Remove all the swap_control stuff from glxgears demo (restored to vers 1.2).

New glxswapcontrol.c file added.

3 files changed, 833 insertions, 331 deletions

diff --git a/progs/xdemos/Makefile.X11 b/progs/xdemos/Makefile.X11
index 36fa9e5..264fc24 100644
--- a/progs/xdemos/Makefile.X11
+++ b/progs/xdemos/Makefile.X11
@@ -17,6 +17,7 @@ PROGS = glthreads \
 	glxheads \
 	glxinfo \
 	glxpixmap \
+	glxswapcontrol \
 	manywin \
 	offset \
 	pbinfo \
diff --git a/progs/xdemos/glxgears.c b/progs/xdemos/glxgears.c
index da2ba1e..5969151 100644
--- a/progs/xdemos/glxgears.c
+++ b/progs/xdemos/glxgears.c
@@ -23,15 +23,9 @@
  * This is a port of the infamous "gears" demo to straight GLX (i.e. no GLUT)
  * Port by Brian Paul  23 March 2001
  *
- * Modified by Ian Romanick <idr@us.ibm.com> 09 April 2003 to support
- * GLX_{MESA,SGI}_swap_control and GLX_OML_sync_control.
- *
  * Command line options:
- *    -display       Name of the display to use.
- *    -info          print GL implementation information
- *    -swap N        Attempt to set the swap interval to 1/N second
- *    -forcegetrate  Get the display refresh rate even if the required GLX
- *                   extension is not supported.
+ *    -info      print GL implementation information
+ *
  */
 
 
@@ -41,32 +35,12 @@
 #include <string.h>
 #include <X11/Xlib.h>
 #include <X11/keysym.h>
-#ifndef __VMS
-# include <stdint.h>
-#endif
-# define GLX_GLXEXT_PROTOTYPES
 #include <GL/gl.h>
 #include <GL/glx.h>
 
-#ifndef GLX_MESA_swap_control
-typedef GLint ( * PFNGLXSWAPINTERVALMESAPROC) (unsigned interval);
-typedef GLint ( * PFNGLXGETSWAPINTERVALMESAPROC) ( void );
-#endif
-
-#if !defined( GLX_OML_sync_control ) && defined( _STDINT_H )
-#define GLX_OML_sync_control 1
-typedef Bool ( * PFNGLXGETMSCRATEOMLPROC) (Display *dpy, GLXDrawable drawable, int32_t *numerator, int32_t *denominator);
-#endif
-
-#ifndef GLX_MESA_swap_frame_usage
-#define GLX_MESA_swap_frame_usage 1
-typedef int ( * PFNGLXGETFRAMEUSAGEMESAPROC) (Display *dpy, GLXDrawable drawable, float * usage );
-#endif
 
 #define BENCHMARK
 
-PFNGLXGETFRAMEUSAGEMESAPROC get_frame_usage = NULL;
-
 #ifdef BENCHMARK
 
 /* XXX this probably isn't very portable */
@@ -74,8 +48,6 @@ PFNGLXGETFRAMEUSAGEMESAPROC get_frame_usage = NULL;
 #include <sys/time.h>
 #include <unistd.h>
 
-#define NUL '\0'
-
 /* return current time (in seconds) */
 static int
 current_time(void)
@@ -112,16 +84,6 @@ static GLfloat view_rotx = 20.0, view_roty = 30.0, view_rotz = 0.0;
 static GLint gear1, gear2, gear3;
 static GLfloat angle = 0.0;
 
-static GLboolean has_OML_sync_control = GL_FALSE;
-static GLboolean has_SGI_swap_control = GL_FALSE;
-static GLboolean has_MESA_swap_control = GL_FALSE;
-static GLboolean has_MESA_swap_frame_usage = GL_FALSE;
-
-static char ** extension_table = NULL;
-static unsigned num_extensions;
-
-static GLboolean use_ztrick = GL_FALSE;
-static GLfloat   aspect;
 
