Bezier Solution [Open Source]

@yasirkula i get an exception if i use segment like this: BezierSpline.Segment segment = BezierSplineComponent.GetSegmentAt(.5f);

Exception:

ArgumentOutOfRangeException: Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index
System.ThrowHelper.ThrowArgumentOutOfRangeException (System.ExceptionArgument argument, System.ExceptionResource resource) (at <695d1cc93cca45069c528c15c9fdd749>:0)
System.ThrowHelper.ThrowArgumentOutOfRangeException () (at <695d1cc93cca45069c528c15c9fdd749>:0)
System.Collections.Generic.List`1[T].get_Item (System.Int32 index) (at <695d1cc93cca45069c528c15c9fdd749>:0)
BezierSolution.BezierSpline.GetSegmentAt (System.Single normalizedT) (at Assets/UnyXEngine/Core/Runtime/Lib/BezierSolution/BezierSpline.cs:848)
...

Please can you investigate?

EDIT: mmm...i dont' understand why endPoints on BezierSpline component is empty....this is cause exception
RESOLVED: bezier spline is inner a deactivated gameobject

 

Yes the spline is initialized in Awake. But perhaps adding

[SerializeField]

attribute to BezierSpline.endPoints variable would remove this requirement.

 

How would one go about setting a 2D sprite to face the direction of the path its following?

 

You can try

sprite.transform.right = spline.GetTangent(normalizedT);

 

@yasirkula

Hey there, long time!

I still appreciate this asset of yours. I wanted to ask a question about the spline walker.

How would you suggest coding the spline walker so that, say, it keeps moving in front of a chasing object at whatever speed the chasing object is moving?

 

Does the chasing object also move along the spline? If so, does it use BezierWalker, as well?

 

Admittedly, no, it doesn't move along the spline (and intentionally so - I don't want to make the computer look like they don't do natural movements for a racer)

I can't say it uses the BezierWalker itself.

 

As far as I understand, you always want the bezier walker to be 5 units ahead of the chaser object in Z+ axis. In this case, the only solution I can think of is not using a bezier walker but instead calling BezierSpline's FindNearestPointToLine function to move that object in Update. For example:

Code (CSharp):

1. public BezierSpline spline;
2. public Transform chaser;
3. public float distance = 5f;
4. public float accuracy = 250f; // The higher this value, the better. But CPU cost will increase proportionally
5.  
6. void LateUpdate()
7. {
8.     Vector3 chaserAheadPos = chaser.position + new Vector3( 0f, 0f, distance );
9.     Vector3 lineStart = new Vector3( chaserAheadPos.x - 5f, chaserAheadPos.y, chaserAheadPos.z );
10.     Vector3 lineEnd = new Vector3( chaserAheadPos.x + 5f, chaserAheadPos.y, chaserAheadPos.z );
11.    
12.     Vector3 pointOnLine;
13.     float normalizedT;
14.     Vector3 position = spline.FindNearestPointToLine( lineStart, lineEnd, out pointOnLine, out normalizedT, accuracy );
15.    
16.     transform.position = position;
17.    
18.     // Alternatively, lerp the position. While lerping, you can also try decreasing accuracy to boost performance
19.     //transform.position = Vector3.Lerp( transform.position, position, 10f * Time.deltaTime );
20.    
21.     transform.rotation = Quaternion.Lerp( transform.rotation, Quaternion.LookRotation( spline.GetTangent( normalizedT ) ), 10f * Time.deltaTime );
22. }

 

This is great, thank you.

Is there a way to call an event when you reach a bezier point? Thank you.

 

Unfortunately not. You could continuously check the value of spline.GetSegmentAt(normalizedT).point1 and raise the event when the returned point changes but if the object moves very fast or the game lags, it can skip some points (i.e. it only happens if the object passes multiple bezier points in a single frame).

 

Thank you, that works in the tests I've just ran perfectly for what I was hoping to achieve

Have a cup of coffee on me

 

Thank you for your support!

 

Hi yasirkula. First of all, thank you so much for this, it's a wonderful asset!

Just a question: Is there any way to use BezierWalkerWithTime while keeping a constant speed? I have different curves, side by side, where the objects must walk at a constant speed (not necessarily the same speed between each curve, as they have different properties) and arrive at the end in x seconds. Is it possible?

Again, thank you.

 

Yes! Simple enable High Quality option.

 

Hi! First of all, thanks for your awnser.
I already tried the high quality option but it still seems a bit odd. I don't know how to describe it, so I made a gif.

