pbuffer info and demo programs

4 files changed, 878 insertions, 0 deletions

diff --git a/progs/xdemos/pbdemo.c b/progs/xdemos/pbdemo.c
new file mode 100644
index 00000000000..611e7e594fd
--- /dev/null
+++ b/progs/xdemos/pbdemo.c
@@ -0,0 +1,477 @@
+/* $Id: pbdemo.c,v 1.1 2002/10/05 18:30:13 brianp Exp $ */
+
+/*
+ * This program demonstrates how to do "off-screen" rendering using
+ * the GLX pixel buffer extension.
+ *
+ * Written by Brian Paul for the "OpenGL and Window System Integration"
+ * course presented at SIGGRAPH '97.  Updated on 5 October 2002.
+ *
+ * Usage:
+ *   pbuffers width height imgfile
+ * Where:
+ *   width is the width, in pixels, of the image to generate.
+ *   height is the height, in pixels, of the image to generate.
+ *   imgfile is the name of the PPM image file to write.
+ *
+ *
+ * This demo draws 3-D boxes with random orientation.  A pbuffer with
+ * a depth (Z) buffer is prefered but if such a pbuffer can't be created
+ * we use a non-depth-buffered config.
+ *
+ * On machines such as the SGI Indigo you may have to reconfigure your
+ * display/X server to enable pbuffers.  Look in the /usr/gfx/ucode/MGRAS/vof/
+ * directory for display configurationswith the _pbuf suffix.  Use
+ * setmon -x <vof> to configure your X server and display for pbuffers.
+ *
+ * O2 systems seem to support pbuffers well.
+ *
+ * IR systems (at least 1RM systems) don't have single-buffered, RGBA,
+ * Z-buffered pbuffer configs.  BUT, they DO have DOUBLE-buffered, RGBA,
+ * Z-buffered pbuffers.  Note how we try four different fbconfig attribute
+ * lists below!
+ */
+
+
+#include <assert.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <X11/Xlib.h>
+#include "pbutil.h"
+
+
+/* Some ugly global vars */
+static GLXFBConfigSGIX gFBconfig = 0;
+static Display *gDpy = NULL;
+static int gScreen = 0;
+static GLXPbufferSGIX gPBuffer = 0;
+static int gWidth, gHeight;
+
+
+
+/*
+ * Create the pbuffer and return a GLXPbufferSGIX handle.
+ */
+static GLXPbufferSGIX
+MakePbuffer( Display *dpy, int screen, int width, int height )
+{
+#define NUM_FB_CONFIGS 4
+   char fbString[NUM_FB_CONFIGS][100] = {
+      "Single Buffered, depth buffer",
+      "Double Buffered, depth buffer",
+      "Single Buffered, no depth buffer",
+      "Double Buffered, no depth buffer"
+   };
+   int fbAttribs[NUM_FB_CONFIGS][100] = {
+      {
+         /* Single buffered, with depth buffer */
+         GLX_RENDER_TYPE_SGIX, GLX_RGBA_BIT_SGIX,
+         GLX_DRAWABLE_TYPE_SGIX, GLX_PIXMAP_BIT_SGIX,
+         GLX_RED_SIZE, 1,
+         GLX_GREEN_SIZE, 1,
+         GLX_BLUE_SIZE, 1,
+         GLX_DEPTH_SIZE, 1,
+         GLX_DOUBLEBUFFER, 0,
+         GLX_STENCIL_SIZE, 0,
+         None
+      },
+      {
+         /* Double buffered, with depth buffer */
+         GLX_RENDER_TYPE_SGIX, GLX_RGBA_BIT_SGIX,
+         GLX_DRAWABLE_TYPE_SGIX, GLX_PIXMAP_BIT_SGIX,
+         GLX_RED_SIZE, 1,
+         GLX_GREEN_SIZE, 1,
+         GLX_BLUE_SIZE, 1,
+         GLX_DEPTH_SIZE, 1,
+         GLX_DOUBLEBUFFER, 1,
+         GLX_STENCIL_SIZE, 0,
+         None
+      },
+      {
+         /* Single bufferd, without depth buffer */
