Haoyan Zhang / Mbed 2 deprecated el17h2z1

deemo1

Dependencies:   mbed

Gamepad/Gamepad.cpp@0:08b2bdddf22e, 2020-04-28 (annotated)

Committer:
haoyan
Date:
Tue Apr 28 14:38:02 2020 +0000
Revision:
0:08b2bdddf22e
deemo

Who changed what in which revision?

UserRevisionLine numberNew contents of line
haoyan 0:08b2bdddf22e 1 #include "Gamepad.h"
haoyan 0:08b2bdddf22e 2
haoyan 0:08b2bdddf22e 3 #include "mbed.h"
haoyan 0:08b2bdddf22e 4
haoyan 0:08b2bdddf22e 5 //////////// constructor/destructor ////////////
haoyan 0:08b2bdddf22e 6 Gamepad::Gamepad()
haoyan 0:08b2bdddf22e 7 :
haoyan 0:08b2bdddf22e 8 _led1(new PwmOut(PTA1)),
haoyan 0:08b2bdddf22e 9 _led2(new PwmOut(PTA2)),
haoyan 0:08b2bdddf22e 10 _led3(new PwmOut(PTC2)),
haoyan 0:08b2bdddf22e 11 _led4(new PwmOut(PTC3)),
haoyan 0:08b2bdddf22e 12 _led5(new PwmOut(PTC4)),
haoyan 0:08b2bdddf22e 13 _led6(new PwmOut(PTD3)),
haoyan 0:08b2bdddf22e 14
haoyan 0:08b2bdddf22e 15 _button_A(new InterruptIn(PTB9)),
haoyan 0:08b2bdddf22e 16 _button_B(new InterruptIn(PTD0)),
haoyan 0:08b2bdddf22e 17 _button_X(new InterruptIn(PTC17)),
haoyan 0:08b2bdddf22e 18 _button_Y(new InterruptIn(PTC12)),
haoyan 0:08b2bdddf22e 19 _button_L(new InterruptIn(PTB18)),
haoyan 0:08b2bdddf22e 20 _button_R(new InterruptIn(PTB3)),
haoyan 0:08b2bdddf22e 21 _button_back(new InterruptIn(PTB19)),
haoyan 0:08b2bdddf22e 22 _button_start(new InterruptIn(PTC5)),
haoyan 0:08b2bdddf22e 23 _button_joystick(new InterruptIn(PTC16)),
haoyan 0:08b2bdddf22e 24
haoyan 0:08b2bdddf22e 25 _vert(new AnalogIn(PTB10)),
haoyan 0:08b2bdddf22e 26 _horiz(new AnalogIn(PTB11)),
haoyan 0:08b2bdddf22e 27
haoyan 0:08b2bdddf22e 28 _buzzer(new PwmOut(PTC10)),
haoyan 0:08b2bdddf22e 29 _pot(new AnalogIn(PTB2)),
haoyan 0:08b2bdddf22e 30
haoyan 0:08b2bdddf22e 31 _timeout(new Timeout()),
haoyan 0:08b2bdddf22e 32
haoyan 0:08b2bdddf22e 33 _event_state(0),
haoyan 0:08b2bdddf22e 34
haoyan 0:08b2bdddf22e 35 _x0(0),
haoyan 0:08b2bdddf22e 36 _y0(0)
haoyan 0:08b2bdddf22e 37 {}
haoyan 0:08b2bdddf22e 38
haoyan 0:08b2bdddf22e 39 Gamepad::~Gamepad()
haoyan 0:08b2bdddf22e 40 {
haoyan 0:08b2bdddf22e 41 delete _led1,_led2,_led3,_led4,_led5,_led6;
haoyan 0:08b2bdddf22e 42 delete _button_A,_button_B,_button_joystick,_vert,_horiz;
haoyan 0:08b2bdddf22e 43 delete _button_X,_button_Y,_button_back,_button_start;
haoyan 0:08b2bdddf22e 44 delete _button_L,_button_R, _buzzer, _pot, _timeout;
haoyan 0:08b2bdddf22e 45 }
haoyan 0:08b2bdddf22e 46
haoyan 0:08b2bdddf22e 47 ///////////////// public methods /////////////////
haoyan 0:08b2bdddf22e 48
haoyan 0:08b2bdddf22e 49 void Gamepad::init()
haoyan 0:08b2bdddf22e 50 {
haoyan 0:08b2bdddf22e 51 leds_off();
haoyan 0:08b2bdddf22e 52 init_buttons();
haoyan 0:08b2bdddf22e 53
haoyan 0:08b2bdddf22e 54 // read centred values of joystick
