Demo/Mesa/bounce.c

   1
   2 /*
   3  * Bouncing ball demo.
   4  *
   5  * This program is in the public domain
   6  *
   7  * Brian Paul
   8  *
   9  * Conversion to GLUT by Mark J. Kilgard
  10  */
  11
  12
  13 #include <math.h>
  14 #include <stdlib.h>
  15 #include <string.h>
  16 #include <GL/glut.h>
  17
  18 #define COS(X)   cos( (X) * 3.14159/180.0 )
  19 #define SIN(X)   sin( (X) * 3.14159/180.0 )
  20
  21 #define RED 1
  22 #define WHITE 2
  23 #define VIOLET 3
  24
  25 GLboolean IndexMode = GL_FALSE;
  26 GLuint Ball;
  27 GLenum Mode;
  28 GLfloat Zrot = 0.0, Zstep = 180.0;
  29 GLfloat Xpos = 0.0, Ypos = 1.0;
  30 GLfloat Xvel = 2.0, Yvel = 0.0;
  31 GLfloat Xmin = -4.0, Xmax = 4.0;
  32 GLfloat Ymin = -3.8, Ymax = 4.0;
  33 GLfloat G = -9.8;
  34
  35 static GLuint
  36 make_ball(void)
  37 {
  38   GLuint list;
  39   GLfloat a, b;
  40   GLfloat da = 22.5, db = 22.5;
  41   GLfloat radius = 1.0;
  42   GLuint color;
  43   GLfloat x, y, z;
  44
  45   list = glGenLists(1);
  46
  47   glNewList(list, GL_COMPILE);
  48
  49   color = 0;
  50   for (a = -90.0; a + da <= 90.0; a += da) {
  51
  52     glBegin(GL_QUAD_STRIP);
  53     for (b = 0.0; b <= 360.0; b += db) {
  54
  55       if (color) {
  56         glIndexi(RED);
  57         glColor3f(1, 0, 0);
  58       } else {
  59         glIndexi(WHITE);
  60         glColor3f(1, 1, 1);
  61       }
  62
  63       x = radius * COS(b) * COS(a);
  64       y = radius * SIN(b) * COS(a);
  65       z = radius * SIN(a);
  66       glVertex3f(x, y, z);
  67
  68       x = radius * COS(b) * COS(a + da);
  69       y = radius * SIN(b) * COS(a + da);
  70       z = radius * SIN(a + da);
  71       glVertex3f(x, y, z);
  72
  73       color = 1 - color;
  74     }
  75     glEnd();
  76
  77   }
  78
  79   glEndList();
  80
  81   return list;
  82 }
  83
  84 static void
  85 reshape(int width, int height)
  86 {
  87   float aspect = (float) width / (float) height;
  88   glViewport(0, 0, (GLint) width, (GLint) height);
  89   glMatrixMode(GL_PROJECTION);
  90   glLoadIdentity();
  91   glOrtho(-6.0 * aspect, 6.0 * aspect, -6.0, 6.0, -6.0, 6.0);
  92   glMatrixMode(GL_MODELVIEW);
  93 }
  94
  95 /* ARGSUSED1 */
  96 static void
  97 key(unsigned char k, int x, int y)
  98 {
  99   switch (k) {
 100   case 27:  /* Escape */
 101     exit(0);
 102   }
 103 }
 104
 105 static void
 106 draw(void)
 107 {
 108   GLint i;
 109
 110   glClearColor(0.6f, 0.6f, 0.6f, 1.0f);
 111   glClear(GL_COLOR_BUFFER_BIT);
 112
 113   glIndexi(VIOLET);
 114   glColor3f(0.7, 0.45, 0.7);
 115   glLineWidth(2.5);
 116   glBegin(GL_LINES);
 117   for (i = -5; i <= 5; i++) {
 118     glVertex2i(i, -5);
 119     glVertex2i(i, 5);
 120   }
 121   for (i = -5; i <= 5; i++) {
 122     glVertex2i(-5, i);
 123     glVertex2i(5, i);
 124   }
 125   for (i = -5; i <= 5; i++) {
 126     glVertex2i(i, -5);
 127     glVertex2f(i * 1.15, -5.9);
 128   }
 129   glVertex2f(-5.3, -5.35);
 130   glVertex2f(5.3, -5.35);
 131   glVertex2f(-5.75, -5.9);
 132   glVertex2f(5.75, -5.9);
 133   glEnd();
 134   glLineWidth(1.0);
 135
 136   glPushMatrix();
 137   glTranslatef(Xpos, Ypos, 0.0);
 138   glScalef(2.0, 2.0, 2.0);
 139   glRotatef(-20.0, 0.0, 0.0, 1.0);
 140   glRotatef(90.0, 1.0, 0.0, 0.0);
 141   glRotatef(Zrot, 0.0, 0.0, 1.0);
 142
 143   glCallList(Ball);
 144
 145   glPopMatrix();
 146
 147   glFlush();
 148   glutSwapBuffers();
 149
 150 }
 151
 152 static void
 153 idle(void)
 154 {
 155   static float vel0 = -100.0;
 156   static double t0 = -1.;
 157   double t, dt;
 158   t = glutGet(GLUT_ELAPSED_TIME) / 1000.;
 159   if (t0 < 0.)
