XJEL2645 (18/19) / Mbed 2 deprecated Snake_Project

Du Xianjie 201089059

Dependencies:   mbed FXOS8700Q

Gamepad/Gamepad.cpp@0:bc1d36f5f772, 2019-05-05 (annotated)

Committer:
VivianDu
Date:
Sun May 05 14:06:00 2019 +0000
Revision:
0:bc1d36f5f772
version_change

Who changed what in which revision?

UserRevisionLine numberNew contents of line
VivianDu 0:bc1d36f5f772 1 #include "Gamepad.h"
VivianDu 0:bc1d36f5f772 2
VivianDu 0:bc1d36f5f772 3 #include "mbed.h"
VivianDu 0:bc1d36f5f772 4
VivianDu 0:bc1d36f5f772 5 //////////// constructor/destructor ////////////
VivianDu 0:bc1d36f5f772 6 Gamepad::Gamepad()
VivianDu 0:bc1d36f5f772 7 :
VivianDu 0:bc1d36f5f772 8 _led1(new PwmOut(PTA1)),
VivianDu 0:bc1d36f5f772 9 _led2(new PwmOut(PTA2)),
VivianDu 0:bc1d36f5f772 10 _led3(new PwmOut(PTC2)),
VivianDu 0:bc1d36f5f772 11 _led4(new PwmOut(PTC3)),
VivianDu 0:bc1d36f5f772 12 _led5(new PwmOut(PTC4)),
VivianDu 0:bc1d36f5f772 13 _led6(new PwmOut(PTD3)),
VivianDu 0:bc1d36f5f772 14
VivianDu 0:bc1d36f5f772 15 _button_A(new InterruptIn(PTB9)),
VivianDu 0:bc1d36f5f772 16 _button_B(new InterruptIn(PTD0)),
VivianDu 0:bc1d36f5f772 17 _button_X(new InterruptIn(PTC17)),
VivianDu 0:bc1d36f5f772 18 _button_Y(new InterruptIn(PTC12)),
VivianDu 0:bc1d36f5f772 19 _button_L(new InterruptIn(PTB18)),
VivianDu 0:bc1d36f5f772 20 _button_R(new InterruptIn(PTB3)),
VivianDu 0:bc1d36f5f772 21 _button_back(new InterruptIn(PTB19)),
VivianDu 0:bc1d36f5f772 22 _button_start(new InterruptIn(PTC5)),
VivianDu 0:bc1d36f5f772 23 _button_joystick(new InterruptIn(PTC16)),
VivianDu 0:bc1d36f5f772 24
VivianDu 0:bc1d36f5f772 25 _vert(new AnalogIn(PTB10)),
VivianDu 0:bc1d36f5f772 26 _horiz(new AnalogIn(PTB11)),
VivianDu 0:bc1d36f5f772 27
VivianDu 0:bc1d36f5f772 28 _buzzer(new PwmOut(PTC10)),
VivianDu 0:bc1d36f5f772 29 _pot(new AnalogIn(PTB2)),
VivianDu 0:bc1d36f5f772 30
VivianDu 0:bc1d36f5f772 31 _timeout(new Timeout()),
VivianDu 0:bc1d36f5f772 32
VivianDu 0:bc1d36f5f772 33 _event_state(0),
VivianDu 0:bc1d36f5f772 34
VivianDu 0:bc1d36f5f772 35 _x0(0),
VivianDu 0:bc1d36f5f772 36 _y0(0)
VivianDu 0:bc1d36f5f772 37 {}
VivianDu 0:bc1d36f5f772 38
VivianDu 0:bc1d36f5f772 39 Gamepad::~Gamepad()
VivianDu 0:bc1d36f5f772 40 {
VivianDu 0:bc1d36f5f772 41 delete _led1,_led2,_led3,_led4,_led5,_led6;
VivianDu 0:bc1d36f5f772 42 delete _button_A,_button_B,_button_joystick,_vert,_horiz;
VivianDu 0:bc1d36f5f772 43 delete _button_X,_button_Y,_button_back,_button_start;
VivianDu 0:bc1d36f5f772 44 delete _button_L,_button_R, _buzzer, _pot, _timeout;
VivianDu 0:bc1d36f5f772 45 }
VivianDu 0:bc1d36f5f772 46
VivianDu 0:bc1d36f5f772 47 ///////////////// public methods /////////////////
VivianDu 0:bc1d36f5f772 48
VivianDu 0:bc1d36f5f772 49 void Gamepad::init()
VivianDu 0:bc1d36f5f772 50 {
VivianDu 0:bc1d36f5f772 51 leds_off();
VivianDu 0:bc1d36f5f772 52 init_buttons();
VivianDu 0:bc1d36f5f772 53
VivianDu 0:bc1d36f5f772 54 // read centred values of joystick
