🦋 Butterfly Escape – VHDL FPGA Game

The game is inspired by the original Butterfly-Escape game and it is implemented by VHDL and deployed on FPGA hardware with VGA output.2

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📸 Initialization

Figure 1: Initial seven-segment and board state at system startup

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👨‍💻 Contributors

Name
Ashkan Marali
Alireza Sobhdoost

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📖 Overview

Butterfly Escape is a real-time hardware game where the player shoots colored balls into a moving chain. Matching three or more balls eliminates them and increases the score.

The entire system is designed in pure VHDL, including:

• VGA controller
• Game logic
• Memory controller
• User input handling
• Seven-segment display

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⭐ Features

• 🎮 Real-time gameplay on FPGA
• 🖥️ VGA output (640×480 @60Hz)
• 🔢 Hardware seven-segment score display
• ⚙️ Modular FSM-based design
• 💥 Special balls and chain reactions
• 🎯 5-button control system
• 📊 Score & timer system

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🎥 Gameplay Demonstration

Shooting and Impact

Figure 2: Shooting sequence of red balls

Figure 3: Shooting sequence of a special ball impact

Gameplay Animations (GIFs)

Shooting

Figure 4: Ball shooting mechanism

Spawning

Figure 5: Continuous ball spawning

Explosion

Figure 6: Ball elimination effect

Random Movement

Figure 7: Random chain movement

Special Ball Impact

Figure 8: Special ball behavior

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🏗️ System Architecture

Figure 9: Main game state machine

The system is based on multiple interconnected FSMs:

• Game controller
• Ball manager
• Shooting controller
• Memory handler
• VGA renderer

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📊 Internal State Machines

Ball & Shooting States

Figure 10: Ball handling and shooting FSMs

User & Memory States

Figure 11: User input and memory management FSMs

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🕹️ Game States on VGA Monitor

Figure 12: INIT, WIN, and LOSS screens

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🔢 Seven-Segment Display

Initial State

Figure 13: Initial 7-segment display

Score & Timer

Figure 14: Score update after special impact

Win & Lose

Figure 15: Final game states on seven-segment display

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🎲 Random & Normal Board Generation

Figure 16: Random and normal spawning boards (you can choose the type of generated board bu a switch on fpga)

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🎮 Controls

Button	Function
BTN1	Rotate Right
BTN4	Rotate Left
BTN2	Shoot
BTN3	Start
RSTN	Reset

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🧪 Build & Simulation

Requirements

• GHDL
• GTKWave
• Quartus Prime
• GNU Make

Commands

make compile <entity's name>
make compile-tb <test-bench's entity name>
make simu <test-bench's entity name>
make wave <test-bench's entity name>

as an example

make compile board_pkg,game_types_pkg,lfsr_pkg,graphics_pkg,led_manager,seven_seg_driver,button_ctrl,game_fsm,memory,lfsr_generator,board_gen,ball_shift_fsm,ball_shooting,vga_controller,projectile_renderer,projectile_fsm,collision_detector,vga_display,global_timer,board_to_ram,butterfly_escape

make compile-tb lfsr_tb
make simu lfsr_tb

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📁 Project Structure

Butterfly-Escape-VHDL/
│
├── rtl/          # Main VHDL sources
├── tb/           # Testbenches
├── docs/         # Documentation
├── Imgs&Vids/    # Images and GIFs
├── synthesis/    # FPGA synthesis
├── sim/          # Simulation outputs

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💾 Memory Architecture

• 32-bit encoded ball data
• Parallel VGA and logic access
• Buffered write system

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🖥️ VGA Caching Technique

To prevent visual artifacts:

• Writes occur during blanking intervals
• Display reads are isolated
• Double-buffering logic is applied
• Synchronization with VGA clock

Benefits

✔️ No flicker ✔️ Smooth animation ✔️ Stable rendering ✔️ Efficient memory usage

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⚙️ Technical Specifications

Parameter	Value
System Clock	50 MHz
VGA Resolution	640×480
FPGA Resource Use	~8k LUTs
FPGA Board	Cyclone V FPGA 5CEBA4F23C7N
Color Depth	12-bit
Projectile Speed	8 px/frame
Timer Tick	1 s

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📜 License

This project is developed for educational purposes under the MIT LICENSE .

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🙏 Acknowledgments

• Guilan University – Computer Engineering
• Course: Computer Aided Digital Systems by Dr. Aminian
• Tools: Quartus, GHDL, GTKWave
• Platform: Cyclone V FPGA

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Designed and implemented with passion for digital systems