00001 
00002 /* Copyright (c) Mark J. Kilgard, 1996. */
00003 
00004 /* This program is freely distributable without licensing fees 
00005    and is provided without guarantee or warrantee expressed or 
00006    implied. This program is -not- in the public domain. */
00007 
00008 /* compile: cc -o glxdino glxdino.c -lGLU -lGL -lXmu -lXext -lX11 -lm */
00009 
00010 /* C library header files. */
00011 #include <stdio.h>
00012 #include <stdlib.h>
00013 #include <string.h>
00014 #include <math.h>
00015 
00016 /* OpenGL header files. */
00017 #include <GL/gl.h>
00018 #include <GL/glx.h>
00019 #include <GL/glu.h>
00020 
00021 /* X header files. */
00022 #include <X11/Xlib.h>
00023 #include <X11/Xatom.h>
00024 #include <X11/Xmu/StdCmap.h>
00025 #include <X11/keysym.h>
00026 
00027 Display *dpy;
00028 Window win;
00029 GLfloat angle = -150;   /* in degrees */
00030 Bool doubleBuffer = True, iconic = False, keepAspect = False;
00031 int W = 300, H = 300;
00032 XSizeHints sizeHints = {0};
00033 GLdouble bodyWidth = 2.0;
00034 int configuration[] = {GLX_DOUBLEBUFFER, GLX_RGBA, GLX_DEPTH_SIZE, 12,
00035   GLX_RED_SIZE, 1, GLX_BLUE_SIZE, 1, GLX_GREEN_SIZE, 1, None};
00036 
00037 typedef enum {
00038   RESERVED, BODY_SIDE, BODY_EDGE, BODY_WHOLE, ARM_SIDE, ARM_EDGE, ARM_WHOLE,
00039   LEG_SIDE, LEG_EDGE, LEG_WHOLE, EYE_SIDE, EYE_EDGE, EYE_WHOLE, DINOSAUR
00040 } displayLists;
00041 
00042 void extrudeSolidFromPolygon(GLfloat data[][2], unsigned int dataSize,
00043   GLdouble thickness, GLuint side, GLuint edge, GLuint whole);
00044 void redraw(void);
00045 void makeDinosaur(void);
00046 void contextInit(void);
00047 
00048 void
00049 fatalError(char *message)
00050 {
00051   fprintf(stderr, "glxdino: %s\n", message);
00052   exit(1);
00053 }
00054 
00055 Colormap
00056 getShareableColormap(XVisualInfo * vi)
00057 {
00058   Status status;
00059   XStandardColormap *standardCmaps;
00060   Colormap cmap;
00061   int i, numCmaps;
00062 
00063   /* be lazy; using DirectColor too involved for this example */
00064   if (vi->class != TrueColor)
00065     fatalError("No support for non-TrueColor visual.");
00066   /* if no standard colormap but TrueColor, just make an
00067      unshared one */
00068   status = XmuLookupStandardColormap(dpy, vi->screen, vi->visualid,
00069     vi->depth, XA_RGB_DEFAULT_MAP, /* replace */ False, /* retain */ True);
00070   if (status == 1) {
00071     status = XGetRGBColormaps(dpy, RootWindow(dpy, vi->screen),
00072       &standardCmaps, &numCmaps, XA_RGB_DEFAULT_MAP);
00073     if (status == 1)
00074       for (i = 0; i < numCmaps; i++)
00075         if (standardCmaps[i].visualid == vi->visualid) {
00076           cmap = standardCmaps[i].colormap;
00077           XFree(standardCmaps);
00078           return cmap;
00079         }
00080   }
00081   cmap = XCreateColormap(dpy, RootWindow(dpy, vi->screen),
00082     vi->visual, AllocNone);
00083   return cmap;
00084 }
00085 
00086 void extrudeSolidFromPolygon(GLfloat data[][2], unsigned int dataSize,
00087   GLdouble thickness, GLuint side, GLuint edge, GLuint whole);
