/* $Id: fakeglx.c,v 1.12.2.10 2000/07/19 15:15:55 brianp Exp $ */

/*
 * Mesa 3-D graphics library
 * Version:  3.2.1
 * 
 * Copyright (C) 1999-2000  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.
 */





/*
 * A pseudo-GLX implementation to allow OpenGL/GLX programs to work with Mesa.
 * The Fake_glX*() functions implemented here are called from glxapi.c
 *
 * Thanks to the contributors:
 *
 * Initial version:  Philip Brown (philb@CSUA.Berkeley.EDU)
 * Better glXGetConfig() support: Armin Liebchen (liebchen@asylum.cs.utah.edu)
 * Further visual-handling refinements: Wolfram Gloger
 *    (wmglo@Dent.MED.Uni-Muenchen.DE).
 *
 * Notes:
 *   Don't be fooled, stereo isn't supported yet.
 */



#ifdef HAVE_CONFIG_H
#include "conf.h"
#endif

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include "GL/gl.h"
#include "GL/xmesa.h"
#include "context.h"
#include "config.h"
#include "fakeglx.h"
#include "macros.h"
#include "types.h"
#include "xmesaP.h"



/* Silence compiler warnings */
void Fake_glXDummyFunc( void )
{
   (void) kernel8;
   (void) DitherValues;
   (void) HPCR_DRGB;
   (void) kernel1;
}



#define DONT_CARE -1



#define MAX_VISUALS 100
static XMesaVisual VisualTable[MAX_VISUALS];
static int NumVisuals = 0;



/*
 * This struct and some code fragments borrowed
 * from Mark Kilgard's GLUT library.
 */
typedef struct _OverlayInfo {
  /* Avoid 64-bit portability problems by being careful to use
     longs due to the way XGetWindowProperty is specified. Note
     that these parameters are passed as CARD32s over X
     protocol. */
  unsigned long overlay_visual;
  long transparent_type;
  long value;
  long layer;
} OverlayInfo;



/* Macro to handle c_class vs class field name in XVisualInfo struct */
#if defined(__cplusplus) || defined(c_plusplus)
#define CLASS c_class
#else
#define CLASS class
#endif




/*
 * Test if the given XVisualInfo is usable for Mesa rendering.
 */
static GLboolean is_usable_visual( XVisualInfo *vinfo )
{
   switch (vinfo->CLASS) {
      case StaticGray:
      case GrayScale:
         /* Any StaticGray/GrayScale visual works in RGB or CI mode */
         return GL_TRUE;
      case StaticColor:
      case PseudoColor:
	 /* Any StaticColor/PseudoColor visual of at least 4 bits */
	 if (vinfo->depth>=4) {
	    return GL_TRUE;
	 }
	 else {
	    return GL_FALSE;
	 }
      case TrueColor:
      case DirectColor:
	 /* Any depth of TrueColor or DirectColor works in RGB mode */
	 return GL_TRUE;
      default:
	 /* This should never happen */
	 return GL_FALSE;
   }
}



/*
 * Return the level (overlay, normal, underlay) of a given XVisualInfo.
 * Input:  dpy - the X display
 *         vinfo - the XVisualInfo to test
 * Return:  level of the visual:
 *             0 = normal planes
 *            >0 = overlay planes
 *            <0 = underlay planes
 */
static int level_of_visual( Display *dpy, XVisualInfo *vinfo )
{
   Atom overlayVisualsAtom;
   OverlayInfo *overlay_info = NULL;
   int numOverlaysPerScreen;
   Status status;
   Atom actualType;
   int actualFormat;
   unsigned long sizeData, bytesLeft;
   int i;

   /*
    * The SERVER_OVERLAY_VISUALS property on the root window contains
    * a list of overlay visuals.  Get that list now.
    */
   overlayVisualsAtom = XInternAtom(dpy,"SERVER_OVERLAY_VISUALS", True);
   if (overlayVisualsAtom == None) {
      return 0;
   }

   status = XGetWindowProperty(dpy, RootWindow( dpy, vinfo->screen ),
                               overlayVisualsAtom, 0L, (long) 10000, False,
                               overlayVisualsAtom, &actualType, &actualFormat,
                               &sizeData, &bytesLeft,
                               (unsigned char **) &overlay_info );

   if (status != Success || actualType != overlayVisualsAtom ||
       actualFormat != 32 || sizeData < 4) {
      /* something went wrong */
      XFree((void *) overlay_info);
      return 0;
   }

   /* search the overlay visual list for the visual ID of interest */
   numOverlaysPerScreen = (int) (sizeData / 4);
   for (i=0;i<numOverlaysPerScreen;i++) {
      OverlayInfo *ov;
      ov = overlay_info + i;
      if (ov->overlay_visual==vinfo->visualid) {
         /* found the visual */
         if (/*ov->transparent_type==1 &&*/ ov->layer!=0) {
            int level = ov->layer;
            XFree((void *) overlay_info);
            return level;
         }
         else {
            XFree((void *) overlay_info);
            return 0;
         }
      }
   }

   /* The visual ID was not found in the overlay list. */
   XFree((void *) overlay_info);
   return 0;
}




/*
 * Given an XVisualInfo and RGB, Double, and Depth buffer flags, save the
 * configuration in our list of GLX visuals.
 */
static XMesaVisual
save_glx_visual( Display *dpy, XVisualInfo *vinfo,
                 GLboolean rgbFlag, GLboolean alphaFlag, GLboolean dbFlag,
                 GLboolean stereoFlag,
                 GLint depth_size, GLint stencil_size,
                 GLint accum_size, GLint level )
{
   GLboolean ximageFlag = GL_TRUE;
   XMesaVisual xmvis;
   GLint i;
   GLboolean comparePointers;

   if (dbFlag) {
      /* Check if the MESA_BACK_BUFFER env var is set */
      char *backbuffer = getenv("MESA_BACK_BUFFER");
      if (backbuffer) {
         if (backbuffer[0]=='p' || backbuffer[0]=='P') {
            ximageFlag = GL_FALSE;
         }
         else if (backbuffer[0]=='x' || backbuffer[0]=='X') {
            ximageFlag = GL_TRUE;
         }
         else {
            fprintf(stderr, "Mesa: invalid value for MESA_BACK_BUFFER ");
            fprintf(stderr, "environment variable, using an XImage.\n");
         }
      }
   }

