Pointers As Short Names

Inside a function, combine & with a let-declaration to create a short name for something in a larger structure, as in the example.

You may have to use parentheses around the dereference, because member access and array indexing bind more tightly.

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struct Particle {
  pos: vec3f
}
var<private> particles: array<Particle,10>;

fn f(i: i32) {
  let p = &particles[i];

  // This works.
  (*p).pos = vec3f();

  // This left hand side is an error, because it means
  // *(p.pos), and you can't do member access on a pointer.
  *p.pos = vec3f();
}

struct Particle { momentum: vec3f, pos: vec3f, velocity: vec3f, } @group(0) @binding(0) var<storage,read_write> particles: array<Particle>; fn sequentially_update_momenta() { let particles_ptr = &particles; // Here is a pointer for (var i: u32; i < arrayLength(particles_ptr); i++) { // Use & to get a pointer as a short name for something inside a big variable. let a_particle = &particles[i]; // We could have spelled out the pointer type in full. // let a_particle: ptr<storage,Particle,read_write> = &particles[i]; // Now use 'a_particle' as a short name. let its_pos = (*a_particle).pos; // Parentheses are required. let its_velocity = (*a_particle).velocity; (*a_particle).momentum = its_pos * its_velocity; } }