ELEC2645 (2018/19) / Mbed 2 deprecated ml17z4c_attempt2

ZIYI CHEN ml17z4c 201214999

Dependencies:   mbed

Gamepad/Gamepad.cpp@14:60c31d25d895, 2019-05-09 (annotated)

Committer:
ziyi11
Date:
Thu May 09 14:48:43 2019 +0000
Revision:
14:60c31d25d895
Parent:
0:bf56f20b9c5a
Child:
2:3e4189eae232
can not add doc;

Who changed what in which revision?

UserRevisionLine numberNew contents of line
ziyi11 0:bf56f20b9c5a 1 #include "Gamepad.h"
ziyi11 0:bf56f20b9c5a 2
ziyi11 0:bf56f20b9c5a 3 #include "mbed.h"
ziyi11 0:bf56f20b9c5a 4
ziyi11 0:bf56f20b9c5a 5 //////////// constructor/destructor ////////////
ziyi11 0:bf56f20b9c5a 6 Gamepad::Gamepad()
ziyi11 0:bf56f20b9c5a 7 :
ziyi11 0:bf56f20b9c5a 8 _led1(new PwmOut(PTA1)),
ziyi11 0:bf56f20b9c5a 9 _led2(new PwmOut(PTA2)),
ziyi11 0:bf56f20b9c5a 10 _led3(new PwmOut(PTC2)),
ziyi11 0:bf56f20b9c5a 11 _led4(new PwmOut(PTC3)),
ziyi11 0:bf56f20b9c5a 12 _led5(new PwmOut(PTC4)),
ziyi11 0:bf56f20b9c5a 13 _led6(new PwmOut(PTD3)),
ziyi11 0:bf56f20b9c5a 14
ziyi11 0:bf56f20b9c5a 15 _button_A(new InterruptIn(PTB9)),
ziyi11 0:bf56f20b9c5a 16 _button_B(new InterruptIn(PTD0)),
ziyi11 0:bf56f20b9c5a 17 _button_X(new InterruptIn(PTC17)),
ziyi11 0:bf56f20b9c5a 18 _button_Y(new InterruptIn(PTC12)),
ziyi11 0:bf56f20b9c5a 19 _button_L(new InterruptIn(PTB18)),
ziyi11 0:bf56f20b9c5a 20 _button_R(new InterruptIn(PTB3)),
ziyi11 0:bf56f20b9c5a 21 _button_back(new InterruptIn(PTB19)),
ziyi11 0:bf56f20b9c5a 22 _button_start(new InterruptIn(PTC5)),
ziyi11 0:bf56f20b9c5a 23 _button_joystick(new InterruptIn(PTC16)),
ziyi11 0:bf56f20b9c5a 24
ziyi11 0:bf56f20b9c5a 25 _vert(new AnalogIn(PTB10)),
ziyi11 0:bf56f20b9c5a 26 _horiz(new AnalogIn(PTB11)),
ziyi11 0:bf56f20b9c5a 27
ziyi11 0:bf56f20b9c5a 28 _buzzer(new PwmOut(PTC10)),
ziyi11 0:bf56f20b9c5a 29 _pot(new AnalogIn(PTB2)),
ziyi11 0:bf56f20b9c5a 30
ziyi11 0:bf56f20b9c5a 31 _timeout(new Timeout()),
ziyi11 0:bf56f20b9c5a 32
ziyi11 0:bf56f20b9c5a 33 _event_state(0),
ziyi11 0:bf56f20b9c5a 34
ziyi11 0:bf56f20b9c5a 35 _x0(0),
ziyi11 0:bf56f20b9c5a 36 _y0(0)
ziyi11 0:bf56f20b9c5a 37 {}
ziyi11 0:bf56f20b9c5a 38
ziyi11 0:bf56f20b9c5a 39 Gamepad::~Gamepad()
ziyi11 0:bf56f20b9c5a 40 {
ziyi11 0:bf56f20b9c5a 41 delete _led1,_led2,_led3,_led4,_led5,_led6;
ziyi11 0:bf56f20b9c5a 42 delete _button_A,_button_B,_button_joystick,_vert,_horiz;
