Building a Desktop Tetris Game with C# and WPF

The Problem

A falling-block game must coordinate a timed game loop, keyboard input, collision detection, rotation, scoring, rendering, and game-over rules without allowing the interface and domain logic to become inseparable.

Each tetromino also requires multiple rotation states and a consistent way to translate local tile positions into board coordinates. Invalid movement must be reversed safely while completed rows are removed and the remaining grid collapses correctly.

Technical Leadership

• Modeled all seven tetrominoes through a shared abstract Block type with specialized rotation data.
• Kept authoritative gameplay rules inside GameState instead of embedding them in WPF event handlers.
• Created a grid abstraction responsible for boundaries, occupied cells, completed rows, and row movement.
• Coordinated an asynchronous game loop with immediate keyboard input and deterministic redraws.
• Studied and adapted a guided reference implementation while maintaining a readable project structure and documenting the source material.

What I Did

The design separates what the game means from how WPF displays it.

GameState owns the active block, queue, held block, score, collision rules, placement, and game-over evaluation. MainWindow translates that state into images and connects player input to explicit game actions.

• Represented rotations as arrays of tile coordinates for each tetromino.
• Implemented reversible movement and rotation when a proposed position does not fit the grid.
• Added hard drop, ghost-block projection, held-block swapping, and next-block preview.
• Cleared complete rows from the bottom upward and shifted remaining rows into the emptied space.
• Increased game speed as the score rises while enforcing a minimum delay.
• Added replay behavior that creates a clean GameState after game over.

Testing and Validation

• Exercised movement and rotation at the left, right, and bottom boundaries.
• Verified blocks cannot overlap occupied grid cells.
• Confirmed full rows clear and higher rows move down correctly.
• Validated hold restrictions, hard-drop distance, score updates, and game-over behavior.
• Checked the redraw cycle after timed and keyboard-driven state changes.

Outcome

• Delivered a complete keyboard-controlled Tetris experience for Windows.
• Demonstrated practical use of inheritance, encapsulation, collections, and two-dimensional arrays.
• Kept gameplay rules independently understandable from WPF rendering code.
• Implemented several polished gameplay features beyond basic falling-block movement.