Joystick.cpp

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/* Copyright (C) 2013 Wildfire Games.
 * This file is part of 0 A.D.
 *
 * 0 A.D. is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * 0 A.D. is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "precompiled.h"

#include "Joystick.h"

#include "lib/external_libraries/libsdl.h"
#include "ps/CLogger.h"
#include "ps/ConfigDB.h"

CJoystick g_Joystick;

CJoystick::CJoystick() :
    m_Joystick(NULL), m_Deadzone(0)
{
}

void CJoystick::Initialise()
{
    bool joystickEnable = false;
    CFG_GET_VAL("joystick.enable", Bool, joystickEnable);
    if (!joystickEnable)
        return;

    CFG_GET_VAL("joystick.deadzone", Int, m_Deadzone);

    if (SDL_InitSubSystem(SDL_INIT_JOYSTICK) < 0)
    {
        LOGERROR(L"CJoystick::Initialise failed to initialise joysticks (\"%hs\")", SDL_GetError());
        return;
    }

    int numJoysticks = SDL_NumJoysticks();

    LOGMESSAGE(L"Found %d joystick(s)", numJoysticks);

    for (int i = 0; i < numJoysticks; ++i)
    {
#if SDL_VERSION_ATLEAST(2, 0, 0)
        SDL_Joystick* stick = SDL_JoystickOpen(i);
        if (!stick)
        {
            LOGERROR(L"CJoystick::Initialise failed to open joystick %d (\"%hs\")", i, SDL_GetError());
            continue;
        }
        const char* name = SDL_JoystickName(stick);
#else // SDL 1.2
        const char* name = SDL_JoystickName(i);
#endif
        LOGMESSAGE(L"Joystick %d: %hs", i, name);
#if SDL_VERSION_ATLEAST(2, 0, 0)
        SDL_JoystickClose(stick);
#endif
    }

    if (numJoysticks)
    {
        SDL_JoystickEventState(SDL_ENABLE);

        // Always pick the first joystick, and assume that's the right one
        m_Joystick = SDL_JoystickOpen(0);
        if (!m_Joystick)
            LOGERROR(L"CJoystick::Initialise failed to open joystick (\"%hs\")", SDL_GetError());
    }
}

bool CJoystick::IsEnabled()
{
    return (m_Joystick != NULL);
}

float CJoystick::GetAxisValue(int axis)
{
    if (!m_Joystick || axis < 0 || axis >= SDL_JoystickNumAxes(m_Joystick))
        return 0.f;

    int16_t val = SDL_JoystickGetAxis(m_Joystick, axis);

    // Normalize values into the range [-1, +1] excluding the deadzone around 0
    float norm;
    if (val > m_Deadzone)
        norm = (val - m_Deadzone) / (float)(32767 - m_Deadzone);
    else if (val < -m_Deadzone)
        norm = (val + m_Deadzone) / (float)(32767 - m_Deadzone);
    else
        norm = 0.f;

    return norm;
}