ArrayMesh Material Appears Rotated

[creatures-5]

Godot Version

4.3.stable

Question

I’m attempting to render a very simple mesh via ArrayMesh: two square planes, one on top of the other, with separate surfaces. I have this part working, but for some reason whenever I apply a texture as the material, it appears rotated on the mesh. Any idea how to fix this?

extends MeshInstance3D

func _ready() -> void:
	var data = []
	data.resize(ArrayMesh.ARRAY_MAX)
	data[ArrayMesh.ARRAY_VERTEX] = PackedVector3Array([
		Vector3(0,0,0),
		Vector3(1,1,0),
		Vector3(1,0,0),
		
		Vector3(0,0,0),
		Vector3(0,1,0),
		Vector3(1,1,0)
	])
	data[ArrayMesh.ARRAY_TEX_UV] = PackedVector2Array([
		Vector2(0,0),
		Vector2(1,1),
		Vector2(1,0),
		
		Vector2(0,0),
		Vector2(0,1),
		Vector2(1,1)
	])
	mesh = ArrayMesh.new()
	mesh.add_surface_from_arrays(Mesh.PRIMITIVE_TRIANGLES,data)
	
	#second surface
	data[ArrayMesh.ARRAY_VERTEX] = PackedVector3Array([
		Vector3(0,1,0),
		Vector3(1,2,0),
		Vector3(1,1,0),
		
		Vector3(0,1,0),
		Vector3(0,2,0),
		Vector3(1,2,0)
	])
	data[ArrayMesh.ARRAY_TEX_UV] = PackedVector2Array([
		Vector2(0,1),
		Vector2(1,2),
		Vector2(1,1),
		
		Vector2(0,1),
		Vector2(0,2),
		Vector2(1,2)
	])
	mesh.add_surface_from_arrays(Mesh.PRIMITIVE_TRIANGLES,data)
	ResourceSaver.save(mesh, "res://mesh_test_flip3.tres", ResourceSaver.FLAG_COMPRESS)

The highlights of the tile should be facing the top left not the bottom left. No matter what I change in the vertex ordering it doesn’t seem to change this.

[creatures-5]

I might switch to an immediatemesh if I can’t figure this out

[normalized]

Shift (or flip) the UVs.

[creatures-5]

Every time I change them to not match the vertices it leads to some weird errors

[normalized]

Well they need to match the vertices. Just change the order. Draw your triangles on a piece of paper.

[creatures-5]

I’ve tried that a few times, but it doesn’t seem to rotate it

[normalized]

Post the results you’re getting vs what you’re expecting to get.

[creatures-5]

The first image is what I’m getting (with a material applied to surface 0 of the mesh). The second image is what I expect to get (which is the same material but properly oriented)

[normalized]

That looks like you need to rotate the UVs clockwise. You can also just rotate the texture in an image editing app.

UVs rotated clockwise:
0,0 becomes 0,1
0,1 becomes 1,1
1,1 becomes 1,0
1,0 becomes 0,0

[creatures-5]

Thank you! That seemed to rotate it counterclockwise not clockwise for some reason, but I did it three times and it worked.

[normalized]

Well it depends from which side you look at the polygons. To rotate it in opposite direction just do the reverse of what I wrote above so:
0,1 → 0,0
1,1 → 0,1
1,0 → 1,1
0,0 → 1,0

[creatures-5]

For some reason this only seems to work for some textures. I have a handful of 64x64 textures, and 2 of them work fine for this while a third one appears rotated and flipped despite being fine elsewhere

[normalized]

Keep your UVs in 0-1 range. The code you initially posted seems to be having UVs that are larger than 1.

[creatures-5]

Oh wait I realized what it was. My own sprite confused me, the original code wasn’t rotated it was flipped. Thanks!