VivianDu 0:bc1d36f5f772 55 _x0 = _horiz->read();
VivianDu 0:bc1d36f5f772 56 _y0 = _vert->read();
VivianDu 0:bc1d36f5f772 57
VivianDu 0:bc1d36f5f772 58 // clear all flags
VivianDu 0:bc1d36f5f772 59 _event_state = 0;
VivianDu 0:bc1d36f5f772 60 }
VivianDu 0:bc1d36f5f772 61
VivianDu 0:bc1d36f5f772 62 void Gamepad::leds_off()
VivianDu 0:bc1d36f5f772 63 {
VivianDu 0:bc1d36f5f772 64 leds(0.0);
VivianDu 0:bc1d36f5f772 65 }
VivianDu 0:bc1d36f5f772 66
VivianDu 0:bc1d36f5f772 67 void Gamepad::leds_on()
VivianDu 0:bc1d36f5f772 68 {
VivianDu 0:bc1d36f5f772 69 leds(1.0);
VivianDu 0:bc1d36f5f772 70 }
VivianDu 0:bc1d36f5f772 71
VivianDu 0:bc1d36f5f772 72 void Gamepad::leds(float val) const
VivianDu 0:bc1d36f5f772 73 {
VivianDu 0:bc1d36f5f772 74 if (val < 0.0f) {
VivianDu 0:bc1d36f5f772 75 val = 0.0f;
VivianDu 0:bc1d36f5f772 76 }
VivianDu 0:bc1d36f5f772 77 if (val > 1.0f) {
VivianDu 0:bc1d36f5f772 78 val = 1.0f;
VivianDu 0:bc1d36f5f772 79 }
VivianDu 0:bc1d36f5f772 80
VivianDu 0:bc1d36f5f772 81 // leds are active-low, so subtract from 1.0
VivianDu 0:bc1d36f5f772 82 // 0.0 corresponds to fully-off, 1.0 to fully-on
VivianDu 0:bc1d36f5f772 83 val = 1.0f - val;
VivianDu 0:bc1d36f5f772 84
VivianDu 0:bc1d36f5f772 85 _led1->write(val);
VivianDu 0:bc1d36f5f772 86 _led2->write(val);
VivianDu 0:bc1d36f5f772 87 _led3->write(val);
VivianDu 0:bc1d36f5f772 88 _led4->write(val);
VivianDu 0:bc1d36f5f772 89 _led5->write(val);
VivianDu 0:bc1d36f5f772 90 _led6->write(val);
VivianDu 0:bc1d36f5f772 91 }
VivianDu 0:bc1d36f5f772 92
VivianDu 0:bc1d36f5f772 93 void Gamepad::led(int n,float val) const
VivianDu 0:bc1d36f5f772 94 {
VivianDu 0:bc1d36f5f772 95 // ensure they are within vlaid range
VivianDu 0:bc1d36f5f772 96 if (val < 0.0f) {
VivianDu 0:bc1d36f5f772 97 val = 0.0f;
VivianDu 0:bc1d36f5f772 98 }
VivianDu 0:bc1d36f5f772 99 if (val > 1.0f) {
VivianDu 0:bc1d36f5f772 100 val = 1.0f;
VivianDu 0:bc1d36f5f772 101 }
VivianDu 0:bc1d36f5f772 102
VivianDu 0:bc1d36f5f772 103 switch (n) {
VivianDu 0:bc1d36f5f772 104
VivianDu 0:bc1d36f5f772 105 // check for valid LED number and set value
VivianDu 0:bc1d36f5f772 106
VivianDu 0:bc1d36f5f772 107 case 1:
VivianDu 0:bc1d36f5f772 108 _led1->write(1.0f-val); // active-low so subtract from 1
VivianDu 0:bc1d36f5f772 109 break;
VivianDu 0:bc1d36f5f772 110 case 2:
VivianDu 0:bc1d36f5f772 111 _led2->write(1.0f-val); // active-low so subtract from 1
VivianDu 0:bc1d36f5f772 112 break;
VivianDu 0:bc1d36f5f772 113 case 3:
VivianDu 0:bc1d36f5f772 114 _led3->write(1.0f-val); // active-low so subtract from 1
VivianDu 0:bc1d36f5f772 115 break;
VivianDu 0:bc1d36f5f772 116 case 4:
VivianDu 0:bc1d36f5f772 117 _led4->write(1.0f-val); // active-low so subtract from 1
VivianDu 0:bc1d36f5f772 118 break;
VivianDu 0:bc1d36f5f772 119 case 5:
VivianDu 0:bc1d36f5f772 120 _led5->write(1.0f-val); // active-low so subtract from 1
VivianDu 0:bc1d36f5f772 121 break;