   /* Comparing IDs uses less memory but sometimes fails. */
   /* XXX revisit this after 3.0 is finished. */
   if (getenv("MESA_GLX_VISUAL_HACK"))
      comparePointers = GL_TRUE;
   else
      comparePointers = GL_FALSE;

   /* First check if a matching visual is already in the list */
   for (i=0; i<NumVisuals; i++) {
      XMesaVisual v = VisualTable[i];
      if (v->display == dpy
          && v->level == level
          && v->ximage_flag == ximageFlag
          && v->gl_visual->RGBAflag == rgbFlag
          && v->gl_visual->DBflag == dbFlag
          && v->gl_visual->StereoFlag == stereoFlag
          && (v->gl_visual->AlphaBits > 0) == alphaFlag
          && (v->gl_visual->DepthBits >= depth_size || depth_size == 0)
          && (v->gl_visual->StencilBits >= stencil_size || stencil_size == 0)
          && (v->gl_visual->AccumBits >= accum_size || accum_size == 0)) {
         /* now either compare XVisualInfo pointers or visual IDs */
         if ((!comparePointers && v->visinfo->visualid == vinfo->visualid)
             || (comparePointers && v->vishandle == vinfo)) {
            return v;
         }
      }
   }

   /* Create a new visual and add it to the list. */

   if (NumVisuals>=MAX_VISUALS) {
      fprintf( stderr, "GLX Error: maximum number of visuals exceeded\n");
      return NULL;
   }

   xmvis = XMesaCreateVisual( dpy, vinfo, rgbFlag, alphaFlag, dbFlag,
                              stereoFlag, ximageFlag,
                              depth_size, stencil_size, accum_size, level );
   if (xmvis) {
      VisualTable[NumVisuals] = xmvis;
      NumVisuals++;
   }
   return xmvis;
}



/*
 * Create a GLX visual from a regular XVisualInfo.
 */
static XMesaVisual
create_glx_visual( Display *dpy, XVisualInfo *visinfo )
{
   int vislevel;

   vislevel = level_of_visual( dpy, visinfo );
   if (vislevel) {
      /* Configure this visual as a CI, single-buffered overlay */
      return save_glx_visual( dpy, visinfo,
                              GL_FALSE,  /* rgb */
                              GL_FALSE,  /* alpha */
                              GL_FALSE,  /* double */
                              GL_FALSE,  /* stereo */
                              0,         /* depth bits */
                              0,         /* stencil bits */
                              0,         /* accum bits */
                              vislevel   /* level */
                            );
   }
   else if (is_usable_visual( visinfo )) {
      /* Configure this visual as RGB, double-buffered, depth-buffered. */
      /* This is surely wrong for some people's needs but what else */
      /* can be done?  They should use glXChooseVisual(). */
      return save_glx_visual( dpy, visinfo,
                              GL_TRUE,   /* rgb */
                              GL_FALSE,  /* alpha */
                              GL_TRUE,   /* double */
                              GL_FALSE,  /* stereo */
                              8*sizeof(GLdepth),
                              8*sizeof(GLstencil),
                              8*sizeof(GLaccum),
                              0          /* level */
                            );
   }
   else {
      fprintf(stderr,"Mesa: error in glXCreateContext: bad visual\n");
      return NULL;
   }
}



/*
 * Find the GLX visual associated with an XVisualInfo.
 */
static XMesaVisual
find_glx_visual( Display *dpy, XVisualInfo *vinfo )
{
   int i;

   /* First try to match pointers */
   for (i=0;i<NumVisuals;i++) {
      if (VisualTable[i]->display==dpy && VisualTable[i]->vishandle==vinfo) {
         return VisualTable[i];
      }
   }
   /* try to match visual id */
   for (i=0;i<NumVisuals;i++) {
      if (VisualTable[i]->display==dpy
          && VisualTable[i]->visinfo->visualid == vinfo->visualid) {
         return VisualTable[i];
      }
   }
   return NULL;
}



/*
 * Return the transparent pixel value for a GLX visual.
 * Input:  glxvis - the glx_visual
 * Return:  a pixel value or -1 if no transparent pixel
 */
static int transparent_pixel( XMesaVisual glxvis )
{
   Display *dpy = glxvis->display;
   XVisualInfo *vinfo = glxvis->visinfo;
   Atom overlayVisualsAtom;
   OverlayInfo *overlay_info = NULL;
   int numOverlaysPerScreen;
   Status status;
   Atom actualType;
   int actualFormat;
   unsigned long sizeData, bytesLeft;
   int i;

   /*
    * The SERVER_OVERLAY_VISUALS property on the root window contains
    * a list of overlay visuals.  Get that list now.
    */
   overlayVisualsAtom = XInternAtom(dpy,"SERVER_OVERLAY_VISUALS", True);
   if (overlayVisualsAtom == None) {
      return -1;
   }

   status = XGetWindowProperty(dpy, RootWindow( dpy, vinfo->screen ),
                               overlayVisualsAtom, 0L, (long) 10000, False,
                               overlayVisualsAtom, &actualType, &actualFormat,
                               &sizeData, &bytesLeft,
                               (unsigned char **) &overlay_info );

   if (status != Success || actualType != overlayVisualsAtom ||
       actualFormat != 32 || sizeData < 4) {
      /* something went wrong */
      XFree((void *) overlay_info);
      return -1;
   }

   /* search the overlay visual list for the visual ID of interest */
   numOverlaysPerScreen = (int) (sizeData / 4);
   for (i=0;i<numOverlaysPerScreen;i++) {
      OverlayInfo *ov;
      ov = overlay_info + i;
      if (ov->overlay_visual==vinfo->visualid) {
         /* found it! */
         if (ov->transparent_type==0) {
            /* type 0 indicates no transparency */
            XFree((void *) overlay_info);
            return -1;
         }
         else {
            /* ov->value is the transparent pixel */
            XFree((void *) overlay_info);
            return ov->value;
         }
      }
   }