+         GLX_RENDER_TYPE_SGIX, GLX_RGBA_BIT_SGIX,
+         GLX_DRAWABLE_TYPE_SGIX, GLX_PIXMAP_BIT_SGIX,
+         GLX_RED_SIZE, 1,
+         GLX_GREEN_SIZE, 1,
+         GLX_BLUE_SIZE, 1,
+         GLX_DEPTH_SIZE, 0,
+         GLX_DOUBLEBUFFER, 0,
+         GLX_STENCIL_SIZE, 0,
+         None
+      },
+      {
+         /* Double bufferd, without depth buffer */
+         GLX_RENDER_TYPE_SGIX, GLX_RGBA_BIT_SGIX,
+         GLX_DRAWABLE_TYPE_SGIX, GLX_PIXMAP_BIT_SGIX,
+         GLX_RED_SIZE, 1,
+         GLX_GREEN_SIZE, 1,
+         GLX_BLUE_SIZE, 1,
+         GLX_DEPTH_SIZE, 0,
+         GLX_DOUBLEBUFFER, 1,
+         GLX_STENCIL_SIZE, 0,
+         None
+      }
+   };
+   int pbAttribs[] = {
+      GLX_LARGEST_PBUFFER_SGIX, True,
+      GLX_PRESERVED_CONTENTS_SGIX, False,
+      None
+   };
+   GLXFBConfigSGIX *fbConfigs;
+   GLXPbufferSGIX pBuffer = None;
+   int nConfigs;
+   int i;
+   int attempt;
+
+   for (attempt=0; attempt<NUM_FB_CONFIGS; attempt++) {
+
+      /* Get list of possible frame buffer configurations */
+      fbConfigs = glXChooseFBConfigSGIX(dpy, screen, fbAttribs[attempt], &nConfigs);
+      if (nConfigs==0 || !fbConfigs) {
+         printf("Error: glxChooseFBConfigSGIX failed\n");
+         XCloseDisplay(dpy);
+         return 0;
+      }
+
+#ifdef DEBUG
+      for (i=0;i<nConfigs;i++) {
+         printf("Config %d\n", i);
+         PrintFBConfigInfo(dpy, fbConfigs[i], 0);
+      }
+#endif
+
+      /* Create the pbuffer using first fbConfig in the list that works. */
+      for (i=0;i<nConfigs;i++) {
+         pBuffer = CreatePbuffer(dpy, fbConfigs[i], width, height, pbAttribs);
+         if (pBuffer) {
+            gFBconfig = fbConfigs[i];
+            gWidth = width;
+            gHeight = height;
+            break;
+         }
+      }
+
+      if (pBuffer!=None) {
+         break;
+      }
+   }
+
+   if (pBuffer) {
+      printf("Using: %s\n", fbString[attempt]);
+   }
+
+   XFree(fbConfigs);
+
+   return pBuffer;
+#undef NUM_FB_CONFIGS
+}
+
+
+
+/*
+ * Do all the X / GLX setup stuff.
+ */
+static int
+Setup(int width, int height)
+{
+#if defined(GLX_SGIX_fbconfig) && defined(GLX_SGIX_pbuffer)
+   XVisualInfo *visInfo;
+   GLXContext glCtx;
+
+   /* Open the X display */
+   gDpy = XOpenDisplay(NULL);
+   if (!gDpy) {
+      printf("Error: couldn't open default X display.\n");
+      return 0;
+   }
+
+   /* Get default screen */
+   gScreen = DefaultScreen(gDpy);
+
+   /* Test that pbuffers are available */
+   if (!QueryPbuffers(gDpy, gScreen)) {
+      printf("Error: pbuffers not available on this screen\n");
+      XCloseDisplay(gDpy);
+      return 0;
+   }
+
+   /* Create Pbuffer */
+   gPBuffer = MakePbuffer( gDpy, gScreen, width, height );
+   if (gPBuffer==None) {
+      printf("Error: couldn't create pbuffer\n");
+      XCloseDisplay(gDpy);
+      return 0;
+   }
+
+   /* Get corresponding XVisualInfo */
+   visInfo = glXGetVisualFromFBConfigSGIX(gDpy, gFBconfig);
+   if (!visInfo) {
+      printf("Error: can't get XVisualInfo from FBconfig\n");
+      XCloseDisplay(gDpy);
+      return 0;
+   }
+
+   /* Create GLX context */
