progs/xdemos/glxgears_fbconfig.c - fp2-dev/platform/external/mesa3d - Gitiles

 /*
  * Copyright (C) 1999-2001  Brian Paul   All Rights Reserved.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
  * to deal in the Software without restriction, including without limitation
  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  * and/or sell copies of the Software, and to permit persons to whom the
  * Software is furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice shall be included
  * in all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  */

 /**
  * \file glxgears_fbconfig.c
  * Yet-another-version of gears.  Originally ported to GLX by Brian Paul on
  * 23 March 2001.  Modified to use fbconfigs by Ian Romanick on 10 Feb 2004.
  *
  * Command line options:
  *    -info      print GL implementation information
  *
  * \author Brian Paul
  * \author Ian Romanick <idr@us.ibm.com>
  */


 #include <math.h>
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
 #include <X11/Xlib.h>
 #include <X11/keysym.h>
 #include <GL/gl.h>
 #include <GL/glx.h>
 #include <GL/glxext.h>
 #include <assert.h>
 #include "pbutil.h"

 /* I had to the the SGIX versions of these because for some reason glxext.h
  * doesn't define the core versions if GLX_VERSION_1_3 is defined, and glx.h
  * doesn't define them at all.  One or both header files is clearly broken.
  */
 static PFNGLXCHOOSEFBCONFIGSGIXPROC choose_fbconfig = NULL;
 static PFNGLXGETVISUALFROMFBCONFIGSGIXPROC get_visual_from_fbconfig = NULL;
 static PFNGLXCREATECONTEXTWITHCONFIGSGIXPROC create_new_context = NULL;

 #define BENCHMARK

 #ifdef BENCHMARK

 /* XXX this probably isn't very portable */

 #include <sys/time.h>
 #include <unistd.h>

 /* return current time (in seconds) */
 static int
 current_time(void)
 {
    struct timeval tv;
 #ifdef __VMS
    (void) gettimeofday(&tv, NULL );
 #else
    struct timezone tz;
    (void) gettimeofday(&tv, &tz);
 #endif
    return (int) tv.tv_sec;
 }

 #else /*BENCHMARK*/

 /* dummy */
 static int
 current_time(void)
 {
    return 0;
 }

 #endif /*BENCHMARK*/


 #ifndef M_PI
 #define M_PI 3.14159265
 #endif


 static GLfloat view_rotx = 20.0, view_roty = 30.0, view_rotz = 0.0;
 static GLint gear1, gear2, gear3;
 static GLfloat angle = 0.0;


 /*
  *
  *  Draw a gear wheel.  You'll probably want to call this function when
  *  building a display list since we do a lot of trig here.
  *
  *  Input:  inner_radius - radius of hole at center
  *          outer_radius - radius at center of teeth
  *          width - width of gear
  *          teeth - number of teeth
  *          tooth_depth - depth of tooth
  */
 static void
 gear(GLfloat inner_radius, GLfloat outer_radius, GLfloat width,
      GLint teeth, GLfloat tooth_depth)
 {
    GLint i;
    GLfloat r0, r1, r2;
    GLfloat angle, da;
    GLfloat u, v, len;

    r0 = inner_radius;
    r1 = outer_radius - tooth_depth / 2.0;
    r2 = outer_radius + tooth_depth / 2.0;

    da = 2.0 * M_PI / teeth / 4.0;

    glShadeModel(GL_FLAT);

    glNormal3f(0.0, 0.0, 1.0);

    /* draw front face */
    glBegin(GL_QUAD_STRIP);
    for (i = 0; i <= teeth; i++) {
       angle = i * 2.0 * M_PI / teeth;
       glVertex3f(r0 * cos(angle), r0 * sin(angle), width * 0.5);
       glVertex3f(r1 * cos(angle), r1 * sin(angle), width * 0.5);
       if (i < teeth) {
 	 glVertex3f(r0 * cos(angle), r0 * sin(angle), width * 0.5);
 	 glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da),
 		    width * 0.5);
       }
    }
    glEnd();

    /* draw front sides of teeth */
    glBegin(GL_QUADS);
    da = 2.0 * M_PI / teeth / 4.0;
    for (i = 0; i < teeth; i++) {
       angle = i * 2.0 * M_PI / teeth;

       glVertex3f(r1 * cos(angle), r1 * sin(angle), width * 0.5);
       glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), width * 0.5);
       glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da),
 		 width * 0.5);
       glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da),
 		 width * 0.5);
    }
    glEnd();

    glNormal3f(0.0, 0.0, -1.0);

    /* draw back face */
    glBegin(GL_QUAD_STRIP);
    for (i = 0; i <= teeth; i++) {
       angle = i * 2.0 * M_PI / teeth;
       glVertex3f(r1 * cos(angle), r1 * sin(angle), -width * 0.5);
       glVertex3f(r0 * cos(angle), r0 * sin(angle), -width * 0.5);
       if (i < teeth) {
 	 glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da),
 		    -width * 0.5);
 	 glVertex3f(r0 * cos(angle), r0 * sin(angle), -width * 0.5);
       }
    }
    glEnd();

