This is a simple libretro core for testing out the lightgun API with absolute position mice. An absolute mouse is a mouse that reports its absolute position relative to its movement surface rather than its relative movement. For example a touchscreen, or real lightgun would report its absolute position rather than relative movement.
The plan is for the core draw a cursor, and display the button presses on screen as well as show a message when the gun is pointed off screen.
I have been using python-uinput in conjunction with this core to generate absolute mouse inputs.
This short python recipe can be used in an interactive python shell to simulate an absolute mouse. Use the move method to move the cursor around the screen.
import uinput
events = (
uinput.ABS_X + (0, 320, 0, 0), # absolute ranges (min, max, fuzz, flat)
uinput.ABS_Y + (0, 240, 0, 0),
uinput.BTN_LEFT, uinput.BTN_RIGHT
)
device = uinput.Device(events, name="fake-abs-mouse")
def move(x, y):
device.emit(uinput.ABS_X, x, syn=False)
device.emit(uinput.ABS_Y, y)The min and max ranges for ABS_X and ABS_Y do not make any difference as they are normalised to between -0x7fff and 0x8000 by libretro and then must be normalised to screen position by the core. However, a larger range in the ABS_X/Y axis will allow for higher resolution movement if the screen is large enough.
If you start a python shell and create the fake-abs-mouse device, you should also be able to monitor the events using evtest.
For example, using move(320//2, 240//2) will result in the follow ABS_X/Y messages.
Input device name: "fake-abs-mouse"
Supported events:
Event type 0 (EV_SYN)
Event type 1 (EV_KEY)
Event code 272 (BTN_LEFT)
Event code 273 (BTN_RIGHT)
Event type 3 (EV_ABS)
Event code 0 (ABS_X)
Value 0
Min 0
Max 320
Event code 1 (ABS_Y)
Value 0
Min 0
Max 240
Properties:
Testing ... (interrupt to exit)
Event: time 1551224310.202565, type 3 (EV_ABS), code 0 (ABS_X), value 160
Event: time 1551224310.202565, type 3 (EV_ABS), code 1 (ABS_Y), value 120
Event: time 1551224310.202565, -------------- SYN_REPORT ------------