Yudong Xiao / Mbed OS pokemon

This is test version of Pokemongo game. ELEC 2645 final project.

Dependencies:   Tone

pokeball/Joystick.cpp@0:819c2d6a69ac, 2021-04-15 (annotated)

Committer:
shalwego
Date:
Thu Apr 15 15:35:12 2021 +0000
Revision:
0:819c2d6a69ac
Issue about music playing

Who changed what in which revision?

UserRevisionLine numberNew contents of line
shalwego 0:819c2d6a69ac 1 #include "Joystick.h"
shalwego 0:819c2d6a69ac 2
shalwego 0:819c2d6a69ac 3 Joystick::Joystick(PinName vertPin,PinName horizPin)
shalwego 0:819c2d6a69ac 4 {
shalwego 0:819c2d6a69ac 5 vert = new AnalogIn(vertPin);
shalwego 0:819c2d6a69ac 6 horiz = new AnalogIn(horizPin);
shalwego 0:819c2d6a69ac 7 }
shalwego 0:819c2d6a69ac 8
shalwego 0:819c2d6a69ac 9 void Joystick::init()
shalwego 0:819c2d6a69ac 10 {
shalwego 0:819c2d6a69ac 11 // read centred values of joystick
shalwego 0:819c2d6a69ac 12 _x0 = horiz->read();
shalwego 0:819c2d6a69ac 13 _y0 = vert->read();
shalwego 0:819c2d6a69ac 14
shalwego 0:819c2d6a69ac 15 // this assumes that the joystick is centred when the init function is called
shalwego 0:819c2d6a69ac 16 // if perfectly centred, the pots should read 0.5, but this may
shalwego 0:819c2d6a69ac 17 // not be the case and x0 and y0 will be used to calibrate readings
shalwego 0:819c2d6a69ac 18 }
shalwego 0:819c2d6a69ac 19
shalwego 0:819c2d6a69ac 20 Direction Joystick::get_direction()
shalwego 0:819c2d6a69ac 21 {
shalwego 0:819c2d6a69ac 22 float angle = get_angle(); // 0 to 360, -1 for centred
shalwego 0:819c2d6a69ac 23
shalwego 0:819c2d6a69ac 24 Direction d;
shalwego 0:819c2d6a69ac 25 // partition 360 into segments and check which segment the angle is in
shalwego 0:819c2d6a69ac 26 if (angle < 0.0f) {
shalwego 0:819c2d6a69ac 27 d = CENTRE; // check for -1.0 angle
shalwego 0:819c2d6a69ac 28 } else if (angle < 22.5f) { // then keep going in 45 degree increments
shalwego 0:819c2d6a69ac 29 d = N;
shalwego 0:819c2d6a69ac 30 } else if (angle < 67.5f) {
shalwego 0:819c2d6a69ac 31 d = NE;
shalwego 0:819c2d6a69ac 32 } else if (angle < 112.5f) {
shalwego 0:819c2d6a69ac 33 d = E;
shalwego 0:819c2d6a69ac 34 } else if (angle < 157.5f) {
shalwego 0:819c2d6a69ac 35 d = SE;
shalwego 0:819c2d6a69ac 36 } else if (angle < 202.5f) {
shalwego 0:819c2d6a69ac 37 d = S;
shalwego 0:819c2d6a69ac 38 } else if (angle < 247.5f) {
shalwego 0:819c2d6a69ac 39 d = SW;
shalwego 0:819c2d6a69ac 40 } else if (angle < 292.5f) {
shalwego 0:819c2d6a69ac 41 d = W;
shalwego 0:819c2d6a69ac 42 } else if (angle < 337.5f) {
shalwego 0:819c2d6a69ac 43 d = NW;
shalwego 0:819c2d6a69ac 44 } else {
shalwego 0:819c2d6a69ac 45 d = N;
shalwego 0:819c2d6a69ac 46 }
shalwego 0:819c2d6a69ac 47
shalwego 0:819c2d6a69ac 48 return d;
shalwego 0:819c2d6a69ac 49 }
shalwego 0:819c2d6a69ac 50
shalwego 0:819c2d6a69ac 51 // this method gets the magnitude of the joystick movement
shalwego 0:819c2d6a69ac 52 float Joystick::get_mag() {
shalwego 0:819c2d6a69ac 53 Polar p = get_polar();
shalwego 0:819c2d6a69ac 54 return p.mag;
shalwego 0:819c2d6a69ac 55 }
shalwego 0:819c2d6a69ac 56
shalwego 0:819c2d6a69ac 57 // this method gets the angle of joystick movement (0 to 360, 0 North)
shalwego 0:819c2d6a69ac 58 float Joystick::get_angle()
shalwego 0:819c2d6a69ac 59 {
shalwego 0:819c2d6a69ac 60 Polar p = get_polar();
shalwego 0:819c2d6a69ac 61 return p.angle;
shalwego 0:819c2d6a69ac 62 }
shalwego 0:819c2d6a69ac 63
shalwego 0:819c2d6a69ac 64 // get raw joystick coordinate in range -1 to 1
shalwego 0:819c2d6a69ac 65 // Direction (x,y)
shalwego 0:819c2d6a69ac 66 // North (0,1)
shalwego 0:819c2d6a69ac 67 // East (1,0)