ziyi11 0:bf56f20b9c5a 43 delete _button_X,_button_Y,_button_back,_button_start;
ziyi11 0:bf56f20b9c5a 44 delete _button_L,_button_R, _buzzer, _pot, _timeout;
ziyi11 0:bf56f20b9c5a 45 }
ziyi11 0:bf56f20b9c5a 46
ziyi11 0:bf56f20b9c5a 47 ///////////////// public methods /////////////////
ziyi11 0:bf56f20b9c5a 48
ziyi11 0:bf56f20b9c5a 49 void Gamepad::init()
ziyi11 0:bf56f20b9c5a 50 {
ziyi11 0:bf56f20b9c5a 51 leds_off();
ziyi11 0:bf56f20b9c5a 52 init_buttons();
ziyi11 0:bf56f20b9c5a 53
ziyi11 0:bf56f20b9c5a 54 // read centred values of joystick
ziyi11 0:bf56f20b9c5a 55 _x0 = _horiz->read();
ziyi11 0:bf56f20b9c5a 56 _y0 = _vert->read();
ziyi11 0:bf56f20b9c5a 57
ziyi11 0:bf56f20b9c5a 58 // clear all flags
ziyi11 0:bf56f20b9c5a 59 _event_state = 0;
ziyi11 0:bf56f20b9c5a 60 }
ziyi11 0:bf56f20b9c5a 61
ziyi11 0:bf56f20b9c5a 62 void Gamepad::leds_off()
ziyi11 0:bf56f20b9c5a 63 {
ziyi11 0:bf56f20b9c5a 64 leds(0.0);
ziyi11 0:bf56f20b9c5a 65 }
ziyi11 0:bf56f20b9c5a 66
ziyi11 0:bf56f20b9c5a 67 void Gamepad::leds_on()
ziyi11 0:bf56f20b9c5a 68 {
ziyi11 0:bf56f20b9c5a 69 leds(1.0);
ziyi11 0:bf56f20b9c5a 70 }
ziyi11 0:bf56f20b9c5a 71
ziyi11 0:bf56f20b9c5a 72 void Gamepad::leds(float val) const
ziyi11 0:bf56f20b9c5a 73 {
ziyi11 0:bf56f20b9c5a 74 if (val < 0.0f) {
ziyi11 0:bf56f20b9c5a 75 val = 0.0f;
ziyi11 0:bf56f20b9c5a 76 }
ziyi11 0:bf56f20b9c5a 77 if (val > 1.0f) {
ziyi11 0:bf56f20b9c5a 78 val = 1.0f;
ziyi11 0:bf56f20b9c5a 79 }
ziyi11 0:bf56f20b9c5a 80
ziyi11 0:bf56f20b9c5a 81 // leds are active-low, so subtract from 1.0
ziyi11 0:bf56f20b9c5a 82 // 0.0 corresponds to fully-off, 1.0 to fully-on
ziyi11 0:bf56f20b9c5a 83 val = 1.0f - val;
ziyi11 0:bf56f20b9c5a 84
ziyi11 0:bf56f20b9c5a 85 _led1->write(val);
ziyi11 0:bf56f20b9c5a 86 _led2->write(val);
ziyi11 0:bf56f20b9c5a 87 _led3->write(val);
ziyi11 0:bf56f20b9c5a 88 _led4->write(val);
ziyi11 0:bf56f20b9c5a 89 _led5->write(val);
ziyi11 0:bf56f20b9c5a 90 _led6->write(val);
ziyi11 0:bf56f20b9c5a 91 }
ziyi11 0:bf56f20b9c5a 92
ziyi11 0:bf56f20b9c5a 93 void Gamepad::led(int n,float val) const
ziyi11 0:bf56f20b9c5a 94 {
ziyi11 0:bf56f20b9c5a 95 // ensure they are within vlaid range
ziyi11 0:bf56f20b9c5a 96 if (val < 0.0f) {
ziyi11 0:bf56f20b9c5a 97 val = 0.0f;
ziyi11 0:bf56f20b9c5a 98 }
ziyi11 0:bf56f20b9c5a 99 if (val > 1.0f) {
ziyi11 0:bf56f20b9c5a 100 val = 1.0f;