 

In the gif, it looks like the selected object abruptly slows down and speeds up but it might also be the case if the gif wasn't recorded with stable framerate. Could you explain the issue? What are your BezierWalker values?

 

Yes, that is exactly the problem, it's not related to the gif, it happens in the editor as well. The selected object is where the problem is most visible but it happens with basically all objects, to different degrees.

 

If possible, one quick solution would be to decrease Movement Lerp Modifier. Otherwise, try increasing the default parameters of

BezierSpline.CalculateEvenlySpacedPoints

function by modifying BezierSpline.cs: https://github.com/yasirkula/UnityB.../Plugins/BezierSolution/BezierSpline.cs#L1156

 

Even with the default value (10) the problem still happens

I had to leave the computer but when I get back I'll try the second option and come back here with the result.

 

So I tried changing the resolution parameter to 1 and it seems to work and all the objects are in sync, but it's still not at a constant speed, especially towards the end where they slow down slightly.

 

You need to increase those parameters, not decrease them.

 

@yasirkula

when i call MoveAlongSpline(ref float normalizedT, float deltaMovement, int accuracy = 3) method with parameters like:
normalizedT = 0f
deltaMovement = 0.09932098

the result is a Infinity normalizedT.... why? (I see that is happens caused division by zero in BezierSpline.cs row: 918 from GetTangent(0).magnitude = 0)

You can check please?

[RESOLVED]
mmmm...ok...i found the problem... i have a point with proceding and followin points at 0 with warning panel... it would be useful not to return an infinite value anyway, maybe some safety check or at most to clamp the result before the division so as not to divide by zero

 

Thank you for bringing it to my attention.

 

@yasirkula how to get exact normalizedT at some spline point position?

 

You can call spline.FindNearestPointTo. Note that it doesn't have pinpoint accuracy but you can increase its accuracy until you get acceptable results.

 

but this method return a Vector3, i need the reverse function, so vector3 -> normalizeT

 

It takes an optional

out float normalizedT

parameter.

 

@yasirkula how to get spline position point by normalizedT? GetPoint() return wrong value. I have a spline and if i pass 0.5f for middle position the result position is not middle, but approx about 30% the lenght of spline! Why?

I use GetSegmentAt(0.5f) and after segment.GetPoint()

 

That's how splines work. You can see the mathematical reasoning behind that in this video. What you can do is, calling

spline.GetSegmentAt(spline.evenlySpacedPoints.GetNormalizedTAtPercentage(0.5f))

instead.

 

@ yasirkula, first of all, a big thank you for your magnificent asset! Well made!

I have a question:
Would it be possible to get from a BezierSpline the exact (or at least reliable approximations of) t values for the endpoints with which it has been initialized?

Why am I asking?
I have the following use case:

GIVEN A dense and noisy polyline (OriginalPolyline).
OriginalPolyline is generated from tracking the position of a VR controller.
As a consequense, it has a non-uniform, variable, point density/segment length.

I WANT TO Generate a smooth polyline SmoothPolyline from OriginalPolyline with comparable point density.


My approach:
1) Generate a simplified polyline EndpointsPolyline from OriginalPolyline, using Unity's built-in LineUtility.Simplify() function.
2) Initialize a BezierSpline Spline with the points from EndpointsPolyline.
3) Get the t value for each endpoint, using Spline.FindNearestPointTo(endpoint.position).
4) Generete intermediate t values between each successive pair of endpoint t values, to get the same number of t values in each spline segment, as there were points in the corresponding section of OriginalPolyline.
5) Use this extended t values list to generate the points for SmoothPolyline from Spline.


The problem:
The BezierSpline.FindNearestPointTo(Vector3 position) call is an iterative approximation.
It quite often gives a wrong t value, where it seems to returns t values for points on parts of the spline that are near the actual endpoint, but much later (or earlier) in the polyline. (polyline self near-intersections)
This results in the successive values in the t values list acquired in step (3) to have t values jumping up and down sometimes.
(Note: I am using the default parameter values everywhere)

 

When a spline has 3 points, these points' t values are: 0f, 0.5f and 1f. As you can see, these t values don't take into account the distance between each point at all (because of which, I've added evenlySpacedPoints and pointCache helpers to the spline but these seem unrelated to your problem).

P.S. But if the spline is looped, then these 3 points' t values will be: 0f, 0.33f, 0.66f (and GetPoint(1f) will return the first point again).