 /*
  *
@@ -265,65 +227,7 @@ gear(GLfloat inner_radius, GLfloat outer_radius, GLfloat width,
 static void
 draw(void)
 {
-   if ( use_ztrick ) {
-      static GLboolean flip = GL_FALSE;
-      static const GLfloat vert[4][3] = {
-	 { -1, -1, -0.999 },
-	 {  1, -1, -0.999 },
-	 {  1,  1, -0.999 },
-	 { -1,  1, -0.999 }
-      };
-      static const GLfloat col[4][3] = {
-	 { 1.0, 0.6, 0.0 },
-	 { 1.0, 0.6, 0.0 },
-	 { 0.0, 0.0, 0.0 },
-	 { 0.0, 0.0, 0.0 },
-      };
-      
-      if ( flip ) {
-	 glDepthRange(0, 0.5);
-	 glDepthFunc(GL_LEQUAL);
-      }
-      else {
-	 glDepthRange(1.0, 0.4999);
-	 glDepthFunc(GL_GEQUAL);
-      }
-
-      flip = !flip;
-
-      /* The famous Quake "Z trick" only works when the whole screen is
-       * re-drawn each frame.
-       */
-
-      glMatrixMode(GL_MODELVIEW);
-      glLoadIdentity();
-      glMatrixMode(GL_PROJECTION);
-      glLoadIdentity();
-      glOrtho(-1, 1, -1, 1, -1, 1);
-      glDisable(GL_LIGHTING);
-      glShadeModel(GL_SMOOTH);
-
-      glEnable( GL_VERTEX_ARRAY );
-      glEnable( GL_COLOR_ARRAY );
-      glVertexPointer( 3, GL_FLOAT, 0, vert );
-      glColorPointer( 3, GL_FLOAT, 0, col );
-      glDrawArrays( GL_POLYGON, 0, 4 );
-      glDisable( GL_COLOR_ARRAY );
-      glDisable( GL_VERTEX_ARRAY );
-
-      glMatrixMode(GL_PROJECTION);
-      glLoadIdentity();
-      glFrustum(-1.0, 1.0, -aspect, aspect, 5.0, 60.0);
-
-      glEnable(GL_LIGHTING);
-
-      glMatrixMode(GL_MODELVIEW);
-      glLoadIdentity();
-      glTranslatef(0.0, 0.0, -40.0);
-   }
-   else {
-      glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
-   }
+   glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 
    glPushMatrix();
    glRotatef(view_rotx, 1.0, 0.0, 0.0);
@@ -356,14 +260,12 @@ draw(void)
 static void
 reshape(int width, int height)
 {
-   aspect = (GLfloat) height / (GLfloat) width;
+   GLfloat h = (GLfloat) height / (GLfloat) width;
 
-   
    glViewport(0, 0, (GLint) width, (GLint) height);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
-
-   glFrustum(-1.0, 1.0, -aspect, aspect, 5.0, 60.0);
+   glFrustum(-1.0, 1.0, -h, h, 5.0, 60.0);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    glTranslatef(0.0, 0.0, -40.0);
@@ -480,8 +382,6 @@ make_window( Display *dpy, const char *name,
 static void
 event_loop(Display *dpy, Window win)
 {
-   float  frame_usage = 0.0;
-
    while (1) {
       while (XPending(dpy) > 0) {
          XEvent event;
@@ -526,13 +426,6 @@ event_loop(Display *dpy, Window win)
       angle += 2.0;
 
       draw();
-      if ( get_frame_usage != NULL ) {
-	 GLfloat   temp;
-	 
-	 (*get_frame_usage)( dpy, win, & temp );
-	 frame_usage += temp;
-      }
-
       glXSwapBuffers(dpy, win);
 
       /* calc framerate */
@@ -549,152 +442,16 @@ event_loop(Display *dpy, Window win)
          if (t - t0 >= 5.0) {
             GLfloat seconds = t - t0;
             GLfloat fps = frames / seconds;
-	    if ( get_frame_usage != NULL ) {
-	       printf("%d frames in %3.1f seconds = %6.3f FPS (%3.1f%% usage)\n",
-		      frames, seconds, fps,
-		      (frame_usage * 100.0) / (float) frames );
-	    }
-	    else {
-	       printf("%d frames in %3.1f seconds = %6.3f FPS\n",
-		      frames, seconds, fps);
-	    }
-
+            printf("%d frames in %3.1f seconds = %6.3f FPS\n", frames, seconds,
+                   fps);
             t0 = t;
             frames = 0;
-	    frame_usage = 0.0;
          }
       }
    }
 }
 