ziyi11 0:bf56f20b9c5a 101 }
ziyi11 0:bf56f20b9c5a 102
ziyi11 0:bf56f20b9c5a 103 switch (n) {
ziyi11 0:bf56f20b9c5a 104
ziyi11 0:bf56f20b9c5a 105 // check for valid LED number and set value
ziyi11 0:bf56f20b9c5a 106
ziyi11 0:bf56f20b9c5a 107 case 1:
ziyi11 0:bf56f20b9c5a 108 _led1->write(1.0f-val); // active-low so subtract from 1
ziyi11 0:bf56f20b9c5a 109 break;
ziyi11 0:bf56f20b9c5a 110 case 2:
ziyi11 0:bf56f20b9c5a 111 _led2->write(1.0f-val); // active-low so subtract from 1
ziyi11 0:bf56f20b9c5a 112 break;
ziyi11 0:bf56f20b9c5a 113 case 3:
ziyi11 0:bf56f20b9c5a 114 _led3->write(1.0f-val); // active-low so subtract from 1
ziyi11 0:bf56f20b9c5a 115 break;
ziyi11 0:bf56f20b9c5a 116 case 4:
ziyi11 0:bf56f20b9c5a 117 _led4->write(1.0f-val); // active-low so subtract from 1
ziyi11 0:bf56f20b9c5a 118 break;
ziyi11 0:bf56f20b9c5a 119 case 5:
ziyi11 0:bf56f20b9c5a 120 _led5->write(1.0f-val); // active-low so subtract from 1
ziyi11 0:bf56f20b9c5a 121 break;
ziyi11 0:bf56f20b9c5a 122 case 6:
ziyi11 0:bf56f20b9c5a 123 _led6->write(1.0f-val); // active-low so subtract from 1
ziyi11 0:bf56f20b9c5a 124 break;
ziyi11 0:bf56f20b9c5a 125
ziyi11 0:bf56f20b9c5a 126 }
ziyi11 0:bf56f20b9c5a 127 }
ziyi11 0:bf56f20b9c5a 128
ziyi11 0:bf56f20b9c5a 129 float Gamepad::read_pot() const
ziyi11 0:bf56f20b9c5a 130 {
ziyi11 0:bf56f20b9c5a 131 return _pot->read();
ziyi11 0:bf56f20b9c5a 132 }
ziyi11 0:bf56f20b9c5a 133
ziyi11 0:bf56f20b9c5a 134 void Gamepad::tone(float frequency, float duration)
ziyi11 0:bf56f20b9c5a 135 {
ziyi11 0:bf56f20b9c5a 136 _buzzer->period(1.0f/frequency);
ziyi11 0:bf56f20b9c5a 137 _buzzer->write(0.5); // 50% duty cycle - square wave
ziyi11 0:bf56f20b9c5a 138 _timeout->attach(callback(this, &Gamepad::tone_off), duration );
ziyi11 0:bf56f20b9c5a 139 }
ziyi11 0:bf56f20b9c5a 140
ziyi11 0:bf56f20b9c5a 141 bool Gamepad::check_event(GamepadEvent const id)
ziyi11 0:bf56f20b9c5a 142 {
ziyi11 0:bf56f20b9c5a 143 // Check whether event flag is set
ziyi11 0:bf56f20b9c5a 144 if (_event_state[id]) {
ziyi11 0:bf56f20b9c5a 145 _event_state.reset(id); // clear flag
ziyi11 0:bf56f20b9c5a 146 return true;
ziyi11 0:bf56f20b9c5a 147 } else {
ziyi11 0:bf56f20b9c5a 148 return false;
ziyi11 0:bf56f20b9c5a 149 }
ziyi11 0:bf56f20b9c5a 150 }
ziyi11 0:bf56f20b9c5a 151
ziyi11 0:bf56f20b9c5a 152 // this method gets the magnitude of the joystick movement
