PongEngine.cpp

00001 #include "PongEngine.h"
00002 
00003 PongEngine::PongEngine()
00004 {
00005 
00006 }
00007 
00008 PongEngine::~PongEngine()
00009 {
00010 
00011 }
00012 
00013 void PongEngine::init(int paddle_width,int paddle_height,int ball_size,int speed)
00014 {
00015     // initialise the game parameters
00016     _paddle_width = paddle_width;
00017     _paddle_height = paddle_height;
00018     _ball_size = ball_size;
00019     _speed = speed;
00020 
00021     // x position on screen - WIDTH is defined in N5110.h
00022     _p1x = GAP;
00023     _p2x = WIDTH - GAP - _paddle_width;
00024 
00025     // puts paddles and ball in middle
00026     _p1.init(_p1x,_paddle_height,_paddle_width);
00027     _p2.init(_p2x,_paddle_height,_paddle_width);
00028     _ball.init(_ball_size,_speed);
00029 }
00030 
00031 void PongEngine::read_input(Gamepad &pad)
00032 {
00033     _d = pad.get_direction();
00034     _mag = pad.get_mag();
00035 }
00036 
00037 void PongEngine::draw(N5110 &lcd)
00038 {
00039     // draw the elements in the LCD buffer
00040     // pitch
00041     lcd.drawRect(0,0,WIDTH,HEIGHT,FILL_TRANSPARENT);
00042     lcd.drawLine(WIDTH/2,0,WIDTH/2,HEIGHT-1,2);
00043     //score
00044     print_scores(lcd);
00045     // paddles
00046     _p1.draw(lcd);
00047     _p2.draw(lcd);
00048     // ball
00049     _ball.draw(lcd);
00050 }
00051 
00052 void PongEngine::update(Gamepad &pad)
00053 {
00054     check_goal(pad);
00055     // important to update paddles and ball before checking collisions so can
00056     // correct for it before updating the display
00057     _p1.update(_d,_mag);
00058     _p2.update(_d,_mag);
00059     _ball.update();
00060 
00061     check_wall_collision(pad);
00062     check_paddle_collisions(pad);
00063 }
00064 
00065 void PongEngine::check_wall_collision(Gamepad &pad)
00066 {
00067     // read current ball attributes
00068     Vector2D ball_pos = _ball.get_pos();
00069     Vector2D ball_velocity = _ball.get_velocity();
00070 
00071     // check if hit top wall
00072     if (ball_pos.y <= 1) {  //  1 due to 1 pixel boundary
00073         ball_pos.y = 1;  // bounce off ceiling without going off screen
00074         ball_velocity.y = -ball_velocity.y;
00075         // audio feedback
00076         pad.tone(750.0,0.1);
00077     }
00078     // check if hit bottom wall
00079     else if (ball_pos.y + _ball_size >= (HEIGHT-1) ) { // bottom pixel is 47
00080         // hit bottom
00081         ball_pos.y = (HEIGHT-1) - _ball_size;  // stops ball going off screen
00082         ball_velocity.y = -ball_velocity.y;
00083         // audio feedback
00084         pad.tone(750.0,0.1);
00085     }
00086 
00087     // update ball parameters
00088     _ball.set_velocity(ball_velocity);
00089     _ball.set_pos(ball_pos);
00090 }
00091 
00092 void PongEngine::check_paddle_collisions(Gamepad &pad)
00093 {
00094     // read current ball attributes
00095     Vector2D ball_pos = _ball.get_pos();
00096     Vector2D ball_velocity = _ball.get_velocity();
00097 
00098     // check p1 first
00099     Vector2D p1_pos = _p1.get_pos();
00100 
00101     // see if ball has hit the paddle by checking for overlaps
00102     if (
00103         (ball_pos.y >= p1_pos.y) && //top
00104         (ball_pos.y <= p1_pos.y + _paddle_height) && //bottom
00105         (ball_pos.x >= _p1x) && //left
00106         (ball_pos.x <= _p1x + _paddle_width)  //right
00107     ) {
00108         // if it has, fix position and reflect x velocity
00109         ball_pos.x = _p1x + _paddle_width;
00110         ball_velocity.x = -ball_velocity.x;
00111         // audio feedback
00112         pad.tone(1000.0,0.1);
00113     }
00114 
00115     // check p2 next
00116     Vector2D p2_pos = _p2.get_pos();
00117 
00118     // see if ball has hit the paddle by checking for overlaps
00119     if (
00120         (ball_pos.y >= p2_pos.y) && //top
00121         (ball_pos.y <= p2_pos.y + _paddle_height) && //bottom
00122         (ball_pos.x + _ball_size >= _p2x) && //left
00123         (ball_pos.x + _ball_size <= _p2x + _paddle_width)  //right
00124     ) {
00125         // if it has, fix position and reflect x velocity
00126         ball_pos.x = _p2x - _ball_size;
00127         ball_velocity.x = -ball_velocity.x;
00128         // audio feedback
00129         pad.tone(1000.0,0.1);
00130     }
00131 
00132     // write new attributes
00133     _ball.set_velocity(ball_velocity);
00134     _ball.set_pos(ball_pos);
00135 }
00136 
00137 void PongEngine::check_goal(Gamepad &pad)
00138 {
00139     Vector2D ball_pos = _ball.get_pos();
00140     // P2 has scored
00141     if (ball_pos.x + _ball_size < 0) {
00142         _p2.add_score();
00143         _ball.init(_ball_size,_speed);
00144         pad.tone(1500.0,0.5);
00145         pad.leds_on();
00146         wait(0.5);
00147         pad.leds_off();
00148     }
00149 
00150     // P1 has scored
00151     if (ball_pos.x > WIDTH) {
00152         _p1.add_score();
00153         _ball.init(_ball_size,_speed);
00154         pad.tone(1500.0,0.5);
00155         pad.leds_on();
00156         wait(0.5);
00157         pad.leds_off();
00158     }
00159 }
00160 
00161 void PongEngine::print_scores(N5110 &lcd)
00162 {
00163     // get scores from paddles
00164     int p1_score = _p1.get_score();
00165     int p2_score = _p2.get_score();
00166 
00167     // print to LCD i
00168     char buffer1[14];
00169     sprintf(buffer1,"%2d",p1_score);
00170     lcd.printString(buffer1,WIDTH/2 - 20,1);  // font is 8 wide, so leave 4 pixel gape from middle assuming two digits
00171     char buffer2[14];
00172     sprintf(buffer2,"%2d",p2_score);
00173     lcd.printString(buffer2,WIDTH/2 + 4,1);
00174 }