 
-/**
- * Display the refresh rate of the display using the GLX_OML_sync_control
- * extension.
- */
-
-static void
-show_refresh_rate( Display * dpy )
-{
-#ifdef GLX_OML_sync_control
-   PFNGLXGETMSCRATEOMLPROC  get_msc_rate;
-   int32_t  n;
-   int32_t  d;
-
-   get_msc_rate = (PFNGLXGETMSCRATEOMLPROC) glXGetProcAddressARB( (const GLubyte *) "glXGetMscRateOML" );
-   if ( get_msc_rate != NULL ) {
-      (*get_msc_rate)( dpy, glXGetCurrentDrawable(), &n, &d );
-      printf( "refresh rate: %.1fHz\n", (float) n / d );
-      return;
-   }
-#endif
-   printf( "glXGetMscRateOML not supported.\n" );
-}
-
-
-/**
- * Fill in the table of extension strings from a supplied extensions string
- * (as returned by glXQueryExtensionsString).
- *
- * \param string   String of GLX extensions.
- * \sa is_extension_supported
- */
-
-static void
-make_extension_table( const char * string )
-{
-   char ** string_tab;
-   unsigned  num_strings;
-   unsigned  base;
-   unsigned  idx;
-   unsigned  i;
-      
-   /* Count the number of spaces in the string.  That gives a base-line
-    * figure for the number of extension in the string.
-    */
-   
-   num_strings = 1;
-   for ( i = 0 ; string[i] != NUL ; i++ ) {
-      if ( string[i] == ' ' ) {
-	 num_strings++;
-      }
-   }
-   
-   string_tab = (char **) malloc( sizeof( char * ) * num_strings );
-   if ( string_tab == NULL ) {
-      return;
-   }
-
-   base = 0;
-   idx = 0;
-
-   while ( string[ base ] != NUL ) {
-      /* Determine the length of the next extension string.
-       */
-
-      for ( i = 0 
-	    ; (string[ base + i ] != NUL) && (string[ base + i ] != ' ')
-	    ; i++ ) {
-	 /* empty */ ;
-      }
-
-      if ( i > 0 ) {
-	 /* If the string was non-zero length, add it to the table.  We
-	  * can get zero length strings if there is a space at the end of
-	  * the string or if there are two (or more) spaces next to each
-	  * other in the string.
-	  */
-
-	 string_tab[ idx ] = malloc( sizeof( char ) * (i + 1) );
-	 if ( string_tab[ idx ] == NULL ) {
-	    return;
-	 }
-
-	 (void) memcpy( string_tab[ idx ], & string[ base ], i );
-	 string_tab[ idx ][i] = NUL;
-	 idx++;
-      }
-
-
-      /* Skip to the start of the next extension string.
-       */
-
-      for ( base += i
-	    ; (string[ base ] == ' ') && (string[ base ] != NUL) 
-	    ; base++ ) {
-	 /* empty */ ;
-      }
-   }
-
-   extension_table = string_tab;
-   num_extensions = idx;
-}
-
-    
-/**
- * Determine of an extension is supported.  The extension string table
- * must have already be initialized by calling \c make_extension_table.
- * 
- * \praram ext  Extension to be tested.
- * \return GL_TRUE of the extension is supported, GL_FALSE otherwise.
- * \sa make_extension_table
- */
-
-static GLboolean
-is_extension_supported( const char * ext )
-{
-   unsigned   i;
-   
-   for ( i = 0 ; i < num_extensions ; i++ ) {
-      if ( strcmp( ext, extension_table[i] ) == 0 ) {
-	 return GL_TRUE;
-      }
-   }
-   
-   return GL_FALSE;
-}
-
-
 int
 main(int argc, char *argv[])
 {
@@ -702,49 +459,17 @@ main(int argc, char *argv[])
    Window win;
    GLXContext ctx;
    char *dpyName = ":0";
-   int swap_interval = 1;
-   GLboolean do_swap_interval = GL_FALSE;
-   GLboolean force_get_rate = GL_FALSE;
    GLboolean printInfo = GL_FALSE;
    int i;
-   PFNGLXSWAPINTERVALMESAPROC set_swap_interval = NULL;
-   PFNGLXGETSWAPINTERVALMESAPROC get_swap_interval = NULL;
-
 