+   glCtx = glXCreateContext(gDpy, visInfo, NULL, True);
+   if (!glCtx) {
+      /* try indirect */
+      glCtx = glXCreateContext(gDpy, visInfo, NULL, False);
+      if (!glCtx) {
+         printf("Error: Couldn't create GLXContext\n");
+         XFree(visInfo);
+         XCloseDisplay(gDpy);
+         return 0;
+      }
+      else {
+         printf("Warning: using indirect GLXContext\n");
+      }
+   }
+
+   /* Bind context to pbuffer */
+   if (!glXMakeCurrent(gDpy, gPBuffer, glCtx)) {
+      printf("Error: glXMakeCurrent failed\n");
+      XFree(visInfo);
+      XCloseDisplay(gDpy);
+      return 0;
+   }
+
+   return 1;  /* Success!! */
+#else
+   printf("Error: GLX_SGIX_fbconfig and/or GLX_SGIX_pbuffer extensions not"
+                  " available at compile-time.\n");
+   return 0;
+#endif
+}
+
+
+
+/* One-time GL setup */
+static void
+InitGL(void)
+{
+   static GLfloat pos[4] = {0.0, 0.0, 10.0, 0.0};
+   glEnable(GL_LIGHTING);
+   glEnable(GL_LIGHT0);
+   glLightfv(GL_LIGHT0, GL_POSITION, pos);
+   glEnable(GL_NORMALIZE);
+   glEnable(GL_DEPTH_TEST);
+   glEnable(GL_CULL_FACE);
+
+   glViewport(0, 0, gWidth, gHeight);
+   glMatrixMode( GL_PROJECTION );
+   glLoadIdentity();
+   glFrustum( -1.0, 1.0, -1.0, 1.0, 5.0, 25.0 );
+   glMatrixMode( GL_MODELVIEW );
+   glLoadIdentity();
+   glTranslatef( 0.0, 0.0, -15.0 );
+
+}
+
+
+/* Return random float in [0,1] */
+static float
+Random(void)
+{
+   int i = rand();
+   return (float) (i % 1000) / 1000.0;
+}
+
+
+static void
+RandomColor(void)
+{
+   GLfloat c[4];
+   c[0] = Random();
+   c[1] = Random();
+   c[2] = Random();
+   c[3] = 1.0;
+   glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, c);
+}
+
+
+/* This function borrowed from Mark Kilgard's GLUT */
+static void
+drawBox(GLfloat x0, GLfloat x1, GLfloat y0, GLfloat y1,
+  GLfloat z0, GLfloat z1, GLenum type)
+{
+  static GLfloat n[6][3] =
+  {
+    {-1.0, 0.0, 0.0},
+    {0.0, 1.0, 0.0},
+    {1.0, 0.0, 0.0},
+    {0.0, -1.0, 0.0},
+    {0.0, 0.0, 1.0},
+    {0.0, 0.0, -1.0}
+  };
+  static GLint faces[6][4] =
+  {
+    {0, 1, 2, 3},
+    {3, 2, 6, 7},
+    {7, 6, 5, 4},
+    {4, 5, 1, 0},
+    {5, 6, 2, 1},
+    {7, 4, 0, 3}
+  };
+  GLfloat v[8][3], tmp;
+  GLint i;
+
+  if (x0 > x1) {
+    tmp = x0;
+    x0 = x1;
+    x1 = tmp;
+  }
+  if (y0 > y1) {
+    tmp = y0;
+    y0 = y1;
+    y1 = tmp;
+  }
+  if (z0 > z1) {
+    tmp = z0;
+    z0 = z1;
+    z1 = tmp;
+  }
+  v[0][0] = v[1][0] = v[2][0] = v[3][0] = x0;
+  v[4][0] = v[5][0] = v[6][0] = v[7][0] = x1;
+  v[0][1] = v[1][1] = v[4][1] = v[5][1] = y0;
+  v[2][1] = v[3][1] = v[6][1] = v[7][1] = y1;
+  v[0][2] = v[3][2] = v[4][2] = v[7][2] = z0;
+  v[1][2] = v[2][2] = v[5][2] = v[6][2] = z1;
+
+  for (i = 0; i < 6; i++) {
+    glBegin(type);
+    glNormal3fv(&n[i][0]);
+    glVertex3fv(&v[faces[i][0]][0]);
+    glVertex3fv(&v[faces[i][1]][0]);
+    glVertex3fv(&v[faces[i][2]][0]);
+    glVertex3fv(&v[faces[i][3]][0]);
+    glEnd();
+  }
+}
+
+
+
+/* Render a scene */
+static void
+Render(void)
+{
+   int NumBoxes = 100;
+   int i;
+
+   InitGL();
+   glClearColor(0.2, 0.2, 0.9, 0.0);