 

A big shoutout @ yasirkula, for the swift response and clear explanation - everything works as expected now!
Is there a way to show our gratitude (in a monetary way) for making your unity asset available, and your helpful support?

 

Thank you very much! You can support me that way via the "support me" link in my signature.

 

Hi there,
I'd like to show the different points on the inspector and be able to change their position from there.
Any way to do that?

 

You can't see them all at once for the time being. You'd need to modify the source to achieve this.

 

Thanks for your answer @yasirkula

 

Hi, Timeline is probably modifying the underlying private fields whereas the component refreshes itself when its public properties are invoked. You can call the component's Refresh function at each frame while the animation is running to force update the mesh.

 

Hi!

I'm getting no handles now for curves that I create. This seems to be a new thing. Maybe since upgrading Unity.

See here: https://cln.sh/NlRz34

Unity version: 2021.2.7
Bezier version: 2.3.1

Thanks!

 

You need to enable gizmos via the top-right button in Scene window.

 

Hi, I love the assets and it works great, but I ran into problems when trying to export to UWP

 

I see, I'll need to check for UWP compatibility.

 

@AndresOrtiz Can you build the game after deleting BezierSolution to verify that BezierSolution is to blame here?

 

Hello, sorry for not warning, but BezierSolution was not to blame. I spent so much time solving it that I forgot to write to you later.

 

Thank you for your great assets, yasirkula!

I notice in a lot of places, e.g. GetPoint, GetTangent, you have:

Code (CSharp):

1. while( normalizedT < 0f )
2.     normalizedT += 1f;
3. while( normalizedT >= 1f )
4.     normalizedT -= 1f;

This can (obviously) lead to serious performance problems if you're not careful with the normalizedT you pass in. You might say you should make sure to pass in a normalized value, which is a fine argument. Seeing as you're still allowing and handling non-normalized values though, might I suggest something like:

normalizedT = ((normalizedT % 1.0f) + 1.0f) % 1.0f;

instead?

Maybe this is rarely a problem in practice, but it feels like a potentially head-scratchy bug to figure out if you do run into it. I did so accidentally while benchmarking:

MoveAlongSpline(ref splineT, Time.deltaTime * speed)

and noticing it got significantly slower as time went on. As I never actually altered splineT myself I also wasn't normalizing it.

 

Hi! I believe you're right! I shall benchmark your solution to see how it fares when compared to the current solution and then I'll update the plugin when I get the chance.

 

Hi there, I'm trying to accomplish similar function. It's a track that takes a gameobject and moves it onto another track.
I want to accomplish the following:
1) Each static track has a spline.
2) The dynamic track (can spin) adds a point to the static track when aligned.
3) cylinder can move onto dynamic track.
4) cylinder can be rotated and attached to another static track.

FindNearestPointTo() doesn't get the cylinder to stay in place. If I have a BezierAttachment attached to the cylinder, it jumps before it can retrieve the nearest point.

Code (CSharp):

1. _spline = spline;
2.  _spline.InsertNewPointAt(2);
3.  _spline[2].position = transform.position;
4.  
5. _spline.FindNearestPointTo(_power.transform.position, out float normalizedT);

The normalizedT should return ~0.4 but since the moment the spline inserts a new point, gameobject jumps. So how would you FindNearestPointTo with the traversing object?

 

@mikeohc BezierAttachment is supposed to update the object's position in LateUpdate actually. Is there a hidden _spline.Refresh function before FindNearestPointTo, because that'd refresh BezierAttachment immediately and cause this issue. I'd recommend putting a Debug.Log inside BezierAttachment.RefreshInternal to see where it's being triggered from. If it's indeed called immediately after inserting a new point, then we'll at least see the stacktrace.

In the worst case that we can't prevent this immediate-update, then the only solution that comes to mind is fetching the attachments' position prior to adding a new point to the spline.

 

I think I found the issue. It's because when the dynamic track snaps to the static track, I am invoking an event to call FindNearestPointTo(). But if I call FindNearestPointTo() within the same script before invoking, I can retrieve the correct NormalizedT.

Thanks for the help!

 

hey thanks for the asset. how would you exactly set things up to make a character grind?

 

Hi, I don't know the exact steps, but after setting up a spline, I'd probably call spline.FindNearestPointTo to find the nearest point on the spline to the character and start grinding from there. While grinding, I'd call spline.MoveAlongSpline or spline.GetPoint at each frame.