    for (i = 1; i < argc; i++) {
-      if (strcmp(argv[i], "-display") == 0 && i + 1 < argc) {
+      if (strcmp(argv[i], "-display") == 0) {
          dpyName = argv[i+1];
          i++;
       }
       else if (strcmp(argv[i], "-info") == 0) {
          printInfo = GL_TRUE;
       }
-      else if (strcmp(argv[i], "-swap") == 0 && i + 1 < argc) {
-	 swap_interval = atoi( argv[i+1] );
-	 do_swap_interval = GL_TRUE;
-	 i++;
-      }
-      else if (strcmp(argv[i], "-forcegetrate") == 0) {
-	 /* This option was put in because some DRI drivers don't support the
-	  * full GLX_OML_sync_control extension, but they do support
-	  * glXGetMscRateOML.
-	  */
-	 force_get_rate = GL_TRUE;
-      }
-      else if (strcmp(argv[i], "-ztrick") == 0) {
-	 use_ztrick = GL_TRUE;
-      }
-      else if (strcmp(argv[i], "-help") == 0) {
-         printf("Usage:\n");
-         printf("  gears [options]\n");
-         printf("Options:\n");
-         printf("  -help                   Print this information\n");
-         printf("  -display displayName    Specify X display\n");
-         printf("  -info                   Display GL information\n");
-         printf("  -swap N                 Swap no more than once per N vertical refreshes\n");
-         printf("  -forcegetrate           Try to use glXGetMscRateOML function\n");
-         return 0;
-      }
    }
 
    dpy = XOpenDisplay(dpyName);
@@ -757,59 +482,11 @@ main(int argc, char *argv[])
    XMapWindow(dpy, win);
    glXMakeCurrent(dpy, win, ctx);
 
-   make_extension_table( (char *) glXQueryExtensionsString(dpy,DefaultScreen(dpy)) );
-   has_OML_sync_control = is_extension_supported( "GLX_OML_sync_control" );
-   has_SGI_swap_control = is_extension_supported( "GLX_SGI_swap_control" );
-   has_MESA_swap_control = is_extension_supported( "GLX_MESA_swap_control" );
-   has_MESA_swap_frame_usage = is_extension_supported( "GLX_MESA_swap_frame_usage" );
-
-   if ( has_MESA_swap_control ) {
-      set_swap_interval = (PFNGLXSWAPINTERVALMESAPROC) glXGetProcAddressARB( (const GLubyte *) "glXSwapIntervalMESA" );
-      get_swap_interval = (PFNGLXGETSWAPINTERVALMESAPROC) glXGetProcAddressARB( (const GLubyte *) "glXGetSwapIntervalMESA" );
-   }
-   else if ( has_SGI_swap_control ) {
-      set_swap_interval = (PFNGLXSWAPINTERVALMESAPROC) glXGetProcAddressARB( (const GLubyte *) "glXSwapIntervalSGI" );
-   }
-
-
-   if ( has_MESA_swap_frame_usage ) {
-      get_frame_usage = (PFNGLXGETFRAMEUSAGEMESAPROC)  glXGetProcAddressARB( (const GLubyte *) "glXGetFrameUsageMESA" );
-   }
-      
-
    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));
-      if ( has_OML_sync_control || force_get_rate ) {
-	 show_refresh_rate( dpy );
-      }
-
-      if ( get_swap_interval != NULL ) {
-	 printf("Default swap interval = %d\n", (*get_swap_interval)() );
-      }
-   }
-
-   if ( do_swap_interval ) {
-      if ( set_swap_interval != NULL ) {
-	 if ( ((swap_interval == 0) && !has_MESA_swap_control)
-	      || (swap_interval < 0) ) {
-	    printf( "Swap interval must be non-negative or greater than zero "
-		    "if GLX_MESA_swap_control is not supported.\n" );
-	 }
-	 else {
-	    (*set_swap_interval)( swap_interval );
-	 }
-
-	 if ( printInfo && (get_swap_interval != NULL) ) {
-	    printf("Current swap interval = %d\n", (*get_swap_interval)() );
-	 }
-      }
-      else {
-	 printf("Unable to set swap-interval.  Neither GLX_SGI_swap_control "
-		"nor GLX_MESA_swap_control are supported.\n" );
-      }
    }
 
