src/x11/glcanvas.cpp

/////////////////////////////////////////////////////////////////////////////
// Name:        glcanvas.cpp
// Purpose:     wxGLCanvas, for using OpenGL with wxWindows 2.0 for Motif.
//              Uses the GLX extension.
// Author:      Julian Smart and Wolfram Gloger
// Modified by:
// Created:     1995, 1999
// RCS-ID:      $Id$
// Copyright:   (c) Julian Smart, Wolfram Gloger
// Licence:   	wxWindows licence
/////////////////////////////////////////////////////////////////////////////

#ifdef __GNUG__
#pragma implementation "glcanvas.h"
#endif

#include "wx/setup.h"

#if wxUSE_GLCANVAS

#include "wx/glcanvas.h"
#include "wx/utils.h"
#include "wx/app.h"

#ifdef __VMS
# pragma message disable nosimpint
#endif
#include <Xm/Xm.h>
#ifdef __VMS
# pragma message enable nosimpint
#endif
#include "wx/motif/private.h"

#ifdef OLD_MESA
// workaround for bug in Mesa's glx.c
static int bitcount( unsigned long n )
{
    int bits;
    for (bits=0; n>0;) {
	if(n & 1) bits++;
	n = n >> 1;
    }
    return bits;
}
#endif

/*
 * GLContext implementation
 */

IMPLEMENT_CLASS(wxGLContext,wxObject)

wxGLContext::wxGLContext( bool WXUNUSED(isRGB), wxWindow *win,
                          const wxPalette& WXUNUSED(palette) )
{
    m_window = win;
    // m_widget = win->m_wxwindow;

    wxGLCanvas *gc = (wxGLCanvas*) win;
    XVisualInfo *vi = (XVisualInfo *) gc->m_vi;

    wxCHECK_RET( vi, "invalid visual for OpenGl" );

    m_glContext = glXCreateContext( (Display *)m_window->GetXDisplay(), vi,
                                    None, GL_TRUE);

    wxCHECK_RET( m_glContext, "Couldn't create OpenGl context" );
}

wxGLContext::wxGLContext(
               bool WXUNUSED(isRGB), wxWindow *win,
               const wxPalette& WXUNUSED(palette),
               const wxGLContext *other        /* for sharing display lists */
)
{
    m_window = win;
    // m_widget = win->m_wxwindow;

    wxGLCanvas *gc = (wxGLCanvas*) win;
    XVisualInfo *vi = (XVisualInfo *) gc->m_vi;

    wxCHECK_RET( vi, "invalid visual for OpenGl" );

    if( other != 0 )
        m_glContext = glXCreateContext( (Display *)m_window->GetXDisplay(), vi,
                                        other->m_glContext, GL_TRUE );
    else
        m_glContext = glXCreateContext( (Display *)m_window->GetXDisplay(), vi,
                                        None, GL_TRUE );

    wxCHECK_RET( m_glContext, "Couldn't create OpenGl context" );
}

wxGLContext::~wxGLContext()
{
    if (!m_glContext) return;

    if (m_glContext == glXGetCurrentContext())
    {
        glXMakeCurrent( (Display*) m_window->GetXDisplay(), None, NULL);
    }

    glXDestroyContext( (Display*) m_window->GetXDisplay(), m_glContext );
}

void wxGLContext::SwapBuffers()
{
    if (m_glContext)
    {
        Display* display = (Display*) m_window->GetXDisplay();
        glXSwapBuffers(display, (Window) m_window->GetXWindow());
    }
}

void wxGLContext::SetCurrent()
{
    if (m_glContext)
    {
        Display* display = (Display*) m_window->GetXDisplay();
        glXMakeCurrent(display, (Window) m_window->GetXWindow(),
                       m_glContext );;
    }
}

void wxGLContext::SetColour(const char *colour)
{
    wxColour *the_colour = wxTheColourDatabase->FindColour(colour);
    if(the_colour) {
	GLboolean b;
	glGetBooleanv(GL_RGBA_MODE, &b);
	if(b) {
	    glColor3ub(the_colour->Red(),
		       the_colour->Green(),
		       the_colour->Blue());
	} else {
            the_colour->CalcPixel(wxTheApp->GetMainColormap(m_window->GetXDisplay()));
	    GLint pix = (GLint)the_colour->GetPixel();
	    if(pix == -1)
            {
                wxLogError("wxGLCanvas: cannot allocate color\n");
		return;
            }
	    glIndexi(pix);
	}
    }
}

void wxGLContext::SetupPixelFormat()
{
}

void wxGLContext::SetupPalette( const wxPalette& WXUNUSED(palette) )
{
}

wxPalette wxGLContext::CreateDefaultPalette()
{
    return wxNullPalette;
}


/*
 * GLCanvas implementation
 */

IMPLEMENT_CLASS(wxGLCanvas, wxScrolledWindow)

