Neon Sand Simulation

Neon Sand is a falling sand simulation built with the Godot Engine. The sand logic is implemented using a C++ GDExtension to handle simulation updates and the interaction of different sand types. The simulation can be run in the Godot editor or exported for the web.

Features

• Sand simulation with various sand types.
• Dynamic sand spawning with a smooth, random distribution.
• Multiple types of sand particles with different behaviors.
• User interaction via mouse input to control sand placement.
• Optimized for performance using grid-based simulation and active cell tracking.

Setup

Requirements

• Godot Engine 4.0+ (for GDExtension compatibility)
• C++ compiler for building the GDExtension (e.g., GCC, Clang)

How to compile for Web

Follow the official Godot documentation on compiling for the web: Compiling for Web

For release version:

scons platform=web target=template_release threads=no

For debug version:

scons platform=web target=template_debug threads=no

Exporting for Web

Refer to the official guide for exporting to web platforms: Exporting for Web

Key Classes and Scripts

• SandSimulation:

  • C++ script
  • Contains the core logic for the sand simulation, including methods for spawning sand, updating the grid, and managing sand types.
  • Stores a 2D grid of sand IDs (0…255) in a low-resolution array.
  • Grid size (derived from screen size / Global.SIM_SCALE) is updated from the Godot code via the grid_updated signal.

• Input:

  • cursor.gd
  • Controls the user input for interacting with the simulation, including adjusting the cursor size and placing sand particles.

• SandRenderer:

  • Handles the visual representation of the simulation.
  • Converts the low-res simulation array into a texture (type_texture).
  • Uses a shader to convert sand IDs into colors via a palette texture (sand_colors).
  • Scales the low-res texture to fit the screen using a TextureRect

• show_fps.gd: Displays the FPS in the corner of the screen.

• title.gd: Displays the title screen with a fadeout animation.

Controls

• Left mouse button: Spawn sand at the cursor position with a dynamic sand type (color changes over time).
• Right mouse button or double-tap: Remove sand from the simulation at the cursor position.
• Mouse wheel or pinch gesture: Adjust the cursor size for sand placement.
• Escape Key: Quit the simulation.

License

This project is licensed under the MIT License - see the LICENSE file for details.

This project makes use of the Dynalight font (https://fontlibrary.org/en/font/dynalight) released under the SIL Open Font License.