testgamecontroller.c

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Hash : 2be75c6a
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Date : 2020-03-13T19:08:45

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!

test/testgamecontroller.c

/*
  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.
*/

/* Simple program to test the SDL game controller routines */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "SDL.h"

#ifdef __EMSCRIPTEN__
#include <emscripten/emscripten.h>
#endif

#ifndef SDL_JOYSTICK_DISABLED

#ifdef __IPHONEOS__
#define SCREEN_WIDTH    480
#define SCREEN_HEIGHT    320
#else
#define SCREEN_WIDTH    512
#define SCREEN_HEIGHT   320
#endif

/* This is indexed by SDL_GameControllerButton. */
static const struct { int x; int y; } button_positions[] = {
    {387, 167},  /* A */
    {431, 132},  /* B */
    {342, 132},  /* X */
    {389, 101},  /* Y */
    {174, 132},  /* BACK */
    {233, 132},  /* GUIDE */
    {289, 132},  /* START */
    {75,  154},  /* LEFTSTICK */
    {305, 230},  /* RIGHTSTICK */
    {77,  40},   /* LEFTSHOULDER */
    {396, 36},   /* RIGHTSHOULDER */
    {154, 188},  /* DPAD_UP */
    {154, 249},  /* DPAD_DOWN */
    {116, 217},  /* DPAD_LEFT */
    {186, 217},  /* DPAD_RIGHT */
};

/* This is indexed by SDL_GameControllerAxis. */
static const struct { int x; int y; double angle; } axis_positions[] = {
    {74,  153, 270.0},  /* LEFTX */
    {74,  153, 0.0},  /* LEFTY */
    {306, 231, 270.0},  /* RIGHTX */
    {306, 231, 0.0},  /* RIGHTY */
    {91, -20, 0.0},     /* TRIGGERLEFT */
    {375, -20, 0.0},    /* TRIGGERRIGHT */
};

SDL_Renderer *screen = NULL;
SDL_bool retval = SDL_FALSE;
SDL_bool done = SDL_FALSE;
SDL_Texture *background, *button, *axis;

static SDL_Texture *
LoadTexture(SDL_Renderer *renderer, const char *file, SDL_bool transparent)
{
    SDL_Surface *temp = NULL;
    SDL_Texture *texture = NULL;

    temp = SDL_LoadBMP(file);
    if (temp == NULL) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't load %s: %s", file, SDL_GetError());
    } else {
        /* Set transparent pixel as the pixel at (0,0) */
        if (transparent) {
            if (temp->format->BytesPerPixel == 1) {
                SDL_SetColorKey(temp, SDL_TRUE, *(Uint8 *)temp->pixels);
            }
        }

        texture = SDL_CreateTextureFromSurface(renderer, temp);
        if (!texture) {
            SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't create texture: %s\n", SDL_GetError());
        }
    }
    if (temp) {
        SDL_FreeSurface(temp);
    }
    return texture;
}

void
loop(void *arg)
{
    SDL_Event event;
    int i;
    SDL_GameController *gamecontroller = (SDL_GameController *)arg;

    /* blank screen, set up for drawing this frame. */
    SDL_SetRenderDrawColor(screen, 0xFF, 0xFF, 0xFF, SDL_ALPHA_OPAQUE);
    SDL_RenderClear(screen);
    SDL_RenderCopy(screen, background, NULL, NULL);

    while (SDL_PollEvent(&event)) {
        switch (event.type) {
        case SDL_CONTROLLERAXISMOTION:
            SDL_Log("Controller axis %s changed to %d\n", SDL_GameControllerGetStringForAxis((SDL_GameControllerAxis)event.caxis.axis), event.caxis.value);
            break;
        case SDL_CONTROLLERBUTTONDOWN:
        case SDL_CONTROLLERBUTTONUP:
            SDL_Log("Controller button %s %s\n", SDL_GameControllerGetStringForButton((SDL_GameControllerButton)event.cbutton.button), event.cbutton.state ? "pressed" : "released");
            break;
        case SDL_KEYDOWN:
            if (event.key.keysym.sym != SDLK_ESCAPE) {
                break;
            }
            /* Fall through to signal quit */
        case SDL_QUIT:
            done = SDL_TRUE;
            break;
        default:
            break;
        }
    }