    /* draw back sides of teeth */
    glBegin(GL_QUADS);
    da = 2.0 * M_PI / teeth / 4.0;
    for (i = 0; i < teeth; i++) {
       angle = i * 2.0 * M_PI / teeth;

       glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da),
 		 -width * 0.5);
       glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da),
 		 -width * 0.5);
       glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), -width * 0.5);
       glVertex3f(r1 * cos(angle), r1 * sin(angle), -width * 0.5);
    }
    glEnd();

    /* draw outward faces of teeth */
    glBegin(GL_QUAD_STRIP);
    for (i = 0; i < teeth; i++) {
       angle = i * 2.0 * M_PI / teeth;

       glVertex3f(r1 * cos(angle), r1 * sin(angle), width * 0.5);
       glVertex3f(r1 * cos(angle), r1 * sin(angle), -width * 0.5);
       u = r2 * cos(angle + da) - r1 * cos(angle);
       v = r2 * sin(angle + da) - r1 * sin(angle);
       len = sqrt(u * u + v * v);
       u /= len;
       v /= len;
       glNormal3f(v, -u, 0.0);
       glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), width * 0.5);
       glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), -width * 0.5);
       glNormal3f(cos(angle), sin(angle), 0.0);
       glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da),
 		 width * 0.5);
       glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da),
 		 -width * 0.5);
       u = r1 * cos(angle + 3 * da) - r2 * cos(angle + 2 * da);
       v = r1 * sin(angle + 3 * da) - r2 * sin(angle + 2 * da);
       glNormal3f(v, -u, 0.0);
       glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da),
 		 width * 0.5);
       glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da),
 		 -width * 0.5);
       glNormal3f(cos(angle), sin(angle), 0.0);
    }

    glVertex3f(r1 * cos(0), r1 * sin(0), width * 0.5);
    glVertex3f(r1 * cos(0), r1 * sin(0), -width * 0.5);

    glEnd();

    glShadeModel(GL_SMOOTH);

    /* draw inside radius cylinder */
    glBegin(GL_QUAD_STRIP);
    for (i = 0; i <= teeth; i++) {
       angle = i * 2.0 * M_PI / teeth;
       glNormal3f(-cos(angle), -sin(angle), 0.0);
       glVertex3f(r0 * cos(angle), r0 * sin(angle), -width * 0.5);
       glVertex3f(r0 * cos(angle), r0 * sin(angle), width * 0.5);
    }
    glEnd();
 }


 static void
 draw(void)
 {
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glPushMatrix();
    glRotatef(view_rotx, 1.0, 0.0, 0.0);
    glRotatef(view_roty, 0.0, 1.0, 0.0);
    glRotatef(view_rotz, 0.0, 0.0, 1.0);

    glPushMatrix();
    glTranslatef(-3.0, -2.0, 0.0);
    glRotatef(angle, 0.0, 0.0, 1.0);
    glCallList(gear1);
    glPopMatrix();

    glPushMatrix();
    glTranslatef(3.1, -2.0, 0.0);
    glRotatef(-2.0 * angle - 9.0, 0.0, 0.0, 1.0);
    glCallList(gear2);
    glPopMatrix();

    glPushMatrix();
    glTranslatef(-3.1, 4.2, 0.0);
    glRotatef(-2.0 * angle - 25.0, 0.0, 0.0, 1.0);
    glCallList(gear3);
    glPopMatrix();

    glPopMatrix();
 }


 /* new window size or exposure */
 static void
 reshape(int width, int height)
 {
    GLfloat h = (GLfloat) height / (GLfloat) width;

    glViewport(0, 0, (GLint) width, (GLint) height);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glFrustum(-1.0, 1.0, -h, h, 5.0, 60.0);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    glTranslatef(0.0, 0.0, -40.0);
 }


 static void
 init(void)
 {
    static GLfloat pos[4] = { 5.0, 5.0, 10.0, 0.0 };
    static GLfloat red[4] = { 0.8, 0.1, 0.0, 1.0 };
    static GLfloat green[4] = { 0.0, 0.8, 0.2, 1.0 };
    static GLfloat blue[4] = { 0.2, 0.2, 1.0, 1.0 };

    glLightfv(GL_LIGHT0, GL_POSITION, pos);
    glEnable(GL_CULL_FACE);
    glEnable(GL_LIGHTING);
    glEnable(GL_LIGHT0);
    glEnable(GL_DEPTH_TEST);