ziyi11 0:bf56f20b9c5a 153 float Gamepad::get_mag()
ziyi11 0:bf56f20b9c5a 154 {
ziyi11 0:bf56f20b9c5a 155 Polar p = get_polar();
ziyi11 0:bf56f20b9c5a 156 return p.mag;
ziyi11 0:bf56f20b9c5a 157 }
ziyi11 0:bf56f20b9c5a 158
ziyi11 0:bf56f20b9c5a 159 // this method gets the angle of joystick movement (0 to 360, 0 North)
ziyi11 0:bf56f20b9c5a 160 float Gamepad::get_angle()
ziyi11 0:bf56f20b9c5a 161 {
ziyi11 0:bf56f20b9c5a 162 Polar p = get_polar();
ziyi11 0:bf56f20b9c5a 163 return p.angle;
ziyi11 0:bf56f20b9c5a 164 }
ziyi11 0:bf56f20b9c5a 165
ziyi11 0:bf56f20b9c5a 166 Direction Gamepad::get_direction()
ziyi11 0:bf56f20b9c5a 167 {
ziyi11 0:bf56f20b9c5a 168 float angle = get_angle(); // 0 to 360, -1 for centred
ziyi11 0:bf56f20b9c5a 169
ziyi11 0:bf56f20b9c5a 170 Direction d;
ziyi11 0:bf56f20b9c5a 171 // partition 360 into segments and check which segment the angle is in
ziyi11 0:bf56f20b9c5a 172 if (angle < 0.0f) {
ziyi11 0:bf56f20b9c5a 173 d = CENTRE; // check for -1.0 angle
ziyi11 0:bf56f20b9c5a 174 } else if (angle < 22.5f) { // then keep going in 45 degree increments
ziyi11 0:bf56f20b9c5a 175 d = N;
ziyi11 0:bf56f20b9c5a 176 } else if (angle < 67.5f) {
ziyi11 0:bf56f20b9c5a 177 d = NE;
ziyi11 0:bf56f20b9c5a 178 } else if (angle < 112.5f) {
ziyi11 0:bf56f20b9c5a 179 d = E;
ziyi11 0:bf56f20b9c5a 180 } else if (angle < 157.5f) {
ziyi11 0:bf56f20b9c5a 181 d = SE;
ziyi11 0:bf56f20b9c5a 182 } else if (angle < 202.5f) {
ziyi11 0:bf56f20b9c5a 183 d = S;
ziyi11 0:bf56f20b9c5a 184 } else if (angle < 247.5f) {
ziyi11 0:bf56f20b9c5a 185 d = SW;
ziyi11 0:bf56f20b9c5a 186 } else if (angle < 292.5f) {
ziyi11 0:bf56f20b9c5a 187 d = W;
ziyi11 0:bf56f20b9c5a 188 } else if (angle < 337.5f) {
ziyi11 0:bf56f20b9c5a 189 d = NW;
ziyi11 0:bf56f20b9c5a 190 } else {
ziyi11 0:bf56f20b9c5a 191 d = N;
ziyi11 0:bf56f20b9c5a 192 }
ziyi11 0:bf56f20b9c5a 193
ziyi11 0:bf56f20b9c5a 194 return d;
ziyi11 0:bf56f20b9c5a 195 }
ziyi11 0:bf56f20b9c5a 196
ziyi11 0:bf56f20b9c5a 197 ///////////////////// private methods ////////////////////////
ziyi11 0:bf56f20b9c5a 198
ziyi11 0:bf56f20b9c5a 199 void Gamepad::tone_off()
ziyi11 0:bf56f20b9c5a 200 {
ziyi11 0:bf56f20b9c5a 201 // called after timeout
ziyi11 0:bf56f20b9c5a 202 _buzzer->write(0.0);
ziyi11 0:bf56f20b9c5a 203 }
ziyi11 0:bf56f20b9c5a 204