BEGIN_EVENT_TABLE(wxGLCanvas, wxScrolledWindow)
//    EVT_SIZE(wxGLCanvas::OnSize)
END_EVENT_TABLE()


wxGLCanvas::wxGLCanvas( wxWindow *parent, wxWindowID id,
                        const wxPoint& pos, const wxSize& size,
			long style, const wxString& name,
                        int *attribList,
			const wxPalette& palette )
: wxScrolledWindow(parent, id, pos, size, style, name)
{
    Create( parent, NULL, NULL, id, pos, size, style, name, attribList, palette );
}

wxGLCanvas::wxGLCanvas( wxWindow *parent,
                        const wxGLContext *shared,
                        wxWindowID id,
                        const wxPoint& pos, const wxSize& size,
			long style, const wxString& name,
                        int *attribList,
			const wxPalette& palette )
: wxScrolledWindow(parent, id, pos, size, style, name)
{
    Create( parent, shared, NULL, id, pos, size, style, name, attribList, palette );
}

wxGLCanvas::wxGLCanvas( wxWindow *parent,
                        const wxGLCanvas *shared,
                        wxWindowID id,
                        const wxPoint& pos, const wxSize& size,
			long style, const wxString& name,
                        int *attribList,
			const wxPalette& palette )
: wxScrolledWindow(parent, id, pos, size, style, name)
{
    Create( parent, NULL, shared, id, pos, size, style, name, attribList, palette );
}


/*
bool wxGLCanvas::Create(wxWindow *parent,
  const wxGLContext *shared, const wxGLCanvas *shared_context_of,
  wxWindowID id = -1, const wxPoint& pos,
  const wxSize& size, long style,
  const wxString& name, int *attribList, const wxPalette& palette):
    wxScrolledWindow(parent, id, pos, size, style, name)
*/

bool wxGLCanvas::Create( wxWindow *parent,
                         const wxGLContext *shared,
                         const wxGLCanvas *shared_context_of,
                         wxWindowID id,
                         const wxPoint& pos, const wxSize& size,
			 long style, const wxString& name,
                         int *attribList,
			 const wxPalette& palette)
{
    XVisualInfo *vi, vi_templ;
    XWindowAttributes xwa;
    int val, n;

    m_sharedContext = (wxGLContext*)shared;  // const_cast
    m_sharedContextOf = (wxGLCanvas*)shared_context_of;  // const_cast
    m_glContext = (wxGLContext*) NULL;

    Display* display = (Display*) GetXDisplay();

    // Check for the presence of the GLX extension
    if(!glXQueryExtension(display, NULL, NULL)) {
	wxDebugMsg("wxGLCanvas: GLX extension is missing\n");
	return false;
    }

    if(attribList) {
      int data[512], arg=0, p=0;

