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
  13 enum {
  14         FRAME=40,
  15         HEIGHT=100,
  16         PADDLESIZE=10
  17 };
  18
  19 static int score1;
  20 static int score2;
  21 static GLdouble paddle1;
  22 static GLdouble paddle2;
  23 static GLdouble ballX;
  24 static GLdouble ballY;
  25 static GLdouble ballVecX;
  26 static GLdouble ballVecY;
  27
  28
  29 static void initball(void) {
  30         ballX = 0.0;
  31         ballY = 0.0;
  32         if(ballVecX < 0)
  33                 ballVecX = -1.0;
  34         else
  35                 ballVecX = 1.0;
  36         ballVecY = 1.0;
  37 }
  38
  39 static void run(void) {
  40         // Check for collisions with paddles
  41         if(ballVecX < 0 && ballX <= -HEIGHT + -ballVecX * 1.5) {
  42                 if(ballY >= paddle1 - PADDLESIZE && ballY <= paddle1 + PADDLESIZE) {
  43                         ballVecX *= -1.15;
  44                         ballVecY *= 1.15;
  45                 }
  46         }
  47         if(ballVecX > 0 && ballX >=  HEIGHT - ballVecX * 1.5) {
  48                 if(ballY >= paddle2 - PADDLESIZE && ballY <= paddle2 + PADDLESIZE) {
  49                         ballVecX *= -1.15;
  50                         ballVecY *= 1.15;
  51                 }
  52         }
  53
  54         // Check if it's past the top or bottom of the screen
  55         if(ballY >= HEIGHT || ballY <= -HEIGHT) {
  56                 ballVecY *= -1;
  57         }
  58
  59         // Check if it's past the sides of the screen
  60         if(ballX >= HEIGHT) {
  61                 ++score1;
  62                 initball();
  63                 return;
  64         }
  65         if(ballX <= -HEIGHT) {
  66                 ++score2;
  67                 initball();
  68                 return;
  69         }
  70
  71         // Move the ball
  72         ballX += ballVecX;
  73         ballY += ballVecY;
  74 }
  75
  76 static void display(void) {
  77         glClear(GL_COLOR_BUFFER_BIT);
  78         glColor3d(0.0, 0.0, 0.0);
  79
  80         // Draw the paddles
  81         glLineWidth(2.0);
  82         glBegin(GL_LINES);
  83         glVertex2d(-HEIGHT + 1, paddle1 - PADDLESIZE);
  84         glVertex2d(-HEIGHT + 1, paddle1 + PADDLESIZE);
  85         glVertex2d( HEIGHT - 1, paddle2 + PADDLESIZE);
  86         glVertex2d( HEIGHT - 1, paddle2 - PADDLESIZE);
  87         glEnd();
  88
  89         // Draw the ball
  90         glPointSize(5.0);
  91         glBegin(GL_POINTS);
  92         glVertex2d(ballX, ballY);
  93         glEnd();
  94
  95         // Write the score
  96         glRasterPos2d(-5.0, HEIGHT - 10.0);
  97         glutBitmapCharacter(GLUT_BITMAP_HELVETICA_18, '0' + score1);
  98         glRasterPos2d( 5.0, HEIGHT - 10.0);
  99         glutBitmapCharacter(GLUT_BITMAP_HELVETICA_18, '0' + score2);
 100
 101         glutSwapBuffers();
 102 }
 103
 104 static void resize(int w, int h) {
 105         glViewport(0, 0, w, h);
 106         glLoadIdentity();
 107         glOrtho(-HEIGHT, HEIGHT, -HEIGHT, HEIGHT, -1.0, 1.0);
 108 }
 109
 110 static void keyboard(unsigned char key, int x, int y) {
 111         (void)x;(void)y;
 112
 113         switch(key) {
 114                 case 'q':
 115                 case 'Q':
 116                 case '\033':
 117                         exit(0);
 118
 119                 case 'w':
 120                         if(paddle1 + PADDLESIZE < HEIGHT)
 121                                 paddle1 += PADDLESIZE;
 122                         break;
 123                 case 's':
 124                         if(paddle1 - PADDLESIZE > -HEIGHT)
 125                                 paddle1 -= PADDLESIZE;
 126                         break;
 127
 128                 case 'i':
 129                         if(paddle2 + PADDLESIZE < HEIGHT)
 130                                 paddle2 += PADDLESIZE;
 131                         break;
 132                 case 'k':
 133                         if(paddle2 - PADDLESIZE > -HEIGHT)
 134                                 paddle2 -= PADDLESIZE;
 135                         break;
 136
 137                 default:
 138                         return;
 139         }
 140         glutPostRedisplay();
 141 }
 142
 143 static void timer(int lastTime) {
 144         int curTime = glutGet(GLUT_ELAPSED_TIME);
 145         do {
 146                 lastTime += FRAME;
 147                 run();
 148         } while(lastTime + FRAME < curTime);
 149         glutPostRedisplay();
 150         glutTimerFunc(FRAME - (curTime - lastTime), timer, curTime);
 151 }
 152
 153 static void init(void) {
 154         glClearColor(1.0, 1.0, 1.0, 0.0);
 155         initball();
 156 }
 157
 158 int main(int argc, char *argv[]) {
 159         glutInitWindowPosition(100, 100);
 160         glutInitWindowSize(640, 480);
 161         glutInit(&argc, argv);
 162         glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE);
 163         glutCreateWindow(argv[0]);
 164         glutDisplayFunc(display);
 165         glutReshapeFunc(resize);
 166         glutKeyboardFunc(keyboard);
 167         glutTimerFunc(FRAME, timer, glutGet(GLUT_ELAPSED_TIME));
 168         init();
 169         glutMainLoop();
 170         return 0;
 171 }
 172