ziyi11 0:bf56f20b9c5a 205 void Gamepad::init_buttons()
ziyi11 0:bf56f20b9c5a 206 {
ziyi11 0:bf56f20b9c5a 207 // turn on pull-downs as other side of button is connected to 3V3
ziyi11 0:bf56f20b9c5a 208 // button is 0 when not pressed and 1 when pressed
ziyi11 0:bf56f20b9c5a 209 _button_A->mode(PullDown);
ziyi11 0:bf56f20b9c5a 210 _button_B->mode(PullDown);
ziyi11 0:bf56f20b9c5a 211 _button_X->mode(PullDown);
ziyi11 0:bf56f20b9c5a 212 _button_Y->mode(PullDown);
ziyi11 0:bf56f20b9c5a 213 _button_back->mode(PullDown);
ziyi11 0:bf56f20b9c5a 214 _button_start->mode(PullDown);
ziyi11 0:bf56f20b9c5a 215 _button_L->mode(PullDown);
ziyi11 0:bf56f20b9c5a 216 _button_R->mode(PullDown);
ziyi11 0:bf56f20b9c5a 217 _button_joystick->mode(PullDown);
ziyi11 0:bf56f20b9c5a 218 // therefore setup rising edge interrupts
ziyi11 0:bf56f20b9c5a 219 _button_A->rise(callback(this,&Gamepad::a_isr));
ziyi11 0:bf56f20b9c5a 220 _button_B->rise(callback(this,&Gamepad::b_isr));
ziyi11 0:bf56f20b9c5a 221 _button_X->rise(callback(this,&Gamepad::x_isr));
ziyi11 0:bf56f20b9c5a 222 _button_Y->rise(callback(this,&Gamepad::y_isr));
ziyi11 0:bf56f20b9c5a 223 _button_L->rise(callback(this,&Gamepad::l_isr));
ziyi11 0:bf56f20b9c5a 224 _button_R->rise(callback(this,&Gamepad::r_isr));
ziyi11 0:bf56f20b9c5a 225 _button_start->rise(callback(this,&Gamepad::start_isr));
ziyi11 0:bf56f20b9c5a 226 _button_back->rise(callback(this,&Gamepad::back_isr));
ziyi11 0:bf56f20b9c5a 227 _button_joystick->rise(callback(this,&Gamepad::joy_isr));
ziyi11 0:bf56f20b9c5a 228 }
ziyi11 0:bf56f20b9c5a 229
ziyi11 0:bf56f20b9c5a 230 // button interrupts ISRs
ziyi11 0:bf56f20b9c5a 231 // Each of these simply sets the appropriate event bit in the _event_state
ziyi11 0:bf56f20b9c5a 232 // variable
ziyi11 0:bf56f20b9c5a 233 void Gamepad::a_isr()
ziyi11 0:bf56f20b9c5a 234 {
ziyi11 0:bf56f20b9c5a 235 _event_state.set(A_PRESSED);
ziyi11 0:bf56f20b9c5a 236 }
ziyi11 0:bf56f20b9c5a 237 void Gamepad::b_isr()
ziyi11 0:bf56f20b9c5a 238 {
ziyi11 0:bf56f20b9c5a 239 _event_state.set(B_PRESSED);
ziyi11 0:bf56f20b9c5a 240 }
ziyi11 0:bf56f20b9c5a 241 void Gamepad::x_isr()
ziyi11 0:bf56f20b9c5a 242 {
ziyi11 0:bf56f20b9c5a 243 _event_state.set(X_PRESSED);
ziyi11 0:bf56f20b9c5a 244 }
ziyi11 0:bf56f20b9c5a 245 void Gamepad::y_isr()
ziyi11 0:bf56f20b9c5a 246 {
ziyi11 0:bf56f20b9c5a 247 _event_state.set(Y_PRESSED);