   /* The visual ID was not found in the overlay list. */
   XFree((void *) overlay_info);
   return -1;
}



/*
 * Return number of bits set in n.
 */
static int bitcount( unsigned long n )
{
   int bits;
   for (bits=0; n>0; n=n>>1) {
      if (n&1) {
         bits++;
      }
   }
   return bits;
}


/*
 * Try to get an X visual which matches the given arguments.
 */
static XVisualInfo *get_visual( Display *dpy, int scr,
			        unsigned int depth, int xclass )
{
   XVisualInfo temp, *vis;
   long mask;
   int n;
   unsigned int default_depth;
   int default_class;

   mask = VisualScreenMask | VisualDepthMask | VisualClassMask;
   temp.screen = scr;
   temp.depth = depth;
   temp.CLASS = xclass;

   default_depth = DefaultDepth(dpy,scr);
   default_class = DefaultVisual(dpy,scr)->CLASS;

   if (depth==default_depth && xclass==default_class) {
      /* try to get root window's visual */
      temp.visualid = DefaultVisual(dpy,scr)->visualid;
      mask |= VisualIDMask;
   }

   vis = XGetVisualInfo( dpy, mask, &temp, &n );

   /* In case bits/pixel > 24, make sure color channels are still <=8 bits.
    * An SGI Infinite Reality system, for example, can have 30bpp pixels:
    * 10 bits per color channel.  Mesa's limited to a max of 8 bits/channel.
    */
   if (vis && depth > 24 && (xclass==TrueColor || xclass==DirectColor)) {
      if (bitcount(vis->red_mask) <= 8
          && bitcount(vis->green_mask) <= 8
          && bitcount(vis->blue_mask) <= 8) {
         return vis;
      }
      else {
         XFree((void *) vis);
         return NULL;
      }
   }

   return vis;
}



/*
 * Retrieve the value of the given environment variable and find
 * the X visual which matches it.
 * Input:  dpy - the display
 *         screen - the screen number
 *         varname - the name of the environment variable
 * Return:  an XVisualInfo pointer to NULL if error.
 */
static XVisualInfo *get_env_visual(Display *dpy, int scr, const char *varname)
{
   char value[100], type[100];
   int depth, xclass = -1;
   XVisualInfo *vis;

   if (!getenv( varname )) {
      return NULL;
   }

   strncpy( value, getenv(varname), 100 );
   value[99] = 0;

   sscanf( value, "%s %d", type, &depth );

   if (strcmp(type,"TrueColor")==0)          xclass = TrueColor;
   else if (strcmp(type,"DirectColor")==0)   xclass = DirectColor;
   else if (strcmp(type,"PseudoColor")==0)   xclass = PseudoColor;
   else if (strcmp(type,"StaticColor")==0)   xclass = StaticColor;
   else if (strcmp(type,"GrayScale")==0)     xclass = GrayScale;
   else if (strcmp(type,"StaticGray")==0)    xclass = StaticGray;

   if (xclass>-1 && depth>0) {
      vis = get_visual( dpy, scr, depth, xclass );
      if (vis) {
	 return vis;
      }
   }

   fprintf( stderr, "Mesa: GLX unable to find visual class=%s, depth=%d.\n",
	    type, depth );
   return NULL;
}



/*
 * Select an X visual which satisfies the RGBA/CI flag and minimum depth.
 * Input:  dpy, screen - X display and screen number
 *         rgba - GL_TRUE = RGBA mode, GL_FALSE = CI mode
 *         min_depth - minimum visual depth
 *         preferred_class - preferred GLX visual class or DONT_CARE
 * Return:  pointer to an XVisualInfo or NULL.
 */
static XVisualInfo *choose_x_visual( Display *dpy, int screen,
				     GLboolean rgba, int min_depth,
                                     int preferred_class )
{
   XVisualInfo *vis;
   int xclass, visclass;
   int depth;

