Interactive Fluid

A compact pressure-projected fluid solver with velocity advection, colorful dye, and pointer or touch stirring.

index.tsx renderer.ts pointer-input.ts simulation.ts validation.ts math.ts fluid-common.wgsl advect-velocity.wgsl curl.wgsl vorticity.wgsl divergence.wgsl pressure.wgsl project.wgsl advect-dye.wgsl display.wgsl

import { Grid, index_of } from "./fluid-common.wgsl";
 
@group(0) @binding(0) var<uniform> grid: Grid;
@group(0) @binding(1) var<storage, read> velocity: array<vec2f>;
@group(0) @binding(2) var<storage, read_write> curl: array<f32>;
 
@compute @workgroup_size(8, 8)
fn main(@builtin(global_invocation_id) id: vec3u) {
  if (any(id.xy >= grid.size)) { return; }
  let p = vec2i(id.xy);
  let left = velocity[index_of(p - vec2i(1, 0), grid.size)].y;
  let right = velocity[index_of(p + vec2i(1, 0), grid.size)].y;
  let top = velocity[index_of(p + vec2i(0, 1), grid.size)].x;
  let bottom = velocity[index_of(p - vec2i(0, 1), grid.size)].x;
  curl[index_of(p, grid.size)] = 0.5 * (right - left - top + bottom);
}