haoyan 0:08b2bdddf22e 55 _x0 = _horiz->read();
haoyan 0:08b2bdddf22e 56 _y0 = _vert->read();
haoyan 0:08b2bdddf22e 57
haoyan 0:08b2bdddf22e 58 // clear all flags
haoyan 0:08b2bdddf22e 59 _event_state = 0;
haoyan 0:08b2bdddf22e 60 }
haoyan 0:08b2bdddf22e 61
haoyan 0:08b2bdddf22e 62 void Gamepad::leds_off()
haoyan 0:08b2bdddf22e 63 {
haoyan 0:08b2bdddf22e 64 leds(0.0);
haoyan 0:08b2bdddf22e 65 }
haoyan 0:08b2bdddf22e 66
haoyan 0:08b2bdddf22e 67 void Gamepad::leds_on()
haoyan 0:08b2bdddf22e 68 {
haoyan 0:08b2bdddf22e 69 leds(1.0);
haoyan 0:08b2bdddf22e 70 }
haoyan 0:08b2bdddf22e 71
haoyan 0:08b2bdddf22e 72 void Gamepad::leds(float val) const
haoyan 0:08b2bdddf22e 73 {
haoyan 0:08b2bdddf22e 74 if (val < 0.0f) {
haoyan 0:08b2bdddf22e 75 val = 0.0f;
haoyan 0:08b2bdddf22e 76 }
haoyan 0:08b2bdddf22e 77 if (val > 1.0f) {
haoyan 0:08b2bdddf22e 78 val = 1.0f;
haoyan 0:08b2bdddf22e 79 }
haoyan 0:08b2bdddf22e 80
haoyan 0:08b2bdddf22e 81 // leds are active-low, so subtract from 1.0
haoyan 0:08b2bdddf22e 82 // 0.0 corresponds to fully-off, 1.0 to fully-on
haoyan 0:08b2bdddf22e 83 val = 1.0f - val;
haoyan 0:08b2bdddf22e 84
haoyan 0:08b2bdddf22e 85 _led1->write(val);
haoyan 0:08b2bdddf22e 86 _led2->write(val);
haoyan 0:08b2bdddf22e 87 _led3->write(val);
haoyan 0:08b2bdddf22e 88 _led4->write(val);
haoyan 0:08b2bdddf22e 89 _led5->write(val);
haoyan 0:08b2bdddf22e 90 _led6->write(val);
haoyan 0:08b2bdddf22e 91 }
haoyan 0:08b2bdddf22e 92
haoyan 0:08b2bdddf22e 93 void Gamepad::led(int n,float val) const
haoyan 0:08b2bdddf22e 94 {
haoyan 0:08b2bdddf22e 95 // ensure they are within vlaid range
haoyan 0:08b2bdddf22e 96 if (val < 0.0f) {
haoyan 0:08b2bdddf22e 97 val = 0.0f;
haoyan 0:08b2bdddf22e 98 }
haoyan 0:08b2bdddf22e 99 if (val > 1.0f) {
haoyan 0:08b2bdddf22e 100 val = 1.0f;
haoyan 0:08b2bdddf22e 101 }
haoyan 0:08b2bdddf22e 102
haoyan 0:08b2bdddf22e 103 switch (n) {
haoyan 0:08b2bdddf22e 104
haoyan 0:08b2bdddf22e 105 // check for valid LED number and set value
haoyan 0:08b2bdddf22e 106
haoyan 0:08b2bdddf22e 107 case 1:
haoyan 0:08b2bdddf22e 108 _led1->write(1.0f-val); // active-low so subtract from 1
haoyan 0:08b2bdddf22e 109 break;
haoyan 0:08b2bdddf22e 110 case 2:
haoyan 0:08b2bdddf22e 111 _led2->write(1.0f-val); // active-low so subtract from 1
haoyan 0:08b2bdddf22e 112 break;
haoyan 0:08b2bdddf22e 113 case 3:
haoyan 0:08b2bdddf22e 114 _led3->write(1.0f-val); // active-low so subtract from 1
haoyan 0:08b2bdddf22e 115 break;
haoyan 0:08b2bdddf22e 116 case 4:
haoyan 0:08b2bdddf22e 117 _led4->write(1.0f-val); // active-low so subtract from 1
haoyan 0:08b2bdddf22e 118 break;
haoyan 0:08b2bdddf22e 119 case 5:
haoyan 0:08b2bdddf22e 120 _led5->write(1.0f-val); // active-low so subtract from 1
haoyan 0:08b2bdddf22e 121 break;
haoyan 0:08b2bdddf22e 122 case 6:
haoyan 0:08b2bdddf22e 123 _led6->write(1.0f-val); // active-low so subtract from 1
haoyan 0:08b2bdddf22e 124 break;
haoyan 0:08b2bdddf22e 125
haoyan 0:08b2bdddf22e 126 }
haoyan 0:08b2bdddf22e 127 }
haoyan 0:08b2bdddf22e 128
haoyan 0:08b2bdddf22e 129 float Gamepad::read_pot() const
haoyan 0:08b2bdddf22e 130 {
haoyan 0:08b2bdddf22e 131 return _pot->read();
haoyan 0:08b2bdddf22e 132 }
haoyan 0:08b2bdddf22e 133
haoyan 0:08b2bdddf22e 134 void Gamepad::tone(float frequency, float duration)
haoyan 0:08b2bdddf22e 135 {
haoyan 0:08b2bdddf22e 136 _buzzer->period(1.0f/frequency);
haoyan 0:08b2bdddf22e 137 _buzzer->write(0.5); // 50% duty cycle - square wave
haoyan 0:08b2bdddf22e 138 _timeout->attach(callback(this, &Gamepad::tone_off), duration );
haoyan 0:08b2bdddf22e 139 }
haoyan 0:08b2bdddf22e 140
haoyan 0:08b2bdddf22e 141 bool Gamepad::check_event(GamepadEvent const id)
haoyan 0:08b2bdddf22e 142 {
haoyan 0:08b2bdddf22e 143 // Check whether event flag is set
haoyan 0:08b2bdddf22e 144 if (_event_state[id]) {
haoyan 0:08b2bdddf22e 145 _event_state.reset(id); // clear flag
haoyan 0:08b2bdddf22e 146 return true;
haoyan 0:08b2bdddf22e 147 } else {
haoyan 0:08b2bdddf22e 148 return false;
haoyan 0:08b2bdddf22e 149 }
haoyan 0:08b2bdddf22e 150 }
haoyan 0:08b2bdddf22e 151
haoyan 0:08b2bdddf22e 152 // this method gets the magnitude of the joystick movement
haoyan 0:08b2bdddf22e 153 float Gamepad::get_mag()
haoyan 0:08b2bdddf22e 154 {
haoyan 0:08b2bdddf22e 155 Polar p = get_polar();
haoyan 0:08b2bdddf22e 156 return p.mag;
haoyan 0:08b2bdddf22e 157 }
haoyan 0:08b2bdddf22e 158
haoyan 0:08b2bdddf22e 159 // this method gets the angle of joystick movement (0 to 360, 0 North)
haoyan 0:08b2bdddf22e 160 float Gamepad::get_angle()
haoyan 0:08b2bdddf22e 161 {
haoyan 0:08b2bdddf22e 162 Polar p = get_polar();
haoyan 0:08b2bdddf22e 163 return p.angle;
haoyan 0:08b2bdddf22e 164 }
haoyan 0:08b2bdddf22e 165
haoyan 0:08b2bdddf22e 166 Direction Gamepad::get_direction()
haoyan 0:08b2bdddf22e 167 {
haoyan 0:08b2bdddf22e 168 float angle = get_angle(); // 0 to 360, -1 for centred
haoyan 0:08b2bdddf22e 169
haoyan 0:08b2bdddf22e 170 Direction d;
haoyan 0:08b2bdddf22e 171 // partition 360 into segments and check which segment the angle is in
haoyan 0:08b2bdddf22e 172 if (angle < 0.0f) {
haoyan 0:08b2bdddf22e 173 d = CENTRE; // check for -1.0 angle
haoyan 0:08b2bdddf22e 174 } else if (angle < 22.5f) { // then keep going in 45 degree increments
haoyan 0:08b2bdddf22e 175 d = N;
haoyan 0:08b2bdddf22e 176 } else if (angle < 67.5f) {
haoyan 0:08b2bdddf22e 177 d = NE;
haoyan 0:08b2bdddf22e 178 } else if (angle < 112.5f) {
haoyan 0:08b2bdddf22e 179 d = E;
haoyan 0:08b2bdddf22e 180 } else if (angle < 157.5f) {
haoyan 0:08b2bdddf22e 181 d = SE;