      while( (attribList[arg]!=0) && (p<512) )
      {
        switch( attribList[arg++] )
        {
          case WX_GL_RGBA: data[p++] = GLX_RGBA; break;
          case WX_GL_BUFFER_SIZE:
            data[p++]=GLX_BUFFER_SIZE; data[p++]=attribList[arg++]; break;
          case WX_GL_LEVEL:
            data[p++]=GLX_LEVEL; data[p++]=attribList[arg++]; break;
          case WX_GL_DOUBLEBUFFER: data[p++] = GLX_DOUBLEBUFFER; break;
          case WX_GL_STEREO: data[p++] = GLX_STEREO; break;
          case WX_GL_AUX_BUFFERS:
            data[p++]=GLX_AUX_BUFFERS; data[p++]=attribList[arg++]; break;
          case WX_GL_MIN_RED:
            data[p++]=GLX_RED_SIZE; data[p++]=attribList[arg++]; break;
          case WX_GL_MIN_GREEN:
            data[p++]=GLX_GREEN_SIZE; data[p++]=attribList[arg++]; break;
          case WX_GL_MIN_BLUE:
            data[p++]=GLX_BLUE_SIZE; data[p++]=attribList[arg++]; break;
          case WX_GL_MIN_ALPHA:
            data[p++]=GLX_ALPHA_SIZE; data[p++]=attribList[arg++]; break;
          case WX_GL_DEPTH_SIZE:
            data[p++]=GLX_DEPTH_SIZE; data[p++]=attribList[arg++]; break;
          case WX_GL_STENCIL_SIZE:
            data[p++]=GLX_STENCIL_SIZE; data[p++]=attribList[arg++]; break;
          case WX_GL_MIN_ACCUM_RED:
            data[p++]=GLX_ACCUM_RED_SIZE; data[p++]=attribList[arg++]; break;
          case WX_GL_MIN_ACCUM_GREEN:
            data[p++]=GLX_ACCUM_GREEN_SIZE; data[p++]=attribList[arg++]; break;
          case WX_GL_MIN_ACCUM_BLUE:
            data[p++]=GLX_ACCUM_BLUE_SIZE; data[p++]=attribList[arg++]; break;
          case WX_GL_MIN_ACCUM_ALPHA:
            data[p++]=GLX_ACCUM_ALPHA_SIZE; data[p++]=attribList[arg++]; break;
          default:
            break;
        }
      }
      data[p] = 0;

      attribList = (int*) data;
      // Get an appropriate visual
      vi = glXChooseVisual(display, DefaultScreen(display), attribList);
      if(!vi) return false;

      // Here we should make sure that vi is the same visual as the
      // one used by the xwindow drawable in wxCanvas.  However,
      // there is currently no mechanism for this in wx_canvs.cc.
    } else {
	// By default, we use the visual of xwindow
        // NI: is this really senseful ? opengl in e.g. color index mode ?
	XGetWindowAttributes(display, (Window) GetXWindow(), &xwa);
	vi_templ.visualid = XVisualIDFromVisual(xwa.visual);
	vi = XGetVisualInfo(display, VisualIDMask, &vi_templ, &n);
	if(!vi) return false;
	glXGetConfig(display, vi, GLX_USE_GL, &val);
	if(!val) return false;
	// Basically, this is it.  It should be possible to use vi
	// in glXCreateContext() below.  But this fails with Mesa.
	// I notified the Mesa author about it; there may be a fix.
#ifdef OLD_MESA
	// Construct an attribute list matching the visual
	int a_list[32];
	n = 0;
	if(vi->c_class==TrueColor || vi->c_class==DirectColor) { // RGBA visual
	    a_list[n++] = GLX_RGBA;
	    a_list[n++] = GLX_RED_SIZE;
	    a_list[n++] = bitcount(vi->red_mask);
	    a_list[n++] = GLX_GREEN_SIZE;
	    a_list[n++] = bitcount(vi->green_mask);
	    a_list[n++] = GLX_BLUE_SIZE;
	    a_list[n++] = bitcount(vi->blue_mask);
	    glXGetConfig(display, vi, GLX_ALPHA_SIZE, &val);
	    a_list[n++] = GLX_ALPHA_SIZE;
	    a_list[n++] = val;
	} else { // Color index visual
	    glXGetConfig(display, vi, GLX_BUFFER_SIZE, &val);
	    a_list[n++] = GLX_BUFFER_SIZE;
	    a_list[n++] = val;
	}
	a_list[n] = None;
	// XFree(vi);
	vi = glXChooseVisual(display, DefaultScreen(display), a_list);
	if(!vi) return false;
#endif /* OLD_MESA */
    }

    m_vi = vi;  // safe for later use

    wxCHECK_MSG( m_vi, FALSE, "required visual couldn't be found" );

    // Create the GLX context and make it current

    wxGLContext *share= m_sharedContext;
    if (share==NULL && m_sharedContextOf)
        share = m_sharedContextOf->GetContext();

    m_glContext = new wxGLContext( TRUE, this, wxNullPalette, share );

