A few examples of creating particles2D in godot using only gdscript

my_particles2d_01.gd

class_name MyParticles2D01
extends Particles2D


# Declare member variables here. Examples:
# var a = 2
# var b = "text"


# Called when the node enters the scene tree for the first time.
func _ready():
	self.emitting = true
	self.amount = 40
	
	#Time:
	self.lifetime = 1.5
	self.one_shot = false
	self.preprocess = 0
	self.speed_scale = 1
	self.explosiveness = 0.07
	self.randomness = 0
	self.fixed_fps = 0
	self.fract_delta = true
	
	#Drawing:
	self.visibility_rect = Rect2(-100, -100, 200, 200)
	self.local_coords = true
	self.draw_order = Particles2D.DRAW_ORDER_INDEX
	
	#Process Material:
	self.process_material = self.get_process_material()
	
	# Textures:
	self.texture = load("res://resources/floaty_64.png")
	
	# Transform:
#	self.transform = Transform2D()
	self.z_index = 0
	self.z_as_relative = true
	
	# Material:
	self.material = self.get_material()

func get_process_material() -> Material:
	var my_m := ParticlesMaterial.new()
	my_m.render_priority = 0
	my_m.next_pass = null
	
	# Time:
	my_m.lifetime_randomness = 0
	
	# Trail:
	my_m.trail_divisor = 1
	my_m.trail_size_modifier = null
	my_m.trail_color_modifier = null
	
	# Emission Shape:
	my_m.emission_shape = ParticlesMaterial.EMISSION_SHAPE_SPHERE
	my_m.emission_sphere_radius = 12
	my_m.emission_ring_axis = Vector3(0, 0, 0)
	
	# Flags:
	my_m.flag_align_y = false
	my_m.flag_rotate_y = false
	my_m.flag_disable_z = true
	
	# Direction:
	my_m.direction = Vector3(1, 0, 1)
	my_m.spread = 180
	my_m.flatness = 0
	
	# Gravity
	my_m.gravity = Vector3(0, -100, 0)
	
	# Initial Velocity:
	my_m.initial_velocity = 50
	my_m.initial_velocity_random = 0
	
	# Angular Velocity:
	my_m.angular_velocity = 100
	my_m.angular_velocity_random = 1
	my_m.angular_velocity_curve = null
	
	# Orbit Velocity:
	my_m.orbit_velocity = 0
	my_m.orbit_velocity_random = 0
	my_m.orbit_velocity_curve = null
	
	# Linear Accel
	my_m.linear_accel = 0
	my_m.linear_accel_random = 0
	my_m.linear_accel_curve = null
	
	# Radial Accel:
	my_m.radial_accel = 0
	my_m.radial_accel_random = 0
	my_m.radial_accel_curve = null
	
	# Tangential Accel:
	my_m.tangential_accel = 0
	my_m.tangential_accel_random = 0
	my_m.tangential_accel_curve = null
	
	# Damping:
	my_m.damping = 50
	my_m.damping_random = 0
	my_m.damping_curve = null
	
	# Angle:
	my_m.angle = 360
	my_m.angle_random = 1
	my_m.angle_curve = null
	
	# Scale:
	my_m.scale = 1
	my_m.scale_random = 0.2
	my_m.scale_curve = null
	
	# Color:
	my_m.color = Color.gray
	
	# Hue Variation:
	my_m.hue_variation = 0.01
	my_m.hue_variation_random = 1
	my_m.hue_variation_curve = null
	
	# Animation:
	my_m.anim_speed = 1
	my_m.anim_speed_random = 0
	my_m.anim_speed_curve = null
	my_m.anim_offset = 0
	my_m.anim_offset_random = 0
	my_m.anim_offset_curve = null
	
	
	
	return my_m

func get_material() -> Material:
	var my_m := CanvasItemMaterial.new()
	my_m.blend_mode = CanvasItemMaterial.BLEND_MODE_ADD
	my_m.light_mode = CanvasItemMaterial.LIGHT_MODE_NORMAL
	my_m.particles_animation = true
	my_m.particles_anim_h_frames = 7
	my_m.particles_anim_v_frames = 7
	my_m.particles_anim_loop = false
	my_m.render_priority = 0
	my_m.next_pass = null
	
	return my_m
	

# Called every frame. 'delta' is the elapsed time since the previous frame.
#func _process(delta):
#	pass

my_particles2d_02.gd

class_name MyParticles2D02
extends Particles2D


# Declare member variables here. Examples:
# var a = 2
# var b = "text"


# Called when the node enters the scene tree for the first time.
func _ready():
	self.emitting = true
	self.amount = 20
	
	#Time:
	self.lifetime = 1
	self.one_shot = false
	self.preprocess = 0
	self.speed_scale = 1
	self.explosiveness = 0.0
	self.randomness = 0
	self.fixed_fps = 0
	self.fract_delta = true
	
