harry rance / Mbed 2 deprecated Revised_Space_Invaders

Harry Rance 200925395 Embedded Systems Project

Dependencies:   mbed

Gamepad.cpp@7:569f3fc70ac5, 2017-05-03 (annotated)

Committer:
harryrance
Date:
Wed May 03 16:33:20 2017 +0000
Revision:
7:569f3fc70ac5
Parent:
2:50feb42b982c 
Committed with full documentation generated.;

Who changed what in which revision?

UserRevisionLine numberNew contents of line
harryrance 0:c9bf674fe0c7 1 #include "Gamepad.h"
harryrance 0:c9bf674fe0c7 2
harryrance 0:c9bf674fe0c7 3 #include "mbed.h"
harryrance 0:c9bf674fe0c7 4
harryrance 0:c9bf674fe0c7 5 //////////// constructor/destructor ////////////
harryrance 0:c9bf674fe0c7 6 Gamepad::Gamepad()
harryrance 0:c9bf674fe0c7 7 :
harryrance 0:c9bf674fe0c7 8 _led1(new PwmOut(PTA1)),
harryrance 0:c9bf674fe0c7 9 _led2(new PwmOut(PTA2)),
harryrance 0:c9bf674fe0c7 10 _led3(new PwmOut(PTC2)),
harryrance 0:c9bf674fe0c7 11 _led4(new PwmOut(PTC3)),
harryrance 0:c9bf674fe0c7 12 _led5(new PwmOut(PTC4)),
harryrance 0:c9bf674fe0c7 13 _led6(new PwmOut(PTD3)),
harryrance 0:c9bf674fe0c7 14
harryrance 0:c9bf674fe0c7 15 _button_A(new InterruptIn(PTB9)),
harryrance 0:c9bf674fe0c7 16 _button_B(new InterruptIn(PTD0)),
harryrance 0:c9bf674fe0c7 17 _button_X(new InterruptIn(PTC17)),
harryrance 0:c9bf674fe0c7 18 _button_Y(new InterruptIn(PTC12)),
harryrance 0:c9bf674fe0c7 19 _button_L(new InterruptIn(PTB18)),
harryrance 0:c9bf674fe0c7 20 _button_R(new InterruptIn(PTB3)),
harryrance 0:c9bf674fe0c7 21 _button_back(new InterruptIn(PTB19)),
harryrance 0:c9bf674fe0c7 22 _button_start(new InterruptIn(PTC5)),
harryrance 0:c9bf674fe0c7 23 _button_joystick(new InterruptIn(PTC16)),
harryrance 0:c9bf674fe0c7 24
harryrance 0:c9bf674fe0c7 25 _vert(new AnalogIn(PTB10)),
harryrance 0:c9bf674fe0c7 26 _horiz(new AnalogIn(PTB11)),
harryrance 0:c9bf674fe0c7 27
harryrance 0:c9bf674fe0c7 28 _buzzer(new PwmOut(PTC10)),
harryrance 0:c9bf674fe0c7 29 _pot(new AnalogIn(PTB2)),
harryrance 0:c9bf674fe0c7 30
harryrance 0:c9bf674fe0c7 31 _timeout(new Timeout()),
harryrance 0:c9bf674fe0c7 32
harryrance 0:c9bf674fe0c7 33 _event_state(0),
harryrance 0:c9bf674fe0c7 34
harryrance 0:c9bf674fe0c7 35 _x0(0),
harryrance 0:c9bf674fe0c7 36 _y0(0)
harryrance 0:c9bf674fe0c7 37 {}
harryrance 0:c9bf674fe0c7 38
harryrance 0:c9bf674fe0c7 39 Gamepad::~Gamepad()
harryrance 0:c9bf674fe0c7 40 {
harryrance 0:c9bf674fe0c7 41 delete _led1,_led2,_led3,_led4,_led5,_led6;
harryrance 0:c9bf674fe0c7 42 delete _button_A,_button_B,_button_joystick,_vert,_horiz;
harryrance 0:c9bf674fe0c7 43 delete _button_X,_button_Y,_button_back,_button_start;
harryrance 0:c9bf674fe0c7 44 delete _button_L,_button_R, _buzzer, _pot, _timeout;
harryrance 0:c9bf674fe0c7 45 }
harryrance 0:c9bf674fe0c7 46
harryrance 0:c9bf674fe0c7 47 ///////////////// public methods /////////////////
harryrance 0:c9bf674fe0c7 48
harryrance 0:c9bf674fe0c7 49 void Gamepad::init()
harryrance 0:c9bf674fe0c7 50 {
harryrance 0:c9bf674fe0c7 51 leds_off();
harryrance 0:c9bf674fe0c7 52 init_buttons();
harryrance 0:c9bf674fe0c7 53