00088 GLfloat body[][2] = { {0, 3}, {1, 1}, {5, 1}, {8, 4}, {10, 4}, {11, 5},
00089   {11, 11.5}, {13, 12}, {13, 13}, {10, 13.5}, {13, 14}, {13, 15}, {11, 16},
00090   {8, 16}, {7, 15}, {7, 13}, {8, 12}, {7, 11}, {6, 6}, {4, 3}, {3, 2},
00091   {1, 2} };
00092 GLfloat arm[][2] = { {8, 10}, {9, 9}, {10, 9}, {13, 8}, {14, 9}, {16, 9},
00093   {15, 9.5}, {16, 10}, {15, 10}, {15.5, 11}, {14.5, 10}, {14, 11}, {14, 10},
00094   {13, 9}, {11, 11}, {9, 11} };
00095 GLfloat leg[][2] = { {8, 6}, {8, 4}, {9, 3}, {9, 2}, {8, 1}, {8, 0.5}, {9, 0},
00096   {12, 0}, {10, 1}, {10, 2}, {12, 4}, {11, 6}, {10, 7}, {9, 7} };
00097 GLfloat eye[][2] = { {8.75, 15}, {9, 14.7}, {9.6, 14.7}, {10.1, 15},
00098   {9.6, 15.25}, {9, 15.25} };
00099 GLfloat skinColor[] = {0.1, 1.0, 0.1, 1.0};   /* Green */
00100 GLfloat eyeColor[] = {1.0, 0.2, 0.2, 1.0};    /* Red */
00101 
00102 void
00103 makeDinosaur(void)
00104 {
00105   GLfloat bodyWidth = 3.0;
00106    
00107   extrudeSolidFromPolygon(body, sizeof(body), bodyWidth,
00108     BODY_SIDE, BODY_EDGE, BODY_WHOLE);
00109   extrudeSolidFromPolygon(arm, sizeof(arm), bodyWidth / 4,
00110     ARM_SIDE, ARM_EDGE, ARM_WHOLE);
00111   extrudeSolidFromPolygon(leg, sizeof(leg), bodyWidth / 2,
00112     LEG_SIDE, LEG_EDGE, LEG_WHOLE);
00113   extrudeSolidFromPolygon(eye, sizeof(eye), bodyWidth + 0.2,
00114     EYE_SIDE, EYE_EDGE, EYE_WHOLE);
00115   glNewList(DINOSAUR, GL_COMPILE);
00116     glMaterialfv(GL_FRONT, GL_DIFFUSE, skinColor);
00117     glCallList(BODY_WHOLE);
00118     glPushMatrix();
00119       glTranslatef(0.0, 0.0, bodyWidth);
00120       glCallList(ARM_WHOLE);
00121       glCallList(LEG_WHOLE);
00122       glTranslatef(0.0, 0.0, -bodyWidth - bodyWidth / 4);
00123       glCallList(ARM_WHOLE);
00124       glTranslatef(0.0, 0.0, -bodyWidth / 4);
00125       glCallList(LEG_WHOLE);
00126       glTranslatef(0.0, 0.0, bodyWidth / 2 - 0.1);
00127       glMaterialfv(GL_FRONT, GL_DIFFUSE, eyeColor);
00128       glCallList(EYE_WHOLE);
00129     glPopMatrix();
00130   glEndList();
00131 }
00132 
00133 /* it seems that some compilers have a new type for the third argument */
00134 /* 03 Aug 2004 [rickr] */
00135 #ifdef LINUX2
00136 #define CAST_GLU_FUNCPTR (_GLUfuncptr)
00137 #else
00138 #define CAST_GLU_FUNCPTR
00139 #endif
00140 
00141 void
00142 extrudeSolidFromPolygon(GLfloat data[][2], unsigned int dataSize,
00143   GLdouble thickness, GLuint side, GLuint edge, GLuint whole)
00144 {
00145   static GLUtriangulatorObj *tobj = NULL;
00146   GLdouble vertex[3], dx, dy, len;
00147   int i;
00148   int count = dataSize / (2 * sizeof(GLfloat));
00149 
00150   if (tobj == NULL) {
00151     tobj = gluNewTess();  /* create and initialize a GLU
00152                              polygon tessellation object */
00153     /* cast 3rd args as _GLUfuncptr for some machines   02 Aug 2004 [rickr] */
00154     gluTessCallback(tobj, GLU_BEGIN, CAST_GLU_FUNCPTR glBegin);
00155     gluTessCallback(tobj, GLU_VERTEX, CAST_GLU_FUNCPTR glVertex2fv);/* tricky */
00156     gluTessCallback(tobj, GLU_END, CAST_GLU_FUNCPTR glEnd);
00157   }
00158   glNewList(side, GL_COMPILE);
00159     glShadeModel(GL_SMOOTH);  /* smooth minimizes seeing
