bedrock-samples/resource_pack/particles/portal_directional.json

{
  "format_version": "1.10.0",
  "particle_effect": {
    "description": {
      "identifier": "minecraft:portal_directional",
      "basic_render_parameters": {
        "material": "particles_alpha",
        "texture": "textures/particle/particles"
      }
    },
    "components": {
      "minecraft:emitter_rate_instant": {
        "num_particles": 1
      },

      "minecraft:emitter_lifetime_expression": {
        "activation_expression": 1,
        "expiration_expression": 1
      },

      "minecraft:emitter_shape_point": {
      },

      "minecraft:particle_lifetime_expression": {
        "max_lifetime": "Math.Random(2.0,2.45)"
      },

      "minecraft:particle_motion_parametric": {
        "relative_position": [
          "variable.alpha = variable.particle_age/variable.particle_lifetime; variable.distance = (1-(-1*(variable.alpha)+Math.Pow((variable.alpha),2)*2)); return variable.direction.x * variable.distance;",
          "variable.direction.y * variable.distance - variable.alpha",
          "variable.direction.z * variable.distance"
        ]
      },

      "minecraft:particle_appearance_billboard": {
        "size": [
          "(variable.particle_random_2 * 0.02 + 0.05) * (1 - Math.Pow((1-(variable.particle_age/variable.particle_lifetime)),2))",
          "(variable.particle_random_2 * 0.02 + 0.05) * (1 - Math.Pow((1-(variable.particle_age/variable.particle_lifetime)),2))"
        ],
        "facing_camera_mode": "lookat_xyz",

        "uv": {
          "texture_width": 128,
          "texture_height": 128,
          "uv": [ "Math.round(variable.particle_random_1*8)*8", 0 ],
          "uv_size": [ 8, 8 ]
        }
      },
      "minecraft:particle_appearance_tinting": {
        "color": [ "variable.particle_random_1 * 0.6 + 0.4", "(variable.particle_random_1 * 0.6 + 0.4) * 0.3", "(variable.particle_random_1 * 0.6 + 0.4) * 0.9", 1.0 ]
      }
    }
  }
}