VivianDu 0:bc1d36f5f772 122 case 6:
VivianDu 0:bc1d36f5f772 123 _led6->write(1.0f-val); // active-low so subtract from 1
VivianDu 0:bc1d36f5f772 124 break;
VivianDu 0:bc1d36f5f772 125
VivianDu 0:bc1d36f5f772 126 }
VivianDu 0:bc1d36f5f772 127 }
VivianDu 0:bc1d36f5f772 128
VivianDu 0:bc1d36f5f772 129 float Gamepad::read_pot() const
VivianDu 0:bc1d36f5f772 130 {
VivianDu 0:bc1d36f5f772 131 return _pot->read();
VivianDu 0:bc1d36f5f772 132 }
VivianDu 0:bc1d36f5f772 133
VivianDu 0:bc1d36f5f772 134 void Gamepad::tone(float frequency, float duration)
VivianDu 0:bc1d36f5f772 135 {
VivianDu 0:bc1d36f5f772 136 _buzzer->period(1.0f/frequency);
VivianDu 0:bc1d36f5f772 137 _buzzer->write(0.5); // 50% duty cycle - square wave
VivianDu 0:bc1d36f5f772 138 _timeout->attach(callback(this, &Gamepad::tone_off), duration );
VivianDu 0:bc1d36f5f772 139 }
VivianDu 0:bc1d36f5f772 140
VivianDu 0:bc1d36f5f772 141 bool Gamepad::check_event(GamepadEvent const id)
VivianDu 0:bc1d36f5f772 142 {
VivianDu 0:bc1d36f5f772 143 // Check whether event flag is set
VivianDu 0:bc1d36f5f772 144 if (_event_state[id]) {
VivianDu 0:bc1d36f5f772 145 _event_state.reset(id); // clear flag
VivianDu 0:bc1d36f5f772 146 return true;
VivianDu 0:bc1d36f5f772 147 } else {
VivianDu 0:bc1d36f5f772 148 return false;
VivianDu 0:bc1d36f5f772 149 }
VivianDu 0:bc1d36f5f772 150 }
VivianDu 0:bc1d36f5f772 151
VivianDu 0:bc1d36f5f772 152 // this method gets the magnitude of the joystick movement
VivianDu 0:bc1d36f5f772 153 float Gamepad::get_mag()
VivianDu 0:bc1d36f5f772 154 {
VivianDu 0:bc1d36f5f772 155 Polar p = get_polar();
VivianDu 0:bc1d36f5f772 156 return p.mag;
VivianDu 0:bc1d36f5f772 157 }
VivianDu 0:bc1d36f5f772 158
VivianDu 0:bc1d36f5f772 159 // this method gets the angle of joystick movement (0 to 360, 0 North)
VivianDu 0:bc1d36f5f772 160 float Gamepad::get_angle()
VivianDu 0:bc1d36f5f772 161 {
VivianDu 0:bc1d36f5f772 162 Polar p = get_polar();
VivianDu 0:bc1d36f5f772 163 return p.angle;
VivianDu 0:bc1d36f5f772 164 }
VivianDu 0:bc1d36f5f772 165
VivianDu 0:bc1d36f5f772 166 Direction Gamepad::get_direction()
VivianDu 0:bc1d36f5f772 167 {
VivianDu 0:bc1d36f5f772 168 float angle = get_angle(); // 0 to 360, -1 for centred
VivianDu 0:bc1d36f5f772 169
VivianDu 0:bc1d36f5f772 170 Direction d;
VivianDu 0:bc1d36f5f772 171 // partition 360 into segments and check which segment the angle is in
VivianDu 0:bc1d36f5f772 172 if (angle < 0.0f) {
VivianDu 0:bc1d36f5f772 173 d = CENTRE; // check for -1.0 angle
VivianDu 0:bc1d36f5f772 174 } else if (angle < 22.5f) { // then keep going in 45 degree increments
VivianDu 0:bc1d36f5f772 175 d = N;
VivianDu 0:bc1d36f5f772 176 } else if (angle < 67.5f) {
VivianDu 0:bc1d36f5f772 177 d = NE;
VivianDu 0:bc1d36f5f772 178 } else if (angle < 112.5f) {
VivianDu 0:bc1d36f5f772 179 d = E;
VivianDu 0:bc1d36f5f772 180 } else if (angle < 157.5f) {
VivianDu 0:bc1d36f5f772 181 d = SE;