	#Drawing:
	self.visibility_rect = Rect2(-100, -100, 200, 200)
	self.local_coords = true
	self.draw_order = Particles2D.DRAW_ORDER_INDEX
	
	#Process Material:
	self.process_material = self.get_process_material()
	
	# Textures:
	self.texture = load("res://resources/offset_glow.png")
	
	# Transform:
#	self.transform = Transform2D()
	self.z_index = 0
	self.z_as_relative = true
	
	# Material:
	self.material = self.get_material()

func get_process_material() -> Material:
	var my_m := ParticlesMaterial.new()
	my_m.render_priority = 0
	my_m.next_pass = null
	
	# Time:
	my_m.lifetime_randomness = 0
	
	# Trail:
	my_m.trail_divisor = 1
	my_m.trail_size_modifier = null
	my_m.trail_color_modifier = null
	
	# Emission Shape:
	my_m.emission_shape = ParticlesMaterial.EMISSION_SHAPE_SPHERE
	my_m.emission_sphere_radius = 5
	my_m.emission_ring_axis = Vector3(0, 0, 1)
	
	# Flags:
	my_m.flag_align_y = false
	my_m.flag_rotate_y = false
	my_m.flag_disable_z = true
	
	# Direction:
	my_m.direction = Vector3(1, 0, 0)
	my_m.spread = 45
	my_m.flatness = 0
	
	# Gravity
	my_m.gravity = Vector3(0, -150, 0)
	
	# Initial Velocity:
	my_m.initial_velocity = 0
	my_m.initial_velocity_random = 0
	
	# Angular Velocity:
	my_m.angular_velocity = 1
	my_m.angular_velocity_random = 1
	my_m.angular_velocity_curve = null
	
	# Orbit Velocity:
	my_m.orbit_velocity = 0
	my_m.orbit_velocity_random = 0
	my_m.orbit_velocity_curve = null
	
	# Linear Accel
	my_m.linear_accel = 0
	my_m.linear_accel_random = 0
	my_m.linear_accel_curve = null
	
	# Radial Accel:
	my_m.radial_accel = 0
	my_m.radial_accel_random = 0
	my_m.radial_accel_curve = null
	
	# Tangential Accel:
	my_m.tangential_accel = 0
	my_m.tangential_accel_random = 0
	my_m.tangential_accel_curve = null
	
	# Damping:
	my_m.damping = 0
	my_m.damping_random = 0
	my_m.damping_curve = null
	
	# Angle:
	my_m.angle = 360
	my_m.angle_random = 1
	my_m.angle_curve = null
	
	# Scale:
	my_m.scale = 0.5
	my_m.scale_random = 0.3
	my_m.scale_curve = null
	
	# Color:
	my_m.color = Color.gray
	
	# Hue Variation:
	my_m.hue_variation = 0.0
	my_m.hue_variation_random = 0
	my_m.hue_variation_curve = null
	
	# Animation:
	my_m.anim_speed = 0
	my_m.anim_speed_random = 0
	my_m.anim_speed_curve = null
	my_m.anim_offset = 0
	my_m.anim_offset_random = 0
	my_m.anim_offset_curve = null
	
	
	
	return my_m

func get_material() -> Material:
	var my_m := CanvasItemMaterial.new()
	my_m.blend_mode = CanvasItemMaterial.BLEND_MODE_ADD
	my_m.light_mode = CanvasItemMaterial.LIGHT_MODE_NORMAL
	my_m.particles_animation = false
#	my_m.particles_anim_h_frames = 7
#	my_m.particles_anim_v_frames = 7
#	my_m.particles_anim_loop = false
	my_m.render_priority = 0
	my_m.next_pass = null
	
	return my_m
	

# Called every frame. 'delta' is the elapsed time since the previous frame.
#func _process(delta):
#	pass

my_particles2d_03.gd

class_name MyParticles2D03
extends Particles2D


# Declare member variables here. Examples:
# var a = 2
# var b = "text"


# Called when the node enters the scene tree for the first time.
func _ready():
	self.emitting = true
	self.amount = 6
	
	#Time:
	self.lifetime = 1
	self.one_shot = false
	self.preprocess = 0
	self.speed_scale = 1
	self.explosiveness = 0.0
	self.randomness = 0
	self.fixed_fps = 0
	self.fract_delta = true
	
