Liquid Acid Drop

A Vulkan-powered puzzle game inspired by the Atari 2600 classic Acid Drop, built with the MX2 Engine.

Overview

To compile this you will need to compile in Vulkan support to libmx2

git clone https://github.com/lostjared/libmx2.git
cd libmx2/libmx
mkdir buildvk
cd buildvk
cmake .. -DEXAMPLES=OFF -DVULKAN=ON -DOPENGL=OFF -DCMAKE_INSTALL_PREFIX=/usr/local/mxvk
cd buildvk
make -j$(nproc)
sudo make install

Then compile AcidDrop

git clone https://github.com/lostjared/AcidDrop.git
cd AcidDrop
mkdir ac
cd ac
cmake .. -DCMAKE_PREFIX_PATH=/usr/local/mxvk -DCMAKE_INSTALL_PREFIX=/usr/local/mxvk
make -j$(nproc)
./AcidDrop -p ..

Liquid Acid Drop is a color-matching puzzle game where players guide falling tri-colored blocks into an 818 grid. Match 3 or more blocks of the same color horizontally, vertically, or diagonally to clear them and score points. The game features GPU-accelerated fragment shader visual effects, persistent high scores, and progressively increasing difficulty.

Built entirely with Vulkan for rendering and SDL2 for windowing/input, this game serves as both a playable title and a showcase for the libmx2 engine's 2D sprite and text rendering capabilities.

Features

• Vulkan Rendering Pipeline All graphics are rendered via Vulkan, including sprite batching, text rendering with SDL_ttf, and custom SPIR-V fragment shaders
• Shader-Driven Visual Effects Backgrounds use kaleidoscope, bubble, and time-warp fragment shaders for psychedelic animated visuals
• Color-Match Puzzle Mechanics Match 3+ blocks horizontally, vertically, or diagonally to clear; cascading gravity triggers chain reactions for bonus points
• Block Rotation & Color Shifting Rotate blocks between vertical and horizontal orientation, and cycle the color order within a piece
• Animated Match Flashing Matched blocks flash before clearing, providing clear visual feedback
• Progressive Difficulty Game speed increases every 10 line clears, with three starting difficulty levels (Easy, Normal, Hard)
• Persistent High Scores Top 10 scores are saved to disk and restored between sessions
• Resizable Window Dynamic font scaling and layout adapts to any window size
• Fullscreen Support Launch in fullscreen mode via command-line flag
• Cross-Platform Builds on Linux, macOS (via MoltenVK), and Windows

How to Play

Controls

Key	Action
** **	Move block left/right
****	Soft drop (move block down faster)
****	Shift colors within the block (forward)
Z	Shift colors within the block (reverse)
Space	Rotate block (vertical horizontal)
P	Pause / Resume
Escape	Return to main menu / Quit
Enter	Confirm menu selection

Gameplay

1. Falling Blocks A piece made of 3 colored segments falls from the top of the grid
2. Position & Rotate Move the piece left/right, rotate it between vertical and horizontal, and shift the color order to set up matches
3. Match to Clear When 3 or more same-colored blocks align horizontally, vertically, or diagonally, they flash and are cleared from the grid
4. Gravity & Chains After blocks are cleared, remaining blocks fall due to gravity, potentially triggering chain reactions for bonus points
5. Score Bonuses Matching 4 blocks awards +25 bonus points; matching 5+ awards +50 (diagonal matches give +35/+75)
6. Speed Up Every 10 line clears, the drop speed increases
7. Game Over The game ends when blocks stack up to the top of the grid

Scoring

Event	Points
Each block cleared	+6
4-block horizontal/vertical match	+25 bonus
5+ block horizontal/vertical match	+50 bonus
4-block diagonal match	+35 bonus
5+ block diagonal match	+75 bonus

Building

Prerequisites

• C++20 compatible compiler (GCC 10+, Clang 10+, MSVC 2019+)
• Vulkan SDK (or MoltenVK on macOS)
• SDL2, SDL2_ttf
• GLM (OpenGL Mathematics)
• libpng, zlib
• CMake 3.10+
• The libmx2 library (parent project)

The game binary AcidDrop will be produced in the build directory.

Running

# Run with default settings (1280x720 windowed)
./AcidDrop -p ..

# Custom resolution
./AcidDrop -p .. -r 1280x720

# Fullscreen
./AcidDrop -p .. -f

The -p flag specifies the path to the game's resource directory (where the data/ folder and font.ttf reside).

Project Structure

AcidDrop/
 skeleton.cpp          # Game logic, screens, input handling, and main()
 vk.hpp                # Vulkan engine header (VKWindow, VKSprite, VKText)
 vk.cpp                # Vulkan engine implementation
 CMakeLists.txt        # Build configuration
 font.ttf              # Default game font
 data/
    *.png             # Sprite assets (blocks, backgrounds, UI screens)
    *_vertex.vert     # GLSL vertex shaders
    *_fragment.frag   # GLSL fragment shaders (kaleidoscope, bubble, warp, etc.)
    *.spv             # Pre-compiled SPIR-V shader binaries
 scores.dat            # Persistent high score data (generated at runtime)

Technical Details

Architecture

The game is built on the MX2 Vulkan framework (mx::VKWindow), which provides:

• Swap chain management with automatic recreation on window resize
• 2D Sprite system (mx::VKSprite) texture loading, batched draw calls, per-sprite custom fragment shaders with uniform parameters
• Text rendering (mx::VKText) SDL_ttf font rasterization uploaded as Vulkan textures with dedicated descriptor sets
• Depth buffering and proper Vulkan synchronization primitives

Game Screens

Screen	Description
Intro	Splash screen with animated bubble shader; auto-advances after 3 seconds
Start Menu	Main menu with New Game, High Scores, Options, Credits, and Quit
Game	Active gameplay with the puzzle grid, score display, and next-piece preview
Game Over	Displays final score and line count
High Scores	Top 10 leaderboard with name entry for qualifying scores
Options	Difficulty selection (Easy / Normal / Hard)
Credits	Attribution screen

Block Colors

The game features 9 distinct block colors: Yellow, Orange, Light Blue, Dark Blue, Purple, Pink, Gray, Red, and Green each with its own sprite texture.

Credits

• Engine & Game Jared Bruni
• Framework libmx2 / MX2 Engine
• Inspired by Acid Drop (Atari 2600, 1992) and Columns (Sega, 1990)

License

This project is part of libmx2. See the LICENSE file for details.