progs/demos/bounce.c

   1 /* $Id: bounce.c,v 1.1 1999/08/19 00:55:40 jtg Exp $ */
   2
   3 /*
   4  * Bouncing ball demo.  Color index mode only!
   5  *
   6  * This program is in the public domain
   7  *
   8  * Brian Paul
   9  */
  10
  11 /* Conversion to GLUT by Mark J. Kilgard */
  12
  13 /*
  14  * $Log: bounce.c,v $
  15  * Revision 1.1  1999/08/19 00:55:40  jtg
  16  * Initial revision
  17  *
  18  * Revision 3.3  1999/03/18 08:16:14  joukj
  19  *
  20  *     cmpstr needs string.h to included to avoid warnings
  21  *
  22  * Revision 3.2  1998/11/28 01:13:02  brianp
  23  * now sets an initial window position and size
  24  *
  25  * Revision 3.1  1998/11/28 01:06:57  brianp
  26  * now works in RGB mode by default
  27  *
  28  * Revision 3.0  1998/02/14 18:42:29  brianp
  29  * initial rev
  30  *
  31  */
  32
  33
  34 #include <math.h>
  35 #include <stdlib.h>
  36 #include <string.h>
  37 #include <GL/glut.h>
  38
  39 #define COS(X)   cos( (X) * 3.14159/180.0 )
  40 #define SIN(X)   sin( (X) * 3.14159/180.0 )
  41
  42 #define RED 1
  43 #define WHITE 2
  44 #define CYAN 3
  45
  46 GLboolean IndexMode = GL_FALSE;
  47 GLuint Ball;
  48 GLenum Mode;
  49 GLfloat Zrot = 0.0, Zstep = 6.0;
  50 GLfloat Xpos = 0.0, Ypos = 1.0;
  51 GLfloat Xvel = 0.2, Yvel = 0.0;
  52 GLfloat Xmin = -4.0, Xmax = 4.0;
  53 GLfloat Ymin = -3.8, Ymax = 4.0;
  54 GLfloat G = -0.1;
  55
  56 static GLuint
  57 make_ball(void)
  58 {
  59   GLuint list;
  60   GLfloat a, b;
  61   GLfloat da = 18.0, db = 18.0;
  62   GLfloat radius = 1.0;
  63   GLuint color;
  64   GLfloat x, y, z;
  65
  66   list = glGenLists(1);
  67
  68   glNewList(list, GL_COMPILE);
  69
  70   color = 0;
  71   for (a = -90.0; a + da <= 90.0; a += da) {
  72
  73     glBegin(GL_QUAD_STRIP);
  74     for (b = 0.0; b <= 360.0; b += db) {
  75
  76       if (color) {
  77         glIndexi(RED);
  78         glColor3f(1, 0, 0);
  79       } else {
  80         glIndexi(WHITE);
  81         glColor3f(1, 1, 1);
  82       }
  83
  84       x = COS(b) * COS(a);
  85       y = SIN(b) * COS(a);
  86       z = SIN(a);
  87       glVertex3f(x, y, z);
  88
  89       x = radius * COS(b) * COS(a + da);
  90       y = radius * SIN(b) * COS(a + da);
  91       z = radius * SIN(a + da);
  92       glVertex3f(x, y, z);
  93
  94       color = 1 - color;
  95     }
  96     glEnd();
  97
  98   }
  99
 100   glEndList();
 101
 102   return list;
 103 }
 104
 105 static void
 106 reshape(int width, int height)
 107 {
 108   float aspect = (float) width / (float) height;
 109   glViewport(0, 0, (GLint) width, (GLint) height);
 110   glMatrixMode(GL_PROJECTION);
 111   glLoadIdentity();
 112   glOrtho(-6.0 * aspect, 6.0 * aspect, -6.0, 6.0, -6.0, 6.0);
 113   glMatrixMode(GL_MODELVIEW);
 114 }
 115
