mirror of
https://github.com/QB64Official/qb64.git
synced 2024-07-16 21:15:15 +00:00
73 lines
2.7 KiB
Markdown
73 lines
2.7 KiB
Markdown
The [_WHEEL](_WHEEL) function returns the relative position of a specified wheel number on a controller device.
|
|
|
|
## Syntax
|
|
|
|
> move = [_WHEEL](_WHEEL)(wheelNumber%)
|
|
|
|
* Returns -1 when scrolling up and 1 when scrolling down with 0 indicating no movement since last read.
|
|
* Add consecutive wheel values to determine a cumulative value over time for scrolling or moving objects.
|
|
* wheelNumber% must be a number which does not exceed the number of wheels found by the [_LASTWHEEL](_LASTWHEEL) function.
|
|
* When a mouse indicates it has 3 wheels, the first two are for relative movement reads. The third wheel is for scrolling.
|
|
* **The number of [_DEVICES](_DEVICES) must be read before using [_DEVICE$](_DEVICE$), [_DEVICEINPUT](_DEVICEINPUT) or [_LASTWHEEL](_LASTWHEEL).**
|
|
|
|
## Example(s)
|
|
|
|
Reading multiple controller device buttons, axis and wheels.
|
|
|
|
```vb
|
|
|
|
FOR i = 1 TO _DEVICES
|
|
PRINT STR$(i) + ") " + _DEVICE$(i) + " Buttons:"; _LASTBUTTON(i); ",Axis:"; _LASTAXIS(i); ",Wheel:"; _LASTWHEEL(i)
|
|
NEXT
|
|
|
|
DO
|
|
d& = _DEVICEINPUT
|
|
IF d& THEN ' the device number cannot be zero!
|
|
PRINT "Found"; d&;
|
|
FOR b = 1 TO _LASTBUTTON(d&)
|
|
PRINT _BUTTONCHANGE(b); _BUTTON(b);
|
|
NEXT
|
|
FOR a = 1 TO _LASTAXIS(d&)
|
|
PRINT _AXIS(a);
|
|
NEXT
|
|
FOR w = 1 TO _LASTWHEEL(d&)
|
|
PRINT _WHEEL(w);
|
|
NEXT
|
|
PRINT
|
|
END IF
|
|
LOOP UNTIL INKEY$ = CHR$(27) 'escape key exit
|
|
|
|
END
|
|
|
|
```
|
|
|
|
> *Note:* When there is no device control to read, a [FOR...NEXT](FOR...NEXT) n = 1 TO 0 loop will not run thus avoiding a control function read error.
|
|
|
|
Why does a mouse have 3 wheels? Relative x and y movements can be read using the first 2 _WHEEL reads.
|
|
|
|
```vb
|
|
|
|
ignore = _MOUSEMOVEMENTX 'dummy call to put mouse into relative movement mode
|
|
|
|
PRINT "Move your mouse and/or your mouse wheel (ESC to exit)"
|
|
|
|
d = _DEVICES ' always read number of devices to enable device input
|
|
DO: _LIMIT 30 'main loop
|
|
DO WHILE _DEVICEINPUT(2) 'loop only runs during a device 2 mouse event
|
|
PRINT _WHEEL(1), _WHEEL(2), _WHEEL(3)
|
|
LOOP
|
|
LOOP UNTIL INKEY$ = CHR$(27)
|
|
|
|
```
|
|
|
|
> *Explanation:* Referencing the [_MOUSEMOVEMENTX](_MOUSEMOVEMENTX) function hides the mouse and sets the mouse to a relative movement mode which can be read by [_WHEEL](_WHEEL). [_DEVICEINPUT](_DEVICEINPUT)(2) returns -1 (true) only when the mouse is moved, scrolled or clicked.
|
|
|
|
## See Also
|
|
|
|
* [_MOUSEWHEEL](_MOUSEWHEEL)
|
|
* [_LASTWHEEL](_LASTWHEEL), [_LASTBUTTON](_LASTBUTTON), [_LASTAXIS](_LASTAXIS)
|
|
* [_AXIS](_AXIS), [_BUTTON](_BUTTON), [_BUTTONCHANGE](_BUTTONCHANGE)
|
|
* [_DEVICES](_DEVICES), [_DEVICE$](_DEVICE$), [_DEVICEINPUT](_DEVICEINPUT)
|
|
* [_MOUSEMOVEMENTX](_MOUSEMOVEMENTX), [_MOUSEMOVEMENTY](_MOUSEMOVEMENTY)
|
|
* [Controller Devices](Controller-Devices)
|