   if (rgba) {
      Atom hp_cr_maps = XInternAtom(dpy, "_HP_RGB_SMOOTH_MAP_LIST", True);
      /* First see if the MESA_RGB_VISUAL env var is defined */
      vis = get_env_visual( dpy, screen, "MESA_RGB_VISUAL" );
      if (vis) {
	 return vis;
      }
      /* Otherwise, search for a suitable visual */
      if (preferred_class==DONT_CARE) {
         for (xclass=0;xclass<6;xclass++) {
            switch (xclass) {
               case 0:  visclass = TrueColor;    break;
               case 1:  visclass = DirectColor;  break;
               case 2:  visclass = PseudoColor;  break;
               case 3:  visclass = StaticColor;  break;
               case 4:  visclass = GrayScale;    break;
               case 5:  visclass = StaticGray;   break;
            }
            if (min_depth==0) {
               /* start with shallowest */
               for (depth=0;depth<=32;depth++) {
                  if (visclass==TrueColor && depth==8 && !hp_cr_maps) {
                     /* Special case:  try to get 8-bit PseudoColor before */
                     /* 8-bit TrueColor */
                     vis = get_visual( dpy, screen, 8, PseudoColor );
                     if (vis) {
                        return vis;
                     }
                  }
                  vis = get_visual( dpy, screen, depth, visclass );
                  if (vis) {
                     return vis;
                  }
               }
            }
            else {
               /* start with deepest */
               for (depth=32;depth>=min_depth;depth--) {
                  if (visclass==TrueColor && depth==8 && !hp_cr_maps) {
                     /* Special case:  try to get 8-bit PseudoColor before */
                     /* 8-bit TrueColor */
                     vis = get_visual( dpy, screen, 8, PseudoColor );
                     if (vis) {
                        return vis;
                     }
                  }
                  vis = get_visual( dpy, screen, depth, visclass );
                  if (vis) {
                     return vis;
                  }
               }
            }
         }
      }
      else {
         /* search for a specific visual class */
         switch (preferred_class) {
            case GLX_TRUE_COLOR_EXT:    visclass = TrueColor;    break;
            case GLX_DIRECT_COLOR_EXT:  visclass = DirectColor;  break;
            case GLX_PSEUDO_COLOR_EXT:  visclass = PseudoColor;  break;
            case GLX_STATIC_COLOR_EXT:  visclass = StaticColor;  break;
            case GLX_GRAY_SCALE_EXT:    visclass = GrayScale;    break;
            case GLX_STATIC_GRAY_EXT:   visclass = StaticGray;   break;
            default:   return NULL;
         }
         if (min_depth==0) {
            /* start with shallowest */
            for (depth=0;depth<=32;depth++) {
               vis = get_visual( dpy, screen, depth, visclass );
               if (vis) {
                  return vis;
               }
            }
         }
         else {
            /* start with deepest */
            for (depth=32;depth>=min_depth;depth--) {
               vis = get_visual( dpy, screen, depth, visclass );
               if (vis) {
                  return vis;
               }
            }
         }
      }
   }
   else {
      /* First see if the MESA_CI_VISUAL env var is defined */
      vis = get_env_visual( dpy, screen, "MESA_CI_VISUAL" );
      if (vis) {
	 return vis;
      }
      /* Otherwise, search for a suitable visual, starting with shallowest */
      if (preferred_class==DONT_CARE) {
         for (xclass=0;xclass<4;xclass++) {
            switch (xclass) {
               case 0:  visclass = PseudoColor;  break;
               case 1:  visclass = StaticColor;  break;
               case 2:  visclass = GrayScale;    break;
               case 3:  visclass = StaticGray;   break;
            }
            /* try 8-bit up through 16-bit */
            for (depth=8;depth<=16;depth++) {
               vis = get_visual( dpy, screen, depth, visclass );
               if (vis) {
                  return vis;
               }
            }
            /* try min_depth up to 8-bit */
            for (depth=min_depth;depth<8;depth++) {
               vis = get_visual( dpy, screen, depth, visclass );
               if (vis) {
                  return vis;
               }
            }
         }
      }
      else {
         /* search for a specific visual class */
         switch (preferred_class) {
            case GLX_TRUE_COLOR_EXT:    visclass = TrueColor;    break;
            case GLX_DIRECT_COLOR_EXT:  visclass = DirectColor;  break;
            case GLX_PSEUDO_COLOR_EXT:  visclass = PseudoColor;  break;
            case GLX_STATIC_COLOR_EXT:  visclass = StaticColor;  break;
            case GLX_GRAY_SCALE_EXT:    visclass = GrayScale;    break;
            case GLX_STATIC_GRAY_EXT:   visclass = StaticGray;   break;
            default:   return NULL;
         }
         /* try 8-bit up through 16-bit */
         for (depth=8;depth<=16;depth++) {
            vis = get_visual( dpy, screen, depth, visclass );
            if (vis) {
               return vis;
            }
         }
         /* try min_depth up to 8-bit */
         for (depth=min_depth;depth<8;depth++) {
            vis = get_visual( dpy, screen, depth, visclass );
            if (vis) {
               return vis;
            }
         }
      }
   }

   /* didn't find a visual */
   return NULL;
}



/*
 * Find the deepest X over/underlay visual of at least min_depth.
 * Input:  dpy, screen - X display and screen number
 *         level - the over/underlay level
 *         trans_type - transparent pixel type: GLX_NONE_EXT,
 *                      GLX_TRANSPARENT_RGB_EXT, GLX_TRANSPARENT_INDEX_EXT,
 *                      or DONT_CARE
 *         trans_value - transparent pixel value or DONT_CARE
 *         min_depth - minimum visual depth
 *         preferred_class - preferred GLX visual class or DONT_CARE
 * Return:  pointer to an XVisualInfo or NULL.
 */
static XVisualInfo *choose_x_overlay_visual( Display *dpy, int scr,
                                             GLboolean rgbFlag,
                                             int level, int trans_type,
                                             int trans_value,
                                             int min_depth,
                                             int preferred_class )
{
   Atom overlayVisualsAtom;
   OverlayInfo *overlay_info;
   int numOverlaysPerScreen;
   Status status;
   Atom actualType;
   int actualFormat;
   unsigned long sizeData, bytesLeft;
   int i;
   XVisualInfo *deepvis;
   int deepest;

   /*DEBUG int tt, tv; */

   switch (preferred_class) {
      case GLX_TRUE_COLOR_EXT:    preferred_class = TrueColor;    break;
      case GLX_DIRECT_COLOR_EXT:  preferred_class = DirectColor;  break;
      case GLX_PSEUDO_COLOR_EXT:  preferred_class = PseudoColor;  break;
      case GLX_STATIC_COLOR_EXT:  preferred_class = StaticColor;  break;
      case GLX_GRAY_SCALE_EXT:    preferred_class = GrayScale;    break;
      case GLX_STATIC_GRAY_EXT:   preferred_class = StaticGray;   break;
      default:                    preferred_class = DONT_CARE;
   }

   /*
    * The SERVER_OVERLAY_VISUALS property on the root window contains
    * a list of overlay visuals.  Get that list now.
    */
   overlayVisualsAtom = XInternAtom(dpy,"SERVER_OVERLAY_VISUALS", True);
   if (overlayVisualsAtom == (Atom) None) {
      return NULL;
   }

   status = XGetWindowProperty(dpy, RootWindow( dpy, scr ),
                               overlayVisualsAtom, 0L, (long) 10000, False,
                               overlayVisualsAtom, &actualType, &actualFormat,
                               &sizeData, &bytesLeft,
                               (unsigned char **) &overlay_info );

   if (status != Success || actualType != overlayVisualsAtom ||
       actualFormat != 32 || sizeData < 4) {
      /* something went wrong */
      return NULL;
   }

   /* Search for the deepest overlay which satisifies all criteria. */
   deepest = min_depth;
   deepvis = NULL;

   numOverlaysPerScreen = (int) (sizeData / 4);
   for (i=0;i<numOverlaysPerScreen;i++) {
      XVisualInfo *vislist, vistemplate;
      int count;
      OverlayInfo *ov;
      ov = overlay_info + i;

      if (ov->layer!=level) {
         /* failed overlay level criteria */
         continue;
      }
      if (!(trans_type==DONT_CARE
            || (trans_type==GLX_TRANSPARENT_INDEX_EXT
                && ov->transparent_type>0)
            || (trans_type==GLX_NONE_EXT && ov->transparent_type==0))) {
         /* failed transparent pixel type criteria */
         continue;
      }
      if (trans_value!=DONT_CARE && trans_value!=ov->value) {
         /* failed transparent pixel value criteria */
         continue;
      }