    /* make the gears */
    gear1 = glGenLists(1);
    glNewList(gear1, GL_COMPILE);
    glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, red);
    gear(1.0, 4.0, 1.0, 20, 0.7);
    glEndList();

    gear2 = glGenLists(1);
    glNewList(gear2, GL_COMPILE);
    glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, green);
    gear(0.5, 2.0, 2.0, 10, 0.7);
    glEndList();

    gear3 = glGenLists(1);
    glNewList(gear3, GL_COMPILE);
    glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, blue);
    gear(1.3, 2.0, 0.5, 10, 0.7);
    glEndList();

    glEnable(GL_NORMALIZE);
 }


 /**
  * Initialize fbconfig related function pointers.
  */
 static void
 init_fbconfig_functions(Display *dpy, int scrnum)
 {
    const char * glx_extensions;
    const char * match;
    static const char ext_name[] = "GLX_SGIX_fbconfig";
    const size_t len = strlen( ext_name );
    int major;
    int minor;
    GLboolean ext_version_supported;
    GLboolean glx_1_3_supported;


    /* Determine if GLX 1.3 or greater is supported.
     */
    glXQueryVersion(dpy, & major, & minor);
    glx_1_3_supported = (major == 1) && (minor >= 3);

    /* Determine if GLX_SGIX_fbconfig is supported.
     */
    glx_extensions = glXQueryExtensionsString(dpy, scrnum);
    match = strstr( glx_extensions, ext_name );

    ext_version_supported = (match != NULL)
        && ((match[len] == '\0') || (match[len] == ' '));

    printf( "GLX 1.3 is %ssupported.\n",
 	   (glx_1_3_supported) ? "" : "not " );
    printf( "%s is %ssupported.\n",
 	   ext_name, (ext_version_supported) ? "" : "not " );

    if ( glx_1_3_supported ) {
       choose_fbconfig = (PFNGLXCHOOSEFBCONFIGSGIXPROC) glXGetProcAddressARB(
 		(GLbyte *) "glXChooseFBConfig");
       get_visual_from_fbconfig = (PFNGLXGETVISUALFROMFBCONFIGSGIXPROC) glXGetProcAddressARB(
 		(GLbyte *) "glXGetVisualFromFBConfig");
       create_new_context = (PFNGLXCREATECONTEXTWITHCONFIGSGIXPROC) glXGetProcAddressARB(
 		(GLbyte *) "glXCreateNewContext");
    }
    else if ( ext_version_supported ) {
       choose_fbconfig = (PFNGLXCHOOSEFBCONFIGSGIXPROC) glXGetProcAddressARB(
 		(GLbyte *) "glXChooseFBConfigSGIX");
       get_visual_from_fbconfig = (PFNGLXGETVISUALFROMFBCONFIGSGIXPROC) glXGetProcAddressARB(
 		(GLbyte *) "glXGetVisualFromFBConfigSGIX");
       create_new_context = (PFNGLXCREATECONTEXTWITHCONFIGSGIXPROC) glXGetProcAddressARB(
 		(GLbyte *) "glXCreateContextWithConfigSGIX");
    }
    else {
       printf( "This demo requires either GLX 1.3 or %s be supported.\n",
 	      ext_name );
       exit(1);
    }

    if ( choose_fbconfig == NULL ) {
       printf( "glXChooseFBConfig not found!\n" );
       exit(1);
    }

    if ( get_visual_from_fbconfig == NULL ) {
       printf( "glXGetVisualFromFBConfig not found!\n" );
       exit(1);
    }

    if ( create_new_context == NULL ) {
       printf( "glXCreateNewContext not found!\n" );
       exit(1);
    }
 }


 /*
  * Create an RGB, double-buffered window.
  * Return the window and context handles.
  */
 static void
 make_window( Display *dpy, const char *name,
              int x, int y, int width, int height,
              Window *winRet, GLXContext *ctxRet)
 {
    int attrib[] = { GLX_DRAWABLE_TYPE, GLX_WINDOW_BIT,
 		    GLX_RENDER_TYPE,   GLX_RGBA_BIT,
 		    GLX_RED_SIZE,      1,
 		    GLX_GREEN_SIZE,    1,
 		    GLX_BLUE_SIZE,     1,
 		    GLX_DOUBLEBUFFER,  GL_TRUE,
 		    GLX_DEPTH_SIZE,    1,
 		    None };
    GLXFBConfig * fbconfig;
    int num_configs;
    int scrnum;
    int i;
    XSetWindowAttributes attr;
    unsigned long mask;
    Window root;
    Window win;
    GLXContext ctx;
    XVisualInfo *visinfo;

    scrnum = DefaultScreen( dpy );
    root = RootWindow( dpy, scrnum );

    init_fbconfig_functions(dpy, scrnum);
    fbconfig = (*choose_fbconfig)(dpy, scrnum, attrib, & num_configs);
    if (fbconfig == NULL) {
       printf("Error: couldn't get an RGB, Double-buffered visual\n");
       exit(1);
    }

    printf("\nThe following fbconfigs meet the requirements.  The first one "
 	  "will be used.\n\n");
    for ( i = 0 ; i < num_configs ; i++ ) {
       PrintFBConfigInfo(dpy, fbconfig[i], GL_TRUE);
    }