+   glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+   for (i=0;i<NumBoxes;i++) {
+      float tx = -2.0 + 4.0 * Random();
+      float ty = -2.0 + 4.0 * Random();
+      float tz =  4.0 - 16.0 * Random();
+      float sx = 0.1 + Random() * 0.4;
+      float sy = 0.1 + Random() * 0.4;
+      float sz = 0.1 + Random() * 0.4;
+      float rx = Random();
+      float ry = Random();
+      float rz = Random();
+      float ra = Random() * 360.0;
+      glPushMatrix();
+      glTranslatef(tx, ty, tz);
+      glRotatef(ra, rx, ry, rz);
+      glScalef(sx, sy, sz);
+      RandomColor();
+      drawBox(-1.0, 1.0, -1.0, 1.0, -1.0, 1.0, GL_POLYGON);
+      glPopMatrix();
+   }
+
+   glFinish();
+}
+
+
+
+static void
+WriteFile(const char *filename)
+{
+   FILE *f;
+   GLubyte *image;
+   int i;
+
+   image = malloc(gWidth * gHeight * 3 * sizeof(GLubyte));
+   if (!image) {
+      printf("Error: couldn't allocate image buffer\n");
+      return;
+   }
+
+   glPixelStorei(GL_PACK_ALIGNMENT, 1);
+   glReadPixels(0, 0, gWidth, gHeight, GL_RGB, GL_UNSIGNED_BYTE, image);
+
+   f = fopen(filename, "w");
+   if (!f) {
+      printf("Couldn't open image file: %s\n", filename);
+      return;
+   }
+   fprintf(f,"P6\n");
+   fprintf(f,"# ppm-file created by %s\n", "trdemo2");
+   fprintf(f,"%i %i\n", gWidth, gHeight);
+   fprintf(f,"255\n");
+   fclose(f);
+   f = fopen(filename, "ab");  /* now append binary data */
+   if (!f) {
+      printf("Couldn't append to image file: %s\n", filename);
+      return;
+   }
+
+   for (i=0;i<gHeight;i++) {
+      GLubyte *rowPtr;
+      /* Remember, OpenGL images are bottom to top.  Have to reverse. */
+      rowPtr = image + (gHeight-1-i) * gWidth*3;
+      fwrite(rowPtr, 1, gWidth*3, f);
+   }
+
+   fclose(f);
+   free(image);
+
+   printf("Wrote %d by %d image file: %s\n", gWidth, gHeight, filename);
+}
+
+
+
+/*
+ * Print message describing command line parameters.
+ */
+static void
+Usage(const char *appName)
+{
+   printf("Usage:\n");
+   printf("  %s width height imgfile\n", appName);
+   printf("Where imgfile is a ppm file\n");
+}
+
+
+
+int
+main(int argc, char *argv[])
+{
+   if (argc!=4) {
+      Usage(argv[0]);
+   }
+   else {
+      int width = atoi(argv[1]);
+      int height = atoi(argv[2]);
+      char *fileName = argv[3];
+      if (width<=0) {
+         printf("Error: width parameter must be at least 1.\n");
+         return 1;
+      }
+      if (height<=0) {
+         printf("Error: height parameter must be at least 1.\n");
+         return 1;
+      }
+      if (!Setup(width, height)) {
+         return 1;
+      }
+      Render();
+      WriteFile(fileName);
+      glXDestroyGLXPbufferSGIX( gDpy, gPBuffer );
+   }
+   return 0;
+}
+
diff --git a/progs/xdemos/pbinfo.c b/progs/xdemos/pbinfo.c
new file mode 100644
index 00000000000..e4e52810f77
--- /dev/null
+++ b/progs/xdemos/pbinfo.c
@@ -0,0 +1,133 @@
+/* $Id: pbinfo.c,v 1.1 2002/10/05 18:30:13 brianp Exp $ */
+
+/*
+ * Print list of fbconfigs and test each to see if a pbuffer can be created
+ * for that config.
+ *
+ * Brian Paul
+ * April 1997
+ * Updated on 5 October 2002.