    init();
diff --git a/progs/xdemos/glxswapcontrol.c b/progs/xdemos/glxswapcontrol.c
new file mode 100644
index 0000000..6a9a852
--- /dev/null
+++ b/progs/xdemos/glxswapcontrol.c
@@ -0,0 +1,824 @@
+/*
+ * 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.
+ */
+
+/*
+ * This is a port of the infamous "gears" demo to straight GLX (i.e. no GLUT)
+ * Port by Brian Paul  23 March 2001
+ *
+ * Modified by Ian Romanick <idr@us.ibm.com> 09 April 2003 to support
+ * GLX_{MESA,SGI}_swap_control and GLX_OML_sync_control.
+ *
+ * Command line options:
+ *    -display       Name of the display to use.
+ *    -info          print GL implementation information
+ *    -swap N        Attempt to set the swap interval to 1/N second
+ *    -forcegetrate  Get the display refresh rate even if the required GLX
+ *                   extension is not supported.
+ */
+
+
+#include <math.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <X11/Xlib.h>
+#include <X11/keysym.h>
+#ifndef __VMS
+/*# include <stdint.h>*/
+#endif
+# define GLX_GLXEXT_PROTOTYPES
+#include <GL/gl.h>
+#include <GL/glx.h>
+
+#ifndef GLX_MESA_swap_control
+typedef GLint ( * PFNGLXSWAPINTERVALMESAPROC) (unsigned interval);
+typedef GLint ( * PFNGLXGETSWAPINTERVALMESAPROC) ( void );
+#endif
+
+#if !defined( GLX_OML_sync_control ) && defined( _STDINT_H )
+#define GLX_OML_sync_control 1
+typedef Bool ( * PFNGLXGETMSCRATEOMLPROC) (Display *dpy, GLXDrawable drawable, int32_t *numerator, int32_t *denominator);
+#endif
+
+#ifndef GLX_MESA_swap_frame_usage
+#define GLX_MESA_swap_frame_usage 1
+typedef int ( * PFNGLXGETFRAMEUSAGEMESAPROC) (Display *dpy, GLXDrawable drawable, float * usage );
+#endif
+
+#define BENCHMARK
+
+PFNGLXGETFRAMEUSAGEMESAPROC get_frame_usage = NULL;
+
+#ifdef BENCHMARK
+
+/* XXX this probably isn't very portable */
+
+#include <sys/time.h>
+#include <unistd.h>
+
+#define NUL '\0'
+
+/* 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;
+
+static GLboolean has_OML_sync_control = GL_FALSE;
+static GLboolean has_SGI_swap_control = GL_FALSE;
+static GLboolean has_MESA_swap_control = GL_FALSE;
+static GLboolean has_MESA_swap_frame_usage = GL_FALSE;
+
+static char ** extension_table = NULL;
+static unsigned num_extensions;
+
+static GLboolean use_ztrick = GL_FALSE;
+static GLfloat   aspect;
+
+/*
+ *
+ *  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)
+{
+   if ( use_ztrick ) {
+      static GLboolean flip = GL_FALSE;
+      static const GLfloat vert[4][3] = {
+	 { -1, -1, -0.999 },
+	 {  1, -1, -0.999 },
+	 {  1,  1, -0.999 },
+	 { -1,  1, -0.999 }
+      };
+      static const GLfloat col[4][3] = {
+	 { 1.0, 0.6, 0.0 },
+	 { 1.0, 0.6, 0.0 },
+	 { 0.0, 0.0, 0.0 },
+	 { 0.0, 0.0, 0.0 },
+      };
+      
+      if ( flip ) {
+	 glDepthRange(0, 0.5);
+	 glDepthFunc(GL_LEQUAL);
+      }
+      else {
+	 glDepthRange(1.0, 0.4999);
+	 glDepthFunc(GL_GEQUAL);
+      }
+
+      flip = !flip;
+
+      /* The famous Quake "Z trick" only works when the whole screen is
+       * re-drawn each frame.
+       */
+
+      glMatrixMode(GL_MODELVIEW);
+      glLoadIdentity();
+      glMatrixMode(GL_PROJECTION);
+      glLoadIdentity();
+      glOrtho(-1, 1, -1, 1, -1, 1);