    /* window attributes */
    visinfo = (*get_visual_from_fbconfig)(dpy, fbconfig[0]);
    assert(visinfo != NULL);
    attr.background_pixel = 0;
    attr.border_pixel = 0;
    attr.colormap = XCreateColormap( dpy, root, visinfo->visual, AllocNone);
    attr.event_mask = StructureNotifyMask | ExposureMask | KeyPressMask;
    mask = CWBackPixel | CWBorderPixel | CWColormap | CWEventMask;

    win = XCreateWindow( dpy, root, 0, 0, width, height,
 		        0, visinfo->depth, InputOutput,
 		        visinfo->visual, mask, &attr );

    /* set hints and properties */
    {
       XSizeHints sizehints;
       sizehints.x = x;
       sizehints.y = y;
       sizehints.width  = width;
       sizehints.height = height;
       sizehints.flags = USSize | USPosition;
       XSetNormalHints(dpy, win, &sizehints);
       XSetStandardProperties(dpy, win, name, name,
                               None, (char **)NULL, 0, &sizehints);
    }

    ctx = (*create_new_context)(dpy, fbconfig[0], GLX_RGBA_BIT, NULL, GL_TRUE);
    if (!ctx) {
       printf("Error: glXCreateNewContext failed\n");
       exit(1);
    }

    XFree(fbconfig);

    *winRet = win;
    *ctxRet = ctx;
 }


 static void
 event_loop(Display *dpy, Window win)
 {
    while (1) {
       while (XPending(dpy) > 0) {
          XEvent event;
          XNextEvent(dpy, &event);
          switch (event.type) {
 	 case Expose:
             /* we'll redraw below */
 	    break;
 	 case ConfigureNotify:
 	    reshape(event.xconfigure.width, event.xconfigure.height);
 	    break;
          case KeyPress:
             {
                char buffer[10];
                int r, code;
                code = XLookupKeysym(&event.xkey, 0);
                if (code == XK_Left) {
                   view_roty += 5.0;
                }
                else if (code == XK_Right) {
                   view_roty -= 5.0;
                }
                else if (code == XK_Up) {
                   view_rotx += 5.0;
                }
                else if (code == XK_Down) {
                   view_rotx -= 5.0;
                }
                else {
                   r = XLookupString(&event.xkey, buffer, sizeof(buffer),
                                     NULL, NULL);
                   if (buffer[0] == 27) {
                      /* escape */
                      return;
                   }
                }
             }
          }
       }

       /* next frame */
       angle += 2.0;

       draw();
       glXSwapBuffers(dpy, win);

       /* calc framerate */
       {
          static int t0 = -1;
          static int frames = 0;
          int t = current_time();

          if (t0 < 0)
             t0 = t;

          frames++;

          if (t - t0 >= 5.0) {
             GLfloat seconds = t - t0;
             GLfloat fps = frames / seconds;
             printf("%d frames in %3.1f seconds = %6.3f FPS\n", frames, seconds,
                    fps);
             t0 = t;
             frames = 0;
          }
       }
    }
 }


 int
 main(int argc, char *argv[])
 {
    Display *dpy;
    Window win;
    GLXContext ctx;
    char *dpyName = ":0";
    GLboolean printInfo = GL_FALSE;
    int i;

    for (i = 1; i < argc; i++) {
       if (strcmp(argv[i], "-display") == 0) {
          dpyName = argv[i+1];
          i++;
       }
       else if (strcmp(argv[i], "-info") == 0) {
          printInfo = GL_TRUE;
       }
    }

    dpy = XOpenDisplay(dpyName);
    if (!dpy) {
       printf("Error: couldn't open display %s\n", dpyName);
       return -1;
    }

    make_window(dpy, "glxgears", 0, 0, 300, 300, &win, &ctx);
    XMapWindow(dpy, win);
    glXMakeCurrent(dpy, win, ctx);

    if (printInfo) {
       printf("GL_RENDERER   = %s\n", (char *) glGetString(GL_RENDERER));
       printf("GL_VERSION    = %s\n", (char *) glGetString(GL_VERSION));
       printf("GL_VENDOR     = %s\n", (char *) glGetString(GL_VENDOR));
       printf("GL_EXTENSIONS = %s\n", (char *) glGetString(GL_EXTENSIONS));
    }

    init();

    event_loop(dpy, win);

    glXDestroyContext(dpy, ctx);
    XDestroyWindow(dpy, win);
    XCloseDisplay(dpy);

    return 0;
 }
	/*
	* Copyright (C) 1999-2001 Brian Paul All Rights Reserved.
	*
	* Permission is hereby granted, free of charge, to any person obtaining a
	* copy of this software and associated documentation files (the "Software"),
	* to deal in the Software without restriction, including without limitation
	* the rights to use, copy, modify, merge, publish, distribute, sublicense,
	* and/or sell copies of the Software, and to permit persons to whom the
	* Software is furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice shall be included
	* in all copies or substantial portions of the Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
	* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
	* BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
	* AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
	* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
	*/