+ */
+
+
+#include <X11/Xlib.h>
+#include <stdio.h>
+#include <string.h>
+#include "pbutil.h"
+
+
+
+
+static void
+PrintConfigs(Display *dpy, int screen, Bool horizFormat)
+{
+   GLXFBConfigSGIX *fbConfigs;
+   int nConfigs;
+   int i;
+   /* Note: you may want to tweek the attribute list to select a different
+    * set of fbconfigs.
+    */
+   int fbAttribs[] = {
+                      GLX_RENDER_TYPE_SGIX, 0,
+		      GLX_DRAWABLE_TYPE_SGIX, 0,
+#if 0
+                      GLX_RENDER_TYPE_SGIX, GLX_RGBA_BIT_SGIX,
+		      GLX_DRAWABLE_TYPE_SGIX, GLX_PIXMAP_BIT_SGIX,
+		      GLX_RED_SIZE, 1,
+		      GLX_GREEN_SIZE, 1,
+		      GLX_BLUE_SIZE, 1,
+		      GLX_DEPTH_SIZE, 1,
+		      GLX_DOUBLEBUFFER, 0,
+		      GLX_STENCIL_SIZE, 0,
+#endif
+		      None};
+
+
+   /* Get list of possible frame buffer configurations */
+#if 0
+   /* SGIX method */
+   fbConfigs = glXChooseFBConfigSGIX(dpy, screen, fbAttribs, &nConfigs);
+#else
+   /* GLX 1.3 method */
+   fbConfigs = glXGetFBConfigs(dpy, screen, &nConfigs);
+#endif
+
+   if (nConfigs==0 || !fbConfigs) {
+      printf("Error: glxChooseFBConfigSGIX failed\n");
+      return;
+   }
+
+   printf("Number of fbconfigs: %d\n", nConfigs);
+
+   if (horizFormat) {
+      printf("  ID  VisualType  Depth Lvl RGB CI DB Stereo  R  G  B  A");
+      printf("   Z  S  AR AG AB AA  MSbufs MSnum  Pbuffer\n");
+   }
+
+   /* Print config info */
+   for (i=0;i<nConfigs;i++) {
+      PrintFBConfigInfo(dpy, fbConfigs[i], horizFormat);
+   }
+
+   /* free the list */
+   XFree(fbConfigs);
+}
+
+
+
+static void
+PrintUsage(void)
+{
+   printf("Options:\n");
+   printf("  -display <display-name>  specify X display name\n");
+   printf("  -t                       print in tabular format\n");
+   printf("  -v                       print in verbose format\n");
+   printf("  -help                    print this information\n");
+}
+
+
+int
+main(int argc, char *argv[])
+{
+   Display *dpy;
+   int scrn;
+   char *dpyName = NULL;
+   Bool horizFormat = True;
+   int i;
+
+   for (i=1; i<argc; i++) {
+      if (strcmp(argv[i],"-display")==0) {
+	 if (i+1<argc) {
+	    dpyName = argv[i+1];
+	    i++;
+	 }
+      }
+      else if (strcmp(argv[i],"-t")==0) {
+	 /* tabular format */
+	 horizFormat = True;
+      }
+      else if (strcmp(argv[i],"-v")==0) {
+	 /* verbose format */
+	 horizFormat = False;
+      }
+      else if (strcmp(argv[i],"-help")==0) {
+	 PrintUsage();
+	 return 0;
+      }
+      else {
+	 printf("Unknown option: %s\n", argv[i]);
+      }
+   }
+
+   dpy = XOpenDisplay(dpyName);
+
+   if (!dpy) {
+      printf("Error: couldn't open display %s\n", dpyName ? dpyName : ":0");
+      return 1;
+   }
+
+   scrn = DefaultScreen(dpy);
+   PrintConfigs(dpy, scrn, horizFormat);
+   XCloseDisplay(dpy);
+   return 0;
+}
diff --git a/progs/xdemos/pbutil.c b/progs/xdemos/pbutil.c
new file mode 100644
index 00000000000..4451a6d1a5b
--- /dev/null
+++ b/progs/xdemos/pbutil.c
@@ -0,0 +1,230 @@
+/* $Id: pbutil.c,v 1.1 2002/10/05 18:30:13 brianp Exp $ */
+
+/*
+ * OpenGL pbuffers utility functions.
+ *
+ * Brian Paul
+ * April 1997
+ * Updated on 5 October 2002
+ */
+
+
+#include <stdio.h>
+#include <string.h>
+#include "pbutil.h"
+
+
+
+/*
+ * Test if we pixel buffers are available for a particular X screen.
