 + (header.chunks * 4);
+    final sounds = <Uint8List>[];
+
+    // Sounds start after the sprites and go to the end of the chunks
+    for (int i = header.soundStart; i < header.chunks; i++) {
+      int offset = header.offsets[i];
+      int length = vswap.getUint16(lengthStart + (i * 2), Endian.little);
+
+      if (offset == 0 || length == 0) {
+        sounds.add(Uint8List(0)); // Empty placeholder
+      } else {
+        // Extract the raw 8-bit PCM audio bytes
+        sounds.add(vswap.buffer.asUint8List(offset, length));
+      }
+    }
+
+    return sounds;
+  }
+
+  // --- Private Helpers ---
+
+  static Sprite _parseWallChunk(ByteData vswap, int offset) {
+    // Generate the 64x64 pixel grid in column-major order functionally
+    return List.generate(
+      64,
+      (x) => List.generate(64, (y) => vswap.getUint8(offset + (x * 64) + y)),
+    );
+  }
+
+  static Sprite _parseSingleSprite(ByteData vswap, int offset) {
+    // 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);
+
+    // Parse vertical columns within the sprite bounds
+    for (int x = leftPix; x <= rightPix; x++) {
+      int colOffset = vswap.getUint16(
+        offset + 4 + ((x - leftPix) * 2),
+        Endian.little,
+      );
+
+      if (colOffset != 0) {
+        _parseSpriteColumn(vswap, sprite, x, offset, offset + colOffset);
+      }
+    }
+
+    return sprite;
+  }
+
+  static void _parseSpriteColumn(
+    ByteData vswap,
+    Sprite sprite,
+    int x,
+    int baseOffset,
+    int cmdOffset,
+  ) {
+    // 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(baseOffset + pixelOfs + y);
+      }
+
+      cmdOffset += 6; // Move to the next 6-byte instruction
+    }
+  }
+}
+
+/// Helper class to parse and store redundant VSWAP header data
+class _VswapHeader {
+  final int chunks;
+  final int spriteStart;
+  final int soundStart;
+  final List<int> offsets;
+
+  _VswapHeader(ByteData vswap)
+    : chunks = vswap.getUint16(0, Endian.little),
+      spriteStart = vswap.getUint16(2, Endian.little),
+      soundStart = vswap.getUint16(4, Endian.little),
+      offsets = List.generate(
+        vswap.getUint16(0, Endian.little), // total chunks
+        (i) => vswap.getUint32(6 + (i * 4), Endian.little),
+      );
+}