ziyi11 0:bf56f20b9c5a 248 }
ziyi11 0:bf56f20b9c5a 249 void Gamepad::l_isr()
ziyi11 0:bf56f20b9c5a 250 {
ziyi11 0:bf56f20b9c5a 251 _event_state.set(L_PRESSED);
ziyi11 0:bf56f20b9c5a 252 }
ziyi11 0:bf56f20b9c5a 253 void Gamepad::r_isr()
ziyi11 0:bf56f20b9c5a 254 {
ziyi11 0:bf56f20b9c5a 255 _event_state.set(R_PRESSED);
ziyi11 0:bf56f20b9c5a 256 }
ziyi11 0:bf56f20b9c5a 257 void Gamepad::back_isr()
ziyi11 0:bf56f20b9c5a 258 {
ziyi11 0:bf56f20b9c5a 259 _event_state.set(BACK_PRESSED);
ziyi11 0:bf56f20b9c5a 260 }
ziyi11 0:bf56f20b9c5a 261 void Gamepad::start_isr()
ziyi11 0:bf56f20b9c5a 262 {
ziyi11 0:bf56f20b9c5a 263 _event_state.set(START_PRESSED);
ziyi11 0:bf56f20b9c5a 264 }
ziyi11 0:bf56f20b9c5a 265 void Gamepad::joy_isr()
ziyi11 0:bf56f20b9c5a 266 {
ziyi11 0:bf56f20b9c5a 267 _event_state.set(JOY_PRESSED);
ziyi11 0:bf56f20b9c5a 268 }
ziyi11 0:bf56f20b9c5a 269
ziyi11 0:bf56f20b9c5a 270 // get raw joystick coordinate in range -1 to 1
ziyi11 0:bf56f20b9c5a 271 // Direction (x,y)
ziyi11 0:bf56f20b9c5a 272 // North (0,1)
ziyi11 0:bf56f20b9c5a 273 // East (1,0)
ziyi11 0:bf56f20b9c5a 274 // South (0,-1)
ziyi11 0:bf56f20b9c5a 275 // West (-1,0)
ziyi11 0:bf56f20b9c5a 276 Vector2D Gamepad::get_coord()
ziyi11 0:bf56f20b9c5a 277 {
ziyi11 0:bf56f20b9c5a 278 // read() returns value in range 0.0 to 1.0 so is scaled and centre value
ziyi11 0:bf56f20b9c5a 279 // substracted to get values in the range -1.0 to 1.0
ziyi11 0:bf56f20b9c5a 280 float x = 2.0f*( _horiz->read() - _x0 );
ziyi11 0:bf56f20b9c5a 281 float y = 2.0f*( _vert->read() - _y0 );
ziyi11 0:bf56f20b9c5a 282
ziyi11 0:bf56f20b9c5a 283 // Note: the x value here is inverted to ensure the positive x is to the
ziyi11 0:bf56f20b9c5a 284 // right. This is simply due to how the potentiometer on the joystick
ziyi11 0:bf56f20b9c5a 285 // I was using was connected up. It could have been corrected in hardware
ziyi11 0:bf56f20b9c5a 286 // by swapping the power supply pins. Instead it is done in software so may
ziyi11 0:bf56f20b9c5a 287 // need to be changed depending on your wiring setup
ziyi11 0:bf56f20b9c5a 288
ziyi11 0:bf56f20b9c5a 289 Vector2D coord = {-x,y};
ziyi11 0:bf56f20b9c5a 290 return coord;
ziyi11 0:bf56f20b9c5a 291 }
ziyi11 0:bf56f20b9c5a 292
ziyi11 0:bf56f20b9c5a 293 // This maps the raw x,y coord onto a circular grid.