      /* get XVisualInfo and check the depth */
      vistemplate.visualid = ov->overlay_visual;
      vistemplate.screen = scr;
      vislist = XGetVisualInfo( dpy, VisualIDMask | VisualScreenMask,
                                &vistemplate, &count );

      if (count!=1) {
         /* something went wrong */
         continue;
      }
      if (preferred_class!=DONT_CARE && preferred_class!=vislist->CLASS) {
         /* wrong visual class */
         continue;
      }

      /* if RGB was requested, make sure we have True/DirectColor */
      if (rgbFlag && vislist->CLASS != TrueColor
          && vislist->CLASS != DirectColor)
         continue;

      /* if CI was requested, make sure we have a color indexed visual */
      if (!rgbFlag
          && (vislist->CLASS == TrueColor || vislist->CLASS == DirectColor))
         continue;

      if (deepvis==NULL || vislist->depth > deepest) {
         /* YES!  found a satisfactory visual */
         if (deepvis) {
            XFree( deepvis );
         }
         deepest = vislist->depth;
         deepvis = vislist;
         /* DEBUG  tt = ov->transparent_type;*/
         /* DEBUG  tv = ov->value; */
      }
   }

/*DEBUG
   if (deepvis) {
      printf("chose 0x%x:  layer=%d depth=%d trans_type=%d trans_value=%d\n",
             deepvis->visualid, level, deepvis->depth, tt, tv );
   }
*/
   return deepvis;
}



XVisualInfo *Fake_glXChooseVisual( Display *dpy, int screen, int *list )
{
   int *parselist;
   XVisualInfo *vis;
   int min_ci = 0;
   int min_red=0, min_green=0, min_blue=0;
   GLboolean rgb_flag = GL_FALSE;
   GLboolean alpha_flag = GL_FALSE;
   GLboolean double_flag = GL_FALSE;
   GLboolean stereo_flag = GL_FALSE;
   GLint depth_size = 0;
   GLint stencil_size = 0;
   GLint accum_size = 0;
   int level = 0;
   int visual_type = DONT_CARE;
   int trans_type = DONT_CARE;
   int trans_value = DONT_CARE;

   parselist = list;

   while (*parselist) {

      switch (*parselist) {
	 case GLX_USE_GL:
	    /* ignore */
	    parselist++;
	    break;
	 case GLX_BUFFER_SIZE:
	    parselist++;
	    min_ci = *parselist++;
	    break;
	 case GLX_LEVEL:
	    parselist++;
            level = *parselist++;
	    break;
	 case GLX_RGBA:
	    rgb_flag = GL_TRUE;
	    parselist++;
	    break;
	 case GLX_DOUBLEBUFFER:
	    double_flag = GL_TRUE;
	    parselist++;
	    break;
	 case GLX_STEREO:
            stereo_flag = GL_TRUE;
            return NULL;
	 case GLX_AUX_BUFFERS:
	    /* ignore */
	    parselist++;
	    parselist++;
	    break;
	 case GLX_RED_SIZE:
	    parselist++;
	    min_red = *parselist++;
	    break;
	 case GLX_GREEN_SIZE:
	    parselist++;
	    min_green = *parselist++;
	    break;
	 case GLX_BLUE_SIZE:
	    parselist++;
	    min_blue = *parselist++;
	    break;
	 case GLX_ALPHA_SIZE:
	    parselist++;
            {
               GLint size = *parselist++;
               alpha_flag = size>0 ? 1 : 0;
            }
	    break;
	 case GLX_DEPTH_SIZE:
	    parselist++;
	    depth_size = *parselist++;
	    break;
	 case GLX_STENCIL_SIZE:
	    parselist++;
	    stencil_size = *parselist++;
	    break;
	 case GLX_ACCUM_RED_SIZE:
	 case GLX_ACCUM_GREEN_SIZE:
	 case GLX_ACCUM_BLUE_SIZE:
	 case GLX_ACCUM_ALPHA_SIZE:
	    parselist++;
            {
               GLint size = *parselist++;
               accum_size = MAX2( accum_size, size );
            }
	    break;

         /*
          * GLX_EXT_visual_info extension
          */
         case GLX_X_VISUAL_TYPE_EXT:
            parselist++;
            visual_type = *parselist++;
            break;
         case GLX_TRANSPARENT_TYPE_EXT:
            parselist++;
            trans_type = *parselist++;
            break;
         case GLX_TRANSPARENT_INDEX_VALUE_EXT:
            parselist++;
            trans_value = *parselist++;
            break;
         case GLX_TRANSPARENT_RED_VALUE_EXT:
         case GLX_TRANSPARENT_GREEN_VALUE_EXT:
         case GLX_TRANSPARENT_BLUE_VALUE_EXT:
         case GLX_TRANSPARENT_ALPHA_VALUE_EXT:
	    /* ignore */
	    parselist++;
	    parselist++;
	    break;
         
	 case None:
	    break;
	 default:
	    /* undefined attribute */
	    return NULL;
      }
   }

