Fixed bug 5028 - Virtual Joysticks (new joystick backend)
David Ludwig I have created a new driver for SDL's Joystick and Game-Controller subsystem: a Virtual driver. This driver allows one to create a software-based joystick, which to SDL applications will look and react like a real joystick, but whose state can be set programmatically. A primary use case for this is to help enable developers to add touch-screen joysticks to their apps. The driver comes with a set of new, public APIs, with functions to attach and detach joysticks, set virtual-joystick state, and to determine if a joystick is a virtual-one. Use of virtual joysticks goes as such: 1. Attach one or more virtual joysticks by calling SDL_JoystickAttachVirtual. If successful, this returns the virtual-device's joystick-index. 2. Open the virtual joysticks (using indicies returned by SDL_JoystickAttachVirtual). 3. Call any of the SDL_JoystickSetVirtual* functions when joystick-state changes. Please note that virtual-joystick state will only get applied on the next call to SDL_JoystickUpdate, or when pumping or polling for SDL events (via SDL_PumpEvents or SDL_PollEvent). Here is a listing of the new, public APIs, at present and subject to change: ------------------------------------------------------------ /** * Attaches a new virtual joystick. * Returns the joystick's device index, or -1 if an error occurred. */ extern DECLSPEC int SDLCALL SDL_JoystickAttachVirtual(SDL_JoystickType type, int naxes, int nballs, int nbuttons, int nhats); /** * Detaches a virtual joystick * Returns 0 on success, or -1 if an error occurred. */ extern DECLSPEC int SDLCALL SDL_JoystickDetachVirtual(int device_index); /** * Indicates whether or not a virtual-joystick is at a given device index. */ extern DECLSPEC SDL_bool SDLCALL SDL_JoystickIsVirtual(int device_index); /** * Set values on an opened, virtual-joystick's controls. * Returns 0 on success, -1 on error. */ extern DECLSPEC int SDLCALL SDL_JoystickSetVirtualAxis(SDL_Joystick * joystick, int axis, Sint16 value); extern DECLSPEC int SDLCALL SDL_JoystickSetVirtualBall(SDL_Joystick * joystick, int ball, Sint16 xrel, Sint16 yrel); extern DECLSPEC int SDLCALL SDL_JoystickSetVirtualButton(SDL_Joystick * joystick, int button, Uint8 value); extern DECLSPEC int SDLCALL SDL_JoystickSetVirtualHat(SDL_Joystick * joystick, int hat, Uint8 value); ------------------------------------------------------------ Miscellaneous notes on the initial patch, which are also subject to change: 1. no test code is present in SDL, yet. This should, perhaps, change. Initial development was done with an ImGui-based app, which potentially is too thick for use in SDL-official. If tests are to be added, what kind of tests? Automated? Graphical? 2. virtual game controllers can be created by calling SDL_JoystickAttachVirtual with a joystick-type of SDL_JOYSTICK_TYPE_GAME_CONTROLLER, with naxes (num axes) set to SDL_CONTROLLER_AXIS_MAX, and with nbuttons (num buttons) set to SDL_CONTROLLER_BUTTON_MAX. When updating their state, values of type SDL_GameControllerAxis or SDL_GameControllerButton can be casted to an int and used for the control-index (in calls to SDL_JoystickSetVirtual* functions). 3. virtual joysticks' guids are mostly all-zeros with the exception of the last two bytes, the first of which is a 'v', to indicate that the guid is a virtual one, and the second of which is a SDL_JoystickType that has been converted into a Uint8. 4. virtual joysticks are ONLY turned into virtual game-controllers if and when their joystick-type is set to SDL_JOYSTICK_TYPE_GAMECONTROLLER. This is controlled by having SDL's default list of game-controllers have a single entry for a virtual game controller (of guid, "00000000000000000000000000007601", which is subject to the guid-encoding described above). 5. regarding having to call SDL_JoystickUpdate, either directly or indirectly via SDL_PumpEvents or SDL_PollEvents, before new virtual-joystick state becomes active (as specified via SDL_JoystickSetVirtual* function-calls), this was done to match behavior found in SDL's other joystick drivers, almost all of which will only update SDL-state during SDL_JoystickUpdate. 6. the initial patch is based off of SDL 2.0.12 7. the virtual joystick subsystem is disabled by default. It should be possible to enable it by building with SDL_JOYSTICK_VIRTUAL=1 Questions, comments, suggestions, or bug reports very welcome!