00160                                  tessellation */
00161     gluBeginPolygon(tobj);
00162     for (i = 0; i < count; i++) {
00163       vertex[0] = data[i][0];
00164       vertex[1] = data[i][1];
00165       vertex[2] = 0;
00166       gluTessVertex(tobj, vertex, &data[i]);
00167     }
00168     gluEndPolygon(tobj);
00169   glEndList();
00170   glNewList(edge, GL_COMPILE);
00171     glShadeModel(GL_FLAT);  /* flat shade keeps angular hands
00172                                from being "smoothed" */
00173     glBegin(GL_QUAD_STRIP);
00174     for (i = 0; i <= count; i++) {
00175       /* mod function handles closing the edge */
00176       glVertex3f(data[i % count][0], data[i % count][1], 0.0);
00177       glVertex3f(data[i % count][0], data[i % count][1], thickness);
00178       /* Calculate a unit normal by dividing by Euclidean
00179          distance.  We could be lazy and use glEnable(GL_NORMALIZE)
00180          so we could pass in arbitrary normals for a very slight
00181          performance hit. */
00182       dx = data[(i + 1) % count][1] - data[i % count][1];
00183       dy = data[i % count][0] - data[(i + 1) % count][0];
00184       len = sqrt(dx * dx + dy * dy);
00185       glNormal3f(dx / len, dy / len, 0.0);
00186     }
00187     glEnd();
00188   glEndList();
00189   glNewList(whole, GL_COMPILE);
00190     glFrontFace(GL_CW);
00191     glCallList(edge);
00192     glNormal3f(0.0, 0.0, -1.0);  /* constant normal for side */
00193     glCallList(side);
00194     glPushMatrix();
00195       glTranslatef(0.0, 0.0, thickness);
00196       glFrontFace(GL_CCW);
00197       glNormal3f(0.0, 0.0, 1.0);  /* reverse normal for other side */
00198       glCallList(side);
00199     glPopMatrix();
00200   glEndList();
00201 }
00202 
00203 GLfloat lightZeroPosition[] = {10.0, 4.0, 10.0, 1.0};
00204 GLfloat lightZeroColor[] = {0.8, 1.0, 0.8, 1.0}; /* green-tinted */
00205 GLfloat lightOnePosition[] = {-1.0, -2.0, 1.0, 0.0};
00206 GLfloat lightOneColor[] = {0.6, 0.3, 0.2, 1.0};  /* red-tinted */
00207 
00208 void
00209 contextInit(void)
00210 {
00211   glEnable(GL_CULL_FACE);  /* Up to 50% better perfomance than no
00212                               back-face culling. */
00213   glEnable(GL_DEPTH_TEST); /* Enable depth buffering. */
00214 
00215   glLightModeli(GL_LIGHT_MODEL_LOCAL_VIEWER, 1);
00216   glLightfv(GL_LIGHT0, GL_POSITION, lightZeroPosition);
00217   glLightfv(GL_LIGHT0, GL_DIFFUSE, lightZeroColor);
00218   glLightf(GL_LIGHT0, GL_CONSTANT_ATTENUATION, 0.1);
00219   glLightf(GL_LIGHT0, GL_LINEAR_ATTENUATION, 0.05);
00220   glLightfv(GL_LIGHT1, GL_POSITION, lightOnePosition);
00221   glLightfv(GL_LIGHT1, GL_DIFFUSE, lightOneColor);
00222 
00223   /* Enable both lights. */
00224   glEnable(GL_LIGHT0);
00225   glEnable(GL_LIGHT1);
00226   glEnable(GL_LIGHTING);
00227 
00228   /* Set up projection transform. */
00229   glMatrixMode(GL_PROJECTION);
00230   gluPerspective(
00231     40.0,               /* Field of view in degree */
00232     1.0,                /* Aspect ratio */
00233     1.0,                /* Z near */
