Lining a Sprite up With Polygon2D Vertices.

MrAldersonMaths

Edit: I've clearly done something wrong trying to format the code. I've a lesson to teach so I'll have to fix it later. Sorry!

I apologize if this is a really daft question, I'm very new to programming. I'm trying to put together something to help me explain exterior angles of polygons to my students.

It would let them create/pick a polygon and have a sprite walk around the outside of it, tracing out exterior angles as he goes. I've got a decent idea of how I'm going to do most of it, but I can't for the life of me figure out how to work with the vertices of the polygon.

I've defined a polygon2D called Quadrilateral to test. Defined a variable for each Vector2 in Quadrilateral.polygon[n] and used the Vector2s to determine the position of a sprite. The problem is, the sprite never lines up with the vertices. I've tried using both .position and .global_position and neither lines it up correctly.

func trace():
# Set the coordinates of the polygon. 
# Eventually will take inputs from a control
	Quadrilateral.polygon[0] = Vector2(100,200)
	Quadrilateral.polygon[1] = Vector2(100,100)
	Quadrilateral.polygon[2] = Vector2(200,100)
	Quadrilateral.polygon[3] = Vector2(200,200)
# Set variables for each vertex
	var Vertex1 : Vector2 = Quadrilateral.polygon[0]
	var Vertex2 : Vector2 = Quadrilateral.polygon[1]
	var Vertex3 : Vector2 = Quadrilateral.polygon[2]
	var Vertex4 : Vector2 = Quadrilateral.polygon[3]
# Move spirte (Pointer) to the coordinates of vertex 1
	Pointer.global_position = Vertex1
# $Label to output coords for troubleshooting, does not affect code.
	$Label.text = str(Vertex1,  Vertex2, Pointer.position.x, Pointer.position.y)

I have a hunch that my issue is that I'm not using the global coordinates for the vertices of the polygon but I have no idea on how I would do that.

TwistedTwigleg

@MrAldersonMaths said: Edit: I've clearly done something wrong trying to format the code. I've a lesson to teach so I'll have to fix it later. Sorry!

No problem! I fixed it for you :smile:

The issue was you were formatting it as an inline code segment, which unfortunately doesn't work with multi-line code blocks. You can mark code as multi-line either by indenting everything by a tab, or by surrounding the code in three ~ on either side. The Vanilla code drop down unfortunately defaults to inline code segments, which doesn't help.

MrAldersonMaths

I really appreciate you doing that and explaining how I can make it work in the future @TwistedTwigleg

I'm always a bit anxious on entering a new community and the fact that my first interaction was a positive one means a lot. Thank you.

llasram

Can you attach a screenshot of what you're seeing? Regardless, I can think of two things that might be happening:

More likely: the Sprite isn't a direct child of the Polygon2D, and the Polygon2D has its own non-zero position. The polygon points will be relative to the transform of the Polygon2D, and the sprite position will be relative to the transform of its parent. Try moving your "pointer" sprite to be a direct child of the Polygon2D and set its position (not global_position). If that works, you just need to make sure nothing is shifted from the origin, or account for node transforms as you match things up. (Or just leave the pointer a child of the polygon, which is possibly easiest.)
Less likely: the Sprite offset properties aren't set up to draw the sprite where you want it given the sprite shape, such as with centered true when the sprite is an up-pointing arrow.

MrAldersonMaths

@llasram said: Can you attach a screenshot of what you're seeing? Regardless, I can think of two things that might be happening:

More likely: the Sprite isn't a direct child of the Polygon2D, and the Polygon2D has its own non-zero position. The polygon points will be relative to the transform of the Polygon2D, and the sprite position will be relative to the transform of its parent. Try moving your "pointer" sprite to be a direct child of the Polygon2D and set its position (not global_position). If that works, you just need to make sure nothing is shifted from the origin, or account for node transforms as you match things up. (Or just leave the pointer a child of the polygon, which is possibly easiest.)

Less likely: the Sprite offset properties aren't set up to draw the sprite where you want it given the sprite shape, such as with centered true when the sprite is an up-pointing arrow.

It was number 1. I didn't have Pointer as a child of Quadrilateral. Thank you :)