Diff: Gamepad.cpp

Revision:

3:964a6d95acdd

Parent:

2:ea5538fcfe2f

Child:

4:bafb7f483e93

--- a/Gamepad.cpp	Sat Feb 04 16:21:19 2017 +0000
+++ b/Gamepad.cpp	Mon Feb 06 19:33:29 2017 +0000
@@ -10,7 +10,6 @@
     led_5 = new PwmOut(PTC4);
     led_6 = new PwmOut(PTD3);
 
-    lcd = new N5110(PTC9,PTC0,PTC7,PTD2,PTD1,PTC11);
     joystick = new Joystick(PTB10,PTB11,PTC16);
 
     button_A = new InterruptIn(PTB9);
@@ -21,6 +20,10 @@
     button_start = new InterruptIn(PTC5);
     button_L = new InterruptIn(PTB18);
     button_R = new InterruptIn(PTB3);
+    button_joystick = new InterruptIn(PTC16);
+    
+    vert = new AnalogIn(PTB10);
+    horiz = new AnalogIn(PTB11);
 
     buzzer = new PwmOut(PTC10);
     pot = new AnalogIn(PTB2);
@@ -32,7 +35,7 @@
 Gamepad::~Gamepad()
 {
     delete led_1,led_2,led_3,led_4,led_5,led_6;
-    delete lcd,joystick,button_A,button_B;
+    delete button_A,button_B,button_joystick,vert,horiz;
     delete button_X, button_Y, button_back, button_start;
     delete button_L, button_R, buzzer, pot, timeout;
 }
@@ -42,13 +45,17 @@
 void Gamepad::init()
 {
     lcd->init();
-    joystick->init();
     leds_off();
+    
+    // read centred values of joystick
+    _x0 = horiz->read();
+    _y0 = vert->read();
 
     buzzer->period(1.0/1000.0);  // 1 kHz
 
     // clear all flags
-    a_flag=0,b_flag=0,x_flag=0,y_flag=0,l_flag=0,r_flag=0,back_flag=0,start_flag=0;
+    a_flag=0,b_flag=0,x_flag=0,y_flag=0,joy_flag=0;
+    l_flag=0,r_flag=0,back_flag=0,start_flag=0;
 
 }
 
@@ -182,6 +189,63 @@
         return false;
     }
 }
+
+bool Gamepad::joystick_pressed()
+{
+    // ISR must have been triggered
+    if (joy_flag) {
+        joy_flag = 0;  // clear flag
+        return true;
+    } else {
+        return false;
+    }
+}
+
+// this method gets the magnitude of the joystick movement
+float Gamepad::get_mag()
+{
+    Polar p = get_polar();
+    return p.mag;
+}
+
+// this method gets the angle of joystick movement (0 to 360, 0 North)
+float Gamepad::get_angle()
+{
+    Polar p = get_polar();
+    return p.angle;
+}
+
+Direction Joystick::get_direction()
+{
+    float angle = get_angle();  // 0 to 360, -1 for centred
+
+    Direction d;
+    // partition 360 into segments and check which segment the angle is in
+    if (angle < 0.0f) {
+        d = CENTRE;   // check for -1.0 angle
+    } else if (angle < 22.5f) {  // then keep going in 45 degree increments
+        d = N;
+    } else if (angle < 67.5f) {
+        d = NE;
+    } else if (angle < 112.5f) {
+        d = E;
+    } else if (angle < 157.5f) {
+        d = SE;
+    } else if (angle < 202.5f) {
+        d = S;
+    } else if (angle < 247.5f) {
+        d = SW;
+    } else if (angle < 292.5f) {
+        d = W;
+    } else if (angle < 337.5f) {
+        d = NW;
+    } else {
+        d = N;
+    }
+
+    return d;
+}
+
 ///////////////////// private methods ////////////////////////
 
 void Gamepad::tone_off()
@@ -201,6 +265,7 @@
     button_start->mode(PullDown);
     button_L->mode(PullDown);
     button_R->mode(PullDown);
+    button_joystick->mode(PullDown);
     // therefore setup rising edge interrupts
     button_A->rise(callback(this,&Gamepad::a_isr));
     button_B->rise(callback(this,&Gamepad::b_isr));
@@ -210,6 +275,7 @@
     button_R->rise(callback(this,&Gamepad::r_isr));
     button_start->rise(callback(this,&Gamepad::start_isr));
     button_back->rise(callback(this,&Gamepad::back_isr));
+    button_joystick->rise(callback(this,&Gamepad::joy_isr));
 }
 
 // button interrupts ISRs
@@ -244,4 +310,81 @@
 void Gamepad::start_isr()
 {
     start_flag=1;
+}
+void Gamepad::joy_isr()
+{
+    joy_flag=1;
+}
+
+// get raw joystick coordinate in range -1 to 1
+// Direction (x,y)
+// North     (0,1)
+// East      (1,0)
+// South     (0,-1)
+// West      (-1,0)
+Vector2D Gamepad::get_coord()
+{
+    // read() returns value in range 0.0 to 1.0 so is scaled and centre value
+    // substracted to get values in the range -1.0 to 1.0
+    float x = 2.0f*( horiz->read() - _x0 );
+    float y = 2.0f*( vert->read() - _y0 );
+
+    // Note: the x value here is inverted to ensure the positive x is to the
+    // right. This is simply due to how the potentiometer on the joystick
+    // I was using was connected up. It could have been corrected in hardware
+    // by swapping the power supply pins. Instead it is done in software so may
+    // need to be changed depending on your wiring setup
+
+    Vector2D coord = {-x,y};
+    return coord;
+}
+
+// This maps the raw x,y coord onto a circular grid.
+// See:  http://mathproofs.blogspot.co.uk/2005/07/mapping-square-to-circle.html
+Vector2D Gamepad::get_mapped_coord()
+{
+    Vector2D coord = get_coord();
+
+    // do the transformation
+    float x = coord.x*sqrt(1.0f-pow(coord.y,2.0f)/2.0f);
+    float y = coord.y*sqrt(1.0f-pow(coord.x,2.0f)/2.0f);
+
+    Vector2D mapped_coord = {x,y};
+    return mapped_coord;
+}
+
+// this function converts the mapped coordinates into polar form
+Polar Gamepad::get_polar()
+{
+    // get the mapped coordinate
+    Vector2D coord = get_mapped_coord();
+
+    // at this point, 0 degrees (i.e. x-axis) will be defined to the East.
+    // We want 0 degrees to correspond to North and increase clockwise to 359
+    // like a compass heading, so we need to swap the axis and invert y
+    float x = coord.y;
+    float y = coord.x;
+
+    float mag = sqrt(x*x+y*y);  // pythagoras
+    float angle = RAD2DEG*atan2(y,x);
+    // angle will be in range -180 to 180, so add 360 to negative angles to
+    // move to 0 to 360 range
+    if (angle < 0.0f) {
+        angle+=360.0f;
+    }
+
+    // the noise on the ADC causes the values of x and y to fluctuate slightly
+    // around the centred values. This causes the random angle values to get
+    // calculated when the joystick is centred and untouched. This is also when
+    // the magnitude is very small, so we can check for a small magnitude and then
+    // set the angle to -1. This will inform us when the angle is invalid and the
+    // joystick is centred
+
+    if (mag < TOL) {
+        mag = 0.0f;
+        angle = -1.0f;
+    }
+
+    Polar p = {mag,angle};
+    return p;
 }
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