Starting to move data loader to its own package

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

packages/wolf_3d_data/.gitignore

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+# https://dart.dev/guides/libraries/private-files
+# Created by `dart pub`
+.dart_tool/
+
+# Avoid committing pubspec.lock for library packages; see
+# https://dart.dev/guides/libraries/private-files#pubspeclock.
+pubspec.lock

packages/wolf_3d_data/CHANGELOG.md

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+## 1.0.0
+
+- Initial version.

packages/wolf_3d_data/README.md

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+<!-- 
+This README describes the package. If you publish this package to pub.dev,
+this README's contents appear on the landing page for your package.
+
+For information about how to write a good package README, see the guide for
+[writing package pages](https://dart.dev/tools/pub/writing-package-pages). 
+
+For general information about developing packages, see the Dart guide for
+[creating packages](https://dart.dev/guides/libraries/create-packages)
+and the Flutter guide for
+[developing packages and plugins](https://flutter.dev/to/develop-packages). 
+-->
+
+TODO: Put a short description of the package here that helps potential users
+know whether this package might be useful for them.
+
+## Features
+
+TODO: List what your package can do. Maybe include images, gifs, or videos.
+
+## Getting started
+
+TODO: List prerequisites and provide or point to information on how to
+start using the package.
+
+## Usage
+
+TODO: Include short and useful examples for package users. Add longer examples
+to `/example` folder. 
+
+```dart
+const like = 'sample';
+```
+
+## Additional information
+
+TODO: Tell users more about the package: where to find more information, how to 
+contribute to the package, how to file issues, what response they can expect 
+from the package authors, and more.

packages/wolf_3d_data/analysis_options.yaml

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+# This file configures the static analysis results for your project (errors,
+# warnings, and lints).
+#
+# This enables the 'recommended' set of lints from `package:lints`.
+# This set helps identify many issues that may lead to problems when running
+# or consuming Dart code, and enforces writing Dart using a single, idiomatic
+# style and format.
+#
+# If you want a smaller set of lints you can change this to specify
+# 'package:lints/core.yaml'. These are just the most critical lints
+# (the recommended set includes the core lints).
+# The core lints are also what is used by pub.dev for scoring packages.
+
+include: package:lints/recommended.yaml
+
+# Uncomment the following section to specify additional rules.
+
+# linter:
+#   rules:
+#     - camel_case_types
+
+# analyzer:
+#   exclude:
+#     - path/to/excluded/files/**
+
+# For more information about the core and recommended set of lints, see
+# https://dart.dev/go/core-lints
+
+# For additional information about configuring this file, see
+# https://dart.dev/guides/language/analysis-options

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;

packages/wolf_3d_data/pubspec.yaml

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+name: wolf_3d_data
+description: A starting point for Dart libraries or applications.
+version: 1.0.0
+# repository: https://github.com/my_org/my_repo
+
+environment:
+  sdk: ^3.11.1
+
+resolution: workspace
+
+dev_dependencies:
+  lints: ^6.0.0
+  test: ^1.25.6