    /* Update visual controller state */
    for (i = 0; i < SDL_CONTROLLER_BUTTON_MAX; ++i) {
        if (SDL_GameControllerGetButton(gamecontroller, (SDL_GameControllerButton)i) == SDL_PRESSED) {
            const SDL_Rect dst = { button_positions[i].x, button_positions[i].y, 50, 50 };
            SDL_RenderCopyEx(screen, button, NULL, &dst, 0, NULL, SDL_FLIP_NONE);
        }
    }

    for (i = 0; i < SDL_CONTROLLER_AXIS_MAX; ++i) {
        const Sint16 deadzone = 8000;  /* !!! FIXME: real deadzone */
        const Sint16 value = SDL_GameControllerGetAxis(gamecontroller, (SDL_GameControllerAxis)(i));
        if (value < -deadzone) {
            const SDL_Rect dst = { axis_positions[i].x, axis_positions[i].y, 50, 50 };
            const double angle = axis_positions[i].angle;
            SDL_RenderCopyEx(screen, axis, NULL, &dst, angle, NULL, SDL_FLIP_NONE);
        } else if (value > deadzone) {
            const SDL_Rect dst = { axis_positions[i].x, axis_positions[i].y, 50, 50 };
            const double angle = axis_positions[i].angle + 180.0;
            SDL_RenderCopyEx(screen, axis, NULL, &dst, angle, NULL, SDL_FLIP_NONE);
        }
    }

    /* Update rumble based on trigger state */
    {
        Uint16 low_frequency_rumble = SDL_GameControllerGetAxis(gamecontroller, SDL_CONTROLLER_AXIS_TRIGGERLEFT) * 2;
        Uint16 high_frequency_rumble = SDL_GameControllerGetAxis(gamecontroller, SDL_CONTROLLER_AXIS_TRIGGERRIGHT) * 2;
        SDL_GameControllerRumble(gamecontroller, low_frequency_rumble, high_frequency_rumble, 250);
    }

    SDL_RenderPresent(screen);

    if (!SDL_GameControllerGetAttached(gamecontroller)) {
        done = SDL_TRUE;
        retval = SDL_TRUE;  /* keep going, wait for reattach. */
    }

#ifdef __EMSCRIPTEN__
    if (done) {
        emscripten_cancel_main_loop();
    }
#endif
}

SDL_bool
WatchGameController(SDL_GameController * gamecontroller)
{
    const char *name = SDL_GameControllerName(gamecontroller);
    const char *basetitle = "Game Controller Test: ";
    const size_t titlelen = SDL_strlen(basetitle) + SDL_strlen(name) + 1;
    char *title = (char *)SDL_malloc(titlelen);
    SDL_Window *window = NULL;

    retval = SDL_FALSE;
    done = SDL_FALSE;

    if (title) {
        SDL_snprintf(title, titlelen, "%s%s", basetitle, name);
    }

    /* Create a window to display controller state */
    window = SDL_CreateWindow(title, SDL_WINDOWPOS_CENTERED,
                              SDL_WINDOWPOS_CENTERED, SCREEN_WIDTH,
                              SCREEN_HEIGHT, 0);
    SDL_free(title);
    title = NULL;
    if (window == NULL) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't create window: %s\n", SDL_GetError());
        return SDL_FALSE;
    }

    screen = SDL_CreateRenderer(window, -1, 0);
    if (screen == NULL) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't create renderer: %s\n", SDL_GetError());
        SDL_DestroyWindow(window);
        return SDL_FALSE;
    }

    SDL_SetRenderDrawColor(screen, 0x00, 0x00, 0x00, SDL_ALPHA_OPAQUE);
    SDL_RenderClear(screen);
    SDL_RenderPresent(screen);
    SDL_RaiseWindow(window);

    /* scale for platforms that don't give you the window size you asked for. */
    SDL_RenderSetLogicalSize(screen, SCREEN_WIDTH, SCREEN_HEIGHT);

    background = LoadTexture(screen, "controllermap.bmp", SDL_FALSE);
    button = LoadTexture(screen, "button.bmp", SDL_TRUE);
    axis = LoadTexture(screen, "axis.bmp", SDL_TRUE);

    if (!background || !button || !axis) {
        SDL_DestroyRenderer(screen);
        SDL_DestroyWindow(window);
        return SDL_FALSE;
    }
    SDL_SetTextureColorMod(button, 10, 255, 21);
    SDL_SetTextureColorMod(axis, 10, 255, 21);

    /* !!! FIXME: */
    /*SDL_RenderSetLogicalSize(screen, background->w, background->h);*/

    /* Print info about the controller we are watching */
    SDL_Log("Watching controller %s\n",  name ? name : "Unknown Controller");

    /* Loop, getting controller events! */
#ifdef __EMSCRIPTEN__
    emscripten_set_main_loop_arg(loop, gamecontroller, 0, 1);
#else
    while (!done) {
        loop(gamecontroller);
    }
#endif

    SDL_DestroyRenderer(screen);
    screen = NULL;
    background = NULL;
    button = NULL;
    axis = NULL;
    SDL_DestroyWindow(window);
    return retval;
}

int
main(int argc, char *argv[])
{
    int i;
    int nController = 0;
    int retcode = 0;
    char guid[64];
    SDL_GameController *gamecontroller;

    /* Enable standard application logging */
    SDL_LogSetPriority(SDL_LOG_CATEGORY_APPLICATION, SDL_LOG_PRIORITY_INFO);

    /* Initialize SDL (Note: video is required to start event loop) */
    if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_JOYSTICK | SDL_INIT_GAMECONTROLLER ) < 0) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't initialize SDL: %s\n", SDL_GetError());
        return 1;
    }
    