haoyan 0:08b2bdddf22e 182 } else if (angle < 202.5f) {
haoyan 0:08b2bdddf22e 183 d = S;
haoyan 0:08b2bdddf22e 184 } else if (angle < 247.5f) {
haoyan 0:08b2bdddf22e 185 d = SW;
haoyan 0:08b2bdddf22e 186 } else if (angle < 292.5f) {
haoyan 0:08b2bdddf22e 187 d = W;
haoyan 0:08b2bdddf22e 188 } else if (angle < 337.5f) {
haoyan 0:08b2bdddf22e 189 d = NW;
haoyan 0:08b2bdddf22e 190 } else {
haoyan 0:08b2bdddf22e 191 d = N;
haoyan 0:08b2bdddf22e 192 }
haoyan 0:08b2bdddf22e 193
haoyan 0:08b2bdddf22e 194 return d;
haoyan 0:08b2bdddf22e 195 }
haoyan 0:08b2bdddf22e 196
haoyan 0:08b2bdddf22e 197 ///////////////////// private methods ////////////////////////
haoyan 0:08b2bdddf22e 198
haoyan 0:08b2bdddf22e 199 void Gamepad::tone_off()
haoyan 0:08b2bdddf22e 200 {
haoyan 0:08b2bdddf22e 201 // called after timeout
haoyan 0:08b2bdddf22e 202 _buzzer->write(0.0);
haoyan 0:08b2bdddf22e 203 }
haoyan 0:08b2bdddf22e 204
haoyan 0:08b2bdddf22e 205 void Gamepad::init_buttons()
haoyan 0:08b2bdddf22e 206 {
haoyan 0:08b2bdddf22e 207 // turn on pull-downs as other side of button is connected to 3V3
haoyan 0:08b2bdddf22e 208 // button is 0 when not pressed and 1 when pressed
haoyan 0:08b2bdddf22e 209 _button_A->mode(PullDown);
haoyan 0:08b2bdddf22e 210 _button_B->mode(PullDown);
haoyan 0:08b2bdddf22e 211 _button_X->mode(PullDown);
haoyan 0:08b2bdddf22e 212 _button_Y->mode(PullDown);
haoyan 0:08b2bdddf22e 213 _button_back->mode(PullDown);
haoyan 0:08b2bdddf22e 214 _button_start->mode(PullDown);
haoyan 0:08b2bdddf22e 215 _button_L->mode(PullDown);
haoyan 0:08b2bdddf22e 216 _button_R->mode(PullDown);
haoyan 0:08b2bdddf22e 217 _button_joystick->mode(PullDown);
haoyan 0:08b2bdddf22e 218 // therefore setup rising edge interrupts
haoyan 0:08b2bdddf22e 219 _button_A->rise(callback(this,&Gamepad::a_isr));
haoyan 0:08b2bdddf22e 220 _button_B->rise(callback(this,&Gamepad::b_isr));
haoyan 0:08b2bdddf22e 221 _button_X->rise(callback(this,&Gamepad::x_isr));
haoyan 0:08b2bdddf22e 222 _button_Y->rise(callback(this,&Gamepad::y_isr));
haoyan 0:08b2bdddf22e 223 _button_L->rise(callback(this,&Gamepad::l_isr));
haoyan 0:08b2bdddf22e 224 _button_R->rise(callback(this,&Gamepad::r_isr));
haoyan 0:08b2bdddf22e 225 _button_start->rise(callback(this,&Gamepad::start_isr));
haoyan 0:08b2bdddf22e 226 _button_back->rise(callback(this,&Gamepad::back_isr));
haoyan 0:08b2bdddf22e 227 _button_joystick->rise(callback(this,&Gamepad::joy_isr));
haoyan 0:08b2bdddf22e 228 }
haoyan 0:08b2bdddf22e 229
haoyan 0:08b2bdddf22e 230 // button interrupts ISRs
haoyan 0:08b2bdddf22e 231 // Each of these simply sets the appropriate event bit in the _event_state
haoyan 0:08b2bdddf22e 232 // variable
haoyan 0:08b2bdddf22e 233 void Gamepad::a_isr()
haoyan 0:08b2bdddf22e 234 {
haoyan 0:08b2bdddf22e 235 _event_state.set(A_PRESSED);
