Curved movement
Move objects on curved paths.
Authors and contributors to this community extension: pampogokiraly, D8H.
This extension allows to move objects on Bézier curve paths.
- Paths can be built dynamically or from predetermined paths in SVG format.
- A behavior moves objects in a given duration a bit like the Tween extension does.
- Another behavior moves objects using a speed and an acceleration.
- Expressions give access to the path trajectory values for more complex movements.
This extension can be used to:
- Move enemies that follow a pattern
- Animate decorations
A collection of small examples shows how to use this extension.
2 examples use it:
- a 3D racing game (open the project online)
- a Zuma-like (open the project online)
Tip
Learn how to install new extensions by following a step-by-step guide.
Actions
Append a curve
Append a cubic Bezier curve at the end of the path.
Append a line
Append a line at the end of the path.
Append a smooth curve
Append a cubic Bezier curve to the end of an object's path. The first control point is symmetrical to the last control point of the path.
Append a path
Append a path to another path.
Append a rotated path
Append a path to another path. The appended path is rotated to have a smooth junction.
Close a path
Append a line to close the path.
Create a path from SVG
Create a path from SVG commands, for instance "M 0,0 C 55,0 100,45 100,100". Commands are: M = Move, C = Curve, S = Smooth, L = Line. Lower case is for relative positions. The preferred way to build the commands is to use an external SVG editor like Inkscape.
Delete a path
Delete a path from the memory.
Duplicate a path
Duplicate a path.
Invert a path
Invert a path, the end becomes the beginning.
Rotate a path
Rotate a path.
Scale a path
Scale a path.
Speed scale Y
Change the speed scale on Y axis. This allows to change the view point of a path (top-dwon or isometry).
Conditions
Is closed
Check if a path is closed.
Path exists
Path exists.
Expressions
| Expression | Description | |
|---|---|---|
CurvedMovement::ElementCount() |
Return the number of lines or curves that make the path. | |
CurvedMovement::FirstControlX() |
Return the first control point position on X axis of a curve. | |
CurvedMovement::FirstControlY() |
Return the first control point position on Y axis of a curve. | |
CurvedMovement::OriginX() |
Return the origin position on X axis of a curve. | |
CurvedMovement::OriginY() |
Return the origin position on Y axis of a curve. | |
CurvedMovement::PathAngle() |
Return the direction angle of the path for a given length (in degree). | |
CurvedMovement::PathEndX() |
Return the displacement on X axis of the path end. | |
CurvedMovement::PathEndY() |
Return the displacement on Y axis of the path end. | |
CurvedMovement::PathLength() |
Return the length of the path. | |
CurvedMovement::PathX() |
Return the position on X axis of the path for a given length. | |
CurvedMovement::PathY() |
Return the position on Y axis of the path for a given length. | |
CurvedMovement::SecondControlX() |
Return the second control point position on X axis of a curve. | |
CurvedMovement::SecondControlY() |
Return the second control point position on Y axis of a curve. | |
CurvedMovement::SpeedScaleY() |
Return the speed scale on Y axis. This is used to change the view point of a path (top-dwon or isometry). | |
CurvedMovement::TargetX() |
Return the target position on X axis of a curve. | |
CurvedMovement::TargetY() |
Return the target position on Y axis of a curve. | |
CurvedMovement::ToSvg() |
Return the SVG commands of a path. |
Movement on a curve (speed-based)
Move objects on curved paths at a given speed.
Behavior actions
Accelerate
Make an object accelerate until it reaches a given speed.
Accelerate during
Make an object accelerate to reaches a speed in a given amount of time.
Draw the trajectory
Draw the object trajectory.
Follow a path
Change the path followed by an object.
Follow a path to a position
Change the path followed by an object to reach a position.
Position on the path
Change the length between the trajectory origin and the current position counting the loops.
Speed
Change the speed of the object.
Behavior conditions
Can move further
Check if the object can still move in the current direction.
Reach an end
Check if the object has reached one of the 2 ends of the path.
Reached path origin
Check if the object has reached the origin position of the path.
Reached path target
Check if the object has reached the target position of the path.
Current loop
Compare the number time the object loop the trajectory.
Position on the loop
Compare the length between the trajectory origin and the current position without counting the loops.
Position on the path
Compare the length between the trajectory origin and the current position counting the loops.
Speed
Compare the speed of the object.
Behavior expressions
| Expression | Description | |
|---|---|---|
Object.SpeedPathMovement::Loop() |
Return the number time the object loop the trajectory. | |
Object.SpeedPathMovement::MovementAngle() |
Return the angle of movement on its path. | |
Object.SpeedPathMovement::PathOriginX() |
Return the path origin on X axis of the object. | |
Object.SpeedPathMovement::PathOriginY() |
Return the path origin on Y axis of the object. | |
Object.SpeedPathMovement::PositionOnLoop() |
Return the length between the trajectory origin and the current position without counting the loops. | |
Object.SpeedPathMovement::PositionOnPath() |
Return the length between the trajectory origin and the current position counting the loops. | |
Object.SpeedPathMovement::Speed() |
Return the speed of the object. |
Movement on a curve (duration-based)
Move objects on curved paths in a given duration and tween easing function.
Behavior actions
Draw the trajectory
Draw the object trajectory.
Move on path
Move the object by following a path.
Move back and forth
Move the object by following a path and go back.
Move on path to a position
Move the object to a position by following a path.
Move back and forth to a position
Move the object to a position by following a path and go back.
Behavior conditions
Finished to move
Check if the object has finished to move on the path.
Reached an end
Check if the object has reached one of the 2 ends of the path.
Behavior expressions
| Expression | Description | |
|---|---|---|
Object.TweenPathMovement::MovementAngle() |
Return the angle of movement on its path. |
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