Library for ELEC2645 Gamepad PCB. University of Leeds Version 2 January 2020
Dependents: ELEC2645_Ticker_WAV ELEC2645_Project_username ELEC2645_Project_el18vgt ELEC2645_Project_el17oc11 ... more
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; } \ No newline at end of file