Struct FluidGrid 

pub struct FluidGrid {

    pub width: usize,
    pub height: usize,
    pub dx: f32,
    pub vx: Vec<f32>,
    pub vy: Vec<f32>,
    pub density: Vec<f32>,
    pub temp: Vec<f32>,
    pub color_r: Vec<f32>,
    pub color_g: Vec<f32>,
    pub color_b: Vec<f32>,
    pub pressure: Vec<f32>,
    pub obstacle: Vec<f32>,
    pub viscosity: f32,
    pub diffusion: f32,
    pub buoyancy: f32,
    pub ambient_temp: f32,
    pub vorticity_strength: f32,
    pub gravity: Vec2,
    pub decay: f32,
    pub time: f32,
    /* private fields */
}

2D Eulerian fluid simulation grid.

Fields

width: usize

Grid width in cells.

height: usize

Grid height in cells.

dx: f32

Physical size of one cell (world units).

vx: Vec<f32>

Velocity X component (cell-centered).

vy: Vec<f32>

Velocity Y component (cell-centered).

density: Vec<f32>

Density / smoke field.

temp: Vec<f32>

Temperature field (buoyancy driving).

color_r: Vec<f32>

Color R channel for multi-fluid visualization.

color_g: Vec<f32>

Color G channel.

color_b: Vec<f32>

Color B channel.

pressure: Vec<f32>

Pressure field (intermediate, used in projection).

obstacle: Vec<f32>

Obstacle / solid mask: 1.0 = fluid, 0.0 = solid.

viscosity: f32

Kinematic viscosity (m^2/s). Default 1e-4.

diffusion: f32

Density diffusion coefficient.

buoyancy: f32

Buoyancy lift coefficient (hot gas rises).

ambient_temp: f32

Ambient temperature. Cells above this experience upward force.

vorticity_strength: f32

Vorticity confinement strength (adds swirl detail). Default 0.3.

gravity: Vec2

Gravity direction and magnitude.

decay: f32

Global density decay per second (smoke dissipation).

time: f32

Seconds elapsed since creation.

Implementations

impl FluidGrid

pub fn new(width: usize, height: usize, dx: f32) -> Self

Create a new fluid grid of given dimensions and cell size.

pub fn idx(&self, x: usize, y: usize) -> usize

pub fn add_velocity(&mut self, cx: usize, cy: usize, dvx: f32, dvy: f32)

Add velocity impulse at cell (cx, cy).

pub fn add_density(&mut self, cx: usize, cy: usize, amount: f32)

Add density at cell.

pub fn add_temperature(&mut self, cx: usize, cy: usize, dt: f32)

Add temperature at cell.

pub fn add_color(&mut self, cx: usize, cy: usize, r: f32, g: f32, b: f32)

Add colored smoke/fluid at cell.

pub fn add_obstacle_circle(&mut self, cx: f32, cy: f32, radius: f32)

Paint a circular solid obstacle.

pub fn add_obstacle_rect(&mut self, x0: usize, y0: usize, x1: usize, y1: usize)

Paint a rectangular solid obstacle.

pub fn step(&mut self, dt: f32)

Advance the simulation by dt seconds.

pub fn sample_velocity(&self, wx: f32, wy: f32) -> Vec2

Sample velocity at world position (bilinear).

pub fn sample_density(&self, wx: f32, wy: f32) -> f32

Sample density at world position.

pub fn sample_color(&self, wx: f32, wy: f32) -> (f32, f32, f32)

Sample color at world position.

pub fn max_velocity(&self) -> f32

Maximum velocity magnitude in the grid.

pub fn total_density(&self) -> f32

Total density integral (conservation check).

pub fn clear(&mut self)

Clear all velocity, density, and color fields.

pub fn splash(&mut self, cx: f32, cy: f32, radius: f32, strength: f32)

Apply a circular velocity splash (radial outward impulse).

pub fn swirl(&mut self, cx: f32, cy: f32, radius: f32, strength: f32)

Apply a swirl vortex impulse (clockwise tangential velocity).

pub fn resize(&mut self, new_width: usize, new_height: usize)

Resize the grid (clears all data).

pub fn to_rgba_density(&self, tint: (u8, u8, u8)) -> Vec<u8>

Render the density field as a flat RGBA byte buffer (width × height × 4). Useful for debug visualization.

pub fn to_rgba_velocity(&self) -> Vec<u8>

Render the velocity field as a flat RGBA byte buffer (speed-encoded).

Trait Implementations

impl Clone for FluidGrid

fn clone(&self) -> FluidGrid

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for FluidGrid

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.