haoyan 0:08b2bdddf22e 236 }
haoyan 0:08b2bdddf22e 237 void Gamepad::b_isr()
haoyan 0:08b2bdddf22e 238 {
haoyan 0:08b2bdddf22e 239 _event_state.set(B_PRESSED);
haoyan 0:08b2bdddf22e 240 }
haoyan 0:08b2bdddf22e 241 void Gamepad::x_isr()
haoyan 0:08b2bdddf22e 242 {
haoyan 0:08b2bdddf22e 243 _event_state.set(X_PRESSED);
haoyan 0:08b2bdddf22e 244 }
haoyan 0:08b2bdddf22e 245 void Gamepad::y_isr()
haoyan 0:08b2bdddf22e 246 {
haoyan 0:08b2bdddf22e 247 _event_state.set(Y_PRESSED);
haoyan 0:08b2bdddf22e 248 }
haoyan 0:08b2bdddf22e 249 void Gamepad::l_isr()
haoyan 0:08b2bdddf22e 250 {
haoyan 0:08b2bdddf22e 251 _event_state.set(L_PRESSED);
haoyan 0:08b2bdddf22e 252 }
haoyan 0:08b2bdddf22e 253 void Gamepad::r_isr()
haoyan 0:08b2bdddf22e 254 {
haoyan 0:08b2bdddf22e 255 _event_state.set(R_PRESSED);
haoyan 0:08b2bdddf22e 256 }
haoyan 0:08b2bdddf22e 257 void Gamepad::back_isr()
haoyan 0:08b2bdddf22e 258 {
haoyan 0:08b2bdddf22e 259 _event_state.set(BACK_PRESSED);
haoyan 0:08b2bdddf22e 260 }
haoyan 0:08b2bdddf22e 261 void Gamepad::start_isr()
haoyan 0:08b2bdddf22e 262 {
haoyan 0:08b2bdddf22e 263 _event_state.set(START_PRESSED);
haoyan 0:08b2bdddf22e 264 }
haoyan 0:08b2bdddf22e 265 void Gamepad::joy_isr()
haoyan 0:08b2bdddf22e 266 {
haoyan 0:08b2bdddf22e 267 _event_state.set(JOY_PRESSED);
haoyan 0:08b2bdddf22e 268 }
haoyan 0:08b2bdddf22e 269
haoyan 0:08b2bdddf22e 270 // get raw joystick coordinate in range -1 to 1
haoyan 0:08b2bdddf22e 271 // Direction (x,y)
haoyan 0:08b2bdddf22e 272 // North (0,1)
haoyan 0:08b2bdddf22e 273 // East (1,0)
haoyan 0:08b2bdddf22e 274 // South (0,-1)
haoyan 0:08b2bdddf22e 275 // West (-1,0)
haoyan 0:08b2bdddf22e 276 Vector2D Gamepad::get_coord()
haoyan 0:08b2bdddf22e 277 {
haoyan 0:08b2bdddf22e 278 // read() returns value in range 0.0 to 1.0 so is scaled and centre value
haoyan 0:08b2bdddf22e 279 // substracted to get values in the range -1.0 to 1.0
haoyan 0:08b2bdddf22e 280 float x = 2.0f*( _horiz->read() - _x0 );
haoyan 0:08b2bdddf22e 281 float y = 2.0f*( _vert->read() - _y0 );
haoyan 0:08b2bdddf22e 282
haoyan 0:08b2bdddf22e 283 // Note: the x value here is inverted to ensure the positive x is to the
haoyan 0:08b2bdddf22e 284 // right. This is simply due to how the potentiometer on the joystick
haoyan 0:08b2bdddf22e 285 // I was using was connected up. It could have been corrected in hardware
haoyan 0:08b2bdddf22e 286 // by swapping the power supply pins. Instead it is done in software so may
haoyan 0:08b2bdddf22e 287 // need to be changed depending on your wiring setup
haoyan 0:08b2bdddf22e 288
haoyan 0:08b2bdddf22e 289 Vector2D coord = {-x,y};
haoyan 0:08b2bdddf22e 290 return coord;
haoyan 0:08b2bdddf22e 291 }
haoyan 0:08b2bdddf22e 292
haoyan 0:08b2bdddf22e 293 // This maps the raw x,y coord onto a circular grid.