ziyi11 0:bf56f20b9c5a 294 // See: http://mathproofs.blogspot.co.uk/2005/07/mapping-square-to-circle.html
ziyi11 0:bf56f20b9c5a 295 Vector2D Gamepad::get_mapped_coord()
ziyi11 0:bf56f20b9c5a 296 {
ziyi11 0:bf56f20b9c5a 297 Vector2D coord = get_coord();
ziyi11 0:bf56f20b9c5a 298
ziyi11 0:bf56f20b9c5a 299 // do the transformation
ziyi11 0:bf56f20b9c5a 300 float x = coord.x*sqrt(1.0f-pow(coord.y,2.0f)/2.0f);
ziyi11 0:bf56f20b9c5a 301 float y = coord.y*sqrt(1.0f-pow(coord.x,2.0f)/2.0f);
ziyi11 0:bf56f20b9c5a 302
ziyi11 0:bf56f20b9c5a 303 Vector2D mapped_coord = {x,y};
ziyi11 0:bf56f20b9c5a 304 return mapped_coord;
ziyi11 0:bf56f20b9c5a 305 }
ziyi11 0:bf56f20b9c5a 306
ziyi11 0:bf56f20b9c5a 307 // this function converts the mapped coordinates into polar form
ziyi11 0:bf56f20b9c5a 308 Polar Gamepad::get_polar()
ziyi11 0:bf56f20b9c5a 309 {
ziyi11 0:bf56f20b9c5a 310 // get the mapped coordinate
ziyi11 0:bf56f20b9c5a 311 Vector2D coord = get_mapped_coord();
ziyi11 0:bf56f20b9c5a 312
ziyi11 0:bf56f20b9c5a 313 // at this point, 0 degrees (i.e. x-axis) will be defined to the East.
ziyi11 0:bf56f20b9c5a 314 // We want 0 degrees to correspond to North and increase clockwise to 359
ziyi11 0:bf56f20b9c5a 315 // like a compass heading, so we need to swap the axis and invert y
ziyi11 0:bf56f20b9c5a 316 float x = coord.y;
ziyi11 0:bf56f20b9c5a 317 float y = coord.x;
ziyi11 0:bf56f20b9c5a 318
ziyi11 0:bf56f20b9c5a 319 float mag = sqrt(x*x+y*y); // pythagoras
ziyi11 0:bf56f20b9c5a 320 float angle = RAD2DEG*atan2(y,x);
ziyi11 0:bf56f20b9c5a 321 // angle will be in range -180 to 180, so add 360 to negative angles to
ziyi11 0:bf56f20b9c5a 322 // move to 0 to 360 range
ziyi11 0:bf56f20b9c5a 323 if (angle < 0.0f) {
ziyi11 0:bf56f20b9c5a 324 angle+=360.0f;
ziyi11 0:bf56f20b9c5a 325 }
ziyi11 0:bf56f20b9c5a 326
ziyi11 0:bf56f20b9c5a 327 // the noise on the ADC causes the values of x and y to fluctuate slightly
ziyi11 0:bf56f20b9c5a 328 // around the centred values. This causes the random angle values to get
ziyi11 0:bf56f20b9c5a 329 // calculated when the joystick is centred and untouched. This is also when
ziyi11 0:bf56f20b9c5a 330 // the magnitude is very small, so we can check for a small magnitude and then
ziyi11 0:bf56f20b9c5a 331 // set the angle to -1. This will inform us when the angle is invalid and the
ziyi11 0:bf56f20b9c5a 332 // joystick is centred
ziyi11 0:bf56f20b9c5a 333
ziyi11 0:bf56f20b9c5a 334 if (mag < TOL) {
ziyi11 0:bf56f20b9c5a 335 mag = 0.0f;
ziyi11 0:bf56f20b9c5a 336 angle = -1.0f;
ziyi11 0:bf56f20b9c5a 337 }
ziyi11 0:bf56f20b9c5a 338
ziyi11 0:bf56f20b9c5a 339 Polar p = {mag,angle};
ziyi11 0:bf56f20b9c5a 340 return p;
ziyi11 0:bf56f20b9c5a 341 }