geometry-dash

Hardware implementation of the popular polygon parkour game

Physical address: 0x0000_8000

Image Table Memory Map (Sprite ROM)

RAM Layout

• Total sprites: 256
• Sprite size: 8 × 8 pixels
• Pixel format: 24-bit RGB
• Total pixels: 256 × 64 = 16,384
• Total memory: 16,384 × 3 bytes = 49,152 bytes

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Address Format (14 bits)

Each 14-bit address selects one pixel:

[13:6]  = Image ID (8 bits)     → 256 images
[5:3]   = Y pixel row (3 bits)  → 8 rows
[2:0]   = X pixel col (3 bits)  → 8 columns

Bit Diagram

 Address[13:0]:
 ┌──────┬───────┬───────┐
 │ 13:6 │  5:3  │  2:0  │
 └──────┴───────┴───────┘
   Img     Y       X

Output Data: 24 bits (RGB)

Output[23:0]:
 ┌────────┬────────┬────────┐
 │ 23:16  │ 15:8   │  7:0   │
 └────────┴────────┴────────┘
     Red     Green   Blue

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Sprite File Generation

Run gen_sprites.py to convert 16×16 PNGs in the images/ folder into sprites.hex.

Requirements

pip install Pillow

Usage

python3 gen_sprites.py

This generates sprites.hex, a 32-bit word file preloading your ROM in Platform Designer.

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Quartus Configuration

• Component: On-Chip Memory (ROM)
• Total Memory: 49152 bytes
• Data Width: 24 or 32 bits
• Address Width: 14 bits
• Init File: sprites.hex

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Example Image Layout

Assuming Image ID = 0x12, pixel at (x=3, y=5):

• Address = 0x12 << 6 | 5 << 3 | 3 = 0x12A3
• Data = RGB value of that pixel

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Folder Structure

lab3-hw/
├── images/            # PNG sprite sources (16×16, RGB)
├── gen_sprites.py     # PNG → HEX generator
├── sprites.hex        # Memory init file
├── vga_ball.sv        # Display logic
└── soc_system.qsys    # Platform Designer system