haoyan 0:08b2bdddf22e 294 // See: http://mathproofs.blogspot.co.uk/2005/07/mapping-square-to-circle.html
haoyan 0:08b2bdddf22e 295 Vector2D Gamepad::get_mapped_coord()
haoyan 0:08b2bdddf22e 296 {
haoyan 0:08b2bdddf22e 297 Vector2D coord = get_coord();
haoyan 0:08b2bdddf22e 298
haoyan 0:08b2bdddf22e 299 // do the transformation
haoyan 0:08b2bdddf22e 300 float x = coord.x*sqrt(1.0f-pow(coord.y,2.0f)/2.0f);
haoyan 0:08b2bdddf22e 301 float y = coord.y*sqrt(1.0f-pow(coord.x,2.0f)/2.0f);
haoyan 0:08b2bdddf22e 302
haoyan 0:08b2bdddf22e 303 Vector2D mapped_coord = {x,y};
haoyan 0:08b2bdddf22e 304 return mapped_coord;
haoyan 0:08b2bdddf22e 305 }
haoyan 0:08b2bdddf22e 306
haoyan 0:08b2bdddf22e 307 // this function converts the mapped coordinates into polar form
haoyan 0:08b2bdddf22e 308 Polar Gamepad::get_polar()
haoyan 0:08b2bdddf22e 309 {
haoyan 0:08b2bdddf22e 310 // get the mapped coordinate
haoyan 0:08b2bdddf22e 311 Vector2D coord = get_mapped_coord();
haoyan 0:08b2bdddf22e 312
haoyan 0:08b2bdddf22e 313 // at this point, 0 degrees (i.e. x-axis) will be defined to the East.
haoyan 0:08b2bdddf22e 314 // We want 0 degrees to correspond to North and increase clockwise to 359
haoyan 0:08b2bdddf22e 315 // like a compass heading, so we need to swap the axis and invert y
haoyan 0:08b2bdddf22e 316 float x = coord.y;
haoyan 0:08b2bdddf22e 317 float y = coord.x;
haoyan 0:08b2bdddf22e 318
haoyan 0:08b2bdddf22e 319 float mag = sqrt(x*x+y*y); // pythagoras
haoyan 0:08b2bdddf22e 320 float angle = RAD2DEG*atan2(y,x);
haoyan 0:08b2bdddf22e 321 // angle will be in range -180 to 180, so add 360 to negative angles to
haoyan 0:08b2bdddf22e 322 // move to 0 to 360 range
haoyan 0:08b2bdddf22e 323 if (angle < 0.0f) {
haoyan 0:08b2bdddf22e 324 angle+=360.0f;
haoyan 0:08b2bdddf22e 325 }
haoyan 0:08b2bdddf22e 326
haoyan 0:08b2bdddf22e 327 // the noise on the ADC causes the values of x and y to fluctuate slightly
haoyan 0:08b2bdddf22e 328 // around the centred values. This causes the random angle values to get
haoyan 0:08b2bdddf22e 329 // calculated when the joystick is centred and untouched. This is also when
haoyan 0:08b2bdddf22e 330 // the magnitude is very small, so we can check for a small magnitude and then
haoyan 0:08b2bdddf22e 331 // set the angle to -1. This will inform us when the angle is invalid and the
haoyan 0:08b2bdddf22e 332 // joystick is centred
haoyan 0:08b2bdddf22e 333
haoyan 0:08b2bdddf22e 334 if (mag < TOL) {
haoyan 0:08b2bdddf22e 335 mag = 0.0f;
haoyan 0:08b2bdddf22e 336 angle = -1.0f;
haoyan 0:08b2bdddf22e 337 }
haoyan 0:08b2bdddf22e 338
haoyan 0:08b2bdddf22e 339 Polar p = {mag,angle};
haoyan 0:08b2bdddf22e 340 return p;
haoyan 0:08b2bdddf22e 341 }