struct Simulation {
  i : u32;
}

struct Particle {
  position : array<vec3<f32>, 8>;
  lifetime : f32;
  color : vec4<f32>;
  velocity : vec3<f32>;
}

struct Particles {
  p : array<Particle>;
}

@group(1) @binding(3) var<storage, read> particles : Particles;

@group(1) @binding(4) var<uniform> sim : Simulation;

@stage(compute) @workgroup_size(1)
fn main() {
  var particle = particles.p[0];
  particle.position[sim.i] = particle.position[sim.i];
}