simvx.core.nodes_2d.trail

Trail2D – Ribbon trail that follows a moving node.

Module Contents

Classes

Trail2D

Ribbon trail that follows this node’s movement.

API

class simvx.core.nodes_2d.trail.Trail2D(**kwargs)

Bases: simvx.core.nodes_2d.node2d.Node2D

Ribbon trail that follows this node’s movement.

Records positions over time and renders a fading ribbon. Attach as child of a moving node for sword swipes, missile trails, movement effects, etc.

The node manages the point buffer and self-renders via on_draw, emitting one tapered, colour-graded line segment per pair of trail points. trail_points exposes the per-point centreline (position, width, colour); trail_geometry expands the same points into a triangle-strip ribbon for custom rendering or editor tooling.

Initialization

dynamic

True

length

‘Property(…)’

width

‘Property(…)’

width_curve

‘Property(…)’

colour

‘Colour(…)’

colour_end

‘Colour(…)’

lifetime

‘Property(…)’

emit

‘Property(…)’

gizmo_colour

‘Colour(…)’

on_update(dt: float)

Record position, age points, and cull expired ones.

on_draw(renderer)

Draw the ribbon as tapered, colour-graded line segments.

trail_points are already world-space (built from world_position in :meth:on_update), so they are drawn directly: the 2D submit path applies only the camera affine to on_draw geometry and never re-applies the node’s world transform, so world-space points land on the moving node without a double offset.

clear()

Remove all trail points immediately.

property trail_points: list[dict]

Trail point data for rendering.

Each dict has: position (Vec2), normalized_age (0=new, 1=expired), width (float), colour (tuple).

property trail_geometry: list[dict]

Vertices for a triangle strip suitable for rendering.

Each vertex dict has: position (Vec2), colour (tuple). For each trail point, two vertices are generated offset perpendicular to the trail direction by +/- half the interpolated width.

get_gizmo_lines() → list[tuple[simvx.core.math.types.Vec2, simvx.core.math.types.Vec2]]

Return the trail centerline as connected line segments for editor gizmos.

position

‘_SpatialVecProperty(…)’

rotation

‘Property(…)’

scale

‘_SpatialVecProperty(…)’

z_index

‘Property(…)’

z_as_relative

‘Property(…)’

render_layer

‘Property(…)’

set_render_layer(index: int, enabled: bool = True) → None

is_on_render_layer(index: int) → bool

property absolute_z_index: int

property rotation_degrees: float

property world_position: simvx.core.math.types.Vec2

property world_rotation: float

property world_scale: simvx.core.math.types.Vec2

property world_transform: tuple[simvx.core.math.types.Vec2, simvx.core.math.types.Vec2, float]

property forward: simvx.core.math.types.Vec2

property right: simvx.core.math.types.Vec2

translate(offset: tuple[float, float] | numpy.ndarray)

rotate(radians: float)

rotate_deg(degrees: float)

look_at(target: tuple[float, float] | numpy.ndarray)

transform_points(points: list[simvx.core.math.types.Vec2]) → list[simvx.core.math.types.Vec2]

draw_polygon(renderer, points: list[simvx.core.math.types.Vec2], closed=True, colour=None)

wrap_screen(margin: float = 20)

hdr

‘Property(…)’

property transform_render_dirty: bool

strict_errors: ClassVar[bool]

True

script_error_raised

‘Signal(…)’

classmethod __init_subclass__(**kwargs)

property name: str

property update_mode: simvx.core.descriptors.UpdateMode

property visible: bool

reset_error() → None

add_child(node: simvx.core.node.Node) → simvx.core.node.Node

remove_child(node: simvx.core.node.Node)

reparent(new_parent: simvx.core.node.Node)

get_node(path: str) → simvx.core.node.Node

get_node_or_none(path: str) → simvx.core.node.Node | None

find(target, *, direct: bool = False)

find_all(target, *, direct: bool = False)

walk(*, include_self: bool = True) → collections.abc.Iterator[simvx.core.node.Node]

property path: str

add_to_group(group: str)

remove_from_group(group: str)

is_in_group(group: str) → bool

on_ready() → None

on_enter_tree() → None

on_exit_tree() → None

on_fixed_update(dt: float) → None

on_picked(event: simvx.core.events.InputEvent) → None

on_unhandled_input(event: simvx.core.events.TreeInputEvent) → None

start_coroutine(gen: simvx.core.descriptors.Coroutine) → simvx.core.descriptors.CoroutineHandle

stop_coroutine(gen_or_handle)

queue_redraw() → None

property render_dirty: bool

clear_children()

destroy()

call_deferred(method: collections.abc.Callable[..., Any], *args: Any) → None

property app

property tree: simvx.core.scene_tree.SceneTree

property physics

property physics_2d

__getitem__(key: str)

classmethod get_properties() → dict[str, simvx.core.descriptors.Property]

__repr__()