00234     40.0);              /* Z far */
00235 
00236   /* Now, change to modelview. */
00237   glMatrixMode(GL_MODELVIEW);
00238   gluLookAt(
00239     0.0, 0.0, 30.0,     /* Eye is at (0,0,30) */
00240     0.0, 0.0, 0.0,      /* Center is at (0,0,0) */
00241     0.0, 1.0, 0.);      /* Up is in positive Y direction */
00242   glPushMatrix();       /* Dummy push so we can pop on model
00243                            recalc. */
00244 }
00245 
00246 int
00247 main(int argc, char **argv)
00248 {
00249   XVisualInfo *vi;
00250   Colormap cmap;
00251   XSetWindowAttributes swa;
00252   XWMHints *wmHints;
00253   Atom wmDeleteWindow;
00254   GLXContext cx;
00255   XEvent event;
00256   KeySym ks;
00257   Bool needRedraw = False, recalcModelView = True;
00258   char *display = NULL, *geometry = NULL;
00259   int flags, x, y, width, height, lastX = 0, i;
00260   
00261   for (i = 1; i < argc; i++) {
00262     if (!strcmp(argv[i], "-geometry")) {
00263       if (++i >= argc)
00264         fatalError("follow -geometry option with geometry parameter");
00265       geometry = argv[i];
00266     } else if (!strcmp(argv[i], "-display")) {
00267       if (++i >= argc)
00268         fatalError("follow -display option with display parameter");
00269       display = argv[i];
00270     } else if (!strcmp(argv[i], "-iconic"))
00271       iconic = True;
00272     else if (!strcmp(argv[i], "-keepaspect"))
00273       keepAspect = True;
00274     else if (!strcmp(argv[i], "-single"))
00275       doubleBuffer = False;
00276     else
00277       fatalError("bad option");
00278   }
00279 
00280   dpy = XOpenDisplay(display);
00281   if (dpy == NULL)
00282     fatalError("could not open display");
00283 
00284   if (!glXQueryExtension(dpy, NULL, NULL))
00285     fatalError("X server has no OpenGL GLX extension");
00286 
00287   /* Find an OpenGL-capable RGB visual with depth buffer. */
00288   if (!doubleBuffer)
00289     goto SingleBufferOverride;
00290   vi = glXChooseVisual(dpy, DefaultScreen(dpy), configuration);
00291   if (vi == NULL) {
00292   SingleBufferOverride:
00293     vi = glXChooseVisual(dpy, DefaultScreen(dpy), &configuration[1]);
00294     if (vi == NULL)
00295       fatalError("no appropriate RGB visual with depth buffer");
00296     doubleBuffer = False;
00297   }
00298   cmap = getShareableColormap(vi);
00299 
00300   /* Create an OpenGL rendering context. */
00301   cx = glXCreateContext(dpy, vi,
00302     /* No sharing of display lists */ NULL,
00303     /* Direct rendering if possible */ True);
00304   if (cx == NULL)
00305     fatalError("could not create rendering context");
00306 
00307   flags = XParseGeometry(geometry, &x, &y,
00308     (unsigned int *) &width, (unsigned int *) &height);
00309   if (WidthValue & flags) {
00310     sizeHints.flags |= USSize;
00311     sizeHints.width = width;
00312     W = width;
00313   }
00314   if (HeightValue & flags) {
00315     sizeHints.flags |= USSize;
00316     sizeHints.height = height;
00317     H = height;
00318   }
00319   if (XValue & flags) {
00320     if (XNegative & flags)
00321       x = DisplayWidth(dpy, DefaultScreen(dpy)) + x - sizeHints.width;