+ * Input:  dpy - the X display
+ *         screen - screen number
+ * Return:  0 = pixel buffers not available.
+ *          1 = pixel buffers are available.
+ */
+int
+QueryPbuffers(Display *dpy, int screen)
+{
+#if defined(GLX_SGIX_fbconfig) && defined(GLX_SGIX_pbuffer)
+   char *extensions;
+
+   extensions = (char *) glXQueryServerString(dpy, screen, GLX_EXTENSIONS);
+   if (!strstr(extensions,"GLX_SGIX_fbconfig")) {
+      return 0;
+   }
+   if (!strstr(extensions,"GLX_SGIX_pbuffer")) {
+      return 0;
+   }
+   return 1;
+#else
+   return 0;
+#endif
+}
+
+
+
+#ifdef GLX_SGIX_fbconfig
+
+
+/*
+ * Print parameters for a GLXFBConfig to stdout.
+ * Input:  dpy - the X display
+ *         fbConfig - the fbconfig handle
+ *         horizFormat - if true, print in horizontal format
+ */
+void
+PrintFBConfigInfo(Display *dpy, GLXFBConfigSGIX fbConfig, Bool horizFormat)
+{
+   int pbAttribs[] = {GLX_LARGEST_PBUFFER_SGIX, True,
+		      GLX_PRESERVED_CONTENTS_SGIX, False,
+		      None};
+   GLXPbufferSGIX pBuffer;
+   int width=2, height=2;
+   int bufferSize, level, doubleBuffer, stereo, auxBuffers;
+   int redSize, greenSize, blueSize, alphaSize;
+   int depthSize, stencilSize;
+   int accumRedSize, accumBlueSize, accumGreenSize, accumAlphaSize;
+   int sampleBuffers, samples;
+   int drawableType, renderType, xRenderable, xVisual, id;
+   int maxWidth, maxHeight, maxPixels;
+   int optWidth, optHeight;
+
+   glXGetFBConfigAttribSGIX(dpy, fbConfig, GLX_BUFFER_SIZE, &bufferSize);
+   glXGetFBConfigAttribSGIX(dpy, fbConfig, GLX_LEVEL, &level);
+   glXGetFBConfigAttribSGIX(dpy, fbConfig, GLX_DOUBLEBUFFER, &doubleBuffer);
+   glXGetFBConfigAttribSGIX(dpy, fbConfig, GLX_STEREO, &stereo);
+   glXGetFBConfigAttribSGIX(dpy, fbConfig, GLX_AUX_BUFFERS, &auxBuffers);
+   glXGetFBConfigAttribSGIX(dpy, fbConfig, GLX_RED_SIZE, &redSize);
+   glXGetFBConfigAttribSGIX(dpy, fbConfig, GLX_GREEN_SIZE, &greenSize);
+   glXGetFBConfigAttribSGIX(dpy, fbConfig, GLX_BLUE_SIZE, &blueSize);
+   glXGetFBConfigAttribSGIX(dpy, fbConfig, GLX_ALPHA_SIZE, &alphaSize);
+   glXGetFBConfigAttribSGIX(dpy, fbConfig, GLX_DEPTH_SIZE, &depthSize);
+   glXGetFBConfigAttribSGIX(dpy, fbConfig, GLX_STENCIL_SIZE, &stencilSize);
+   glXGetFBConfigAttribSGIX(dpy, fbConfig, GLX_ACCUM_RED_SIZE, &accumRedSize);
+   glXGetFBConfigAttribSGIX(dpy, fbConfig, GLX_ACCUM_GREEN_SIZE, &accumGreenSize);
+   glXGetFBConfigAttribSGIX(dpy, fbConfig, GLX_ACCUM_BLUE_SIZE, &accumBlueSize);
+   glXGetFBConfigAttribSGIX(dpy, fbConfig, GLX_ACCUM_ALPHA_SIZE, &accumAlphaSize);
+   glXGetFBConfigAttribSGIX(dpy, fbConfig, GLX_SAMPLE_BUFFERS_SGIS, &sampleBuffers);
+   glXGetFBConfigAttribSGIX(dpy, fbConfig, GLX_SAMPLES_SGIS, &samples);
+   glXGetFBConfigAttribSGIX(dpy, fbConfig, GLX_DRAWABLE_TYPE_SGIX, &drawableType);
+   glXGetFBConfigAttribSGIX(dpy, fbConfig, GLX_RENDER_TYPE_SGIX, &renderType);
+   glXGetFBConfigAttribSGIX(dpy, fbConfig, GLX_X_RENDERABLE_SGIX, &xRenderable);
+   glXGetFBConfigAttribSGIX(dpy, fbConfig, GLX_X_VISUAL_TYPE_EXT, &xVisual);