 160      t0 = t;
 161   dt = t - t0;
 162   t0 = t;
 163
 164   Zrot -= Zstep*dt;
 165
 166   Xpos += Xvel*dt;
 167   if (Xpos >= Xmax) {
 168     Xpos = Xmax;
 169     Xvel = -Xvel;
 170     Zstep = -Zstep;
 171   }
 172   if (Xpos <= Xmin) {
 173     Xpos = Xmin;
 174     Xvel = -Xvel;
 175     Zstep = -Zstep;
 176   }
 177   Ypos += Yvel*dt;
 178   Yvel += G*dt;
 179   if (Ypos < Ymin) {
 180     Ypos = Ymin;
 181     if (vel0 == -100.0)
 182       vel0 = fabs(Yvel);
 183     Yvel = vel0;
 184   }
 185   glutPostRedisplay();
 186 }
 187
 188 static void
 189 visible(int vis)
 190 {
 191   if (vis == GLUT_VISIBLE)
 192     glutIdleFunc(idle);
 193   else
 194     glutIdleFunc(NULL);
 195 }
 196
 197 #include <proto/exec.h>
 198 #include <proto/dos.h>
 199
 200 #define ARG_TEMPLATE "WINPOSX=X/N/K,WINPOSY=Y/N/K"
 201 #define ARG_X 0
 202 #define ARG_Y 1
 203 #define NUM_ARGS 2
 204
 205 static IPTR args[NUM_ARGS];
 206 WORD                    winx = -1, winy = -1;
 207 #define W 320
 208 #define H 200
 209
 210 static void correctpos(void)
 211 {
 212     if (winx == -1) winx = 100;
 213     if (winy == -1) winy = 100;
 214 }
 215
 216 static void getarguments(void)
 217 {
 218     struct RDArgs *myargs;
 219
 220     if ((myargs = ReadArgs(ARG_TEMPLATE, args, NULL)))
 221     {
 222
 223         if (args[ARG_X]) winx = *(IPTR *)args[ARG_X];
 224         if (args[ARG_Y]) winy = *(IPTR *)args[ARG_Y];
 225
 226         FreeArgs(myargs);
 227     }
 228 }
 229
 230
 231 int main(int argc, char *argv[])
 232 {
 233   getarguments();
 234   correctpos();
 235
 236   glutInit(&argc, argv);
 237   glutInitWindowPosition(winx, winy);
 238   glutInitWindowSize(W, H);
 239
 240
 241   IndexMode = argc > 1 && strcmp(argv[1], "-ci") == 0;
 242   if (IndexMode)
 243      glutInitDisplayMode(GLUT_INDEX | GLUT_DOUBLE);
 244   else
 245      glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE);
 246
 247   glutCreateWindow("Bounce");
 248   Ball = make_ball();
 249   glCullFace(GL_BACK);
 250   glEnable(GL_CULL_FACE);
 251   glDisable(GL_DITHER);
 252   glShadeModel(GL_FLAT);
 253
 254   glutDisplayFunc(draw);
 255   glutReshapeFunc(reshape);
 256   glutVisibilityFunc(visible);
 257   glutKeyboardFunc(key);
 258
 259   if (IndexMode) {
 260     glutSetColor(RED, 1.0, 0.0, 0.0);
 261     glutSetColor(WHITE, 1.0, 1.0, 1.0);
 262     glutSetColor(VIOLET, 0.7, 0.45, 0.7);
 263   }
 264
 265   glutMainLoop();
 266   return 0;             /* ANSI C requires main to return int. */
 267 }