#ifndef OLD_MESA
    // XFree(vi);
#endif
    SetCurrent();

    return true;
}

wxGLCanvas::~wxGLCanvas(void)
{
    XVisualInfo *vi = (XVisualInfo *) m_vi;

    if (vi) XFree( vi );
    if (m_glContext) delete m_glContext;

    // Display* display = (Display*) GetXDisplay();
    // if(glx_cx) glXDestroyContext(display, glx_cx);
}

void wxGLCanvas::SwapBuffers()
{
    if( m_glContext ) m_glContext->SwapBuffers();

    // Display* display = (Display*) GetXDisplay();
    // if(glx_cx) glXSwapBuffers(display, (Window) GetXWindow());
}

void wxGLCanvas::SetCurrent()
{
    if( m_glContext ) m_glContext->SetCurrent();

    // Display* display = (Display*) GetXDisplay();
    // if(glx_cx) glXMakeCurrent(display, (Window) GetXWindow(), glx_cx);
}

void wxGLCanvas::SetColour(const char *col)
{
    if( m_glContext ) m_glContext->SetColour(col);
}

#endif
    // wxUSE_GLCANVAS
Commit	Line	Data
	1	/////////////////////////////////////////////////////////////////////////////
	2	// Name: glcanvas.cpp
	3	// Purpose: wxGLCanvas, for using OpenGL with wxWindows 2.0 for Motif.
	4	// Uses the GLX extension.
	5	// Author: Julian Smart and Wolfram Gloger
	6	// Modified by:
	7	// Created: 1995, 1999
	8	// RCS-ID: $Id$
	9	// Copyright: (c) Julian Smart, Wolfram Gloger
	10	// Licence: wxWindows licence
	11	/////////////////////////////////////////////////////////////////////////////
	12
	13	#ifdef __GNUG__
	14	#pragma implementation "glcanvas.h"
	15	#endif
	16
	17	#include "wx/setup.h"
	18
	19	#if wxUSE_GLCANVAS
	20
	21	#include "wx/glcanvas.h"
	22	#include "wx/utils.h"
	23	#include "wx/app.h"
	24
	25	#ifdef __VMS
	26	# pragma message disable nosimpint
	27	#endif
	28	#include <Xm/Xm.h>
	29	#ifdef __VMS
	30	# pragma message enable nosimpint
	31	#endif
	32	#include "wx/motif/private.h"
	33
	34	#ifdef OLD_MESA
	35	// workaround for bug in Mesa's glx.c
	36	static int bitcount( unsigned long n )
	37	{
	38	int bits;
	39	for (bits=0; n>0;) {
	40	if(n & 1) bits++;
	41	n = n >> 1;
	42	}
	43	return bits;
	44	}
	45	#endif
	46
	47	/*
	48	* GLContext implementation
	49	*/
	50
	51	IMPLEMENT_CLASS(wxGLContext,wxObject)
	52
	53	wxGLContext::wxGLContext( bool WXUNUSED(isRGB), wxWindow *win,
	54	const wxPalette& WXUNUSED(palette) )
	55	{
	56	m_window = win;
	57	// m_widget = win->m_wxwindow;
	58
	59	wxGLCanvas gc = (wxGLCanvas) win;
	60	XVisualInfo vi = (XVisualInfo ) gc->m_vi;
	61
	62	wxCHECK_RET( vi, "invalid visual for OpenGl" );
	63
	64	m_glContext = glXCreateContext( (Display *)m_window->GetXDisplay(), vi,
	65	None, GL_TRUE);
	66
	67	wxCHECK_RET( m_glContext, "Couldn't create OpenGl context" );
	68	}
	69
	70	wxGLContext::wxGLContext(
	71	bool WXUNUSED(isRGB), wxWindow *win,
	72	const wxPalette& WXUNUSED(palette),
	73	const wxGLContext other / for sharing display lists */
	74	)
	75	{
	76	m_window = win;
	77	// m_widget = win->m_wxwindow;
	78
	79	wxGLCanvas gc = (wxGLCanvas) win;
	80	XVisualInfo vi = (XVisualInfo ) gc->m_vi;
	81
	82	wxCHECK_RET( vi, "invalid visual for OpenGl" );
	83
	84	if( other != 0 )
	85	m_glContext = glXCreateContext( (Display *)m_window->GetXDisplay(), vi,
