SDL/src/joystick/SDL_joystick_c.h

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/*
Simple DirectMedia Layer
2020-01-17 04:49:25 +00:00
Copyright (C) 1997-2020 Sam Lantinga <slouken@libsdl.org>
This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any damages
arising from the use of this software.
Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:
1. The origin of this software must not be misrepresented; you must not
claim that you wrote the original software. If you use this software
in a product, an acknowledgment in the product documentation would be
appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be
misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
*/
#ifndef SDL_joystick_c_h_
#define SDL_joystick_c_h_
#include "../SDL_internal.h"
/* Useful functions and variables from SDL_joystick.c */
#include "SDL_gamecontroller.h"
#include "SDL_joystick.h"
struct _SDL_JoystickDriver;
/* Initialization and shutdown functions */
extern int SDL_JoystickInit(void);
extern void SDL_JoystickQuit(void);
/* Function to get the next available joystick instance ID */
extern SDL_JoystickID SDL_GetNextJoystickInstanceID(void);
/* Initialization and shutdown functions */
extern int SDL_GameControllerInitMappings(void);
extern void SDL_GameControllerQuitMappings(void);
extern int SDL_GameControllerInit(void);
extern void SDL_GameControllerQuit(void);
/* Function to get the joystick driver and device index for an API device index */
extern SDL_bool SDL_GetDriverAndJoystickIndex(int device_index, struct _SDL_JoystickDriver **driver, int *driver_index);
/* Function to return the device index for a joystick ID, or -1 if not found */
extern int SDL_JoystickGetDeviceIndexFromInstanceID(SDL_JoystickID instance_id);
/* Function to extract information from an SDL joystick GUID */
extern void SDL_GetJoystickGUIDInfo(SDL_JoystickGUID guid, Uint16 *vendor, Uint16 *product, Uint16 *version);
/* Function to standardize the name for a controller
This should be freed with SDL_free() when no longer needed
*/
extern char *SDL_CreateJoystickName(Uint16 vendor, Uint16 product, const char *vendor_name, const char *product_name);
/* Function to return the type of a controller */
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extern SDL_GameControllerType SDL_GetJoystickGameControllerTypeFromGUID(SDL_JoystickGUID guid, const char *name);
extern SDL_GameControllerType SDL_GetJoystickGameControllerType(const char *name, Uint16 vendor, Uint16 product, int interface_number, int interface_class, int interface_subclass, int interface_protocol);
/* Function to return whether a joystick is a Nintendo Switch Pro controller */
extern SDL_bool SDL_IsJoystickNintendoSwitchProInputOnly(Uint16 vendor_id, Uint16 product_id);
/* Function to return whether a joystick is a Steam Controller */
extern SDL_bool SDL_IsJoystickSteamController(Uint16 vendor_id, Uint16 product_id);
/* Function to return whether a joystick guid comes from the XInput driver */
extern SDL_bool SDL_IsJoystickXInput(SDL_JoystickGUID guid);
/* Function to return whether a joystick guid comes from the HIDAPI driver */
extern SDL_bool SDL_IsJoystickHIDAPI(SDL_JoystickGUID guid);
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!
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/* Function to return whether a joystick guid comes from the Virtual driver */
extern SDL_bool SDL_IsJoystickVirtual(SDL_JoystickGUID guid);
/* Function to return whether a joystick should be ignored */
extern SDL_bool SDL_ShouldIgnoreJoystick(const char *name, SDL_JoystickGUID guid);
/* Function to return whether a joystick name and GUID is a game controller */
extern SDL_bool SDL_IsGameControllerNameAndGUID(const char *name, SDL_JoystickGUID guid);
/* Function to return whether a game controller should be ignored */
extern SDL_bool SDL_ShouldIgnoreGameController(const char *name, SDL_JoystickGUID guid);
/* Handle delayed guide button on a game controller */
extern void SDL_GameControllerHandleDelayedGuideButton(SDL_Joystick *joystick);
/* Internal event queueing functions */
extern void SDL_PrivateJoystickAdded(SDL_JoystickID device_instance);
extern void SDL_PrivateJoystickRemoved(SDL_JoystickID device_instance);
extern int SDL_PrivateJoystickAxis(SDL_Joystick * joystick,
Uint8 axis, Sint16 value);
extern int SDL_PrivateJoystickBall(SDL_Joystick * joystick,
Uint8 ball, Sint16 xrel, Sint16 yrel);
extern int SDL_PrivateJoystickHat(SDL_Joystick * joystick,
Uint8 hat, Uint8 value);
extern int SDL_PrivateJoystickButton(SDL_Joystick * joystick,
Uint8 button, Uint8 state);
extern void SDL_PrivateJoystickBatteryLevel(SDL_Joystick * joystick,
SDL_JoystickPowerLevel ePowerLevel);
/* Internal sanity checking functions */
extern SDL_bool SDL_PrivateJoystickValid(SDL_Joystick * joystick);
#endif /* SDL_joystick_c_h_ */
/* vi: set ts=4 sw=4 expandtab: */