	/**
	* \file glxgears_fbconfig.c
	* Yet-another-version of gears. Originally ported to GLX by Brian Paul on
	* 23 March 2001. Modified to use fbconfigs by Ian Romanick on 10 Feb 2004.
	*
	* Command line options:
	* -info print GL implementation information
	*
	* \author Brian Paul
	* \author Ian Romanick <idr@us.ibm.com>
	*/


	#include <math.h>
	#include <stdlib.h>
	#include <stdio.h>
	#include <string.h>
	#include <X11/Xlib.h>
	#include <X11/keysym.h>
	#include <GL/gl.h>
	#include <GL/glx.h>
	#include <GL/glxext.h>
	#include <assert.h>
	#include "pbutil.h"

	/* I had to the the SGIX versions of these because for some reason glxext.h
	* doesn't define the core versions if GLX_VERSION_1_3 is defined, and glx.h
	* doesn't define them at all. One or both header files is clearly broken.
	*/
	static PFNGLXCHOOSEFBCONFIGSGIXPROC choose_fbconfig = NULL;
	static PFNGLXGETVISUALFROMFBCONFIGSGIXPROC get_visual_from_fbconfig = NULL;
	static PFNGLXCREATECONTEXTWITHCONFIGSGIXPROC create_new_context = NULL;

	#define BENCHMARK

	#ifdef BENCHMARK

	/* XXX this probably isn't very portable */

	#include <sys/time.h>
	#include <unistd.h>

	/* return current time (in seconds) */
	static int
	current_time(void)
	{
	struct timeval tv;
	#ifdef __VMS
	(void) gettimeofday(&tv, NULL );
	#else
	struct timezone tz;
	(void) gettimeofday(&tv, &tz);
	#endif
	return (int) tv.tv_sec;
	}

	#else /BENCHMARK/

	/* dummy */
	static int
	current_time(void)
	{
	return 0;
	}

	#endif /BENCHMARK/



	#ifndef M_PI
	#define M_PI 3.14159265
	#endif


	static GLfloat view_rotx = 20.0, view_roty = 30.0, view_rotz = 0.0;
	static GLint gear1, gear2, gear3;
	static GLfloat angle = 0.0;


	/*
	*
	* Draw a gear wheel. You'll probably want to call this function when
	* building a display list since we do a lot of trig here.
	*
	* Input: inner_radius - radius of hole at center
	* outer_radius - radius at center of teeth
	* width - width of gear
	* teeth - number of teeth
	* tooth_depth - depth of tooth
	*/
	static void
	gear(GLfloat inner_radius, GLfloat outer_radius, GLfloat width,
	GLint teeth, GLfloat tooth_depth)
	{
	GLint i;
	GLfloat r0, r1, r2;
	GLfloat angle, da;
	GLfloat u, v, len;

	r0 = inner_radius;
	r1 = outer_radius - tooth_depth / 2.0;
	r2 = outer_radius + tooth_depth / 2.0;

	da = 2.0 * M_PI / teeth / 4.0;

	glShadeModel(GL_FLAT);

	glNormal3f(0.0, 0.0, 1.0);

	/* draw front face */
	glBegin(GL_QUAD_STRIP);
	for (i = 0; i <= teeth; i++) {
	angle = i * 2.0 * M_PI / teeth;
	glVertex3f(r0 * cos(angle), r0 * sin(angle), width * 0.5);
	glVertex3f(r1 * cos(angle), r1 * sin(angle), width * 0.5);
	if (i < teeth) {
	glVertex3f(r0 * cos(angle), r0 * sin(angle), width * 0.5);
	glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da),
	width * 0.5);
	}
	}
	glEnd();

	/* draw front sides of teeth */
	glBegin(GL_QUADS);
	da = 2.0 * M_PI / teeth / 4.0;
	for (i = 0; i < teeth; i++) {
	angle = i * 2.0 * M_PI / teeth;

	glVertex3f(r1 * cos(angle), r1 * sin(angle), width * 0.5);
	glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), width * 0.5);
	glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da),
	width * 0.5);
	glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da),
	width * 0.5);
	}
	glEnd();

	glNormal3f(0.0, 0.0, -1.0);

