Block Blast Solver

An advisor for the mobile puzzle game Block Blast. You play the game on your phone; this program tells you the optimal way to place each set of 3 blocks the game deals you, on an 8×8 grid.

The program supports any shape — when the game gives you a block, you draw it on the canvas and the solver handles it. There's no fixed block palette to keep in sync with the game's set.

How it works

1. Open Block Blast on your phone.
2. Run the solver.
3. Click Draw Custom Shapes.
4. For each of the 3 blocks the game just dealt you: click cells on the canvas to draw the shape, then click Done.
5. After the third Done, the view returns to the main grid and the solver computes the optimal placement order.
6. The grid walks you through the placements one at a time. Each step shows where to place the current block (highlighted in green) with the rest of the grid in carried-over magenta. Click Next to advance to the next placement.
7. Mimic each placement on your phone as the solver advances through them.
8. Once you've completed all three placements, click Draw Custom Shapes again to begin the next round.

The solver auto-detects game-over (no valid placement exists for the 3 shapes you drew) and surfaces a dialog.

Screenshot

How the solver works

For the 3 blocks you drew, the solver:

1. Generates all 6 permutations (orderings) of the blocks.
2. For each permutation, brute-force tries every (row, col) anchor for the first block, then expands the search to every anchor for the second, then the third — keeping only sequences where all three blocks fit.
3. Each candidate end-state grid is scored:
   • score = clearedCells × 0.5 + largestConnectedEmptyArea × 0.25
4. The placement sequence with the highest score wins.

Score weighting prioritizes actually clearing rows/columns (0.5) over preserving open space (0.25). The largest empty area is computed via flood fill.

Requirements

• Java 22 or newer
• Maven (for command-line builds — optional if you run from IntelliJ)

Running

From IntelliJ IDEA

Open the project as a Maven project and run dev.pebbled.Main.

From the command line

mvn compile
java -cp target/classes dev.pebbled.Main

Project structure

src/main/java/dev/pebbled/
├── Main.java                  # Entry point — launches BlockBlastFrame on the EDT
├── algorithm/
│   └── FloodFill.java         # Connected-region area calculation
├── blocks/
│   ├── IBlock.java            # Block contract: returns its boolean[][] shape
│   └── impl/
│       └── CustomBlock.java   # Wraps a user-drawn shape as an IBlock
├── grid/
│   ├── Grid.java              # Wraps an int[][] grid + placement history
│   └── Placement.java         # (block, row, col) record
├── gui/
│   ├── BlockBlastFrame.java   # JFrame — owns grid state, swaps views via CardLayout
│   ├── GridPanel.java         # 8×8 grid display with diff-colored cells
│   └── DrawingPanel.java      # 8×8 clickable canvas for drawing shapes
├── solver/
│   └── Solver.java            # getTopGrid + generateBlockCombinations + helpers
└── utils/
    ├── BlockUtil.java         # placeBlock(grid, shape, row, col)
    └── GridUtil.java          # isSpaceEmpty, clearCompletedRow, scoring, printing

Current limitations

• Empty starting grid. Each session starts with an empty 8×8 grid — you have to start the solver at the same time you start a fresh game on your phone.
• No save/load. Closing the program loses the in-memory grid state; you can't pick up an in-progress game between sessions.

Roadmap

• Swing GUI: visual grid renderer, custom-shape drawing canvas, step-through walkthrough
• GUI polish: in-window placement display, distinct color for new placements vs. carried-over cells, round counter
• Custom shape input — user draws each block on an 8×8 canvas
• Manual grid input on startup (so the solver can pick up an in-progress game)
• Save/load grid state across sessions
• GUI overhaul: Make the GUI not just a base Swing GUI with no styling.

Author

Built by Pebbleddd.