 116 /* ARGSUSED1 */
 117 static void
 118 key(unsigned char k, int x, int y)
 119 {
 120   switch (k) {
 121   case 27:  /* Escape */
 122     exit(0);
 123   }
 124 }
 125
 126 static void
 127 draw(void)
 128 {
 129   GLint i;
 130
 131   glClear(GL_COLOR_BUFFER_BIT);
 132
 133   glIndexi(CYAN);
 134   glColor3f(0, 1, 1);
 135   glBegin(GL_LINES);
 136   for (i = -5; i <= 5; i++) {
 137     glVertex2i(i, -5);
 138     glVertex2i(i, 5);
 139   }
 140   for (i = -5; i <= 5; i++) {
 141     glVertex2i(-5, i);
 142     glVertex2i(5, i);
 143   }
 144   for (i = -5; i <= 5; i++) {
 145     glVertex2i(i, -5);
 146     glVertex2f(i * 1.15, -5.9);
 147   }
 148   glVertex2f(-5.3, -5.35);
 149   glVertex2f(5.3, -5.35);
 150   glVertex2f(-5.75, -5.9);
 151   glVertex2f(5.75, -5.9);
 152   glEnd();
 153
 154   glPushMatrix();
 155   glTranslatef(Xpos, Ypos, 0.0);
 156   glScalef(2.0, 2.0, 2.0);
 157   glRotatef(8.0, 0.0, 0.0, 1.0);
 158   glRotatef(90.0, 1.0, 0.0, 0.0);
 159   glRotatef(Zrot, 0.0, 0.0, 1.0);
 160
 161   glCallList(Ball);
 162
 163   glPopMatrix();
 164
 165   glFlush();
 166   glutSwapBuffers();
 167 }
 168
 169 static void
 170 idle(void)
 171 {
 172   static float vel0 = -100.0;
 173
 174   Zrot += Zstep;
 175
 176   Xpos += Xvel;
 177   if (Xpos >= Xmax) {
 178     Xpos = Xmax;
 179     Xvel = -Xvel;
 180     Zstep = -Zstep;
 181   }
 182   if (Xpos <= Xmin) {
 183     Xpos = Xmin;
 184     Xvel = -Xvel;
 185     Zstep = -Zstep;
 186   }
 187   Ypos += Yvel;
 188   Yvel += G;
 189   if (Ypos < Ymin) {
 190     Ypos = Ymin;
 191     if (vel0 == -100.0)
 192       vel0 = fabs(Yvel);
 193     Yvel = vel0;
 194   }
 195   glutPostRedisplay();
 196 }
 197
 198 void
 199 visible(int vis)
 200 {
 201   if (vis == GLUT_VISIBLE)
 202     glutIdleFunc(idle);
 203   else
 204     glutIdleFunc(NULL);
 205 }
 206
 207 int main(int argc, char *argv[])
 208 {
 209   glutInit(&argc, argv);
 210   glutInitWindowPosition(0, 0);
 211   glutInitWindowSize(600, 450);
 212
 213
 214   IndexMode = argc > 1 && strcmp(argv[1], "-ci") == 0;
 215   if (IndexMode)
 216      glutInitDisplayMode(GLUT_INDEX | GLUT_DOUBLE);
 217   else
 218      glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE);
 219
 220   glutCreateWindow("Bounce");
 221   Ball = make_ball();
 222   glCullFace(GL_BACK);
 223   glEnable(GL_CULL_FACE);
 224   glDisable(GL_DITHER);
 225   glShadeModel(GL_FLAT);
 226
 227   glutDisplayFunc(draw);
 228   glutReshapeFunc(reshape);
 229   glutVisibilityFunc(visible);
 230   glutKeyboardFunc(key);
 231
 232   if (IndexMode) {
 233     glutSetColor(RED, 1.0, 0.0, 0.0);
 234     glutSetColor(WHITE, 1.0, 1.0, 1.0);
 235     glutSetColor(CYAN, 0.0, 1.0, 1.0);
 236   }
 237
 238   glutMainLoop();
 239   return 0;             /* ANSI C requires main to return int. */
 240 }