Sparse particle field in Taichi using Pointers

taichi_sparse_particle_field.py

import taichi as ti

ti.init(arch=ti.cuda) # not supported on vulkan

@ti.dataclass
class Particle:
    position: ti.math.vec2
    velocity: ti.math.vec2

@ti.data_oriented
class Particles:
    def __init__(self, n=32):
        self.n = n
        self.field = Particle.field()
        self.pointer = ti.root.pointer(ti.i, self.n).place(self.field)
    @ti.kernel
    def activate(self, i: int):
        ti.activate(self.pointer, [i])
    @ti.kernel
    def deactivate(self, i: int):
        ti.deactivate(self.pointer, [i])

particles = Particles(32)
particles.field[0] = Particle(position=[0.5,0.5],velocity=[0.5,0.5])