fakeglx.c

Mesa is an open-source implementation of the OpenGL specification - a system for rendering interacti

/*
 * Mesa 3-D graphics library
 * Version:  7.1
 *
 * Copyright (C) 1999-2007  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 an emulation of the GLX API which allows Mesa/GLX-based programs
 * to run on X servers which do not have the real GLX extension.
 *
 * Thanks to the contributors:
 *
 * Initial version:  Philip Brown ([e-mail])
 * Better glXGetConfig() support: Armin Liebchen ([e-mail])
 * Further visual-handling refinements: Wolfram Gloger
 *    ([e-mail]).
 *
 * Notes:
 *   Don't be fooled, stereo isn't supported yet.
 */



#include "glxheader.h"
#include "glxapi.h"
#include "GL/xmesa.h"
#include "context.h"
#include "config.h"
#include "macros.h"
#include "imports.h"
#include "mtypes.h"
#include "version.h"
#include "xfonts.h"
#include "xmesaP.h"

#ifdef __VMS
#define _mesa_sprintf sprintf
#endif

/* This indicates the client-side GLX API and GLX encoder version. */
#define CLIENT_MAJOR_VERSION 1
#define CLIENT_MINOR_VERSION 4  /* but don't have 1.3's pbuffers, etc yet */

/* This indicates the server-side GLX decoder version.
 * GLX 1.4 indicates OpenGL 1.3 support
 */
#define SERVER_MAJOR_VERSION 1
#define SERVER_MINOR_VERSION 4

/* This is appended onto the glXGetClient/ServerString version strings. */
#define MESA_GLX_VERSION "Mesa " MESA_VERSION_STRING

/* Who implemented this GLX? */
#define VENDOR "Brian Paul"

#define EXTENSIONS \
   "GLX_MESA_set_3dfx_mode " \
   "GLX_MESA_copy_sub_buffer " \
   "GLX_MESA_pixmap_colormap " \
   "GLX_MESA_release_buffers " \
   "GLX_ARB_get_proc_address " \
   "GLX_EXT_texture_from_pixmap " \
   "GLX_EXT_visual_info " \
   "GLX_EXT_visual_rating " \
   /*"GLX_SGI_video_sync "*/ \
   "GLX_SGIX_fbconfig " \
   "GLX_SGIX_pbuffer "

/*
 * Our fake GLX context will contain a "real" GLX context and an XMesa context.
 *
 * Note that a pointer to a __GLXcontext is a pointer to a fake_glx_context,
 * and vice versa.
 *
 * We really just need this structure in order to make the libGL functions
 * glXGetCurrentContext(), glXGetCurrentDrawable() and glXGetCurrentDisplay()
 * work correctly.
 */
struct fake_glx_context {
   __GLXcontext glxContext;   /* this MUST be first! */
   XMesaContext xmesaContext;
};



/**********************************************************************/
/***                       GLX Visual Code                          ***/
/**********************************************************************/

#define DONT_CARE -1


static XMesaVisual *VisualTable = NULL;
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;
   }
}



/**
 * Get an array OverlayInfo records for specified screen.
 * \param dpy  the display
 * \param screen  screen number
 * \param numOverlays  returns numver of OverlayInfo records
 * \return  pointer to OverlayInfo array, free with XFree()
 */
static OverlayInfo *
GetOverlayInfo(Display *dpy, int screen, int *numOverlays)
{
   Atom overlayVisualsAtom;
   Atom actualType;
   Status status;
   unsigned char *ovInfo;
   unsigned long sizeData, bytesLeft;
   int actualFormat;

   /*
    * 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, screen),
                               overlayVisualsAtom, 0L, (long) 10000, False,
                               overlayVisualsAtom, &actualType, &actualFormat,
                               &sizeData, &bytesLeft,
                               &ovInfo);

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

   *numOverlays = sizeData / 4;
   return (OverlayInfo *) ovInfo;
}



/**
 * 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 )
{
   OverlayInfo *overlay_info;
   int numOverlaysPerScreen, i;

   overlay_info = GetOverlayInfo(dpy, vinfo->screen, &numOverlaysPerScreen);
   if (!overlay_info) {
      return 0;
   }

   /* search the overlay visual list for the visual ID of interest */
   for (i = 0; i < numOverlaysPerScreen; i++) {
      const OverlayInfo *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 accumRedSize, GLint accumGreenSize,
                 GLint accumBlueSize, GLint accumAlphaSize,
                 GLint level, GLint numAuxBuffers )
{
   GLboolean ximageFlag = GL_TRUE;
   XMesaVisual xmvis;
   GLint i;
   GLboolean comparePointers;

   if (dbFlag) {
      /* Check if the MESA_BACK_BUFFER env var is set */
      char *backbuffer = _mesa_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 {
            _mesa_warning(NULL, "Mesa: invalid value for MESA_BACK_BUFFER environment variable, using an XImage.");
         }
      }
   }

   if (stereoFlag) {
      /* stereo not supported */
      return NULL;
   }

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

   /* Force the visual to have an alpha channel */
   if (rgbFlag && _mesa_getenv("MESA_GLX_FORCE_ALPHA"))
      alphaFlag = GL_TRUE;

