source/ps/Joystick.cpp

   1 /* Copyright (C) 2021 Wildfire Games.
   2  * This file is part of 0 A.D.
   3  *
   4  * 0 A.D. is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * 0 A.D. is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #include "precompiled.h"
  19
  20 #include "Joystick.h"
  21
  22 #include "lib/external_libraries/libsdl.h"
  23 #include "ps/CLogger.h"
  24 #include "ps/ConfigDB.h"
  25
  26 CJoystick g_Joystick;
  27
  28 CJoystick::CJoystick() :
  29         m_Joystick(NULL), m_Deadzone(0)
  30 {
  31 }
  32
  33 void CJoystick::Initialise()
  34 {
  35         bool joystickEnable = false;
  36         if (!CConfigDB::IsInitialised())
  37                 return;
  38         CFG_GET_VAL("joystick.enable", joystickEnable);
  39         if (!joystickEnable)
  40                 return;
  41
  42         CFG_GET_VAL("joystick.deadzone", m_Deadzone);
  43
  44         if (SDL_InitSubSystem(SDL_INIT_JOYSTICK) < 0)
  45         {
  46                 LOGERROR("CJoystick::Initialise failed to initialise joysticks (\"%s\")", SDL_GetError());
  47                 return;
  48         }
  49
  50         int numJoysticks = SDL_NumJoysticks();
  51
  52         LOGMESSAGE("Found %d joystick(s)", numJoysticks);
  53
  54         for (int i = 0; i < numJoysticks; ++i)
  55         {
  56                 SDL_Joystick* stick = SDL_JoystickOpen(i);
  57                 if (!stick)
  58                 {
  59                         LOGERROR("CJoystick::Initialise failed to open joystick %d (\"%s\")", i, SDL_GetError());
  60                         continue;
  61                 }
  62                 const char* name = SDL_JoystickName(stick);
  63                 LOGMESSAGE("Joystick %d: %s", i, name);
  64                 SDL_JoystickClose(stick);
  65         }
  66
  67         if (numJoysticks)
  68         {
  69                 SDL_JoystickEventState(SDL_ENABLE);
  70
  71                 // Always pick the first joystick, and assume that's the right one
  72                 m_Joystick = SDL_JoystickOpen(0);
  73                 if (!m_Joystick)
  74                         LOGERROR("CJoystick::Initialise failed to open joystick (\"%s\")", SDL_GetError());
  75         }
  76 }
  77
  78 bool CJoystick::IsEnabled()
  79 {
  80         return (m_Joystick != NULL);
  81 }
  82
  83 float CJoystick::GetAxisValue(int axis)
  84 {
  85         if (!m_Joystick || axis < 0 || axis >= SDL_JoystickNumAxes(m_Joystick))
  86                 return 0.f;
  87
  88         int16_t val = SDL_JoystickGetAxis(m_Joystick, axis);
  89
  90         // Normalize values into the range [-1, +1] excluding the deadzone around 0
  91         float norm;
  92         if (val > m_Deadzone)
  93                 norm = (val - m_Deadzone) / (float)(32767 - m_Deadzone);
  94         else if (val < -m_Deadzone)
  95                 norm = (val + m_Deadzone) / (float)(32767 - m_Deadzone);
  96         else
  97                 norm = 0.f;
  98
  99         return norm;
 100 }