Joystick.cpp

00001 /* mbed Joystick Library
00002  * Copyright (c) 2015, rwunderl, http://mbed.org
00003  *
00004  * Permission is hereby granted, free of charge, to any person obtaining a copy
00005  * of this software and associated documentation files (the "Software"), to deal
00006  * in the Software without restriction, including without limitation the rights
00007  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
00008  * copies of the Software, and to permit persons to whom the Software is
00009  * furnished to do so, subject to the following conditions:
00010  *
00011  * The above copyright notice and this permission notice shall be included in
00012  * all copies or substantial portions of the Software.
00013  *
00014  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00015  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00016  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
00017  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
00018  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00019  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
00020  * THE SOFTWARE.
00021  */
00022 
00023 #include "Joystick.h"
00024 
00025 // apply the deadzone to the axis extremes (comment if you don't want to use this feature)
00026 #define JOYSTICK_DEADZONE_EXTREMES
00027 
00028 // adjust the deadzone value for your application, if required
00029 const double JOYSTICK_DEADZONE = 0.01;
00030 // set up these constants so they don't have to be calculated every time
00031 #ifdef JOYSTICK_DEADZONE_EXTREMES
00032     const double JOYSTICK_MIN    = 0.0 + JOYSTICK_DEADZONE;    // effective minimum joystick value
00033     const double JOYSTICK_MINMID = 0.5 - JOYSTICK_DEADZONE;    // minimum-side midpoint value
00034     const double JOYSTICK_MAXMID = 0.5 + JOYSTICK_DEADZONE;    // maximum-side midpoint value
00035     const double JOYSTICK_MAX    = 1.0 - JOYSTICK_DEADZONE;    // effective maximum joystick value
00036 #else
00037     const double JOYSTICK_MIN    = 0.0;    // minimum joystick value
00038     const double JOYSTICK_MINMID = 0.5 - JOYSTICK_DEADZONE;    // minimum-side midpoint value
00039     const double JOYSTICK_MAXMID = 0.5 + JOYSTICK_DEADZONE;    // maximum-side midpoint value
00040     const double JOYSTICK_MAX    = 1.0;    // maximum joystick value
00041 #endif
00042 
00043 double _map(double value, double in_min, double in_max, double out_min, double out_max) {
00044     return (value - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
00045 }
00046 
00047 double _scale(double pos) {
00048     double scaled = 0;
00049 
00050     if (pos < JOYSTICK_MINMID) {
00051         scaled = _map(pos, JOYSTICK_MIN, JOYSTICK_MINMID, -1, 0);
00052     } else if (pos > JOYSTICK_MAXMID) {
00053         scaled = _map(pos, JOYSTICK_MAXMID, JOYSTICK_MAX, 0, 1);
00054     }
00055 
00056     // check out of bounds [-1.0, 1.0] (happens at the extremes)
00057     if (scaled < -1) {
00058         scaled = -1;
00059     } else if (scaled > 1) {
00060         scaled = 1;
00061     }
00062 
00063     return scaled;
00064 }
00065 
00066 Joystick::Joystick(PinName x, PinName y, PinName a) : _x(x), _y(y), _a(a) {
00067 }
00068 
00069 joypos Joystick::read() {
00070     joypos pos;
00071 
00072     pos.x = getX();
00073     pos.y = getY();
00074 
00075     return pos;
00076 }
00077 
00078 double Joystick::getX() {
00079     double val = _x.read();
00080     val = _scale(val);
00081     return val;
00082 }
00083 
00084 double Joystick::getY() {
00085     double val = _y.read();
00086     val = _scale(val);
00087     return val;
00088 }
00089 
00090 double Joystick::getRawX() {
00091     return _x.read();
00092 }
00093 
00094 double Joystick::getRawY() {
00095     return _y.read();
00096 }
00097 
00098 void Joystick::rise(void (*fptr)(void)) { 
00099     _a.rise(fptr);
00100 }
00101 
00102 void Joystick::fall(void (*fptr)(void)) {
00103     _a.fall(fptr);
00104 }