	/* draw back face */
	glBegin(GL_QUAD_STRIP);
	for (i = 0; i <= teeth; i++) {
	angle = i * 2.0 * M_PI / teeth;
	glVertex3f(r1 * cos(angle), r1 * sin(angle), -width * 0.5);
	glVertex3f(r0 * cos(angle), r0 * sin(angle), -width * 0.5);
	if (i < teeth) {
	glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da),
	-width * 0.5);
	glVertex3f(r0 * cos(angle), r0 * sin(angle), -width * 0.5);
	}
	}
	glEnd();

	/* draw back sides of teeth */
	glBegin(GL_QUADS);
	da = 2.0 * M_PI / teeth / 4.0;
	for (i = 0; i < teeth; i++) {
	angle = i * 2.0 * M_PI / teeth;

	glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da),
	-width * 0.5);
	glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da),
	-width * 0.5);
	glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), -width * 0.5);
	glVertex3f(r1 * cos(angle), r1 * sin(angle), -width * 0.5);
	}
	glEnd();

	/* draw outward faces of teeth */
	glBegin(GL_QUAD_STRIP);
	for (i = 0; i < teeth; i++) {
	angle = i * 2.0 * M_PI / teeth;

	glVertex3f(r1 * cos(angle), r1 * sin(angle), width * 0.5);
	glVertex3f(r1 * cos(angle), r1 * sin(angle), -width * 0.5);
	u = r2 * cos(angle + da) - r1 * cos(angle);
	v = r2 * sin(angle + da) - r1 * sin(angle);
	len = sqrt(u * u + v * v);
	u /= len;
	v /= len;
	glNormal3f(v, -u, 0.0);
	glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), width * 0.5);
	glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), -width * 0.5);
	glNormal3f(cos(angle), sin(angle), 0.0);
	glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da),
	width * 0.5);
	glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da),
	-width * 0.5);
	u = r1 * cos(angle + 3 * da) - r2 * cos(angle + 2 * da);
	v = r1 * sin(angle + 3 * da) - r2 * sin(angle + 2 * da);
	glNormal3f(v, -u, 0.0);
	glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da),
	width * 0.5);
	glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da),
	-width * 0.5);
	glNormal3f(cos(angle), sin(angle), 0.0);
	}

	glVertex3f(r1 * cos(0), r1 * sin(0), width * 0.5);
	glVertex3f(r1 * cos(0), r1 * sin(0), -width * 0.5);

	glEnd();

	glShadeModel(GL_SMOOTH);

	/* draw inside radius cylinder */
	glBegin(GL_QUAD_STRIP);
	for (i = 0; i <= teeth; i++) {
	angle = i * 2.0 * M_PI / teeth;
	glNormal3f(-cos(angle), -sin(angle), 0.0);
	glVertex3f(r0 * cos(angle), r0 * sin(angle), -width * 0.5);
	glVertex3f(r0 * cos(angle), r0 * sin(angle), width * 0.5);
	}
	glEnd();
	}


	static void
	draw(void)
	{
	glClear(GL_COLOR_BUFFER_BIT \| GL_DEPTH_BUFFER_BIT);

	glPushMatrix();
	glRotatef(view_rotx, 1.0, 0.0, 0.0);
	glRotatef(view_roty, 0.0, 1.0, 0.0);
	glRotatef(view_rotz, 0.0, 0.0, 1.0);

	glPushMatrix();
	glTranslatef(-3.0, -2.0, 0.0);
	glRotatef(angle, 0.0, 0.0, 1.0);
	glCallList(gear1);
	glPopMatrix();

	glPushMatrix();
	glTranslatef(3.1, -2.0, 0.0);
	glRotatef(-2.0 * angle - 9.0, 0.0, 0.0, 1.0);
	glCallList(gear2);
	glPopMatrix();

	glPushMatrix();
	glTranslatef(-3.1, 4.2, 0.0);
	glRotatef(-2.0 * angle - 25.0, 0.0, 0.0, 1.0);
	glCallList(gear3);
	glPopMatrix();

	glPopMatrix();
	}


	/* new window size or exposure */
	static void
	reshape(int width, int height)
	{
	GLfloat h = (GLfloat) height / (GLfloat) width;

	glViewport(0, 0, (GLint) width, (GLint) height);
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	glFrustum(-1.0, 1.0, -h, h, 5.0, 60.0);
	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
	glTranslatef(0.0, 0.0, -40.0);
	}


	static void
	init(void)
	{
	static GLfloat pos[4] = { 5.0, 5.0, 10.0, 0.0 };
	static GLfloat red[4] = { 0.8, 0.1, 0.0, 1.0 };
	static GLfloat green[4] = { 0.0, 0.8, 0.2, 1.0 };
	static GLfloat blue[4] = { 0.2, 0.2, 1.0, 1.0 };

	glLightfv(GL_LIGHT0, GL_POSITION, pos);
	glEnable(GL_CULL_FACE);
	glEnable(GL_LIGHTING);
	glEnable(GL_LIGHT0);
	glEnable(GL_DEPTH_TEST);