VivianDu 0:bc1d36f5f772 182 } else if (angle < 202.5f) {
VivianDu 0:bc1d36f5f772 183 d = S;
VivianDu 0:bc1d36f5f772 184 } else if (angle < 247.5f) {
VivianDu 0:bc1d36f5f772 185 d = SW;
VivianDu 0:bc1d36f5f772 186 } else if (angle < 292.5f) {
VivianDu 0:bc1d36f5f772 187 d = W;
VivianDu 0:bc1d36f5f772 188 } else if (angle < 337.5f) {
VivianDu 0:bc1d36f5f772 189 d = NW;
VivianDu 0:bc1d36f5f772 190 } else {
VivianDu 0:bc1d36f5f772 191 d = N;
VivianDu 0:bc1d36f5f772 192 }
VivianDu 0:bc1d36f5f772 193
VivianDu 0:bc1d36f5f772 194 return d;
VivianDu 0:bc1d36f5f772 195 }
VivianDu 0:bc1d36f5f772 196
VivianDu 0:bc1d36f5f772 197 ///////////////////// private methods ////////////////////////
VivianDu 0:bc1d36f5f772 198
VivianDu 0:bc1d36f5f772 199 void Gamepad::tone_off()
VivianDu 0:bc1d36f5f772 200 {
VivianDu 0:bc1d36f5f772 201 // called after timeout
VivianDu 0:bc1d36f5f772 202 _buzzer->write(0.0);
VivianDu 0:bc1d36f5f772 203 }
VivianDu 0:bc1d36f5f772 204
VivianDu 0:bc1d36f5f772 205 void Gamepad::init_buttons()
VivianDu 0:bc1d36f5f772 206 {
VivianDu 0:bc1d36f5f772 207 // turn on pull-downs as other side of button is connected to 3V3
VivianDu 0:bc1d36f5f772 208 // button is 0 when not pressed and 1 when pressed
VivianDu 0:bc1d36f5f772 209 _button_A->mode(PullDown);
VivianDu 0:bc1d36f5f772 210 _button_B->mode(PullDown);
VivianDu 0:bc1d36f5f772 211 _button_X->mode(PullDown);
VivianDu 0:bc1d36f5f772 212 _button_Y->mode(PullDown);
VivianDu 0:bc1d36f5f772 213 _button_back->mode(PullDown);
VivianDu 0:bc1d36f5f772 214 _button_start->mode(PullDown);
VivianDu 0:bc1d36f5f772 215 _button_L->mode(PullDown);
VivianDu 0:bc1d36f5f772 216 _button_R->mode(PullDown);
VivianDu 0:bc1d36f5f772 217 _button_joystick->mode(PullDown);
VivianDu 0:bc1d36f5f772 218 // therefore setup rising edge interrupts
VivianDu 0:bc1d36f5f772 219 _button_A->rise(callback(this,&Gamepad::a_isr));
VivianDu 0:bc1d36f5f772 220 _button_B->rise(callback(this,&Gamepad::b_isr));
VivianDu 0:bc1d36f5f772 221 _button_X->rise(callback(this,&Gamepad::x_isr));
VivianDu 0:bc1d36f5f772 222 _button_Y->rise(callback(this,&Gamepad::y_isr));
VivianDu 0:bc1d36f5f772 223 _button_L->rise(callback(this,&Gamepad::l_isr));
VivianDu 0:bc1d36f5f772 224 _button_R->rise(callback(this,&Gamepad::r_isr));
VivianDu 0:bc1d36f5f772 225 _button_start->rise(callback(this,&Gamepad::start_isr));
VivianDu 0:bc1d36f5f772 226 _button_back->rise(callback(this,&Gamepad::back_isr));
VivianDu 0:bc1d36f5f772 227 _button_joystick->rise(callback(this,&Gamepad::joy_isr));
VivianDu 0:bc1d36f5f772 228 }
VivianDu 0:bc1d36f5f772 229
VivianDu 0:bc1d36f5f772 230 // button interrupts ISRs
VivianDu 0:bc1d36f5f772 231 // Each of these simply sets the appropriate event bit in the _event_state
VivianDu 0:bc1d36f5f772 232 // variable
VivianDu 0:bc1d36f5f772 233 void Gamepad::a_isr()
VivianDu 0:bc1d36f5f772 234 {
VivianDu 0:bc1d36f5f772 235 _event_state.set(A_PRESSED);