harryrance 0:c9bf674fe0c7 54 // read centred values of joystick
harryrance 0:c9bf674fe0c7 55 _x0 = _horiz->read();
harryrance 0:c9bf674fe0c7 56 _y0 = _vert->read();
harryrance 0:c9bf674fe0c7 57
harryrance 0:c9bf674fe0c7 58 // clear all flags
harryrance 0:c9bf674fe0c7 59 _event_state = 0;
harryrance 0:c9bf674fe0c7 60 }
harryrance 0:c9bf674fe0c7 61
harryrance 0:c9bf674fe0c7 62 void Gamepad::leds_off()
harryrance 0:c9bf674fe0c7 63 {
harryrance 0:c9bf674fe0c7 64 leds(0.0);
harryrance 0:c9bf674fe0c7 65 }
harryrance 0:c9bf674fe0c7 66
harryrance 0:c9bf674fe0c7 67 void Gamepad::leds_on()
harryrance 0:c9bf674fe0c7 68 {
harryrance 0:c9bf674fe0c7 69 leds(1.0);
harryrance 0:c9bf674fe0c7 70 }
harryrance 0:c9bf674fe0c7 71
harryrance 0:c9bf674fe0c7 72 void Gamepad::leds(float val) const
harryrance 0:c9bf674fe0c7 73 {
harryrance 0:c9bf674fe0c7 74 if (val < 0.0f) {
harryrance 0:c9bf674fe0c7 75 val = 0.0f;
harryrance 0:c9bf674fe0c7 76 }
harryrance 0:c9bf674fe0c7 77 if (val > 1.0f) {
harryrance 0:c9bf674fe0c7 78 val = 1.0f;
harryrance 0:c9bf674fe0c7 79 }
harryrance 0:c9bf674fe0c7 80
harryrance 0:c9bf674fe0c7 81 // leds are active-low, so subtract from 1.0
harryrance 0:c9bf674fe0c7 82 // 0.0 corresponds to fully-off, 1.0 to fully-on
harryrance 0:c9bf674fe0c7 83 val = 1.0f - val;
harryrance 0:c9bf674fe0c7 84
harryrance 0:c9bf674fe0c7 85 _led1->write(val);
harryrance 0:c9bf674fe0c7 86 _led2->write(val);
harryrance 0:c9bf674fe0c7 87 _led3->write(val);
harryrance 0:c9bf674fe0c7 88 _led4->write(val);
harryrance 0:c9bf674fe0c7 89 _led5->write(val);
harryrance 0:c9bf674fe0c7 90 _led6->write(val);
harryrance 0:c9bf674fe0c7 91 }
harryrance 0:c9bf674fe0c7 92
harryrance 0:c9bf674fe0c7 93 void Gamepad::led(int n,float val) const
harryrance 0:c9bf674fe0c7 94 {
harryrance 0:c9bf674fe0c7 95 // ensure they are within vlaid range
harryrance 0:c9bf674fe0c7 96 if (val < 0.0f) {
harryrance 0:c9bf674fe0c7 97 val = 0.0f;
harryrance 0:c9bf674fe0c7 98 }
harryrance 0:c9bf674fe0c7 99 if (val > 1.0f) {
harryrance 0:c9bf674fe0c7 100 val = 1.0f;
harryrance 0:c9bf674fe0c7 101 }
harryrance 2:50feb42b982c 102
harryrance 0:c9bf674fe0c7 103 switch (n) {
harryrance 2:50feb42b982c 104
harryrance 0:c9bf674fe0c7 105 // check for valid LED number and set value
harryrance 0:c9bf674fe0c7 106
harryrance 0:c9bf674fe0c7 107 case 1:
harryrance 0:c9bf674fe0c7 108 _led1->write(1.0f-val); // active-low so subtract from 1
harryrance 0:c9bf674fe0c7 109 break;
harryrance 0:c9bf674fe0c7 110 case 2:
harryrance 0:c9bf674fe0c7 111 _led2->write(1.0f-val); // active-low so subtract from 1
harryrance 0:c9bf674fe0c7 112 break;
harryrance 0:c9bf674fe0c7 113 case 3:
harryrance 0:c9bf674fe0c7 114 _led3->write(1.0f-val); // active-low so subtract from 1
harryrance 0:c9bf674fe0c7 115 break;
harryrance 0:c9bf674fe0c7 116 case 4:
harryrance 0:c9bf674fe0c7 117 _led4->write(1.0f-val); // active-low so subtract from 1
harryrance 0:c9bf674fe0c7 118 break;
harryrance 0:c9bf674fe0c7 119 case 5:
harryrance 0:c9bf674fe0c7 120 _led5->write(1.0f-val); // active-low so subtract from 1
