glfw/lib/win32/win32_joystick.c

//========================================================================
// GLFW - An OpenGL framework
// Platform:    Win32/WGL
// API version: 3.0
// WWW:         http://www.glfw.org/
//------------------------------------------------------------------------
// Copyright (c) 2002-2006 Marcus Geelnard
// Copyright (c) 2006-2010 Camilla Berglund <elmindreda@elmindreda.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.
//
//========================================================================

#include "internal.h"


//************************************************************************
//****                  GLFW internal functions                       ****
//************************************************************************

//========================================================================
// Return GL_TRUE if joystick is present, else return GL_FALSE.
//========================================================================

static int _glfwJoystickPresent( int joy )
{
    JOYINFO ji;

    // Windows NT 4.0 MMSYSTEM only supports 2 sticks (other Windows
    // versions support 16 sticks)
    if( _glfwLibrary.Sys.winVer == _GLFW_WIN_NT4 && joy > GLFW_JOYSTICK_2 )
    {
        return GL_FALSE;
    }

    // Is it a valid stick ID (Windows don't support more than 16 sticks)?
    if( joy < GLFW_JOYSTICK_1 || joy > GLFW_JOYSTICK_16 )
    {
        return GL_FALSE;
    }

    // Is the joystick present?
    if( _glfw_joyGetPos( joy - GLFW_JOYSTICK_1, &ji ) != JOYERR_NOERROR )
    {
        return GL_FALSE;
    }

    return GL_TRUE;
}


//========================================================================
// Calculate joystick position
//========================================================================

static float _glfwCalcJoystickPos( DWORD pos, DWORD min, DWORD max )
{
    float fpos = (float) pos;
    float fmin = (float) min;
    float fmax = (float) max;
    return (2.0f*(fpos - fmin) / (fmax - fmin)) - 1.0f;
}



//************************************************************************
//****               Platform implementation functions                ****
//************************************************************************

//========================================================================
// Determine joystick capabilities
//========================================================================

int _glfwPlatformGetJoystickParam( int joy, int param )
{
    JOYCAPS jc;

//  return 0;

    // Is joystick present?
    if( !_glfwJoystickPresent( joy ) )
    {
        return 0;
    }

    // We got this far, the joystick is present
    if( param == GLFW_PRESENT )
    {
        return GL_TRUE;
    }

    // Get joystick capabilities
    _glfw_joyGetDevCaps( joy - GLFW_JOYSTICK_1, &jc, sizeof(JOYCAPS) );

    switch( param )
    {
    case GLFW_AXES:
        // Return number of joystick axes
        return jc.wNumAxes;

    case GLFW_BUTTONS:
        // Return number of joystick axes
        return jc.wNumButtons;

    default:
        break;
    }

    return 0;
}


//========================================================================
// Get joystick axis positions
//========================================================================

int _glfwPlatformGetJoystickPos( int joy, float *pos, int numaxes )
{
    JOYCAPS   jc;
    JOYINFOEX ji;
    int       axis;

//  return 0;

    // Is joystick present?
    if( !_glfwJoystickPresent( joy ) )
    {
        return 0;
    }

    // Get joystick capabilities
    _glfw_joyGetDevCaps( joy - GLFW_JOYSTICK_1, &jc, sizeof(JOYCAPS) );

    // Get joystick state
    ji.dwSize = sizeof( JOYINFOEX );
    ji.dwFlags = JOY_RETURNX | JOY_RETURNY | JOY_RETURNZ |
                 JOY_RETURNR | JOY_RETURNU | JOY_RETURNV;
    _glfw_joyGetPosEx( joy - GLFW_JOYSTICK_1, &ji );

    // Get position values for all axes
    axis = 0;
    if( axis < numaxes )
    {
        pos[ axis++ ] = _glfwCalcJoystickPos( ji.dwXpos, jc.wXmin,
                                              jc.wXmax );
    }
    if( axis < numaxes )
    {
        pos[ axis++ ] = -_glfwCalcJoystickPos( ji.dwYpos, jc.wYmin,
                                               jc.wYmax );
    }
    if( axis < numaxes && jc.wCaps & JOYCAPS_HASZ )
    {
        pos[ axis++ ] = _glfwCalcJoystickPos( ji.dwZpos, jc.wZmin,
                                              jc.wZmax );
    }
    if( axis < numaxes && jc.wCaps & JOYCAPS_HASR )
    {
        pos[ axis++ ] = _glfwCalcJoystickPos( ji.dwRpos, jc.wRmin,
                                              jc.wRmax );
    }
    if( axis < numaxes && jc.wCaps & JOYCAPS_HASU )
    {
        pos[ axis++ ] = _glfwCalcJoystickPos( ji.dwUpos, jc.wUmin,
                                              jc.wUmax );
    }
    if( axis < numaxes && jc.wCaps & JOYCAPS_HASV )
    {
        pos[ axis++ ] = -_glfwCalcJoystickPos( ji.dwVpos, jc.wVmin,
                                               jc.wVmax );
    }

    // Return number of returned axes
    return axis;
}


//========================================================================
// Get joystick button states
//========================================================================

int _glfwPlatformGetJoystickButtons( int joy, unsigned char *buttons,
    int numbuttons )
{
    JOYCAPS   jc;
    JOYINFOEX ji;
    int       button;

//  return 0;

    // Is joystick present?
    if( !_glfwJoystickPresent( joy ) )
    {
        return 0;
    }

    // Get joystick capabilities
    _glfw_joyGetDevCaps( joy - GLFW_JOYSTICK_1, &jc, sizeof(JOYCAPS) );

    // Get joystick state
    ji.dwSize = sizeof( JOYINFOEX );
    ji.dwFlags = JOY_RETURNBUTTONS;
    _glfw_joyGetPosEx( joy - GLFW_JOYSTICK_1, &ji );

    // Get states of all requested buttons
    button = 0;
    while( button < numbuttons && button < (int) jc.wNumButtons )
    {
        buttons[ button ] = (unsigned char)
            (ji.dwButtons & (1UL << button) ? GLFW_PRESS : GLFW_RELEASE);
        button ++;
    }

    return button;
}