+      glDisable(GL_LIGHTING);
+      glShadeModel(GL_SMOOTH);
+
+      glEnable( GL_VERTEX_ARRAY );
+      glEnable( GL_COLOR_ARRAY );
+      glVertexPointer( 3, GL_FLOAT, 0, vert );
+      glColorPointer( 3, GL_FLOAT, 0, col );
+      glDrawArrays( GL_POLYGON, 0, 4 );
+      glDisable( GL_COLOR_ARRAY );
+      glDisable( GL_VERTEX_ARRAY );
+
+      glMatrixMode(GL_PROJECTION);
+      glLoadIdentity();
+      glFrustum(-1.0, 1.0, -aspect, aspect, 5.0, 60.0);
+
+      glEnable(GL_LIGHTING);
+
+      glMatrixMode(GL_MODELVIEW);
+      glLoadIdentity();
+      glTranslatef(0.0, 0.0, -40.0);
+   }
+   else {
+      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)
+{
+   aspect = (GLfloat) height / (GLfloat) width;
+
+   
+   glViewport(0, 0, (GLint) width, (GLint) height);
+   glMatrixMode(GL_PROJECTION);
+   glLoadIdentity();
+
+   glFrustum(-1.0, 1.0, -aspect, aspect, 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);
+}
+
+
+/*
+ * 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_RGBA,
+		    GLX_RED_SIZE, 1,
+		    GLX_GREEN_SIZE, 1,
+		    GLX_BLUE_SIZE, 1,
+		    GLX_DOUBLEBUFFER,
+		    GLX_DEPTH_SIZE, 1,
+		    None };
+   int scrnum;
+   XSetWindowAttributes attr;
+   unsigned long mask;
+   Window root;
+   Window win;
+   GLXContext ctx;
+   XVisualInfo *visinfo;
+
+   scrnum = DefaultScreen( dpy );
+   root = RootWindow( dpy, scrnum );
+
+   visinfo = glXChooseVisual( dpy, scrnum, attrib );
+   if (!visinfo) {
+      printf("Error: couldn't get an RGB, Double-buffered visual\n");
+      exit(1);
+   }
+
+   /* window attributes */
+   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 = glXCreateContext( dpy, visinfo, NULL, True );
+   if (!ctx) {
+      printf("Error: glXCreateContext failed\n");
+      exit(1);
+   }
+
+   XFree(visinfo);
+
+   *winRet = win;
+   *ctxRet = ctx;
+}
+
+
+static void
+event_loop(Display *dpy, Window win)
+{
+   float  frame_usage = 0.0;
+
+   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();
+      if ( get_frame_usage != NULL ) {
+	 GLfloat   temp;
+	 
+	 (*get_frame_usage)( dpy, win, & temp );
+	 frame_usage += temp;
+      }
+
+      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;
+	    if ( get_frame_usage != NULL ) {
+	       printf("%d frames in %3.1f seconds = %6.3f FPS (%3.1f%% usage)\n",
+		      frames, seconds, fps,
+		      (frame_usage * 100.0) / (float) frames );
+	    }
+	    else {
+	       printf("%d frames in %3.1f seconds = %6.3f FPS\n",
+		      frames, seconds, fps);
+	    }
+
+            t0 = t;
+            frames = 0;
+	    frame_usage = 0.0;
+         }
+      }
+   }
+}
+
+
+/**
+ * Display the refresh rate of the display using the GLX_OML_sync_control
+ * extension.
+ */
+
+static void
+show_refresh_rate( Display * dpy )
+{
+#ifdef GLX_OML_sync_control
+   PFNGLXGETMSCRATEOMLPROC  get_msc_rate;
+   int32_t  n;
+   int32_t  d;
+
+   get_msc_rate = (PFNGLXGETMSCRATEOMLPROC) glXGetProcAddressARB( (const GLubyte *) "glXGetMscRateOML" );
+   if ( get_msc_rate != NULL ) {
+      (*get_msc_rate)( dpy, glXGetCurrentDrawable(), &n, &d );
+      printf( "refresh rate: %.1fHz\n", (float) n / d );
+      return;
+   }
+#endif