harryrance 0:c9bf674fe0c7 121 break;
harryrance 0:c9bf674fe0c7 122 case 6:
harryrance 0:c9bf674fe0c7 123 _led6->write(1.0f-val); // active-low so subtract from 1
harryrance 0:c9bf674fe0c7 124 break;
harryrance 0:c9bf674fe0c7 125
harryrance 0:c9bf674fe0c7 126 }
harryrance 0:c9bf674fe0c7 127 }
harryrance 0:c9bf674fe0c7 128
harryrance 0:c9bf674fe0c7 129 float Gamepad::read_pot() const
harryrance 0:c9bf674fe0c7 130 {
harryrance 0:c9bf674fe0c7 131 return _pot->read();
harryrance 0:c9bf674fe0c7 132 }
harryrance 0:c9bf674fe0c7 133
harryrance 0:c9bf674fe0c7 134 void Gamepad::tone(float frequency, float duration)
harryrance 0:c9bf674fe0c7 135 {
harryrance 0:c9bf674fe0c7 136 _buzzer->period(1.0f/frequency);
harryrance 0:c9bf674fe0c7 137 _buzzer->write(0.5); // 50% duty cycle - square wave
harryrance 0:c9bf674fe0c7 138 _timeout->attach(callback(this, &Gamepad::tone_off), duration );
harryrance 0:c9bf674fe0c7 139 }
harryrance 0:c9bf674fe0c7 140
harryrance 0:c9bf674fe0c7 141 bool Gamepad::check_event(GamepadEvent const id)
harryrance 0:c9bf674fe0c7 142 {
harryrance 0:c9bf674fe0c7 143 // Check whether event flag is set
harryrance 0:c9bf674fe0c7 144 if (_event_state[id]) {
harryrance 0:c9bf674fe0c7 145 _event_state.reset(id); // clear flag
harryrance 0:c9bf674fe0c7 146 return true;
harryrance 0:c9bf674fe0c7 147 } else {
harryrance 0:c9bf674fe0c7 148 return false;
harryrance 0:c9bf674fe0c7 149 }
harryrance 0:c9bf674fe0c7 150 }
harryrance 0:c9bf674fe0c7 151
harryrance 0:c9bf674fe0c7 152 // this method gets the magnitude of the joystick movement
harryrance 0:c9bf674fe0c7 153 float Gamepad::get_mag()
harryrance 0:c9bf674fe0c7 154 {
harryrance 0:c9bf674fe0c7 155 Polar p = get_polar();
harryrance 0:c9bf674fe0c7 156 return p.mag;
harryrance 0:c9bf674fe0c7 157 }
harryrance 0:c9bf674fe0c7 158
harryrance 0:c9bf674fe0c7 159 // this method gets the angle of joystick movement (0 to 360, 0 North)
harryrance 0:c9bf674fe0c7 160 float Gamepad::get_angle()
harryrance 0:c9bf674fe0c7 161 {
harryrance 0:c9bf674fe0c7 162 Polar p = get_polar();
harryrance 0:c9bf674fe0c7 163 return p.angle;
harryrance 0:c9bf674fe0c7 164 }
harryrance 0:c9bf674fe0c7 165
harryrance 0:c9bf674fe0c7 166 Direction Gamepad::get_direction()
harryrance 0:c9bf674fe0c7 167 {
harryrance 0:c9bf674fe0c7 168 float angle = get_angle(); // 0 to 360, -1 for centred
harryrance 0:c9bf674fe0c7 169
harryrance 0:c9bf674fe0c7 170 Direction d;
harryrance 0:c9bf674fe0c7 171 // partition 360 into segments and check which segment the angle is in
harryrance 0:c9bf674fe0c7 172 if (angle < 0.0f) {
harryrance 0:c9bf674fe0c7 173 d = CENTRE; // check for -1.0 angle
harryrance 0:c9bf674fe0c7 174 } else if (angle < 22.5f) { // then keep going in 45 degree increments
harryrance 0:c9bf674fe0c7 175 d = N;
harryrance 0:c9bf674fe0c7 176 } else if (angle < 67.5f) {
harryrance 0:c9bf674fe0c7 177 d = NE;
harryrance 0:c9bf674fe0c7 178 } else if (angle < 112.5f) {
harryrance 0:c9bf674fe0c7 179 d = E;
harryrance 0:c9bf674fe0c7 180 } else if (angle < 157.5f) {