	#Drawing:
	self.visibility_rect = Rect2(-100, -100, 200, 200)
	self.local_coords = true
	self.draw_order = Particles2D.DRAW_ORDER_INDEX
	
	#Process Material:
	self.process_material = self.get_process_material()
	
	# Textures:
	self.texture = load("res://resources/random_selection.png")
	
	# Transform:
	self.transform = Transform2D(0.0, Vector2(-4, -4))
	self.z_index = 0
	self.z_as_relative = true
	
	# Material:
	self.material = self.get_material()

func get_process_material() -> Material:
	var my_m := ParticlesMaterial.new()
	my_m.render_priority = 0
	my_m.next_pass = null
	
	# Time:
	my_m.lifetime_randomness = 0
	
	# Trail:
	my_m.trail_divisor = 1
	my_m.trail_size_modifier = null
	my_m.trail_color_modifier = null
	
	# Emission Shape:
	my_m.emission_shape = ParticlesMaterial.EMISSION_SHAPE_POINT
	my_m.emission_ring_axis = Vector3(0, 0, 1)
	
	# Flags:
	my_m.flag_align_y = false
	my_m.flag_rotate_y = false
	my_m.flag_disable_z = true
	
	# Direction:
	my_m.direction = Vector3(1, 0, 0)
	my_m.spread = 45
	my_m.flatness = 0
	
	# Gravity
	my_m.gravity = Vector3(0, 0, 0)
	
	# Initial Velocity:
	my_m.initial_velocity = 0
	my_m.initial_velocity_random = 0
	
	# Angular Velocity:
	my_m.angular_velocity = 0
	my_m.angular_velocity_random = 0
	my_m.angular_velocity_curve = null
	
	# Orbit Velocity:
	my_m.orbit_velocity = 0
	my_m.orbit_velocity_random = 0
	my_m.orbit_velocity_curve = null
	
	# Linear Accel
	my_m.linear_accel = 0
	my_m.linear_accel_random = 0
	my_m.linear_accel_curve = null
	
	# Radial Accel:
	my_m.radial_accel = 0
	my_m.radial_accel_random = 0
	my_m.radial_accel_curve = null
	
	# Tangential Accel:
	my_m.tangential_accel = 0
	my_m.tangential_accel_random = 0
	my_m.tangential_accel_curve = null
	
	# Damping:
	my_m.damping = 0
	my_m.damping_random = 0
	my_m.damping_curve = null
	
	# Angle:
	my_m.angle = 360
	my_m.angle_random = 1
	my_m.angle_curve = null
	
	# Scale:
	my_m.scale = 1
	my_m.scale_random = 0.3
	my_m.scale_curve = null
	
	# Color:
	my_m.color = Color.gray
	
	# Hue Variation:
	my_m.hue_variation = 0.2
	my_m.hue_variation_random = 1
	my_m.hue_variation_curve = null
	
	# Animation:
	my_m.anim_speed = 0
	my_m.anim_speed_random = 0
	my_m.anim_speed_curve = null
	my_m.anim_offset = 1
	my_m.anim_offset_random = 1
	my_m.anim_offset_curve = null
	
	
	
	return my_m

func get_material() -> Material:
	var my_m := CanvasItemMaterial.new()
	my_m.blend_mode = CanvasItemMaterial.BLEND_MODE_ADD
	my_m.light_mode = CanvasItemMaterial.LIGHT_MODE_NORMAL
	my_m.particles_animation = true
	my_m.particles_anim_h_frames = 3
	my_m.particles_anim_v_frames = 1
#	my_m.particles_anim_loop = false
	my_m.render_priority = 0
	my_m.next_pass = null
	
	return my_m
	

# Called every frame. 'delta' is the elapsed time since the previous frame.
#func _process(delta):
#	pass

my_particles2d_04.gd

class_name MyParticles2D04
extends Particles2D


# Declare member variables here. Examples:
# var a = 2
# var b = "text"


# Called when the node enters the scene tree for the first time.
func _ready():
	self.emitting = true
	self.amount = 4
	
	#Time:
	self.lifetime = 1
	self.one_shot = false
	self.preprocess = 0
	self.speed_scale = 1
	self.explosiveness = 0.0
	self.randomness = 0
	self.fixed_fps = 0
	self.fract_delta = true
	