   /* 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->mesa_visual.level == level
          && v->mesa_visual.numAuxBuffers == numAuxBuffers
          && v->ximage_flag == ximageFlag
          && v->mesa_visual.rgbMode == rgbFlag
          && v->mesa_visual.doubleBufferMode == dbFlag
          && v->mesa_visual.stereoMode == stereoFlag
          && (v->mesa_visual.alphaBits > 0) == alphaFlag
          && (v->mesa_visual.depthBits >= depth_size || depth_size == 0)
          && (v->mesa_visual.stencilBits >= stencil_size || stencil_size == 0)
          && (v->mesa_visual.accumRedBits >= accumRedSize || accumRedSize == 0)
          && (v->mesa_visual.accumGreenBits >= accumGreenSize || accumGreenSize == 0)
          && (v->mesa_visual.accumBlueBits >= accumBlueSize || accumBlueSize == 0)
          && (v->mesa_visual.accumAlphaBits >= accumAlphaSize || accumAlphaSize == 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. */

   xmvis = XMesaCreateVisual( dpy, vinfo, rgbFlag, alphaFlag, dbFlag,
                              stereoFlag, ximageFlag,
                              depth_size, stencil_size,
                              accumRedSize, accumBlueSize,
                              accumBlueSize, accumAlphaSize, 0, level,
                              GLX_NONE_EXT );
   if (xmvis) {
      /* Save a copy of the pointer now so we can find this visual again
       * if we need to search for it in find_glx_visual().
       */
      xmvis->vishandle = vinfo;
      /* Allocate more space for additional visual */
      VisualTable = (XMesaVisual *) _mesa_realloc( VisualTable, 
                                   sizeof(XMesaVisual) * NumVisuals, 
                                   sizeof(XMesaVisual) * (NumVisuals + 1));
      /* add xmvis to the list */
      VisualTable[NumVisuals] = xmvis;
      NumVisuals++;
      /* XXX minor hack, because XMesaCreateVisual doesn't support an
       * aux buffers parameter.
       */
      xmvis->mesa_visual.numAuxBuffers = numAuxBuffers;
   }
   return xmvis;
}


/**
 * Return the default number of bits for the Z buffer.
 * If defined, use the MESA_GLX_DEPTH_BITS env var value.
 * Otherwise, use the DEFAULT_SOFTWARE_DEPTH_BITS constant.
 * XXX probably do the same thing for stencil, accum, etc.
 */
static GLint
default_depth_bits(void)
{
   int zBits;
   const char *zEnv = _mesa_getenv("MESA_GLX_DEPTH_BITS");
   if (zEnv)
      zBits = _mesa_atoi(zEnv);
   else
      zBits = DEFAULT_SOFTWARE_DEPTH_BITS;
   return zBits;
}

static GLint
default_alpha_bits(void)
{
   int aBits;
   const char *aEnv = _mesa_getenv("MESA_GLX_ALPHA_BITS");
   if (aEnv)
      aBits = _mesa_atoi(aEnv);
   else
      aBits = 0;
   return aBits;
}

static GLint
default_accum_bits(void)
{
   return 16;
}



/*
 * Create a GLX visual from a regular XVisualInfo.
 * This is called when Fake GLX is given an XVisualInfo which wasn't
 * returned by glXChooseVisual.  Since this is the first time we're
 * considering this visual we'll take a guess at reasonable values
 * for depth buffer size, stencil size, accum size, etc.
 * This is the best we can do with a client-side emulation of GLX.
 */
static XMesaVisual
create_glx_visual( Display *dpy, XVisualInfo *visinfo )
{
   int vislevel;
   GLint zBits = default_depth_bits();
   GLint accBits = default_accum_bits();
   GLboolean alphaFlag = default_alpha_bits() > 0;

   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 */
                              0,0,0,0,   /* accum bits */
                              vislevel,  /* level */
                              0          /* numAux */
                            );
   }
   else if (is_usable_visual( visinfo )) {
      if (_mesa_getenv("MESA_GLX_FORCE_CI")) {
         /* Configure this visual as a COLOR INDEX visual. */
         return save_glx_visual( dpy, visinfo,
                                 GL_FALSE,   /* rgb */
                                 GL_FALSE,  /* alpha */
                                 GL_TRUE,   /* double */
                                 GL_FALSE,  /* stereo */
                                 zBits,
                                 STENCIL_BITS,
                                 0, 0, 0, 0, /* accum bits */
                                 0,         /* level */
                                 0          /* numAux */
                               );
      }
      else {
         /* 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 */
                                 alphaFlag, /* alpha */