harryrance 0:c9bf674fe0c7 181 d = SE;
harryrance 0:c9bf674fe0c7 182 } else if (angle < 202.5f) {
harryrance 0:c9bf674fe0c7 183 d = S;
harryrance 0:c9bf674fe0c7 184 } else if (angle < 247.5f) {
harryrance 0:c9bf674fe0c7 185 d = SW;
harryrance 0:c9bf674fe0c7 186 } else if (angle < 292.5f) {
harryrance 0:c9bf674fe0c7 187 d = W;
harryrance 0:c9bf674fe0c7 188 } else if (angle < 337.5f) {
harryrance 0:c9bf674fe0c7 189 d = NW;
harryrance 0:c9bf674fe0c7 190 } else {
harryrance 0:c9bf674fe0c7 191 d = N;
harryrance 0:c9bf674fe0c7 192 }
harryrance 0:c9bf674fe0c7 193
harryrance 0:c9bf674fe0c7 194 return d;
harryrance 0:c9bf674fe0c7 195 }
harryrance 0:c9bf674fe0c7 196
harryrance 0:c9bf674fe0c7 197 ///////////////////// private methods ////////////////////////
harryrance 0:c9bf674fe0c7 198
harryrance 0:c9bf674fe0c7 199 void Gamepad::tone_off()
harryrance 0:c9bf674fe0c7 200 {
harryrance 0:c9bf674fe0c7 201 // called after timeout
harryrance 0:c9bf674fe0c7 202 _buzzer->write(0.0);
harryrance 0:c9bf674fe0c7 203 }
harryrance 0:c9bf674fe0c7 204
harryrance 0:c9bf674fe0c7 205 void Gamepad::init_buttons()
harryrance 0:c9bf674fe0c7 206 {
harryrance 0:c9bf674fe0c7 207 // turn on pull-downs as other side of button is connected to 3V3
harryrance 0:c9bf674fe0c7 208 // button is 0 when not pressed and 1 when pressed
harryrance 0:c9bf674fe0c7 209 _button_A->mode(PullDown);
harryrance 0:c9bf674fe0c7 210 _button_B->mode(PullDown);
harryrance 0:c9bf674fe0c7 211 _button_X->mode(PullDown);
harryrance 0:c9bf674fe0c7 212 _button_Y->mode(PullDown);
harryrance 0:c9bf674fe0c7 213 _button_back->mode(PullDown);
harryrance 0:c9bf674fe0c7 214 _button_start->mode(PullDown);
harryrance 0:c9bf674fe0c7 215 _button_L->mode(PullDown);
harryrance 0:c9bf674fe0c7 216 _button_R->mode(PullDown);
harryrance 0:c9bf674fe0c7 217 _button_joystick->mode(PullDown);
harryrance 0:c9bf674fe0c7 218 // therefore setup rising edge interrupts
harryrance 0:c9bf674fe0c7 219 _button_A->rise(callback(this,&Gamepad::a_isr));
harryrance 0:c9bf674fe0c7 220 _button_B->rise(callback(this,&Gamepad::b_isr));
harryrance 0:c9bf674fe0c7 221 _button_X->rise(callback(this,&Gamepad::x_isr));
harryrance 0:c9bf674fe0c7 222 _button_Y->rise(callback(this,&Gamepad::y_isr));
harryrance 0:c9bf674fe0c7 223 _button_L->rise(callback(this,&Gamepad::l_isr));
harryrance 0:c9bf674fe0c7 224 _button_R->rise(callback(this,&Gamepad::r_isr));
harryrance 0:c9bf674fe0c7 225 _button_start->rise(callback(this,&Gamepad::start_isr));
harryrance 0:c9bf674fe0c7 226 _button_back->rise(callback(this,&Gamepad::back_isr));
harryrance 0:c9bf674fe0c7 227 _button_joystick->rise(callback(this,&Gamepad::joy_isr));
harryrance 0:c9bf674fe0c7 228 }
harryrance 0:c9bf674fe0c7 229
harryrance 0:c9bf674fe0c7 230 // button interrupts ISRs
harryrance 0:c9bf674fe0c7 231 // Each of these simply sets the appropriate event bit in the _event_state
harryrance 0:c9bf674fe0c7 232 // variable
harryrance 0:c9bf674fe0c7 233 void Gamepad::a_isr()
harryrance 0:c9bf674fe0c7 234 {
harryrance 0:c9bf674fe0c7 235 _event_state.set(A_PRESSED);