+   if (!xRenderable || !(drawableType & GLX_WINDOW_BIT_SGIX))
+      xVisual = -1;
+   glXGetFBConfigAttribSGIX(dpy, fbConfig, GLX_FBCONFIG_ID_SGIX, &id);
+
+   glXGetFBConfigAttribSGIX(dpy, fbConfig, GLX_MAX_PBUFFER_WIDTH_SGIX,
+			    &maxWidth);
+   glXGetFBConfigAttribSGIX(dpy, fbConfig, GLX_MAX_PBUFFER_HEIGHT_SGIX,
+			    &maxHeight);
+   glXGetFBConfigAttribSGIX(dpy, fbConfig, GLX_MAX_PBUFFER_PIXELS_SGIX,
+			    &maxPixels);
+   glXGetFBConfigAttribSGIX(dpy, fbConfig, GLX_OPTIMAL_PBUFFER_WIDTH_SGIX,
+			    &optWidth);
+   glXGetFBConfigAttribSGIX(dpy, fbConfig, GLX_OPTIMAL_PBUFFER_HEIGHT_SGIX,
+			    &optHeight);
+
+   pBuffer = CreatePbuffer(dpy, fbConfig, width, height, pbAttribs);
+
+   if (horizFormat) {
+      printf("0x%03x ", id);
+      if (xVisual==GLX_STATIC_GRAY)        printf("StaticGray  ");
+      else if (xVisual==GLX_GRAY_SCALE)    printf("GrayScale   ");
+      else if (xVisual==GLX_STATIC_COLOR)  printf("StaticColor ");
+      else if (xVisual==GLX_PSEUDO_COLOR)  printf("PseudoColor ");
+      else if (xVisual==GLX_TRUE_COLOR)    printf("TrueColor   ");
+      else if (xVisual==GLX_DIRECT_COLOR)  printf("DirectColor ");
+      else                            printf("  -none-    ");
+      printf(" %3d %3d   %s   %s  %s   %2s   ", bufferSize, level,
+	     (renderType & GLX_RGBA_BIT_SGIX) ? "y" : "n",
+	     (renderType & GLX_COLOR_INDEX_BIT_SGIX) ? "y" : "n",
+	     doubleBuffer ? "y" : "n",
+	     stereo ? "y" : "n");
+      printf("%2d %2d %2d %2d  ", redSize, greenSize, blueSize, alphaSize);
+      printf("%2d %2d  ", depthSize, stencilSize);
+      printf("%2d %2d %2d %2d", accumRedSize, accumGreenSize, accumBlueSize,
+	     accumAlphaSize);
+      printf("    %2d    %2d", sampleBuffers, samples);
+      printf("       %s", pBuffer ? "y" : "n");
+      printf("\n");
+   }
+   else {
+      printf("Id 0x%x\n", id);
+      printf("  Buffer Size: %d\n", bufferSize);
+      printf("  Level: %d\n", level);
+      printf("  Double Buffer: %s\n", doubleBuffer ? "yes" : "no");
+      printf("  Stereo: %s\n", stereo ? "yes" : "no");
+      printf("  Aux Buffers: %d\n", auxBuffers);
+      printf("  Red Size: %d\n", redSize);
+      printf("  Green Size: %d\n", greenSize);
+      printf("  Blue Size: %d\n", blueSize);
+      printf("  Alpha Size: %d\n", alphaSize);
+      printf("  Depth Size: %d\n", depthSize);
+      printf("  Stencil Size: %d\n", stencilSize);
+      printf("  Accum Red Size: %d\n", accumRedSize);
+      printf("  Accum Green Size: %d\n", accumGreenSize);
+      printf("  Accum Blue Size: %d\n", accumBlueSize);
+      printf("  Accum Alpha Size: %d\n", accumAlphaSize);
+      printf("  Sample Buffers: %d\n", sampleBuffers);
+      printf("  Samples/Pixel: %d\n", samples);
+      printf("  Drawable Types: ");
+      if (drawableType & GLX_WINDOW_BIT_SGIX)  printf("Window ");
+      if (drawableType & GLX_PIXMAP_BIT_SGIX)  printf("Pixmap ");
+      if (drawableType & GLX_PBUFFER_BIT_SGIX)  printf("PBuffer");
