Can't read length of an OpenFL Vector

1

I have a strange error. My application compiles but gets a runtime error when trying to read the length of an OpenFL Vector. See comment below.

	private function set_pointData(data:Vector<Vector3D>):Vector<Vector3D>
	{
		if (data.length < _pointsPerSegment) … //throws an error saying "Uncaught TypeError TypeError: data.get_length is not a function

In debug mode, when I break on that line I can see that the data consists of 46 entries and does have a length property. I’m compiling to JavaScript. I tried setting -dce to “no”. What could be the problem?

2

Does this work with another target? Otherwise there might be a bug in openfl’s Vector code.

3

There seems to be something about starting with an Array and casting it to Vector of the same length. Compiling to Hashlink fails with Uncaught exception: Can't cast hl.types.ArrayObj to openfl._Vector.ObjectVector but compiling to JavaScript works fine, and the casting works.

If I start with a Vector and populate that before passing to the function, things work fine. I have it working now.

4

You can’t cast from one class to another unrelated class, like you saw it doesn’t work.

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5

Works in JavaScript, but okay. :slight_smile:

6

What do you mean “works”? Unlike hashlink there’s no native compiler that’ll complain, but it clearly doesn’t work, you got a type error.

Haxe is permissive and lets you ignore its typing with force casting, but if you do something that doesn’t make sense you’ll have issues.

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7

What I did was create an Array and then called:
set_pointData(cast(myArray));
At runtime I set a breakpoint within the set_pointData function and inspected the “data” variable. It was populated as I expected in the debugger and did have a length. No error happened until later on in the function it attempted to read the length.

8

But you’re right, it doesn’t work at runtime.

9

Your casting says to haxe “this variable is a vector, don’t complain”.

Then at runtime it doesn’t fail because the array doesn’t have a length, but because it doesn’t have a get_length function like a Vector.

Would also have failed if you tried to access the fixed variable of the array pretending to be a vector, since it wouldn’t have one either.

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10

You can use Vector.ofArray() to convert from Array<T> to openfl.Vector<T>.

1 Like
11

Dang why does that look so familiar? Thanks!