harryrance 0:c9bf674fe0c7 236 }
harryrance 0:c9bf674fe0c7 237 void Gamepad::b_isr()
harryrance 0:c9bf674fe0c7 238 {
harryrance 0:c9bf674fe0c7 239 _event_state.set(B_PRESSED);
harryrance 0:c9bf674fe0c7 240 }
harryrance 0:c9bf674fe0c7 241 void Gamepad::x_isr()
harryrance 0:c9bf674fe0c7 242 {
harryrance 0:c9bf674fe0c7 243 _event_state.set(X_PRESSED);
harryrance 0:c9bf674fe0c7 244 }
harryrance 0:c9bf674fe0c7 245 void Gamepad::y_isr()
harryrance 0:c9bf674fe0c7 246 {
harryrance 0:c9bf674fe0c7 247 _event_state.set(Y_PRESSED);
harryrance 0:c9bf674fe0c7 248 }
harryrance 0:c9bf674fe0c7 249 void Gamepad::l_isr()
harryrance 0:c9bf674fe0c7 250 {
harryrance 0:c9bf674fe0c7 251 _event_state.set(L_PRESSED);
harryrance 0:c9bf674fe0c7 252 }
harryrance 0:c9bf674fe0c7 253 void Gamepad::r_isr()
harryrance 0:c9bf674fe0c7 254 {
harryrance 0:c9bf674fe0c7 255 _event_state.set(R_PRESSED);
harryrance 0:c9bf674fe0c7 256 }
harryrance 0:c9bf674fe0c7 257 void Gamepad::back_isr()
harryrance 0:c9bf674fe0c7 258 {
harryrance 0:c9bf674fe0c7 259 _event_state.set(BACK_PRESSED);
harryrance 0:c9bf674fe0c7 260 }
harryrance 0:c9bf674fe0c7 261 void Gamepad::start_isr()
harryrance 0:c9bf674fe0c7 262 {
harryrance 0:c9bf674fe0c7 263 _event_state.set(START_PRESSED);
harryrance 0:c9bf674fe0c7 264 }
harryrance 0:c9bf674fe0c7 265 void Gamepad::joy_isr()
harryrance 0:c9bf674fe0c7 266 {
harryrance 0:c9bf674fe0c7 267 _event_state.set(JOY_PRESSED);
harryrance 0:c9bf674fe0c7 268 }
harryrance 0:c9bf674fe0c7 269
harryrance 0:c9bf674fe0c7 270 // get raw joystick coordinate in range -1 to 1
harryrance 0:c9bf674fe0c7 271 // Direction (x,y)
harryrance 0:c9bf674fe0c7 272 // North (0,1)
harryrance 0:c9bf674fe0c7 273 // East (1,0)
harryrance 0:c9bf674fe0c7 274 // South (0,-1)
harryrance 0:c9bf674fe0c7 275 // West (-1,0)
harryrance 0:c9bf674fe0c7 276 Vector2D Gamepad::get_coord()
harryrance 0:c9bf674fe0c7 277 {
harryrance 0:c9bf674fe0c7 278 // read() returns value in range 0.0 to 1.0 so is scaled and centre value
harryrance 0:c9bf674fe0c7 279 // substracted to get values in the range -1.0 to 1.0
harryrance 0:c9bf674fe0c7 280 float x = 2.0f*( _horiz->read() - _x0 );
harryrance 0:c9bf674fe0c7 281 float y = 2.0f*( _vert->read() - _y0 );
harryrance 0:c9bf674fe0c7 282
harryrance 0:c9bf674fe0c7 283 // Note: the x value here is inverted to ensure the positive x is to the
harryrance 0:c9bf674fe0c7 284 // right. This is simply due to how the potentiometer on the joystick
harryrance 0:c9bf674fe0c7 285 // I was using was connected up. It could have been corrected in hardware
harryrance 0:c9bf674fe0c7 286 // by swapping the power supply pins. Instead it is done in software so may
harryrance 0:c9bf674fe0c7 287 // need to be changed depending on your wiring setup
harryrance 0:c9bf674fe0c7 288
harryrance 0:c9bf674fe0c7 289 Vector2D coord = {-x,y};
harryrance 0:c9bf674fe0c7 290 return coord;
harryrance 0:c9bf674fe0c7 291 }
harryrance 0:c9bf674fe0c7 292
harryrance 0:c9bf674fe0c7 293 // This maps the raw x,y coord onto a circular grid.