	86	other->m_glContext, GL_TRUE );
	87	else
	88	m_glContext = glXCreateContext( (Display *)m_window->GetXDisplay(), vi,
	89	None, GL_TRUE );
	90
	91	wxCHECK_RET( m_glContext, "Couldn't create OpenGl context" );
	92	}
	93
	94	wxGLContext::~wxGLContext()
	95	{
	96	if (!m_glContext) return;
	97
	98	if (m_glContext == glXGetCurrentContext())
	99	{
	100	glXMakeCurrent( (Display*) m_window->GetXDisplay(), None, NULL);
	101	}
	102
	103	glXDestroyContext( (Display*) m_window->GetXDisplay(), m_glContext );
	104	}
	105
	106	void wxGLContext::SwapBuffers()
	107	{
	108	if (m_glContext)
	109	{
	110	Display* display = (Display*) m_window->GetXDisplay();
	111	glXSwapBuffers(display, (Window) m_window->GetXWindow());
	112	}
	113	}
	114
	115	void wxGLContext::SetCurrent()
	116	{
	117	if (m_glContext)
	118	{
	119	Display* display = (Display*) m_window->GetXDisplay();
	120	glXMakeCurrent(display, (Window) m_window->GetXWindow(),
	121	m_glContext );;
	122	}
	123	}
	124
	125	void wxGLContext::SetColour(const char *colour)
	126	{
	127	wxColour *the_colour = wxTheColourDatabase->FindColour(colour);
	128	if(the_colour) {
	129	GLboolean b;
	130	glGetBooleanv(GL_RGBA_MODE, &b);
	131	if(b) {
	132	glColor3ub(the_colour->Red(),
	133	the_colour->Green(),
	134	the_colour->Blue());
	135	} else {
	136	the_colour->CalcPixel(wxTheApp->GetMainColormap(m_window->GetXDisplay()));
	137	GLint pix = (GLint)the_colour->GetPixel();
	138	if(pix == -1)
	139	{
	140	wxLogError("wxGLCanvas: cannot allocate color\n");
	141	return;
	142	}
	143	glIndexi(pix);
	144	}
	145	}
	146	}
	147
	148	void wxGLContext::SetupPixelFormat()
	149	{
	150	}
	151
	152	void wxGLContext::SetupPalette( const wxPalette& WXUNUSED(palette) )
	153	{
	154	}
	155
	156	wxPalette wxGLContext::CreateDefaultPalette()
	157	{
	158	return wxNullPalette;
	159	}
	160
	161
	162
	163
	164	/*
	165	* GLCanvas implementation
	166	*/
	167
	168	IMPLEMENT_CLASS(wxGLCanvas, wxScrolledWindow)
	169
	170	BEGIN_EVENT_TABLE(wxGLCanvas, wxScrolledWindow)
	171	// EVT_SIZE(wxGLCanvas::OnSize)
	172	END_EVENT_TABLE()
	173
	174
	175	wxGLCanvas::wxGLCanvas( wxWindow *parent, wxWindowID id,
	176	const wxPoint& pos, const wxSize& size,
	177	long style, const wxString& name,
	178	int *attribList,
	179	const wxPalette& palette )
	180	: wxScrolledWindow(parent, id, pos, size, style, name)
	181	{
	182	Create( parent, NULL, NULL, id, pos, size, style, name, attribList, palette );
	183	}
	184
	185	wxGLCanvas::wxGLCanvas( wxWindow *parent,
	186	const wxGLContext *shared,
	187	wxWindowID id,
	188	const wxPoint& pos, const wxSize& size,
	189	long style, const wxString& name,
	190	int *attribList,
	191	const wxPalette& palette )
	192	: wxScrolledWindow(parent, id, pos, size, style, name)
	193	{
	194	Create( parent, shared, NULL, id, pos, size, style, name, attribList, palette );
	195	}
	196
	197	wxGLCanvas::wxGLCanvas( wxWindow *parent,
	198	const wxGLCanvas *shared,
	199	wxWindowID id,
	200	const wxPoint& pos, const wxSize& size,
	201	long style, const wxString& name,
	202	int *attribList,
	203	const wxPalette& palette )
	204	: wxScrolledWindow(parent, id, pos, size, style, name)