	/* make the gears */
	gear1 = glGenLists(1);
	glNewList(gear1, GL_COMPILE);
	glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, red);
	gear(1.0, 4.0, 1.0, 20, 0.7);
	glEndList();

	gear2 = glGenLists(1);
	glNewList(gear2, GL_COMPILE);
	glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, green);
	gear(0.5, 2.0, 2.0, 10, 0.7);
	glEndList();

	gear3 = glGenLists(1);
	glNewList(gear3, GL_COMPILE);
	glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, blue);
	gear(1.3, 2.0, 0.5, 10, 0.7);
	glEndList();

	glEnable(GL_NORMALIZE);
	}


	/**
	* Initialize fbconfig related function pointers.
	*/
	static void
	init_fbconfig_functions(Display *dpy, int scrnum)
	{
	const char * glx_extensions;
	const char * match;
	static const char ext_name[] = "GLX_SGIX_fbconfig";
	const size_t len = strlen( ext_name );
	int major;
	int minor;
	GLboolean ext_version_supported;
	GLboolean glx_1_3_supported;


	/* Determine if GLX 1.3 or greater is supported.
	*/
	glXQueryVersion(dpy, & major, & minor);
	glx_1_3_supported = (major == 1) && (minor >= 3);

	/* Determine if GLX_SGIX_fbconfig is supported.
	*/
	glx_extensions = glXQueryExtensionsString(dpy, scrnum);
	match = strstr( glx_extensions, ext_name );

	ext_version_supported = (match != NULL)
	&& ((match[len] == '\0') \|\| (match[len] == ' '));

	printf( "GLX 1.3 is %ssupported.\n",
	(glx_1_3_supported) ? "" : "not " );
	printf( "%s is %ssupported.\n",
	ext_name, (ext_version_supported) ? "" : "not " );

	if ( glx_1_3_supported ) {
	choose_fbconfig = (PFNGLXCHOOSEFBCONFIGSGIXPROC) glXGetProcAddressARB(
	(GLbyte *) "glXChooseFBConfig");
	get_visual_from_fbconfig = (PFNGLXGETVISUALFROMFBCONFIGSGIXPROC) glXGetProcAddressARB(
	(GLbyte *) "glXGetVisualFromFBConfig");
	create_new_context = (PFNGLXCREATECONTEXTWITHCONFIGSGIXPROC) glXGetProcAddressARB(
	(GLbyte *) "glXCreateNewContext");
	}
	else if ( ext_version_supported ) {
	choose_fbconfig = (PFNGLXCHOOSEFBCONFIGSGIXPROC) glXGetProcAddressARB(
	(GLbyte *) "glXChooseFBConfigSGIX");
	get_visual_from_fbconfig = (PFNGLXGETVISUALFROMFBCONFIGSGIXPROC) glXGetProcAddressARB(
	(GLbyte *) "glXGetVisualFromFBConfigSGIX");
	create_new_context = (PFNGLXCREATECONTEXTWITHCONFIGSGIXPROC) glXGetProcAddressARB(
	(GLbyte *) "glXCreateContextWithConfigSGIX");
	}
	else {
	printf( "This demo requires either GLX 1.3 or %s be supported.\n",
	ext_name );
	exit(1);
	}

	if ( choose_fbconfig == NULL ) {
	printf( "glXChooseFBConfig not found!\n" );
	exit(1);
	}

	if ( get_visual_from_fbconfig == NULL ) {
	printf( "glXGetVisualFromFBConfig not found!\n" );
	exit(1);
	}

	if ( create_new_context == NULL ) {
	printf( "glXCreateNewContext not found!\n" );
	exit(1);
	}
	}


	/*
	* Create an RGB, double-buffered window.
	* Return the window and context handles.
	*/
	static void
	make_window( Display dpy, const char name,
	int x, int y, int width, int height,
	Window winRet, GLXContext ctxRet)
	{
	int attrib[] = { GLX_DRAWABLE_TYPE, GLX_WINDOW_BIT,
	GLX_RENDER_TYPE, GLX_RGBA_BIT,
	GLX_RED_SIZE, 1,
	GLX_GREEN_SIZE, 1,
	GLX_BLUE_SIZE, 1,
	GLX_DOUBLEBUFFER, GL_TRUE,
	GLX_DEPTH_SIZE, 1,
	None };
	GLXFBConfig * fbconfig;
	int num_configs;
	int scrnum;
	int i;
	XSetWindowAttributes attr;
	unsigned long mask;
	Window root;
	Window win;
	GLXContext ctx;
	XVisualInfo *visinfo;

	scrnum = DefaultScreen( dpy );
	root = RootWindow( dpy, scrnum );

	init_fbconfig_functions(dpy, scrnum);
	fbconfig = (*choose_fbconfig)(dpy, scrnum, attrib, & num_configs);
	if (fbconfig == NULL) {
	printf("Error: couldn't get an RGB, Double-buffered visual\n");
	exit(1);
	}

	printf("\nThe following fbconfigs meet the requirements. The first one "
	"will be used.\n\n");
	for ( i = 0 ; i < num_configs ; i++ ) {
	PrintFBConfigInfo(dpy, fbconfig[i], GL_TRUE);
	}