harryrance 0:c9bf674fe0c7 294 // See: http://mathproofs.blogspot.co.uk/2005/07/mapping-square-to-circle.html
harryrance 0:c9bf674fe0c7 295 Vector2D Gamepad::get_mapped_coord()
harryrance 0:c9bf674fe0c7 296 {
harryrance 0:c9bf674fe0c7 297 Vector2D coord = get_coord();
harryrance 0:c9bf674fe0c7 298
harryrance 0:c9bf674fe0c7 299 // do the transformation
harryrance 0:c9bf674fe0c7 300 float x = coord.x*sqrt(1.0f-pow(coord.y,2.0f)/2.0f);
harryrance 0:c9bf674fe0c7 301 float y = coord.y*sqrt(1.0f-pow(coord.x,2.0f)/2.0f);
harryrance 0:c9bf674fe0c7 302
harryrance 0:c9bf674fe0c7 303 Vector2D mapped_coord = {x,y};
harryrance 0:c9bf674fe0c7 304 return mapped_coord;
harryrance 0:c9bf674fe0c7 305 }
harryrance 0:c9bf674fe0c7 306
harryrance 0:c9bf674fe0c7 307 // this function converts the mapped coordinates into polar form
harryrance 0:c9bf674fe0c7 308 Polar Gamepad::get_polar()
harryrance 0:c9bf674fe0c7 309 {
harryrance 0:c9bf674fe0c7 310 // get the mapped coordinate
harryrance 0:c9bf674fe0c7 311 Vector2D coord = get_mapped_coord();
harryrance 0:c9bf674fe0c7 312
harryrance 0:c9bf674fe0c7 313 // at this point, 0 degrees (i.e. x-axis) will be defined to the East.
harryrance 0:c9bf674fe0c7 314 // We want 0 degrees to correspond to North and increase clockwise to 359
harryrance 0:c9bf674fe0c7 315 // like a compass heading, so we need to swap the axis and invert y
harryrance 0:c9bf674fe0c7 316 float x = coord.y;
harryrance 0:c9bf674fe0c7 317 float y = coord.x;
harryrance 0:c9bf674fe0c7 318
harryrance 0:c9bf674fe0c7 319 float mag = sqrt(x*x+y*y); // pythagoras
harryrance 0:c9bf674fe0c7 320 float angle = RAD2DEG*atan2(y,x);
harryrance 0:c9bf674fe0c7 321 // angle will be in range -180 to 180, so add 360 to negative angles to
harryrance 0:c9bf674fe0c7 322 // move to 0 to 360 range
harryrance 0:c9bf674fe0c7 323 if (angle < 0.0f) {
harryrance 0:c9bf674fe0c7 324 angle+=360.0f;
harryrance 0:c9bf674fe0c7 325 }
harryrance 0:c9bf674fe0c7 326
harryrance 0:c9bf674fe0c7 327 // the noise on the ADC causes the values of x and y to fluctuate slightly
harryrance 0:c9bf674fe0c7 328 // around the centred values. This causes the random angle values to get
harryrance 0:c9bf674fe0c7 329 // calculated when the joystick is centred and untouched. This is also when
harryrance 0:c9bf674fe0c7 330 // the magnitude is very small, so we can check for a small magnitude and then
harryrance 0:c9bf674fe0c7 331 // set the angle to -1. This will inform us when the angle is invalid and the
harryrance 0:c9bf674fe0c7 332 // joystick is centred
harryrance 0:c9bf674fe0c7 333
harryrance 0:c9bf674fe0c7 334 if (mag < TOL) {
harryrance 0:c9bf674fe0c7 335 mag = 0.0f;
harryrance 0:c9bf674fe0c7 336 angle = -1.0f;
harryrance 0:c9bf674fe0c7 337 }
harryrance 0:c9bf674fe0c7 338
harryrance 0:c9bf674fe0c7 339 Polar p = {mag,angle};
harryrance 0:c9bf674fe0c7 340 return p;
harryrance 0:c9bf674fe0c7 341 }
harryrance 2:50feb42b982c 342