A Godot newbie here, so please be gentle.

This short code snippet reveals my problem: I’m able to modify vertex colors of a mesh and present them just fine with a create_from_surface & commit_to_surface pair.

But if I read the mesh data again with another create_from_surface and instantly return it with commit_to_surface without doing any other changes, the vertex color data is lost, and the mesh returns to its default color.

Is this how it’s supposed to work? And if so, do I need to save the color data vertex by vertex to a temporary array and then read it back again to preserve the color data? Seems terribly inefficient, or am I missing something?

Thanks in advance!

extends MeshInstance2D
var mdt = MeshDataTool.new()
# Called when the node enters the scene tree for the first time.
func _ready():
    mdt.create_from_surface(mesh, 0)
    var vertex_count = mdt.get_vertex_count()
    for i in range(vertex_count):
        mdt.set_vertex_color(i, Color((mdt.get_vertex(i).x),0,1))
    mdt.commit_to_surface(mesh) # Mesh shows as having a gradient from blue to purple
    mdt.create_from_surface(mesh, 0) # If I un-comment the next line, mesh shows as white 
    #mdt.commit_to_surface(mesh)
    #...