	#Drawing:
	self.visibility_rect = Rect2(-100, -100, 200, 200)
	self.local_coords = true
	self.draw_order = Particles2D.DRAW_ORDER_INDEX
	
	#Process Material:
	self.process_material = self.get_process_material()
	
	# Textures:
	self.texture = load("res://resources/effect_4.png")
	
	# Transform:
	self.transform = Transform2D(0.0, Vector2(-7, -6))
	self.z_index = 0
	self.z_as_relative = true
	
	# Material:
	self.material = self.get_material()

func get_process_material() -> Material:
	var my_m := ParticlesMaterial.new()
	my_m.render_priority = 0
	my_m.next_pass = null
	
	# Time:
	my_m.lifetime_randomness = 0
	
	# Trail:
	my_m.trail_divisor = 1
	my_m.trail_size_modifier = null
	my_m.trail_color_modifier = null
	
	# Emission Shape:
	my_m.emission_shape = ParticlesMaterial.EMISSION_SHAPE_POINT
	my_m.emission_ring_axis = Vector3(0, 0, 1)
	
	# Flags:
	my_m.flag_align_y = false
	my_m.flag_rotate_y = false
	my_m.flag_disable_z = true
	
	# Direction:
	my_m.direction = Vector3(1, 0, 0)
	my_m.spread = 45
	my_m.flatness = 0
	
	# Gravity
	my_m.gravity = Vector3(0, 0, 0)
	
	# Initial Velocity:
	my_m.initial_velocity = 0
	my_m.initial_velocity_random = 0
	
	# Angular Velocity:
	my_m.angular_velocity = -100
	my_m.angular_velocity_random = 0
	my_m.angular_velocity_curve = null
	
	# Orbit Velocity:
	my_m.orbit_velocity = 0
	my_m.orbit_velocity_random = 0
	my_m.orbit_velocity_curve = null
	
	# Linear Accel
	my_m.linear_accel = 0
	my_m.linear_accel_random = 0
	my_m.linear_accel_curve = null
	
	# Radial Accel:
	my_m.radial_accel = 0
	my_m.radial_accel_random = 0
	my_m.radial_accel_curve = null
	
	# Tangential Accel:
	my_m.tangential_accel = 0
	my_m.tangential_accel_random = 0
	my_m.tangential_accel_curve = null
	
	# Damping:
	my_m.damping = 0
	my_m.damping_random = 0
	my_m.damping_curve = null
	
	# Angle:
	my_m.angle = 360
	my_m.angle_random = 1
	my_m.angle_curve = null
	
	# Scale:
	my_m.scale = 1
	my_m.scale_random = 0.0
	my_m.scale_curve = null
	
	# Color:
	my_m.color = Color.gray
	
	# Hue Variation:
	my_m.hue_variation = 0.0
	my_m.hue_variation_random = 0
	my_m.hue_variation_curve = null
	
	# Animation:
	my_m.anim_speed = 0
	my_m.anim_speed_random = 0
	my_m.anim_speed_curve = null
	my_m.anim_offset = 0
	my_m.anim_offset_random = 0
	my_m.anim_offset_curve = null
	
	
	
	return my_m

func get_material() -> Material:
	var my_m := CanvasItemMaterial.new()
	my_m.blend_mode = CanvasItemMaterial.BLEND_MODE_ADD
	my_m.light_mode = CanvasItemMaterial.LIGHT_MODE_NORMAL
	my_m.particles_animation = false
#	my_m.particles_anim_h_frames = 3
#	my_m.particles_anim_v_frames = 1
#	my_m.particles_anim_loop = false
	my_m.render_priority = 0
	my_m.next_pass = null
	
	return my_m
	

# Called every frame. 'delta' is the elapsed time since the previous frame.
#func _process(delta):
#	pass

my_particles2d_05.gd

class_name MyParticles2D05
extends Particles2D


# Declare member variables here. Examples:
# var a = 2
# var b = "text"


# Called when the node enters the scene tree for the first time.
func _ready():
	self.emitting = true
	self.amount = 5
	
	#Time:
	self.lifetime = 1
	self.one_shot = false
	self.preprocess = 0
	self.speed_scale = 1
	self.explosiveness = 0.08
	self.randomness = 0
	self.fixed_fps = 0
	self.fract_delta = true
	
