code.delx.au - pong/blob - pong.c

   1 #if defined(WIN32)
   2 #pragma comment(linker, "/subsystem:\"windows\" /entry:\"mainCRTStartup\"")
   3 #include "glut.h"
   4 #elif defined(__APPLE__) || defined(MACOSX)
   5 #include <GLUT/glut.h>
   6 #else
   7 #include <GL/glut.h>
   8 #endif
   9
  10 #include <stdio.h>
  11 #include <stdlib.h>
  12 #include <math.h>
  13
  14 // Amount to increase speed by on x, y axis, and when bouncing
  15 #define SPEEDXINC   1.1
  16 #define SPEEDYINC   1.1
  17 #define SPEEDBINC   0.15
  18 #define PADDLESPEED 3.0
  19 #define FRAME       40
  20 #define PADDLESIZE  10
  21 #define HEIGHT      100
  22
  23 #define STATE_UI 0
  24 #define STATE_1P 1
  25 #define STATE_2P 2
  26
  27 static char* menu = "";
  28 static int state  = 0;
  29 static int p1move = 0;
  30 static int p2move = 0;
  31 static int score1 = 0;
  32 static int score2 = 0;
  33 static GLdouble paddle1 = 0.0;
  34 static GLdouble paddle2 = 0.0;
  35 static GLdouble ballX = 0.0;
  36 static GLdouble ballY = 0.0;
  37 static GLdouble ballVecX = 0.0;
  38 static GLdouble ballVecY = 0.0;
  39
  40
  41 static inline double myfmax(double a, double b) {
  42         return a > b ? a : b;
  43 }
  44
  45 static void initBall(void) {
  46         ballX = 0.0;
  47         ballY = 0.0;
  48         if(ballVecX < 0)
  49                 ballVecX = -1.2;
  50         else
  51                 ballVecX = 1.2;
  52         ballVecY = 0.7;
  53 }
  54
  55 static void run(void) {
  56         // AI is on
  57         if(state == STATE_1P) {
  58                 if(ballY < paddle2 - PADDLESIZE)
  59                         p2move = -1;
  60                 else if(ballY > paddle2 + PADDLESIZE)
  61                         p2move = 1;
  62                 else
  63                         p2move = 0;
  64         }
  65
  66         // Move the paddles
  67         paddle1 += p1move * PADDLESPEED;
  68         paddle2 += p2move * PADDLESPEED;
  69         if(paddle1 < -HEIGHT)
  70                 paddle1 = -HEIGHT;
  71         if(paddle1 > HEIGHT)
  72                 paddle1 = HEIGHT;
  73         if(paddle2 < -HEIGHT)
  74                 paddle2 = -HEIGHT;
  75         if(paddle2 > HEIGHT)
  76                 paddle2 = HEIGHT;
  77
  78         // Check for collisions with paddles
  79         if(ballVecX < 0 && ballX <= -HEIGHT + -ballVecX * 1.5) {
  80                 if(ballY >= paddle1 - PADDLESIZE && ballY <= paddle1 + PADDLESIZE) {
  81                         GLdouble speedChange = myfmax(1.0, fabs(paddle1 - ballY) * SPEEDBINC);
  82                         ballVecX *= -speedChange * SPEEDXINC;
  83                         ballVecY *= speedChange * SPEEDYINC;
  84                 }
  85         }
  86         if(ballVecX > 0 && ballX >=  HEIGHT - ballVecX * 1.5) {
  87                 if(ballY >= paddle2 - PADDLESIZE && ballY <= paddle2 + PADDLESIZE) {
  88                         GLdouble speedChange = myfmax(1.0, fabs(paddle2 - ballY) * SPEEDBINC);
  89                         ballVecX *= -speedChange * SPEEDXINC;
  90                         ballVecY *= speedChange * SPEEDYINC;
  91                 }
  92         }
  93
  94         // Check if it's past the top or bottom of the screen
  95         if(ballY >= HEIGHT || ballY <= -HEIGHT) {
  96                 ballVecY = -ballVecY;
  97         }
  98
  99         // Check if it's past the sides of the screen
 100         if(ballX >= HEIGHT) {
 101                 ++score1;
 102                 initBall();
 103         }
 104         if(ballX <= -HEIGHT) {
 105                 ++score2;
 106                 initBall();
 107         }
 108
 109         // Move the ball
 110         ballX += ballVecX;
 111         ballY += ballVecY;
 112
 113         // Check scores for winners..