VivianDu 0:bc1d36f5f772 236 }
VivianDu 0:bc1d36f5f772 237 void Gamepad::b_isr()
VivianDu 0:bc1d36f5f772 238 {
VivianDu 0:bc1d36f5f772 239 _event_state.set(B_PRESSED);
VivianDu 0:bc1d36f5f772 240 }
VivianDu 0:bc1d36f5f772 241 void Gamepad::x_isr()
VivianDu 0:bc1d36f5f772 242 {
VivianDu 0:bc1d36f5f772 243 _event_state.set(X_PRESSED);
VivianDu 0:bc1d36f5f772 244 }
VivianDu 0:bc1d36f5f772 245 void Gamepad::y_isr()
VivianDu 0:bc1d36f5f772 246 {
VivianDu 0:bc1d36f5f772 247 _event_state.set(Y_PRESSED);
VivianDu 0:bc1d36f5f772 248 }
VivianDu 0:bc1d36f5f772 249 void Gamepad::l_isr()
VivianDu 0:bc1d36f5f772 250 {
VivianDu 0:bc1d36f5f772 251 _event_state.set(L_PRESSED);
VivianDu 0:bc1d36f5f772 252 }
VivianDu 0:bc1d36f5f772 253 void Gamepad::r_isr()
VivianDu 0:bc1d36f5f772 254 {
VivianDu 0:bc1d36f5f772 255 _event_state.set(R_PRESSED);
VivianDu 0:bc1d36f5f772 256 }
VivianDu 0:bc1d36f5f772 257 void Gamepad::back_isr()
VivianDu 0:bc1d36f5f772 258 {
VivianDu 0:bc1d36f5f772 259 _event_state.set(BACK_PRESSED);
VivianDu 0:bc1d36f5f772 260 }
VivianDu 0:bc1d36f5f772 261 void Gamepad::start_isr()
VivianDu 0:bc1d36f5f772 262 {
VivianDu 0:bc1d36f5f772 263 _event_state.set(START_PRESSED);
VivianDu 0:bc1d36f5f772 264 }
VivianDu 0:bc1d36f5f772 265 void Gamepad::joy_isr()
VivianDu 0:bc1d36f5f772 266 {
VivianDu 0:bc1d36f5f772 267 _event_state.set(JOY_PRESSED);
VivianDu 0:bc1d36f5f772 268 }
VivianDu 0:bc1d36f5f772 269
VivianDu 0:bc1d36f5f772 270 // get raw joystick coordinate in range -1 to 1
VivianDu 0:bc1d36f5f772 271 // Direction (x,y)
VivianDu 0:bc1d36f5f772 272 // North (0,1)
VivianDu 0:bc1d36f5f772 273 // East (1,0)
VivianDu 0:bc1d36f5f772 274 // South (0,-1)
VivianDu 0:bc1d36f5f772 275 // West (-1,0)
VivianDu 0:bc1d36f5f772 276 Vector2D Gamepad::get_coord()
VivianDu 0:bc1d36f5f772 277 {
VivianDu 0:bc1d36f5f772 278 // read() returns value in range 0.0 to 1.0 so is scaled and centre value
VivianDu 0:bc1d36f5f772 279 // substracted to get values in the range -1.0 to 1.0
VivianDu 0:bc1d36f5f772 280 float x = 2.0f*( _horiz->read() - _x0 );
VivianDu 0:bc1d36f5f772 281 float y = 2.0f*( _vert->read() - _y0 );
VivianDu 0:bc1d36f5f772 282
VivianDu 0:bc1d36f5f772 283 // Note: the x value here is inverted to ensure the positive x is to the
VivianDu 0:bc1d36f5f772 284 // right. This is simply due to how the potentiometer on the joystick
VivianDu 0:bc1d36f5f772 285 // I was using was connected up. It could have been corrected in hardware
VivianDu 0:bc1d36f5f772 286 // by swapping the power supply pins. Instead it is done in software so may
VivianDu 0:bc1d36f5f772 287 // need to be changed depending on your wiring setup
VivianDu 0:bc1d36f5f772 288
VivianDu 0:bc1d36f5f772 289 Vector2D coord = {-x,y};
VivianDu 0:bc1d36f5f772 290 return coord;
VivianDu 0:bc1d36f5f772 291 }
VivianDu 0:bc1d36f5f772 292
VivianDu 0:bc1d36f5f772 293 // This maps the raw x,y coord onto a circular grid.