    SDL_GameControllerAddMappingsFromFile("gamecontrollerdb.txt");

    /* Print information about the mappings */
    if (!argv[1]) {
        SDL_Log("Supported mappings:\n");
        for (i = 0; i < SDL_GameControllerNumMappings(); ++i) {
            char *mapping = SDL_GameControllerMappingForIndex(i);
            if (mapping) {
                SDL_Log("\t%s\n", mapping);
                SDL_free(mapping);
            }
        }
        SDL_Log("\n");
    }

    /* Print information about the controller */
    for (i = 0; i < SDL_NumJoysticks(); ++i) {
        const char *name;
        const char *description;

        SDL_JoystickGetGUIDString(SDL_JoystickGetDeviceGUID(i),
                                  guid, sizeof (guid));

        if ( SDL_IsGameController(i) )
        {
            nController++;
            name = SDL_GameControllerNameForIndex(i);
            switch (SDL_GameControllerTypeForIndex(i)) {
            case SDL_CONTROLLER_TYPE_XBOX360:
                description = "XBox 360 Controller";
                break;
            case SDL_CONTROLLER_TYPE_XBOXONE:
                description = "XBox One Controller";
                break;
            case SDL_CONTROLLER_TYPE_PS3:
                description = "PS3 Controller";
                break;
            case SDL_CONTROLLER_TYPE_PS4:
                description = "PS4 Controller";
                break;
            case SDL_CONTROLLER_TYPE_NINTENDO_SWITCH_PRO:
                description = "Nintendo Switch Pro Controller";
                break;
            case SDL_CONTROLLER_TYPE_VIRTUAL:
                description = "Virtual Game Controller";
                break;
            default:
                description = "Game Controller";
                break;
            }
        } else {
            name = SDL_JoystickNameForIndex(i);
            description = "Joystick";
        }
        SDL_Log("%s %d: %s (guid %s, VID 0x%.4x, PID 0x%.4x, player index = %d)\n",
            description, i, name ? name : "Unknown", guid,
            SDL_JoystickGetDeviceVendor(i), SDL_JoystickGetDeviceProduct(i), SDL_JoystickGetDevicePlayerIndex(i));
    }
    SDL_Log("There are %d game controller(s) attached (%d joystick(s))\n", nController, SDL_NumJoysticks());

    if (argv[1]) {
        SDL_bool reportederror = SDL_FALSE;
        SDL_bool keepGoing = SDL_TRUE;
        SDL_Event event;
        int device = atoi(argv[1]);
        if (device >= SDL_NumJoysticks()) {
            SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "%i is an invalid joystick index.\n", device);
            retcode = 1;
        } else {
            SDL_JoystickGetGUIDString(SDL_JoystickGetDeviceGUID(device),
                                      guid, sizeof (guid));
            SDL_Log("Attempting to open device %i, guid %s\n", device, guid);
            gamecontroller = SDL_GameControllerOpen(device);

            if (gamecontroller != NULL) {
                SDL_assert(SDL_GameControllerFromInstanceID(SDL_JoystickInstanceID(SDL_GameControllerGetJoystick(gamecontroller))) == gamecontroller);
            }

            while (keepGoing) {
                if (gamecontroller == NULL) {
                    if (!reportederror) {
                        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't open gamecontroller %d: %s\n", device, SDL_GetError());
                        retcode = 1;
                        keepGoing = SDL_FALSE;
                        reportederror = SDL_TRUE;
                    }
                } else {
                    reportederror = SDL_FALSE;
                    keepGoing = WatchGameController(gamecontroller);
                    SDL_GameControllerClose(gamecontroller);
                }

                gamecontroller = NULL;
                if (keepGoing) {
                    SDL_Log("Waiting for attach\n");
                }
                while (keepGoing) {
                    SDL_WaitEvent(&event);
                    if ((event.type == SDL_QUIT) || (event.type == SDL_FINGERDOWN)
                        || (event.type == SDL_MOUSEBUTTONDOWN)) {
                        keepGoing = SDL_FALSE;
                    } else if (event.type == SDL_CONTROLLERDEVICEADDED) {
                        gamecontroller = SDL_GameControllerOpen(event.cdevice.which);
                        if (gamecontroller != NULL) {
                            SDL_assert(SDL_GameControllerFromInstanceID(SDL_JoystickInstanceID(SDL_GameControllerGetJoystick(gamecontroller))) == gamecontroller);
                        }
                        break;
                    }
                }
            }
        }
    }

    SDL_QuitSubSystem(SDL_INIT_VIDEO | SDL_INIT_JOYSTICK | SDL_INIT_GAMECONTROLLER);

    return retcode;
}

#else

int
main(int argc, char *argv[])
{
    SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "SDL compiled without Joystick support.\n");
    return 1;
}

#endif

/* vi: set ts=4 sw=4 expandtab: */

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