+   printf( "glXGetMscRateOML not supported.\n" );
+}
+
+
+/**
+ * Fill in the table of extension strings from a supplied extensions string
+ * (as returned by glXQueryExtensionsString).
+ *
+ * \param string   String of GLX extensions.
+ * \sa is_extension_supported
+ */
+
+static void
+make_extension_table( const char * string )
+{
+   char ** string_tab;
+   unsigned  num_strings;
+   unsigned  base;
+   unsigned  idx;
+   unsigned  i;
+      
+   /* Count the number of spaces in the string.  That gives a base-line
+    * figure for the number of extension in the string.
+    */
+   
+   num_strings = 1;
+   for ( i = 0 ; string[i] != NUL ; i++ ) {
+      if ( string[i] == ' ' ) {
+	 num_strings++;
+      }
+   }
+   
+   string_tab = (char **) malloc( sizeof( char * ) * num_strings );
+   if ( string_tab == NULL ) {
+      return;
+   }
+
+   base = 0;
+   idx = 0;
+
+   while ( string[ base ] != NUL ) {
+      /* Determine the length of the next extension string.
+       */
+
+      for ( i = 0 
+	    ; (string[ base + i ] != NUL) && (string[ base + i ] != ' ')
+	    ; i++ ) {
+	 /* empty */ ;
+      }
+
+      if ( i > 0 ) {
+	 /* If the string was non-zero length, add it to the table.  We
+	  * can get zero length strings if there is a space at the end of
+	  * the string or if there are two (or more) spaces next to each
+	  * other in the string.
+	  */
+
+	 string_tab[ idx ] = malloc( sizeof( char ) * (i + 1) );
+	 if ( string_tab[ idx ] == NULL ) {
+	    return;
+	 }
+
+	 (void) memcpy( string_tab[ idx ], & string[ base ], i );
+	 string_tab[ idx ][i] = NUL;
+	 idx++;
+      }
+
+
+      /* Skip to the start of the next extension string.
+       */
+
+      for ( base += i
+	    ; (string[ base ] == ' ') && (string[ base ] != NUL) 
+	    ; base++ ) {
+	 /* empty */ ;
+      }
+   }
+
+   extension_table = string_tab;
+   num_extensions = idx;
+}
+
+    
+/**
+ * Determine of an extension is supported.  The extension string table
+ * must have already be initialized by calling \c make_extension_table.
+ * 
+ * \praram ext  Extension to be tested.
+ * \return GL_TRUE of the extension is supported, GL_FALSE otherwise.
+ * \sa make_extension_table
+ */
+
+static GLboolean
+is_extension_supported( const char * ext )
+{
+   unsigned   i;
+   
+   for ( i = 0 ; i < num_extensions ; i++ ) {
+      if ( strcmp( ext, extension_table[i] ) == 0 ) {
+	 return GL_TRUE;
+      }
+   }
+   
+   return GL_FALSE;
+}
+
+
+int
+main(int argc, char *argv[])
+{
+   Display *dpy;
+   Window win;
+   GLXContext ctx;
+   char *dpyName = ":0";
+   int swap_interval = 1;
+   GLboolean do_swap_interval = GL_FALSE;
+   GLboolean force_get_rate = GL_FALSE;
+   GLboolean printInfo = GL_FALSE;
+   int i;
+   PFNGLXSWAPINTERVALMESAPROC set_swap_interval = NULL;
+   PFNGLXGETSWAPINTERVALMESAPROC get_swap_interval = NULL;
+
+
+   for (i = 1; i < argc; i++) {
+      if (strcmp(argv[i], "-display") == 0 && i + 1 < argc) {
+         dpyName = argv[i+1];
+         i++;
+      }
+      else if (strcmp(argv[i], "-info") == 0) {
+         printInfo = GL_TRUE;
+      }
+      else if (strcmp(argv[i], "-swap") == 0 && i + 1 < argc) {
+	 swap_interval = atoi( argv[i+1] );