 114         if(score1 == 9) {
 115                 menu = "Player 1 wins!";
 116                 state = STATE_UI;
 117                 score1 = score2 = 0;
 118         }
 119         if(score2 == 9) {
 120                 menu = "Player 2 wins!";
 121                 state = STATE_UI;
 122                 score1 = score2 = 0;
 123         }
 124 }
 125
 126 static void timer(int lastTime) {
 127         if(state == STATE_UI) {
 128                 return;
 129         }
 130
 131         int curTime = glutGet(GLUT_ELAPSED_TIME);
 132         do {
 133                 lastTime += FRAME;
 134                 run();
 135         } while(lastTime + FRAME < curTime);
 136         glutPostRedisplay();
 137         glutTimerFunc(FRAME - (curTime - lastTime), timer, curTime);
 138 }
 139
 140 static void startGame(void) {
 141         glutTimerFunc(FRAME, timer, glutGet(GLUT_ELAPSED_TIME));
 142         initBall();
 143 }
 144
 145 static void drawText(double x, double y, char* str) {
 146         glRasterPos2d(x, y);
 147         while(*str) {
 148                 glutBitmapCharacter(GLUT_BITMAP_HELVETICA_18, *str);
 149                 ++str;
 150         }
 151 }
 152
 153 static void menuDisplay(void) {
 154         drawText(-20, 50, "Awesome PONG!");
 155         drawText(-50, -50, "Press 1 for a single player game.");
 156         drawText(-50, -60, "Press 2 for a multi player game.");
 157         drawText(-50, -70, "Keys: w/s and i/k");
 158         drawText(-20, 0, menu);
 159 }
 160
 161 static void gameDisplay(void) {
 162         // Draw the paddles
 163         glLineWidth(2.0);
 164         glBegin(GL_LINES);
 165         glVertex2d(-HEIGHT + 1, paddle1 - PADDLESIZE);
 166         glVertex2d(-HEIGHT + 1, paddle1 + PADDLESIZE);
 167         glVertex2d( HEIGHT - 1, paddle2 + PADDLESIZE);
 168         glVertex2d( HEIGHT - 1, paddle2 - PADDLESIZE);
 169         glEnd();
 170
 171         // Draw the ball
 172         glBegin(GL_LINES);
 173         glVertex2d(ballX, ballY);
 174         glVertex2d(ballX - ballVecX, ballY - ballVecY);
 175         glEnd();
 176
 177         // Write the score
 178         glRasterPos2d(-5.0, HEIGHT - 10.0);
 179         glutBitmapCharacter(GLUT_BITMAP_HELVETICA_18, '0' + score1);
 180         glRasterPos2d( 5.0, HEIGHT - 10.0);
 181         glutBitmapCharacter(GLUT_BITMAP_HELVETICA_18, '0' + score2);
 182 }
 183
 184 static void display(void) {
 185         glClear(GL_COLOR_BUFFER_BIT);
 186         glColor3d(0.0, 0.0, 0.0);
 187
 188         if(state == STATE_UI) {
 189                 menuDisplay();
 190         } else {
 191                 gameDisplay();
 192         }
 193
 194         glutSwapBuffers();
 195 }
 196
 197 static void resize(int w, int h) {
 198         glViewport(0, 0, w, h);
 199         glLoadIdentity();
 200         glOrtho(-HEIGHT, HEIGHT, -HEIGHT, HEIGHT, -1.0, 1.0);
 201 }
 202
 203 static void menuKeyboard(unsigned char key) {
 204         switch(key) {
 205                 case '1':
 206                         state = STATE_1P;
 207                         break;
 208
 209                 case '2':
 210                         state = STATE_2P;
 211                         break;
 212
 213                 default:
 214                         return;
 215         }
 216         startGame();
 217 }
 218
 219 static void gameKeyboard(unsigned char key) {
 220         switch(key) {
 221                 case 'w':
 222                         p1move = 1;
 223                         break;
 224                 case 's':
 225                         p1move = -1;
 226                         break;
 227
 228                 case 'i':
 229                         p2move = 1;
 230                         break;
 231                 case 'k':
 232                         p2move = -1;
 233                         break;
 234
 235                 default:
 236                         return;
 237         }
 238         glutPostRedisplay();
 239 }
 240
 241 static void keyboard(unsigned char key, int x, int y) {
 242         (void)x;(void)y;
 243
 244         switch(key) {
 245                 case 'q':
 246                 case 'Q':
 247                 case '\033':
 248                         exit(0);
 249         }
 250
 251
 252         if(state == STATE_UI) {
 253                 menuKeyboard(key);
 254         } else {
 255                 gameKeyboard(key);
 256         }
 257 }
 258
 259 static void keyboardUp(unsigned char key, int x, int y) {
 260         (void)x;(void)y;
 261
 262         switch(key) {
 263                 case 'w':
 264                 case 's':
 265                         p1move = 0;
 266                         break;
 267
 268                 case 'i':
 269                 case 'k':
 270                         p2move = 0;
 271                         p2move = 0;
 272                         break;
 273         }
 274 }
 275
 276 int main(int argc, char *argv[]) {
 277         glutInitWindowPosition(100, 100);
 278         glutInitWindowSize(640, 480);
 279         glutInit(&argc, argv);
 280         glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE);
 281         glutCreateWindow(argv[0]);
 282         glutDisplayFunc(display);
 283         glutReshapeFunc(resize);
 284         glutKeyboardFunc(keyboard);
 285         glutKeyboardUpFunc(keyboardUp);
 286         glClearColor(1.0, 1.0, 1.0, 0.0);
 287         glutMainLoop();
 288         return 0;
 289 }
 290