	#Drawing:
	self.visibility_rect = Rect2(-100, -100, 200, 200)
	self.local_coords = true
	self.draw_order = Particles2D.DRAW_ORDER_INDEX
	
	#Process Material:
	self.process_material = self.get_process_material()
	
	# Textures:
	self.texture = load("res://resources/spotlight_8.png")
	
	# Transform:
	self.transform = Transform2D(0.0, Vector2(-11, -6))
	self.z_index = 0
	self.z_as_relative = true
	
	# Material:
	self.material = self.get_material()

func get_process_material() -> Material:
	var my_m := ParticlesMaterial.new()
	my_m.render_priority = 0
	my_m.next_pass = null
	
	# Time:
	my_m.lifetime_randomness = 0
	
	# Trail:
	my_m.trail_divisor = 1
	my_m.trail_size_modifier = null
	my_m.trail_color_modifier = null
	
	# Emission Shape:
	my_m.emission_shape = ParticlesMaterial.EMISSION_SHAPE_BOX
	my_m.emission_box_extents = Vector3(20, 30, 1)
	my_m.emission_ring_axis = Vector3(0, 0, 1)
	
	# Flags:
	my_m.flag_align_y = false
	my_m.flag_rotate_y = false
	my_m.flag_disable_z = true
	
	# Direction:
	my_m.direction = Vector3(1, 0, 0)
	my_m.spread = 45
	my_m.flatness = 0
	
	# Gravity
	my_m.gravity = Vector3(0, 0, 0)
	
	# Initial Velocity:
	my_m.initial_velocity = 0
	my_m.initial_velocity_random = 0
	
	# Angular Velocity:
	my_m.angular_velocity = 0
	my_m.angular_velocity_random = 0
	my_m.angular_velocity_curve = null
	
	# Orbit Velocity:
	my_m.orbit_velocity = 0
	my_m.orbit_velocity_random = 0
	my_m.orbit_velocity_curve = null
	
	# Linear Accel
	my_m.linear_accel = 0
	my_m.linear_accel_random = 0
	my_m.linear_accel_curve = null
	
	# Radial Accel:
	my_m.radial_accel = 0
	my_m.radial_accel_random = 0
	my_m.radial_accel_curve = null
	
	# Tangential Accel:
	my_m.tangential_accel = 0
	my_m.tangential_accel_random = 0
	my_m.tangential_accel_curve = null
	
	# Damping:
	my_m.damping = 0
	my_m.damping_random = 0
	my_m.damping_curve = null
	
	# Angle:
	my_m.angle = 0
	my_m.angle_random = 0
	my_m.angle_curve = null
	
	# Scale:
	my_m.scale = 0.3
	my_m.scale_random = 0.3
	my_m.scale_curve = load("res://new_curvetexture.curvetex")
	
	# Color:
	my_m.color = Color.gray
	
	# Hue Variation:
	my_m.hue_variation = 0.0
	my_m.hue_variation_random = 0
	my_m.hue_variation_curve = null
	
	# Animation:
	my_m.anim_speed = 0
	my_m.anim_speed_random = 0
	my_m.anim_speed_curve = null
	my_m.anim_offset = 0
	my_m.anim_offset_random = 0
	my_m.anim_offset_curve = null
	
	
	
	return my_m

func get_material() -> Material:
	var my_m := CanvasItemMaterial.new()
	my_m.blend_mode = CanvasItemMaterial.BLEND_MODE_ADD
	my_m.light_mode = CanvasItemMaterial.LIGHT_MODE_NORMAL
	my_m.particles_animation = false
#	my_m.particles_anim_h_frames = 3
#	my_m.particles_anim_v_frames = 1
#	my_m.particles_anim_loop = false
	my_m.render_priority = 0
	my_m.next_pass = null
	
	return my_m
	

# Called every frame. 'delta' is the elapsed time since the previous frame.
#func _process(delta):
#	pass

linear_accel property of process_material acts like the height. the more you increase it, the higher the particle effects will go.
This pic is the highest value (100):

and this pic is for lowest value (-100):

the lower the value, the more they will stay close to the center of their region.