+	 do_swap_interval = GL_TRUE;
+	 i++;
+      }
+      else if (strcmp(argv[i], "-forcegetrate") == 0) {
+	 /* This option was put in because some DRI drivers don't support the
+	  * full GLX_OML_sync_control extension, but they do support
+	  * glXGetMscRateOML.
+	  */
+	 force_get_rate = GL_TRUE;
+      }
+      else if (strcmp(argv[i], "-ztrick") == 0) {
+	 use_ztrick = GL_TRUE;
+      }
+      else if (strcmp(argv[i], "-help") == 0) {
+         printf("Usage:\n");
+         printf("  gears [options]\n");
+         printf("Options:\n");
+         printf("  -help                   Print this information\n");
+         printf("  -display displayName    Specify X display\n");
+         printf("  -info                   Display GL information\n");
+         printf("  -swap N                 Swap no more than once per N vertical refreshes\n");
+         printf("  -forcegetrate           Try to use glXGetMscRateOML function\n");
+         return 0;
+      }
+   }
+
+   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);
+
+   make_extension_table( (char *) glXQueryExtensionsString(dpy,DefaultScreen(dpy)) );
+   has_OML_sync_control = is_extension_supported( "GLX_OML_sync_control" );
+   has_SGI_swap_control = is_extension_supported( "GLX_SGI_swap_control" );
+   has_MESA_swap_control = is_extension_supported( "GLX_MESA_swap_control" );
+   has_MESA_swap_frame_usage = is_extension_supported( "GLX_MESA_swap_frame_usage" );
+
+   if ( has_MESA_swap_control ) {
+      set_swap_interval = (PFNGLXSWAPINTERVALMESAPROC) glXGetProcAddressARB( (const GLubyte *) "glXSwapIntervalMESA" );
+      get_swap_interval = (PFNGLXGETSWAPINTERVALMESAPROC) glXGetProcAddressARB( (const GLubyte *) "glXGetSwapIntervalMESA" );
+   }
+   else if ( has_SGI_swap_control ) {
+      set_swap_interval = (PFNGLXSWAPINTERVALMESAPROC) glXGetProcAddressARB( (const GLubyte *) "glXSwapIntervalSGI" );
+   }
+
+
+   if ( has_MESA_swap_frame_usage ) {
+      get_frame_usage = (PFNGLXGETFRAMEUSAGEMESAPROC)  glXGetProcAddressARB( (const GLubyte *) "glXGetFrameUsageMESA" );
+   }
+      
+
+   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));
+      if ( has_OML_sync_control || force_get_rate ) {
+	 show_refresh_rate( dpy );
+      }
+
+      if ( get_swap_interval != NULL ) {
+	 printf("Default swap interval = %d\n", (*get_swap_interval)() );
+      }
+   }
+
+   if ( do_swap_interval ) {
+      if ( set_swap_interval != NULL ) {
+	 if ( ((swap_interval == 0) && !has_MESA_swap_control)
+	      || (swap_interval < 0) ) {
+	    printf( "Swap interval must be non-negative or greater than zero "
+		    "if GLX_MESA_swap_control is not supported.\n" );
+	 }
+	 else {
+	    (*set_swap_interval)( swap_interval );
+	 }
+
+	 if ( printInfo && (get_swap_interval != NULL) ) {
+	    printf("Current swap interval = %d\n", (*get_swap_interval)() );
+	 }
+      }
+      else {
+	 printf("Unable to set swap-interval.  Neither GLX_SGI_swap_control "
+		"nor GLX_MESA_swap_control are supported.\n" );
+      }
+   }
+
+   init();
+
+   event_loop(dpy, win);
+
+   glXDestroyContext(dpy, ctx);
+   XDestroyWindow(dpy, win);
+   XCloseDisplay(dpy);
+
+   return 0;
+}