VivianDu 0:bc1d36f5f772 294 // See: http://mathproofs.blogspot.co.uk/2005/07/mapping-square-to-circle.html
VivianDu 0:bc1d36f5f772 295 Vector2D Gamepad::get_mapped_coord()
VivianDu 0:bc1d36f5f772 296 {
VivianDu 0:bc1d36f5f772 297 Vector2D coord = get_coord();
VivianDu 0:bc1d36f5f772 298
VivianDu 0:bc1d36f5f772 299 // do the transformation
VivianDu 0:bc1d36f5f772 300 float x = coord.x*sqrt(1.0f-pow(coord.y,2.0f)/2.0f);
VivianDu 0:bc1d36f5f772 301 float y = coord.y*sqrt(1.0f-pow(coord.x,2.0f)/2.0f);
VivianDu 0:bc1d36f5f772 302
VivianDu 0:bc1d36f5f772 303 Vector2D mapped_coord = {x,y};
VivianDu 0:bc1d36f5f772 304 return mapped_coord;
VivianDu 0:bc1d36f5f772 305 }
VivianDu 0:bc1d36f5f772 306
VivianDu 0:bc1d36f5f772 307 // this function converts the mapped coordinates into polar form
VivianDu 0:bc1d36f5f772 308 Polar Gamepad::get_polar()
VivianDu 0:bc1d36f5f772 309 {
VivianDu 0:bc1d36f5f772 310 // get the mapped coordinate
VivianDu 0:bc1d36f5f772 311 Vector2D coord = get_mapped_coord();
VivianDu 0:bc1d36f5f772 312
VivianDu 0:bc1d36f5f772 313 // at this point, 0 degrees (i.e. x-axis) will be defined to the East.
VivianDu 0:bc1d36f5f772 314 // We want 0 degrees to correspond to North and increase clockwise to 359
VivianDu 0:bc1d36f5f772 315 // like a compass heading, so we need to swap the axis and invert y
VivianDu 0:bc1d36f5f772 316 float x = coord.y;
VivianDu 0:bc1d36f5f772 317 float y = coord.x;
VivianDu 0:bc1d36f5f772 318
VivianDu 0:bc1d36f5f772 319 float mag = sqrt(x*x+y*y); // pythagoras
VivianDu 0:bc1d36f5f772 320 float angle = RAD2DEG*atan2(y,x);
VivianDu 0:bc1d36f5f772 321 // angle will be in range -180 to 180, so add 360 to negative angles to
VivianDu 0:bc1d36f5f772 322 // move to 0 to 360 range
VivianDu 0:bc1d36f5f772 323 if (angle < 0.0f) {
VivianDu 0:bc1d36f5f772 324 angle+=360.0f;
VivianDu 0:bc1d36f5f772 325 }
VivianDu 0:bc1d36f5f772 326
VivianDu 0:bc1d36f5f772 327 // the noise on the ADC causes the values of x and y to fluctuate slightly
VivianDu 0:bc1d36f5f772 328 // around the centred values. This causes the random angle values to get
VivianDu 0:bc1d36f5f772 329 // calculated when the joystick is centred and untouched. This is also when
VivianDu 0:bc1d36f5f772 330 // the magnitude is very small, so we can check for a small magnitude and then
VivianDu 0:bc1d36f5f772 331 // set the angle to -1. This will inform us when the angle is invalid and the
VivianDu 0:bc1d36f5f772 332 // joystick is centred
VivianDu 0:bc1d36f5f772 333
VivianDu 0:bc1d36f5f772 334 if (mag < TOL) {
VivianDu 0:bc1d36f5f772 335 mag = 0.0f;
VivianDu 0:bc1d36f5f772 336 angle = -1.0f;
VivianDu 0:bc1d36f5f772 337 }
VivianDu 0:bc1d36f5f772 338
VivianDu 0:bc1d36f5f772 339 Polar p = {mag,angle};
VivianDu 0:bc1d36f5f772 340 return p;
VivianDu 0:bc1d36f5f772 341 }