Developing a chess plugin for Manim!

codevardhan | Dec 10, 2024 min read
Developing a chess plugin for Manim!

Introduction

I first came across Manim while watching 3blue1brown His videos were really helpful to help understand some of the key concepts behind machine learning, statistics and the like. The animation engine he uses is also striking, or rather, the way his animations subtly help him explain vivid concepts really stuck with me. I came across a community managed version of his package here: Manim.

While working with Manim is rewarding, the framework’s steep learning curve and its general-purpose nature can make implementing specific use cases challenging. One such niche is animating chess games—an endeavor that led to the creation of the Manim Chess Plugin

This article explores the journey of developing the Manim Chess Plugin, the challenges faced, and how it serves as both a tool and a case study for working with Manim.

The Inspiration Behind the Plugin

Animating chess games with Manim combines two powerful domains: chess as a game of strategy and logic, and Manim as a medium to visualize and communicate abstract ideas. The motivation was to bridge the gap between these domains by creating a reusable and flexible plugin that could:

  • Render chessboards dynamically.
  • Animate moves in a visually compelling way.
  • Handle advanced chess-specific scenarios like castling and en passant.
  • Support common chess notations like FEN and PGN for easy integration.

Manim as a Development Framework

Manim provides a solid foundation for animation, with its object-oriented approach and mathematical precision. However, its general-purpose nature means that specific implementations require significant customization. The challenge was to build an intuitive plugin while navigating the following complexities:

Core Manim Concepts in the Chess Plugin

1. Grouping and Organizing Elements

Manim’s Group class is used extensively in the plugin to manage collections of objects, like squares, labels, and pieces. This allows for operations to be applied collectively, simplifying the process of managing the chessboard.

self.board = Group(*self.squares.values(), *self.labels, *self.elements) self.add(self.board)

This code combines all the chessboard components into a single Group and adds it to the scene. The use of Group ensures that transformations or animations applied to self.board will propagate to all its child elements.

self.squares['e5'].move_to(UP * 0.5 + RIGHT * 0.5)
self.squares[f'{row}{col}'].next_to(self.squares[f'{row}{col - 1}'], UP, buff=0)

2. Positioning Squares and Pieces

Manim provides precise control over object positioning using methods like move_to and next_to. For example, when laying out the squares on the board:

self.squares['e5'].move_to(UP * 0.5 + RIGHT * 0.5)
self.squares[f'{row}{col}'].next_to(self.squares[f'{row}{col - 1}'], UP, buff=0)
  • move_to: Places the square at a specific coordinate relative to the center of the scene.
  • next_to: Positions squares relative to their neighbors, ensuring proper alignment and spacing.

3. Coloring Squares

Manim’s set_fill method is used to apply colors to the squares, enabling the checkerboard pattern. Here’s the implementation:

self.squares[f'{row}{col}'].set_fill(color, opacity=0.7)
  • color: Sets the fill color of the square.
  • opacity: Controls the transparency of the fill, adding visual depth to the board.

The alternation of colors is achieved through a simple toggle mechanism within nested loops.

4. Animating Chess Moves

Animating piece movements is central to the plugin. The animate property of Manim objects allows for smooth transitions. For example:

move_animation = piece.animate.move_to(end_square)
  • animate: Creates an animation for the specified transformation.
  • move_to: Moves the piece to the target square.

To handle complex animations, like castling or pawn promotion, these basic animations are combined into AnimationGroup.

return AnimationGroup(*animations)

This groups multiple animations together, ensuring they execute simultaneously or sequentially as needed.

5. Handling Special Moves

Special moves like castling and en-passant require careful coordination of multiple animations. For instance, in castling:

rook_move_animation = rook.animate.move_to(rook_end_square)
king_move_animation = king.animate.move_to(king_end_square) animations.append(rook_move_animation)
animations.append(king_move_animation)

The animate property is applied to both the rook and king, creating independent animations that are then combined into an AnimationGroup.

6. Text and Labels

Labels for ranks and files are added using Manim’s Text class. For example:

Text(letter, font="Ubuntu Mono", color=color).move_to(
    self.squares[f'{letter}1'].get_center() + DOWN * 0.35 + RIGHT * 0.35
).scale(0.3)
  • Text: Creates text objects for display.
  • move_to: Positions the labels near the squares.
  • scale: Adjusts the size of the text for visual clarity.

The Manim Chess Plugin in Action

Today, the Manim Chess Plugin empowers users to create:

  • Educational Animations: Demonstrate chess strategies like Fool’s Mate or endgame puzzles.
  • Game Visualizations: Bring historical chess games to life with fluid animations.
  • Creative Content: Use chess as a storytelling medium in animated videos.

Future scope

The manim-chess-plugin has immense potential for growth and enhancement. Some ideas for future developments include:

  • Adding Support for 3D Chess Models: Extending the plugin to work with 3D chess pieces and boards could add a new dimension to the animations, making them more visually engaging and realistic. Leveraging Manim’s 3D capabilities, such as Sphere, Cylinder, and ThreeDScene, would be key to achieving this.
  • Incorporating a Moving Camera: Examples showcasing dynamic camera movements, such as zooming in on specific pieces or following the action during a move, could greatly enhance storytelling and instructional use cases. This would involve utilizing Manim’s Camera and move_camera functionality to create immersive animations.
  • Interactive Chessboard Animations: Adding interactivity to the animations, where users can input moves during runtime, would make the plugin an excellent tool for tutorials, live chess analysis, and online learning.
  • Advanced Game Analysis Features: Introducing features like highlighting potential moves, visualizing threats, and tracking captured pieces could make the animations more informative, particularly for educational content.
  • Integration with AI Chess Engines: Connecting the plugin to popular AI chess engines like Stockfish could allow automated analysis and animations of games, providing a seamless way to visualize strategic insights and evaluations.

Conclusion

It was pretty fun to get into this library, tools like this really help break some of the complexity down of challenging math problems. I really feel videos made using Manim help build good intuition to people dealing with STEM.

For those exploring Manim, this plugin is not just a tool but also a stepping stone to understanding how to tackle real-world animation problems. By sharing this experience, I hope to inspire others to leverage Manim’s potential and contribute to its ecosystem.

If you’re interested in trying out the plugin or contributing, check out the Manim Chess Plugin repository. Happy animating!

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