This commit is contained in:
Sam Lantinga
parent
879f137aec
commit
2be75c6a61
13 changed files with 719 additions and 1 deletions
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@ -46,6 +46,10 @@
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#include <tlhelp32.h>
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#endif
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#if SDL_JOYSTICK_VIRTUAL
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#include "./virtual/SDL_sysjoystick_c.h"
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#endif
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static SDL_JoystickDriver *SDL_joystick_drivers[] = {
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#if defined(SDL_JOYSTICK_DINPUT) || defined(SDL_JOYSTICK_XINPUT)
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&SDL_WINDOWS_JoystickDriver,
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@ -74,6 +78,9 @@ static SDL_JoystickDriver *SDL_joystick_drivers[] = {
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#ifdef SDL_JOYSTICK_HIDAPI
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&SDL_HIDAPI_JoystickDriver,
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#endif
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#ifdef SDL_JOYSTICK_VIRTUAL
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&SDL_VIRTUAL_JoystickDriver,
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#endif
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#if defined(SDL_JOYSTICK_DUMMY) || defined(SDL_JOYSTICK_DISABLED)
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&SDL_DUMMY_JoystickDriver
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#endif
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@ -456,6 +463,115 @@ SDL_JoystickOpen(int device_index)
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}
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int
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SDL_JoystickAttachVirtual(SDL_JoystickType type,
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int naxes,
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int nballs,
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int nbuttons,
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int nhats)
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{
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#if SDL_JOYSTICK_VIRTUAL
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return SDL_JoystickAttachVirtualInner(type,
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naxes,
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nballs,
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nbuttons,
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nhats);
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#else
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return SDL_SetError("SDL not built with virtual-joystick support");
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#endif
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}
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int
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SDL_JoystickDetachVirtual(int device_index)
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{
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#if SDL_JOYSTICK_VIRTUAL
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SDL_JoystickDriver *driver;
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SDL_LockJoysticks();
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if (SDL_GetDriverAndJoystickIndex(device_index, &driver, &device_index)) {
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if (driver == &SDL_VIRTUAL_JoystickDriver) {
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const int result = SDL_JoystickDetachVirtualInner(device_index);
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SDL_UnlockJoysticks();
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return result;
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}
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}
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SDL_UnlockJoysticks();
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return SDL_SetError("Virtual joystick not found at provided index");
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#else
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return SDL_SetError("SDL not built with virtual-joystick support");
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#endif
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}
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SDL_bool
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SDL_JoystickIsVirtual(int device_index)
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{
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#if SDL_JOYSTICK_VIRTUAL
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SDL_JoystickDriver *driver;
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int driver_device_index;
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SDL_bool is_virtual = SDL_FALSE;
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SDL_LockJoysticks();
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if (SDL_GetDriverAndJoystickIndex(device_index, &driver, &driver_device_index)) {
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if (driver == &SDL_VIRTUAL_JoystickDriver) {
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is_virtual = SDL_TRUE;
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}
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}
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SDL_UnlockJoysticks();
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return is_virtual;
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#else
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return SDL_FALSE;
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#endif
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}
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int
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SDL_JoystickSetVirtualAxis(SDL_Joystick * joystick, int axis, Sint16 value)
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{
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#if SDL_JOYSTICK_VIRTUAL
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return SDL_JoystickSetVirtualAxisInner(joystick, axis, value);
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#else
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return SDL_SetError("SDL not built with virtual-joystick support");
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#endif
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}
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int
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SDL_JoystickSetVirtualBall(SDL_Joystick * joystick, int axis, Sint16 xrel, Sint16 yrel)
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{
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#if SDL_JOYSTICK_VIRTUAL
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return SDL_JoystickSetVirtualBallInner(joystick, axis, xrel, yrel);
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#else
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return SDL_SetError("SDL not built with virtual-joystick support");
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#endif
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}
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int
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SDL_JoystickSetVirtualButton(SDL_Joystick * joystick, int button, Uint8 value)
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{
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#if SDL_JOYSTICK_VIRTUAL
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return SDL_JoystickSetVirtualButtonInner(joystick, button, value);
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#else
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return SDL_SetError("SDL not built with virtual-joystick support");
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#endif
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}
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int
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SDL_JoystickSetVirtualHat(SDL_Joystick * joystick, int hat, Uint8 value)
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{
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#if SDL_JOYSTICK_VIRTUAL
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return SDL_JoystickSetVirtualHatInner(joystick, hat, value);
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#else
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return SDL_SetError("SDL not built with virtual-joystick support");
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#endif
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}
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/*
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* Checks to make sure the joystick is valid.
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*/
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@ -1563,6 +1679,8 @@ SDL_GetJoystickGameControllerType(const char *name, Uint16 vendor, Uint16 produc
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SDL_strcmp(name, "Wireless Gamepad") == 0) {
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/* HORI or PowerA Switch Pro Controller clone */
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type = SDL_CONTROLLER_TYPE_NINTENDO_SWITCH_PRO;
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} else if (SDL_strcmp(name, "Virtual Joystick") == 0) {
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type = SDL_CONTROLLER_TYPE_VIRTUAL;
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} else {
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type = SDL_CONTROLLER_TYPE_UNKNOWN;
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}
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@ -1624,6 +1742,12 @@ SDL_IsJoystickHIDAPI(SDL_JoystickGUID guid)
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return (guid.data[14] == 'h') ? SDL_TRUE : SDL_FALSE;
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}
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SDL_bool
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SDL_IsJoystickVirtual(SDL_JoystickGUID guid)
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{
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return (guid.data[14] == 'v') ? SDL_TRUE : SDL_FALSE;
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}
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static SDL_bool SDL_IsJoystickProductWheel(Uint32 vidpid)
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{
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static Uint32 wheel_joysticks[] = {
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@ -1715,6 +1839,10 @@ static SDL_JoystickType SDL_GetJoystickGUIDType(SDL_JoystickGUID guid)
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}
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}
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if (SDL_IsJoystickVirtual(guid)) {
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return (SDL_JoystickType)guid.data[15];
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}
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SDL_GetJoystickGUIDInfo(guid, &vendor, &product, NULL);
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vidpid = MAKE_VIDPID(vendor, product);
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