00322     sizeHints.flags |= USPosition;
00323     sizeHints.x = x;
00324   }
00325   if (YValue & flags) {
00326     if (YNegative & flags)
00327       y = DisplayHeight(dpy, DefaultScreen(dpy)) + y - sizeHints.height;
00328     sizeHints.flags |= USPosition;
00329     sizeHints.y = y;
00330   }
00331   if (keepAspect) {
00332     sizeHints.flags |= PAspect;
00333     sizeHints.min_aspect.x = sizeHints.max_aspect.x = W;
00334     sizeHints.min_aspect.y = sizeHints.max_aspect.y = H;
00335   }
00336   swa.colormap = cmap;
00337   swa.border_pixel = 0;
00338   swa.event_mask = ExposureMask | StructureNotifyMask |
00339     ButtonPressMask | Button1MotionMask | KeyPressMask;
00340   win = XCreateWindow(dpy, RootWindow(dpy, vi->screen),
00341     sizeHints.x, sizeHints.y, W, H,
00342     0, vi->depth, InputOutput, vi->visual,
00343     CWBorderPixel | CWColormap | CWEventMask, &swa);
00344   XSetStandardProperties(dpy, win, "OpenGLosaurus", "glxdino",
00345     None, argv, argc, &sizeHints);
00346   wmHints = XAllocWMHints();
00347   wmHints->initial_state = iconic ? IconicState : NormalState;
00348   wmHints->flags = StateHint;
00349   XSetWMHints(dpy, win, wmHints);
00350   wmDeleteWindow = XInternAtom(dpy, "WM_DELETE_WINDOW", False);
00351   XSetWMProtocols(dpy, win, &wmDeleteWindow, 1);
00352   glXMakeCurrent(dpy, win, cx);
00353   makeDinosaur();
00354   contextInit();
00355   XMapWindow(dpy, win);
00356   for (;;) {
00357     do {
00358       XNextEvent(dpy, &event);
00359       switch (event.type) {
00360       case ConfigureNotify:
00361         glViewport(0, 0,
00362           event.xconfigure.width, event.xconfigure.height);
00363         /* fall through... */
00364       case Expose:
00365         needRedraw = True;
00366         break;
00367       case MotionNotify:
00368         recalcModelView = True;
00369         angle -= (lastX - event.xmotion.x);
00370       case ButtonPress:
00371         lastX = event.xbutton.x;
00372         break;
00373       case KeyPress:
00374         ks = XLookupKeysym((XKeyEvent *) & event, 0);
00375         if (ks == XK_Escape)
00376           exit(0);
00377         break;
00378       case ClientMessage:
00379         if (event.xclient.data.l[0] == wmDeleteWindow)
00380           exit(0);
00381         break;
00382       }
00383     } while (XPending(dpy));  /* Loop to compress events. */
00384     if (recalcModelView) {
00385       glPopMatrix();    /* Pop old rotated matrix (or dummy
00386                            matrix if first time). */
00387       glPushMatrix();
00388       glRotatef(angle, 0.0, 1.0, 0.0);
00389       glTranslatef(-8, -8, -bodyWidth / 2);
00390       recalcModelView = False;
00391       needRedraw = True;
00392     }
00393     if (needRedraw) {
00394       redraw();
00395       needRedraw = False;
00396     }
00397   }
00398 }
00399 
00400 void
00401 redraw(void)
00402 {
00403    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
00404   glCallList(DINOSAUR);
00405   if (doubleBuffer)
00406     glXSwapBuffers(dpy, win);
00407   else
00408     glFlush();
00409 }