	205	{
	206	Create( parent, NULL, shared, id, pos, size, style, name, attribList, palette );
	207	}
	208
	209
	210	/*
	211	bool wxGLCanvas::Create(wxWindow *parent,
	212	const wxGLContext shared, const wxGLCanvas shared_context_of,
	213	wxWindowID id = -1, const wxPoint& pos,
	214	const wxSize& size, long style,
	215	const wxString& name, int *attribList, const wxPalette& palette):
	216	wxScrolledWindow(parent, id, pos, size, style, name)
	217	*/
	218
	219	bool wxGLCanvas::Create( wxWindow *parent,
	220	const wxGLContext *shared,
	221	const wxGLCanvas *shared_context_of,
	222	wxWindowID id,
	223	const wxPoint& pos, const wxSize& size,
	224	long style, const wxString& name,
	225	int *attribList,
	226	const wxPalette& palette)
	227	{
	228	XVisualInfo *vi, vi_templ;
	229	XWindowAttributes xwa;
	230	int val, n;
	231
	232	m_sharedContext = (wxGLContext*)shared; // const_cast
	233	m_sharedContextOf = (wxGLCanvas*)shared_context_of; // const_cast
	234	m_glContext = (wxGLContext*) NULL;
	235
	236	Display* display = (Display*) GetXDisplay();
	237
	238	// Check for the presence of the GLX extension
	239	if(!glXQueryExtension(display, NULL, NULL)) {
	240	wxDebugMsg("wxGLCanvas: GLX extension is missing\n");
	241	return false;
	242	}
	243
	244	if(attribList) {
	245	int data[512], arg=0, p=0;
	246
	247	while( (attribList[arg]!=0) && (p<512) )
	248	{
	249	switch( attribList[arg++] )
	250	{
	251	case WX_GL_RGBA: data[p++] = GLX_RGBA; break;
	252	case WX_GL_BUFFER_SIZE:
	253	data[p++]=GLX_BUFFER_SIZE; data[p++]=attribList[arg++]; break;
	254	case WX_GL_LEVEL:
	255	data[p++]=GLX_LEVEL; data[p++]=attribList[arg++]; break;
	256	case WX_GL_DOUBLEBUFFER: data[p++] = GLX_DOUBLEBUFFER; break;
	257	case WX_GL_STEREO: data[p++] = GLX_STEREO; break;
	258	case WX_GL_AUX_BUFFERS:
	259	data[p++]=GLX_AUX_BUFFERS; data[p++]=attribList[arg++]; break;
	260	case WX_GL_MIN_RED:
	261	data[p++]=GLX_RED_SIZE; data[p++]=attribList[arg++]; break;
	262	case WX_GL_MIN_GREEN:
	263	data[p++]=GLX_GREEN_SIZE; data[p++]=attribList[arg++]; break;
	264	case WX_GL_MIN_BLUE:
	265	data[p++]=GLX_BLUE_SIZE; data[p++]=attribList[arg++]; break;
	266	case WX_GL_MIN_ALPHA:
	267	data[p++]=GLX_ALPHA_SIZE; data[p++]=attribList[arg++]; break;
	268	case WX_GL_DEPTH_SIZE:
	269	data[p++]=GLX_DEPTH_SIZE; data[p++]=attribList[arg++]; break;
	270	case WX_GL_STENCIL_SIZE:
	271	data[p++]=GLX_STENCIL_SIZE; data[p++]=attribList[arg++]; break;
	272	case WX_GL_MIN_ACCUM_RED:
	273	data[p++]=GLX_ACCUM_RED_SIZE; data[p++]=attribList[arg++]; break;
	274	case WX_GL_MIN_ACCUM_GREEN:
	275	data[p++]=GLX_ACCUM_GREEN_SIZE; data[p++]=attribList[arg++]; break;
	276	case WX_GL_MIN_ACCUM_BLUE:
	277	data[p++]=GLX_ACCUM_BLUE_SIZE; data[p++]=attribList[arg++]; break;
	278	case WX_GL_MIN_ACCUM_ALPHA:
	279	data[p++]=GLX_ACCUM_ALPHA_SIZE; data[p++]=attribList[arg++]; break;
	280	default:
	281	break;
	282	}
	283	}
	284	data[p] = 0;
	285
	286	attribList = (int*) data;
	287	// Get an appropriate visual
	288	vi = glXChooseVisual(display, DefaultScreen(display), attribList);
	289	if(!vi) return false;
	290