shalwego 0:819c2d6a69ac 68 // South (0,-1)
shalwego 0:819c2d6a69ac 69 // West (-1,0)
shalwego 0:819c2d6a69ac 70 Vector2D Joystick::get_coord()
shalwego 0:819c2d6a69ac 71 {
shalwego 0:819c2d6a69ac 72 // read() returns value in range 0.0 to 1.0 so is scaled and centre value
shalwego 0:819c2d6a69ac 73 // substracted to get values in the range -1.0 to 1.0
shalwego 0:819c2d6a69ac 74 float x = 2.0f*( horiz->read() - _x0 );
shalwego 0:819c2d6a69ac 75 float y = 2.0f*( vert->read() - _y0 );
shalwego 0:819c2d6a69ac 76
shalwego 0:819c2d6a69ac 77 // Note: the values are negated so positive is up and right.
shalwego 0:819c2d6a69ac 78 Vector2D coord = {-x,y};
shalwego 0:819c2d6a69ac 79 return coord;
shalwego 0:819c2d6a69ac 80 }
shalwego 0:819c2d6a69ac 81
shalwego 0:819c2d6a69ac 82 // This maps the raw x,y coord onto a circular grid.
shalwego 0:819c2d6a69ac 83 // See: http://mathproofs.blogspot.co.uk/2005/07/mapping-square-to-circle.html
shalwego 0:819c2d6a69ac 84 Vector2D Joystick::get_mapped_coord()
shalwego 0:819c2d6a69ac 85 {
shalwego 0:819c2d6a69ac 86 Vector2D coord = get_coord();
shalwego 0:819c2d6a69ac 87
shalwego 0:819c2d6a69ac 88 // do the transformation
shalwego 0:819c2d6a69ac 89 float x = coord.x*sqrt(1.0f-pow(coord.y,2.0f)/2.0f);
shalwego 0:819c2d6a69ac 90 float y = coord.y*sqrt(1.0f-pow(coord.x,2.0f)/2.0f);
shalwego 0:819c2d6a69ac 91
shalwego 0:819c2d6a69ac 92 Vector2D mapped_coord = {x,y};
shalwego 0:819c2d6a69ac 93 return mapped_coord;
shalwego 0:819c2d6a69ac 94 }
shalwego 0:819c2d6a69ac 95
shalwego 0:819c2d6a69ac 96 // this function converts the mapped coordinates into polar form
shalwego 0:819c2d6a69ac 97 Polar Joystick::get_polar()
shalwego 0:819c2d6a69ac 98 {
shalwego 0:819c2d6a69ac 99 // get the mapped coordinate
shalwego 0:819c2d6a69ac 100 Vector2D coord = get_mapped_coord();
shalwego 0:819c2d6a69ac 101
shalwego 0:819c2d6a69ac 102 // at this point, 0 degrees (i.e. x-axis) will be defined to the East.
shalwego 0:819c2d6a69ac 103 // We want 0 degrees to correspond to North and increase clockwise to 359
shalwego 0:819c2d6a69ac 104 // like a compass heading, so we need to swap the axis and invert y
shalwego 0:819c2d6a69ac 105 float x = coord.y;
shalwego 0:819c2d6a69ac 106 float y = coord.x;
shalwego 0:819c2d6a69ac 107
shalwego 0:819c2d6a69ac 108 float mag = sqrt(x*x+y*y); // pythagoras
shalwego 0:819c2d6a69ac 109 float angle = RAD2DEG*atan2(y,x);
shalwego 0:819c2d6a69ac 110 // angle will be in range -180 to 180, so add 360 to negative angles to
shalwego 0:819c2d6a69ac 111 // move to 0 to 360 range
shalwego 0:819c2d6a69ac 112 if (angle < 0.0f) {
shalwego 0:819c2d6a69ac 113 angle+=360.0f;
shalwego 0:819c2d6a69ac 114 }
shalwego 0:819c2d6a69ac 115
shalwego 0:819c2d6a69ac 116 // the noise on the ADC causes the values of x and y to fluctuate slightly
shalwego 0:819c2d6a69ac 117 // around the centred values. This causes the random angle values to get
shalwego 0:819c2d6a69ac 118 // calculated when the joystick is centred and untouched. This is also when
shalwego 0:819c2d6a69ac 119 // the magnitude is very small, so we can check for a small magnitude and then
shalwego 0:819c2d6a69ac 120 // set the angle to -1. This will inform us when the angle is invalid and the
shalwego 0:819c2d6a69ac 121 // joystick is centred
shalwego 0:819c2d6a69ac 122
shalwego 0:819c2d6a69ac 123 if (mag < TOL) {
shalwego 0:819c2d6a69ac 124 mag = 0.0f;
shalwego 0:819c2d6a69ac 125 angle = -1.0f;
shalwego 0:819c2d6a69ac 126 }
shalwego 0:819c2d6a69ac 127
shalwego 0:819c2d6a69ac 128 Polar p = {mag,angle};
shalwego 0:819c2d6a69ac 129 return p;
shalwego 0:819c2d6a69ac 130 }