Snap grid alignment isn't fully accurate

[augustvc]

Tested versions

• Reproducible in 3.6 stable (mono)
• Not reproducible in 3.5.3 stable (mono)

System information

Windows 10, Godot 3.6 (stable), OpenGL ES 2.0

Issue description

Grid alignment is slightly off. The discrepancy seems to be fractional (it is accurate at 0, and off by 0.8 at 640). You can see the grid x on top also isn't 640, but 640.8

Steps to reproduce

Place a Node2D at an x of 640 with the default grid snap settings (8x8). Look at its position in the snap grid. I would expect it to be on a line, but it is slightly off the line (because the line is in fact on x 640.8 instead of on 640)

Minimal reproduction project (MRP)

You can see the issue in a brand new project just as easy, but here's my project.
Godot grid bug test.zip

[augustvc]

duplicate of #98466