About the Simulation
This simulation demonstrates a Forest Fire Cellular Automata model. The grid consists of cells that can exist in one of several states:
- Empty (Dark) – Barren ground.
- Tree (Green) – Healthy vegetation.
- Burning (Red/Orange) – Vegetation on fire.
- Ash (Grey) – Recently burnt ground, temporarily infertile.
The rules applied at each simulation step are:
- A burning cell turns into Ash.
- An Ash cell turns into Empty after one step.
- A Tree ignites if any adjacent (neighbor) cell is burning.
- A Tree may ignite due to wind-borne embers (controlled by arrow keys) from the cell upwind.
- A Tree may spontaneously ignite based on the Ignition probability (f), reduced by Humidity.
- An Empty cell can spontaneously grow a Tree based on the Growth probability (p).
Atmospheric effects (clouds generated using Simplex noise, occasional lightning pixels) provide ambiance. The clouds move according to the wind direction set by the arrow keys. Interactive controls allow adjusting parameters and simulation speed. Use Arrow Keys to change wind direction and Spacebar to pause/resume.
Code Explanation
The simulation uses HTML, CSS, and JavaScript, rendered on an HTML5 Canvas.
- HTML/CSS: Defines the structure, layout, and retro styling. Flexbox is used for better layout. `image-rendering: pixelated` maintains the blocky aesthetic.
- JavaScript:
- Grid Logic: Manages the 2D array representing the forest, cell states (Empty, Tree, Fire, Ash), and update rules.
- Rendering: Draws the grid, atmospheric effects, and UI elements onto the Canvas using `requestAnimationFrame`.
- CA Rules: Implements neighbor checks, wind influence (`pWind`), spontaneous growth (`p`), and spontaneous ignition (`f` modified by `humidity`).
- States: Includes an Ash state (#555) between Fire and Empty.
- Interaction: Handles button clicks (Reset, Pause), slider inputs, and keyboard events (arrows for wind, space for pause).
- Navigation: Switches between content 'pages'.
- Atmospherics (Clouds): Uses an embedded **Simplex Noise** algorithm. The `drawClouds` function samples 3D noise (x, y, time/offset) for each canvas grid cell. If the noise value exceeds a threshold, a semi-transparent cloud block is drawn. The noise offsets are updated in `updateCloudNoise` based on the simulation's `wind` direction and speed, creating flowing cloud patterns.
- Atmospherics (Lightning): Random single pixels are drawn underneath the clouds occasionally.
The simulation attempts a balance between demonstrating CA principles, providing interaction, and maintaining a specific visual style, now with more dynamic cloud visuals.