   /*
    * Since we're only simulating the GLX extension this function will never
    * find any real GL visuals.  Instead, all we can do is try to find an RGB
    * or CI visual of appropriate depth.  Other requested attributes such as
    * double buffering, depth buffer, etc. will be associated with the X
    * visual and stored in the VisualTable[].
    */
   if (level==0) {
      /* normal color planes */
      if (rgb_flag) {
         /* Get an RGB visual */
         int min_rgb = min_red + min_green + min_blue;
         if (min_rgb>1 && min_rgb<8) {
            /* a special case to be sure we can get a monochrome visual */
            min_rgb = 1;
         }
         vis = choose_x_visual( dpy, screen, rgb_flag, min_rgb, visual_type );
      }
      else {
         /* Get a color index visual */
         vis = choose_x_visual( dpy, screen, rgb_flag, min_ci, visual_type );
         accum_size = 0;
      }
   }
   else {
      /* over/underlay planes */
      if (rgb_flag) {
         /* rgba overlay */
         int min_rgb = min_red + min_green + min_blue;
         if (min_rgb>1 && min_rgb<8) {
            /* a special case to be sure we can get a monochrome visual */
            min_rgb = 1;
         }
         vis = choose_x_overlay_visual( dpy, screen, rgb_flag, level,
                              trans_type, trans_value, min_rgb, visual_type );
      }
      else {
         /* color index overlay */
         vis = choose_x_overlay_visual( dpy, screen, rgb_flag, level,
                              trans_type, trans_value, min_ci, visual_type );
      }
   }

   if (vis) {
      if (!save_glx_visual( dpy, vis, rgb_flag, alpha_flag, double_flag,
                            stereo_flag,
                            depth_size, stencil_size, accum_size, level ))
         return NULL;
   }

   return vis;
}




GLXContext Fake_glXCreateContext( Display *dpy, XVisualInfo *visinfo,
                                  GLXContext share_list, Bool direct )
{
   XMesaVisual glxvis;
   XMesaContext xmctx;

   /* deallocate unused windows/buffers */
   XMesaGarbageCollect();

   glxvis = find_glx_visual( dpy, visinfo );
   if (!glxvis) {
      /* This visual wasn't found with glXChooseVisual() */
      glxvis = create_glx_visual( dpy, visinfo );
      if (!glxvis) {
         /* unusable visual */
         return NULL;
      }
   }

   xmctx = XMesaCreateContext( glxvis, (XMesaContext) share_list );
   if (xmctx) {
      /* set the direct/indirect flag */
      xmctx->direct = direct;
   }
   return (GLXContext) xmctx;
}


static GLXDrawable MakeCurrent_PrevDrawable = 0;
static GLXContext MakeCurrent_PrevContext = 0;
static XMesaBuffer MakeCurrent_PrevBuffer = 0;

Bool Fake_glXMakeCurrent( Display *dpy, GLXDrawable drawable, GLXContext ctx )
{
   if (ctx && drawable) {
      XMesaBuffer buffer;

      if (drawable==MakeCurrent_PrevDrawable && ctx==MakeCurrent_PrevContext) {
         buffer = MakeCurrent_PrevBuffer;
      }
      else {
         buffer = XMesaFindBuffer( dpy, drawable );
      }
      if (!buffer) {
         /* drawable must be a new window! */
         buffer = XMesaCreateWindowBuffer2( ctx->xm_visual, drawable, ctx );
         if (!buffer) {
            /* Out of memory, or context/drawable depth mismatch */
            return False;
         }
      }
      MakeCurrent_PrevContext = ctx;
      MakeCurrent_PrevDrawable = drawable;
      MakeCurrent_PrevBuffer = buffer;

      /* Now make current! */
      return (Bool) XMesaMakeCurrent( (XMesaContext) ctx, buffer );
   }
   else if (!ctx && !drawable) {
      /* release current context w/out assigning new one. */
      XMesaMakeCurrent( NULL, NULL );
      MakeCurrent_PrevContext = 0;
      MakeCurrent_PrevDrawable = 0;
      MakeCurrent_PrevBuffer = 0;
      return True;
   }
   else {
      /* ctx XOR drawable is NULL, this is an error */
      return False;
   }
}



GLXPixmap Fake_glXCreateGLXPixmap( Display *dpy, XVisualInfo *visinfo,
                                   Pixmap pixmap )
{
   XMesaVisual v;
   XMesaBuffer b;

   v = find_glx_visual( dpy, visinfo );
   if (!v) {
      v = create_glx_visual( dpy, visinfo );
      if (!v) {
         /* unusable visual */
         return 0;
      }
   }

   b = XMesaCreatePixmapBuffer( v, pixmap, 0 );
   if (!b) {
      return 0;
   }
   return b->frontbuffer;
}


#ifdef GLX_MESA_pixmap_colormap

GLXPixmap Fake_glXCreateGLXPixmapMESA( Display *dpy, XVisualInfo *visinfo,
                                       Pixmap pixmap, Colormap cmap )
{
   XMesaVisual v;
   XMesaBuffer b;

   v = find_glx_visual( dpy, visinfo );
   if (!v) {
      v = create_glx_visual( dpy, visinfo );
      if (!v) {
         /* unusable visual */
         return 0;
      }
   }

   b = XMesaCreatePixmapBuffer( v, pixmap, cmap );
   if (!b) {
      return 0;
   }
   return b->frontbuffer;
}

#endif


void Fake_glXDestroyGLXPixmap( Display *dpy, GLXPixmap pixmap )
{
   XMesaBuffer b = XMesaFindBuffer(dpy, pixmap);
   if (b) {
      XMesaDestroyBuffer(b);
   }
   else if (getenv("MESA_DEBUG")) {
      fprintf( stderr, "Mesa: glXDestroyGLXPixmap: invalid pixmap\n");
   }
}


void Fake_glXCopyContext( Display *dpy, GLXContext src, GLXContext dst,
                          unsigned long mask )
{
   XMesaContext xm_src = (XMesaContext) src;
   XMesaContext xm_dst = (XMesaContext) dst;
   (void) dpy;
   gl_copy_context( xm_src->gl_ctx, xm_dst->gl_ctx, (GLuint) mask );
}



Bool Fake_glXQueryExtension( Display *dpy, int *errorb, int *event )
{
   /* Mesa's GLX isn't really an X extension but we try to act like one. */
   (void) dpy;
   (void) errorb;
   (void) event;
   return True;
}


void _kw_ungrab_all( Display *dpy )
{
   XUngrabPointer( dpy, CurrentTime );
   XUngrabKeyboard( dpy, CurrentTime );
}


void Fake_glXDestroyContext( Display *dpy, GLXContext ctx )
{
   (void) dpy;
   MakeCurrent_PrevContext = 0;
   MakeCurrent_PrevDrawable = 0;
   MakeCurrent_PrevBuffer = 0;
   XMesaDestroyContext( (XMesaContext) ctx );
   XMesaGarbageCollect();
}



