# input_mouse_rebase.ludic — Input.mouse_dx/dy report no motion on the first frame and on the
# frame a cursor-mode change lands, and ordinary motion on every other frame.
#
# The delta is this frame's position minus the last. Before any position has been read the "last"
# one is 0,0, and across a mode change it belongs to another source (a locked cursor's virtual
# reticle against the real cursor) - both used to come out as a jump the size of the screen.
# Driven headless by injection:
#   bin/ludic examples/library/input_mouse_rebase.ludic  ->  0 0 5 -2 0 0 4 3 6 0 0 0
program InputMouseRebase {
  entry {
    # the first frame: the cursor is already at 300,400, which is not 300,400 of motion
    Input.set_mouse(300, 400, 0, 0)
    Input.poll()
    print(Input.mouse_dx())              # 0
    print(Input.mouse_dy())              # 0
    # ordinary motion
    Input.set_mouse(305, 398, 0, 0)
    Input.poll()
    print(Input.mouse_dx())              # 5
    print(Input.mouse_dy())              # -2
    # a mode change: the next position is from another source
    Input.cursor_mode(2)
    Input.set_mouse(900, 100, 0, 0)
    Input.poll()
    print(Input.mouse_dx())              # 0
    print(Input.mouse_dy())              # 0
    Input.set_mouse(904, 103, 0, 0)
    Input.poll()
    print(Input.mouse_dx())              # 4
    print(Input.mouse_dy())              # 3
    # asking for the mode already in force is not a change
    Input.cursor_mode(2)
    Input.set_mouse(910, 103, 0, 0)
    Input.poll()
    print(Input.mouse_dx())              # 6
    print(Input.mouse_dy())              # 0
    # and back: no jump from the reticle to the real cursor
    Input.cursor_mode(0)
    Input.set_mouse(10, 10, 0, 0)
    Input.poll()
    print(Input.mouse_dx())              # 0
    print(Input.mouse_dy())              # 0
  }
}