	/* window attributes */
	visinfo = (*get_visual_from_fbconfig)(dpy, fbconfig[0]);
	assert(visinfo != NULL);
	attr.background_pixel = 0;
	attr.border_pixel = 0;
	attr.colormap = XCreateColormap( dpy, root, visinfo->visual, AllocNone);
	attr.event_mask = StructureNotifyMask \| ExposureMask \| KeyPressMask;
	mask = CWBackPixel \| CWBorderPixel \| CWColormap \| CWEventMask;

	win = XCreateWindow( dpy, root, 0, 0, width, height,
	0, visinfo->depth, InputOutput,
	visinfo->visual, mask, &attr );

	/* set hints and properties */
	{
	XSizeHints sizehints;
	sizehints.x = x;
	sizehints.y = y;
	sizehints.width = width;
	sizehints.height = height;
	sizehints.flags = USSize \| USPosition;
	XSetNormalHints(dpy, win, &sizehints);
	XSetStandardProperties(dpy, win, name, name,
	None, (char **)NULL, 0, &sizehints);
	}

	ctx = (*create_new_context)(dpy, fbconfig[0], GLX_RGBA_BIT, NULL, GL_TRUE);
	if (!ctx) {
	printf("Error: glXCreateNewContext failed\n");
	exit(1);
	}

	XFree(fbconfig);

	*winRet = win;
	*ctxRet = ctx;
	}


	static void
	event_loop(Display *dpy, Window win)
	{
	while (1) {
	while (XPending(dpy) > 0) {
	XEvent event;
	XNextEvent(dpy, &event);
	switch (event.type) {
	case Expose:
	/* we'll redraw below */
	break;
	case ConfigureNotify:
	reshape(event.xconfigure.width, event.xconfigure.height);
	break;
	case KeyPress:
	{
	char buffer[10];
	int r, code;
	code = XLookupKeysym(&event.xkey, 0);
	if (code == XK_Left) {
	view_roty += 5.0;
	}
	else if (code == XK_Right) {
	view_roty -= 5.0;
	}
	else if (code == XK_Up) {
	view_rotx += 5.0;
	}
	else if (code == XK_Down) {
	view_rotx -= 5.0;
	}
	else {
	r = XLookupString(&event.xkey, buffer, sizeof(buffer),
	NULL, NULL);
	if (buffer[0] == 27) {
	/* escape */
	return;
	}
	}
	}
	}
	}

	/* next frame */
	angle += 2.0;

	draw();
	glXSwapBuffers(dpy, win);

	/* calc framerate */
	{
	static int t0 = -1;
	static int frames = 0;
	int t = current_time();

	if (t0 < 0)
	t0 = t;

	frames++;

	if (t - t0 >= 5.0) {
	GLfloat seconds = t - t0;
	GLfloat fps = frames / seconds;
	printf("%d frames in %3.1f seconds = %6.3f FPS\n", frames, seconds,
	fps);
	t0 = t;
	frames = 0;
	}
	}
	}
	}


	int
	main(int argc, char *argv[])
	{
	Display *dpy;
	Window win;
	GLXContext ctx;
	char *dpyName = ":0";
	GLboolean printInfo = GL_FALSE;
	int i;

	for (i = 1; i < argc; i++) {
	if (strcmp(argv[i], "-display") == 0) {
	dpyName = argv[i+1];
	i++;
	}
	else if (strcmp(argv[i], "-info") == 0) {
	printInfo = GL_TRUE;
	}
	}

	dpy = XOpenDisplay(dpyName);
	if (!dpy) {
	printf("Error: couldn't open display %s\n", dpyName);
	return -1;
	}

	make_window(dpy, "glxgears", 0, 0, 300, 300, &win, &ctx);
	XMapWindow(dpy, win);
	glXMakeCurrent(dpy, win, ctx);

	if (printInfo) {
	printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
	printf("GL_VERSION = %s\n", (char *) glGetString(GL_VERSION));
	printf("GL_VENDOR = %s\n", (char *) glGetString(GL_VENDOR));
	printf("GL_EXTENSIONS = %s\n", (char *) glGetString(GL_EXTENSIONS));
	}

	init();

	event_loop(dpy, win);

	glXDestroyContext(dpy, ctx);
	XDestroyWindow(dpy, win);
	XCloseDisplay(dpy);

	return 0;
	}