Bool Fake_glXIsDirect( Display *dpy, GLXContext ctx )
{
   (void) dpy;
   return ((XMesaContext) ctx)->direct;
}



void Fake_glXSwapBuffers( Display *dpy, GLXDrawable drawable )
{
   XMesaBuffer buffer = XMesaFindBuffer( dpy, drawable );

   if (buffer) {
      XMesaSwapBuffers(buffer);
   }
   else if (getenv("MESA_DEBUG")) {
      fprintf(stderr, "Mesa Warning: glXSwapBuffers: invalid drawable\n");
   }
}


void Fake_glXCopySubBufferMESA( Display *dpy, GLXDrawable drawable,
				int x, int y, int width, int height )
{
   XMesaBuffer buffer = XMesaFindBuffer( dpy, drawable );
   if (buffer) {
      XMesaCopySubBuffer(buffer, x, y, width, height);
   }
   else if (getenv("MESA_DEBUG")) {
      fprintf(stderr, "Mesa Warning: glXCopySubBufferMESA: invalid drawable\n");
   }
}



Bool Fake_glXQueryVersion( Display *dpy, int *maj, int *min )
{
   (void) dpy;
   /* Return GLX version, not Mesa version */
   *maj = 1;
   *min = 1;
   return True;
}



/*
 * Query the GLX attributes of the given XVisualInfo.
 */
int Fake_glXGetConfig( Display *dpy, XVisualInfo *visinfo,
                       int attrib, int *value )
{
   XMesaVisual glxvis;

   glxvis = find_glx_visual( dpy, visinfo );
   if (!glxvis) {
      /* this visual wasn't obtained with glXChooseVisual */
      glxvis = create_glx_visual( dpy, visinfo );
      if (!glxvis) {
	 /* this visual can't be used for GL rendering */
	 if (attrib==GLX_USE_GL) {
	    *value = (int) False;
	    return 0;
	 }
	 else {
	    /*fprintf( stderr, "Mesa: Error in glXGetConfig: bad visual\n");*/
	    return GLX_BAD_VISUAL;
	 }
      }
   }

   switch(attrib) {
      case GLX_USE_GL:
         *value = (int) True;
	 return 0;
      case GLX_BUFFER_SIZE:
	 *value = visinfo->depth;
	 return 0;
      case GLX_LEVEL:
	 *value = glxvis->level;
	 return 0;
      case GLX_RGBA:
	 if (glxvis->gl_visual->RGBAflag) {
	    *value = True;
	 }
	 else {
	    *value = False;
	 }
	 return 0;
      case GLX_DOUBLEBUFFER:
	 *value = (int) glxvis->gl_visual->DBflag;
	 return 0;
      case GLX_STEREO:
	 *value = (int) glxvis->gl_visual->StereoFlag;
	 return 0;
      case GLX_AUX_BUFFERS:
	 *value = (int) False;
	 return 0;
      case GLX_RED_SIZE:
         *value = glxvis->gl_visual->RedBits;
	 return 0;
      case GLX_GREEN_SIZE:
         *value = glxvis->gl_visual->GreenBits;
	 return 0;
      case GLX_BLUE_SIZE:
         *value = glxvis->gl_visual->BlueBits;
	 return 0;
      case GLX_ALPHA_SIZE:
         *value = glxvis->gl_visual->AlphaBits;
	 return 0;
      case GLX_DEPTH_SIZE:
         *value = glxvis->gl_visual->DepthBits;
	 return 0;
      case GLX_STENCIL_SIZE:
	 *value = glxvis->gl_visual->StencilBits;
	 return 0;
      case GLX_ACCUM_RED_SIZE:
      case GLX_ACCUM_GREEN_SIZE:
      case GLX_ACCUM_BLUE_SIZE:
	 *value = glxvis->gl_visual->AccumBits;
	 return 0;
      case GLX_ACCUM_ALPHA_SIZE:
         if (glxvis->gl_visual->AlphaBits > 0)
            *value = glxvis->gl_visual->AccumBits;
         else
            *value = 0;
	 return 0;

      /*
       * GLX_EXT_visual_info extension
       */
      case GLX_X_VISUAL_TYPE_EXT:
         switch (glxvis->visinfo->CLASS) {
            case StaticGray:   *value = GLX_STATIC_GRAY_EXT;   return 0;
            case GrayScale:    *value = GLX_GRAY_SCALE_EXT;    return 0;
            case StaticColor:  *value = GLX_STATIC_GRAY_EXT;   return 0;
            case PseudoColor:  *value = GLX_PSEUDO_COLOR_EXT;  return 0;
            case TrueColor:    *value = GLX_TRUE_COLOR_EXT;    return 0;
            case DirectColor:  *value = GLX_DIRECT_COLOR_EXT;  return 0;
         }
         return 0;
      case GLX_TRANSPARENT_TYPE_EXT:
         if (glxvis->level==0) {
            /* normal planes */
            *value = GLX_NONE_EXT;
         }
         else if (glxvis->level>0) {
            /* overlay */
            if (glxvis->gl_visual->RGBAflag) {
               *value = GLX_TRANSPARENT_RGB_EXT;
            }
            else {
               *value = GLX_TRANSPARENT_INDEX_EXT;
            }
         }
         else if (glxvis->level<0) {
            /* underlay */
            *value = GLX_NONE_EXT;
         }
         return 0;
      case GLX_TRANSPARENT_INDEX_VALUE_EXT:
         {
            int pixel = transparent_pixel( glxvis );
            if (pixel>=0) {
               *value = pixel;
            }
            /* else undefined */
         }
         return 0;
      case GLX_TRANSPARENT_RED_VALUE_EXT:
         /* undefined */
         return 0;
      case GLX_TRANSPARENT_GREEN_VALUE_EXT:
         /* undefined */
         return 0;
      case GLX_TRANSPARENT_BLUE_VALUE_EXT:
         /* undefined */
         return 0;
      case GLX_TRANSPARENT_ALPHA_VALUE_EXT:
         /* undefined */
         return 0;