	291	// Here we should make sure that vi is the same visual as the
	292	// one used by the xwindow drawable in wxCanvas. However,
	293	// there is currently no mechanism for this in wx_canvs.cc.
	294	} else {
	295	// By default, we use the visual of xwindow
	296	// NI: is this really senseful ? opengl in e.g. color index mode ?
	297	XGetWindowAttributes(display, (Window) GetXWindow(), &xwa);
	298	vi_templ.visualid = XVisualIDFromVisual(xwa.visual);
	299	vi = XGetVisualInfo(display, VisualIDMask, &vi_templ, &n);
	300	if(!vi) return false;
	301	glXGetConfig(display, vi, GLX_USE_GL, &val);
	302	if(!val) return false;
	303	// Basically, this is it. It should be possible to use vi
	304	// in glXCreateContext() below. But this fails with Mesa.
	305	// I notified the Mesa author about it; there may be a fix.
	306	#ifdef OLD_MESA
	307	// Construct an attribute list matching the visual
	308	int a_list[32];
	309	n = 0;
	310	if(vi->c_class==TrueColor \|\| vi->c_class==DirectColor) { // RGBA visual
	311	a_list[n++] = GLX_RGBA;
	312	a_list[n++] = GLX_RED_SIZE;
	313	a_list[n++] = bitcount(vi->red_mask);
	314	a_list[n++] = GLX_GREEN_SIZE;
	315	a_list[n++] = bitcount(vi->green_mask);
	316	a_list[n++] = GLX_BLUE_SIZE;
	317	a_list[n++] = bitcount(vi->blue_mask);
	318	glXGetConfig(display, vi, GLX_ALPHA_SIZE, &val);
	319	a_list[n++] = GLX_ALPHA_SIZE;
	320	a_list[n++] = val;
	321	} else { // Color index visual
	322	glXGetConfig(display, vi, GLX_BUFFER_SIZE, &val);
	323	a_list[n++] = GLX_BUFFER_SIZE;
	324	a_list[n++] = val;
	325	}
	326	a_list[n] = None;
	327	// XFree(vi);
	328	vi = glXChooseVisual(display, DefaultScreen(display), a_list);
	329	if(!vi) return false;
	330	#endif /* OLD_MESA */
	331	}
	332
	333	m_vi = vi; // safe for later use
	334
	335	wxCHECK_MSG( m_vi, FALSE, "required visual couldn't be found" );
	336
	337	// Create the GLX context and make it current
	338
	339	wxGLContext *share= m_sharedContext;
	340	if (share==NULL && m_sharedContextOf)
	341	share = m_sharedContextOf->GetContext();
	342
	343	m_glContext = new wxGLContext( TRUE, this, wxNullPalette, share );
	344
	345	#ifndef OLD_MESA
	346	// XFree(vi);
	347	#endif
	348	SetCurrent();
	349
	350	return true;
	351	}
	352
	353	wxGLCanvas::~wxGLCanvas(void)
	354	{
	355	XVisualInfo vi = (XVisualInfo ) m_vi;
	356
	357	if (vi) XFree( vi );
	358	if (m_glContext) delete m_glContext;
	359
	360	// Display* display = (Display*) GetXDisplay();
	361	// if(glx_cx) glXDestroyContext(display, glx_cx);
	362	}
	363
	364	void wxGLCanvas::SwapBuffers()
	365	{
	366	if( m_glContext ) m_glContext->SwapBuffers();
	367
	368	// Display* display = (Display*) GetXDisplay();
	369	// if(glx_cx) glXSwapBuffers(display, (Window) GetXWindow());
	370	}
	371
	372	void wxGLCanvas::SetCurrent()
	373	{
	374	if( m_glContext ) m_glContext->SetCurrent();
	375
	376	// Display* display = (Display*) GetXDisplay();
	377	// if(glx_cx) glXMakeCurrent(display, (Window) GetXWindow(), glx_cx);
	378	}
	379
	380	void wxGLCanvas::SetColour(const char *col)
	381	{
	382	if( m_glContext ) m_glContext->SetColour(col);
	383	}
	384
	385	#endif
	386	// wxUSE_GLCANVAS
	387