+      printf("\n");
+      printf("  Render Types: ");
+      if (renderType & GLX_RGBA_BIT_SGIX)  printf("RGBA ");
+      if (renderType & GLX_COLOR_INDEX_BIT_SGIX)  printf("CI ");
+      printf("\n");
+      printf("  X Renderable: %s\n", xRenderable ? "yes" : "no");
+      /*
+      printf("  Max width: %d\n", maxWidth);
+      printf("  Max height: %d\n", maxHeight);
+      printf("  Max pixels: %d\n", maxPixels);
+      printf("  Optimum width: %d\n", optWidth);
+      printf("  Optimum height: %d\n", optHeight);
+      */
+      printf("  Pbuffer: %s\n", pBuffer ? "yes" : "no");
+   }
+
+   if (pBuffer) {
+      glXDestroyGLXPbufferSGIX(dpy, pBuffer);
+   }
+}
+
+
+
+/* This is only used by CreatePbuffer() */
+static int XErrorFlag = 0;
+static int HandleXError( Display *dpy, XErrorEvent *event )
+{
+    XErrorFlag = 1;
+    return 0;
+}
+
+
+/*
+ * Create a pixel buffer.  We loop over the list of fbconfigs trying to create
+ * a pixel buffer.  We return the first pixel buffer which we successfully
+ * create.  This function hides the ugliness of dealing with BadAlloc X
+ * protocol errors.
+ *
+ * Input:  dpy - the X display
+ *         fbConfig - an FBConfig as returned by glXChooseFBConfigSGIX().
+ *         width, height - size of pixel buffer to request, in pixels.
+ *         pbAttribs - list of pixel buffer attributes as used by
+ *                     glXCreateGLXPbufferSGIX().
+ * Return:  a pixel buffer or None.
+ */
+GLXPbufferSGIX
+CreatePbuffer( Display *dpy, GLXFBConfigSGIX fbConfig,
+	       int width, int height, int *pbAttribs )
+{
+   int (*oldHandler)( Display *, XErrorEvent * );
+   GLXPbufferSGIX pBuffer = None;
+
+   /* Catch X protocol errors with our own error handler */
+   oldHandler = XSetErrorHandler( HandleXError );
+
+   XErrorFlag = 0;
+   pBuffer = glXCreateGLXPbufferSGIX(dpy, fbConfig, width, height, pbAttribs);
+
+   /* Restore original X error handler */
+   (void) XSetErrorHandler( oldHandler );
+
+   /* Return pbuffer (may be None) */
+   if (!XErrorFlag && pBuffer!=None) {
+      /*printf("config %d worked!\n", i);*/
+      return pBuffer;
+   }
+   else {
+      return None;
+   }
+}
+
+
+
+#endif  /*GLX_SGIX_fbconfig*/
+
+
diff --git a/progs/xdemos/pbutil.h b/progs/xdemos/pbutil.h
new file mode 100644
index 00000000000..9230b47c311
--- /dev/null
+++ b/progs/xdemos/pbutil.h
@@ -0,0 +1,38 @@
+/* $Id: pbutil.h,v 1.1 2002/10/05 18:30:13 brianp Exp $ */
+
+/*
+ * OpenGL pbuffers utility functions.
+ *
+ * Brian Paul
+ * April 1997
+ */
+
+
+#ifndef PBUTIL_H
+#define PBUTIL_H
+
+
+#define GLX_GLXEXT_PROTOTYPES
+#include <GL/glx.h>
+
+
+extern int
+QueryPbuffers(Display *dpy, int screen);
+
+
+#ifdef GLX_SGIX_fbconfig
+
+
+extern void
+PrintFBConfigInfo(Display *dpy, GLXFBConfigSGIX fbConfig, Bool horizFormat);
+
+
+extern GLXPbufferSGIX
+CreatePbuffer( Display *dpy, GLXFBConfigSGIX fbConfig,
+	       int width, int height, int *pbAttribs );
+
+
+#endif  /*GLX_SGIX_fbconfig*/
+
+
+#endif  /*PBUTIL_H*/