      /*
       * Extensions
       */
      default:
	 return GLX_BAD_ATTRIBUTE;
   }
}



GLXContext Fake_glXGetCurrentContext( void )
{
   return (GLXContext) XMesaGetCurrentContext();
}



GLXDrawable Fake_glXGetCurrentDrawable( void )
{
   XMesaBuffer b = XMesaGetCurrentBuffer();
   if (b) {
      return b->frontbuffer;
   }
   else {
      return 0;
   }
}


void Fake_glXWaitGL( void )
{
   XMesaContext xmesa = XMesaGetCurrentContext();
   XMesaFlush( xmesa );
}



void Fake_glXWaitX( void )
{
   XMesaContext xmesa = XMesaGetCurrentContext();
   XMesaFlush( xmesa );
}


/*
 * Return the extensions string, which is 3Dfx-dependant.
 */
static const char *get_extensions( void )
{
#ifdef FX
   const char *fx = getenv("MESA_GLX_FX");
   if (fx && fx[0] != 'd') {
      return "GLX_MESA_pixmap_colormap GLX_EXT_visual_info GLX_MESA_release_buffers GLX_MESA_copy_sub_buffer GLX_SGI_video_sync GLX_MESA_set_3dfx_mode GLX_ARB_get_proc_address";
   }
#endif
   return "GLX_MESA_pixmap_colormap GLX_EXT_visual_info GLX_MESA_release_buffers GLX_MESA_copy_sub_buffer GLX_SGI_video_sync GLX_ARB_get_proc_address";
}



/* GLX 1.1 and later */
const char *Fake_glXQueryExtensionsString( Display *dpy, int screen )
{
   (void) dpy;
   (void) screen;
   return get_extensions();
}



/* GLX 1.1 and later */
const char *Fake_glXQueryServerString( Display *dpy, int screen, int name )
{
   static char *vendor = "Brian Paul";
   static char *version = "1.1 Mesa 3.2.1";

   (void) dpy;
   (void) screen;

   switch (name) {
      case GLX_EXTENSIONS:
         return get_extensions();
      case GLX_VENDOR:
	 return vendor;
      case GLX_VERSION:
	 return version;
      default:
         return NULL;
   }
}



/* GLX 1.1 and later */
const char *Fake_glXGetClientString( Display *dpy, int name )
{
   static char *vendor = "Brian Paul";
   static char *version = "1.1 Mesa 3.2.1";

   (void) dpy;

   switch (name) {
      case GLX_EXTENSIONS:
         return get_extensions();
      case GLX_VENDOR:
	 return vendor;
      case GLX_VERSION:
	 return version;
      default:
         return NULL;
   }
}



/*
 * Release the depth, stencil, accum buffers attached to a GLXDrawable
 * (a window or pixmap) prior to destroying the GLXDrawable.
 */
Bool Fake_glXReleaseBuffersMESA( Display *dpy, GLXDrawable d )
{
   XMesaBuffer b = XMesaFindBuffer(dpy, d);
   if (b) {
      XMesaDestroyBuffer(b);
      return True;
   }
   return False;
}


/*
 * GLX_MESA_set_3dfx_mode
 */
GLboolean Fake_glXSet3DfxModeMESA( GLint mode )
{
   return XMesaSetFXmode( mode );
}



void (*Fake_glXGetProcAddress( const GLubyte *procName ))()
{
   typedef void (*gl_function)();
   struct proc {
      const char *name;
      gl_function address;
   };
   static struct proc procTable[] = {
      /* GLX 1.0 functions */
      { "glXChooseVisual", (gl_function) glXChooseVisual },
      { "glXCopyContext", (gl_function) glXCopyContext },
      { "glXCreateContext", (gl_function) glXCreateContext },
      { "glXCreateGLXPixmap", (gl_function) glXCreateGLXPixmap },
      { "glXDestroyContext", (gl_function) glXDestroyContext },
      { "glXDestroyGLXPixmap", (gl_function) glXDestroyGLXPixmap },
      { "glXGetConfig", (gl_function) glXGetConfig },
      { "glXGetCurrentContext", (gl_function) glXGetCurrentContext },
      { "glXGetCurrentDrawable", (gl_function) glXGetCurrentDrawable },
      { "glXIsDirect", (gl_function) glXIsDirect },
      { "glXMakeCurrent", (gl_function) glXMakeCurrent },
      { "glXQueryExtension", (gl_function) glXQueryExtension },
      { "glXQueryVersion", (gl_function) glXQueryVersion },
      { "glXSwapBuffers", (gl_function) glXSwapBuffers },
      { "glXUseXFont", (gl_function) glXUseXFont },
      { "glXWaitGL", (gl_function) glXWaitGL },
      { "glXWaitX", (gl_function) glXWaitX },

      /* GLX 1.1 functions */
      { "glXGetClientString", (gl_function) glXGetClientString },
      { "glXQueryExtensionsString", (gl_function) glXQueryExtensionsString },
      { "glXQueryServerString", (gl_function) glXQueryServerString },

      /* Extensions */
      { "glXGetProcAddressARB", (gl_function) glXGetProcAddressARB },
      { "glXCreateGLXPixmapMESA", (gl_function) glXCreateGLXPixmapMESA },
      { "glXReleaseBuffersMESA", (gl_function) glXReleaseBuffersMESA },
      { "glXCopySubBufferMESA", (gl_function) glXCopySubBufferMESA },
      { "glXSet3DfxModeMESA", (gl_function) glXSet3DfxModeMESA },
      { "glXGetVideoSyncSGI", (gl_function) glXGetVideoSyncSGI },
      { "glXWaitVideoSyncSGI", (gl_function) glXWaitVideoSyncSGI },

      { NULL, NULL }  /* end of list token */
   };
   GLuint i;

   /* First, look for core library functions */
   gl_function f = (gl_function) gl_get_proc_address(procName);
   if (f)
      return f;

   /* Second, look for GLX funtion */
   for (i = 0; procTable[i].address; i++) {
      if (strcmp((const char *) procName, procTable[i].name) == 0)
	  return procTable[i].address;
   }

   return NULL;
}