---

from official docs:

● float linear_accel  [default: 0.0]
    set_param(value) setter
    get_param() getter

Linear acceleration applied to each particle in the direction of motion.

---

Setting this property to 0 will result in having a normal linear acceleration. (the default situation)

● float orbit_velocity
    set_param(value) setter
    get_param() getter

Orbital velocity applied to each particle. Makes the particles circle around origin. Specified in number of full rotations around origin per second.

Only available when flag_disable_z is true.

the more you set this to its max value (1000), particles will circle around to the right side (with higher speed), and the more you set this to its min value (-1000), the particles will circle around to the left side (left side as compared to the center of the region), (with higher speed).

if we want a normal speed, we better just set it to 0.

● float angular_velocity [default: 0.0]
    set_param(value) setter
    get_param() getter

Initial angular velocity applied to each particle. Sets the speed of rotation of the particle.

Only applied when flag_disable_z or flag_rotate_y are true or the SpatialMaterial being used to draw the particle is using SpatialMaterial.BILLBOARD_PARTICLES.

Min: -720
Max: +720

---

● float angular_velocity_random [default: 0.0]
    set_param_randomness(value) setter
    get_param_randomness() getter

Angular velocity randomness ratio.

Min: 0.00
Max: 1.00

● float tangential_accel [default: 0.0]
    set_param(value) setter
    get_param() getter

Tangential acceleration applied to each particle. Tangential acceleration is perpendicular to the particle's velocity giving the particles a swirling motion.

Min: -100
Max: 100

---

● float tangential_accel_random [default: 0.0]
    set_param_randomness(value) setter
    get_param_randomness() getter

Tangential acceleration randomness ratio.

Min: 0.00
Max: 1.00

● float damping [default: 0.0]
    set_param(value) setter
    get_param() getter

The rate at which particles lose velocity.

Min: 0
Max: 100

---

● float damping_random [default: 0.0]set_param_randomness(value) setterget_param_randomness() getter

Damping randomness ratio.

Min: 0.00
Max: 1.00

● float angle [default: 0.0]
    set_param(value) setter
    get_param() getter

Initial rotation applied to each particle, in degrees.

Only applied when flag_disable_z or flag_rotate_y are true or the SpatialMaterial being used to draw the particle is using SpatialMaterial.BILLBOARD_PARTICLES.

Min: -720
Max: 720

---

● float angle_random [default: 0.0]
    set_param_randomness(value) setter
    get_param_randomness() getter

Rotation randomness ratio.

Min: 0.00
Max: 1.00

● float scale [default: 1.0]
    set_param(value) setter
    get_param() getter

Initial scale applied to each particle.

warning: don't increase this property too much, you might not even be able to see any particle in the screen if you increase it too much.

Min: 0.00
Max: 1000.00

---

● float scale_random [default: 0.0]set_param_randomness(value) setterget_param_randomness() getter

Scale randomness ratio.

Min: 0.00
Max: 1.00

● float hue_variation [default: 0.0]
    set_param(value) setter
    get_param() getter

Initial hue variation applied to each particle.

Min: -1.00
Max: 1.00

---

Important if you have set hue_variation property to a non-zero value

● float hue_variation_random [default: 0.0]
    set_param_randomness(value) setter
    get_param_randomness() getter

Hue variation randomness ratio.

Min: 0.00
Max: 1.00

● float anim_speed [default: 0.0]
    set_param(value) setter
    get_param() getter

Particle animation speed.

Min: 0.00
Max: 128.00

---

● float anim_speed_random [default: 0.0]
    set_param_randomness(value) setter
    get_param_randomness() getter

Animation speed randomness ratio.

Min: 0.00
Max: 1.00

---

● float anim_offset [default: 0.0]
    set_param(value) setter
    get_param() getter

Particle animation offset.

Min: 0.00
Max: 1.00

---

● float anim_offset_random [default: 0.0]
    set_param_randomness(value) setter
    get_param_randomness() getter

Animation offset randomness ratio.

Min: 0.00
Max: 1.00