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"
#include "wx/log.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 *)wxGetDisplay(), 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 *)wxGetDisplay(), vi,
                                        other->m_glContext, GL_TRUE );
    else
        m_glContext = glXCreateContext( (Display *)wxGetDisplay(), 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*) wxGetDisplay(), None, NULL);
    }

    glXDestroyContext( (Display*) wxGetDisplay(), m_glContext );
}

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

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

    // Check for the presence of the GLX extension
    if(!glXQueryExtension(display, NULL, NULL)) {
	wxLogDebug("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) GetClientAreaWindow(), &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) GetClientAreaWindow());
}

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

    // Display* display = (Display*) GetXDisplay();
    // if(glx_cx) glXMakeCurrent(display, (Window) GetClientAreaWindow(), 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	#include "wx/log.h"
	25
	26	#ifdef __VMS
	27	# pragma message disable nosimpint
	28	#endif
	29	#include <Xm/Xm.h>
	30	#ifdef __VMS
	31	# pragma message enable nosimpint
	32	#endif
	33	#include "wx/motif/private.h"
	34
	35	#ifdef OLD_MESA
	36	// workaround for bug in Mesa's glx.c
	37	static int bitcount( unsigned long n )
	38	{
	39	int bits;
	40	for (bits=0; n>0;) {
	41	if(n & 1) bits++;
	42	n = n >> 1;
	43	}
	44	return bits;
	45	}
	46	#endif
	47
	48	/*
	49	* GLContext implementation
	50	*/
	51
	52	IMPLEMENT_CLASS(wxGLContext,wxObject)
	53
	54	wxGLContext::wxGLContext( bool WXUNUSED(isRGB), wxWindow *win,
	55	const wxPalette& WXUNUSED(palette) )
	56	{
	57	m_window = win;
	58	// m_widget = win->m_wxwindow;
	59
	60	wxGLCanvas gc = (wxGLCanvas) win;
	61	XVisualInfo vi = (XVisualInfo ) gc->m_vi;
	62
	63	wxCHECK_RET( vi, "invalid visual for OpenGl" );
	64
	65	m_glContext = glXCreateContext( (Display *)wxGetDisplay(), vi,
	66	None, GL_TRUE);
	67
	68	wxCHECK_RET( m_glContext, "Couldn't create OpenGl context" );
	69	}
	70
	71	wxGLContext::wxGLContext(
	72	bool WXUNUSED(isRGB), wxWindow *win,
	73	const wxPalette& WXUNUSED(palette),
	74	const wxGLContext other / for sharing display lists */
	75	)
	76	{
	77	m_window = win;
	78	// m_widget = win->m_wxwindow;
	79
	80	wxGLCanvas gc = (wxGLCanvas) win;
	81	XVisualInfo vi = (XVisualInfo ) gc->m_vi;
	82
	83	wxCHECK_RET( vi, "invalid visual for OpenGl" );
	84
	85	if( other != 0 )
	86	m_glContext = glXCreateContext( (Display *)wxGetDisplay(), vi,
	87	other->m_glContext, GL_TRUE );
	88	else
	89	m_glContext = glXCreateContext( (Display *)wxGetDisplay(), vi,
	90	None, GL_TRUE );
	91
	92	wxCHECK_RET( m_glContext, "Couldn't create OpenGl context" );
	93	}
	94
	95	wxGLContext::~wxGLContext()
	96	{
	97	if (!m_glContext) return;
	98
	99	if (m_glContext == glXGetCurrentContext())
	100	{
	101	glXMakeCurrent( (Display*) wxGetDisplay(), None, NULL);
	102	}
	103
	104	glXDestroyContext( (Display*) wxGetDisplay(), m_glContext );
	105	}
	106
	107	void wxGLContext::SwapBuffers()
	108	{
	109	if (m_glContext)
	110	{
	111	Display* display = (Display*) wxGetDisplay();
	112	glXSwapBuffers(display, (Window) m_window->GetClientAreaWindow());
	113	}
	114	}
	115
	116	void wxGLContext::SetCurrent()
	117	{
	118	if (m_glContext)
	119	{
	120	Display* display = (Display*) wxGetDisplay();
	121	glXMakeCurrent(display, (Window) m_window->GetClientAreaWindow(),
	122	m_glContext );;
	123	}
	124	}
	125
	126	void wxGLContext::SetColour(const char *colour)
	127	{
	128	wxColour *the_colour = wxTheColourDatabase->FindColour(colour);
	129	if(the_colour) {
	130	GLboolean b;
	131	glGetBooleanv(GL_RGBA_MODE, &b);
	132	if(b) {
	133	glColor3ub(the_colour->Red(),
	134	the_colour->Green(),
	135	the_colour->Blue());
	136	} else {
	137	the_colour->CalcPixel(wxTheApp->GetMainColormap(wxGetDisplay()));
	138	GLint pix = (GLint)the_colour->GetPixel();
	139	if(pix == -1)
	140	{
	141	wxLogError("wxGLCanvas: cannot allocate color\n");
	142	return;
	143	}
	144	glIndexi(pix);
	145	}
	146	}
	147	}
	148
	149	void wxGLContext::SetupPixelFormat()
	150	{
	151	}
	152
	153	void wxGLContext::SetupPalette( const wxPalette& WXUNUSED(palette) )
	154	{
	155	}
	156
	157	wxPalette wxGLContext::CreateDefaultPalette()
	158	{
	159	return wxNullPalette;
	160	}
	161
	162
	163
	164
	165	/*
	166	* GLCanvas implementation
	167	*/
	168
	169	IMPLEMENT_CLASS(wxGLCanvas, wxScrolledWindow)
	170
	171	BEGIN_EVENT_TABLE(wxGLCanvas, wxScrolledWindow)
	172	// EVT_SIZE(wxGLCanvas::OnSize)
	173	END_EVENT_TABLE()
	174
	175
	176	wxGLCanvas::wxGLCanvas( wxWindow *parent, wxWindowID id,
	177	const wxPoint& pos, const wxSize& size,
	178	long style, const wxString& name,
	179	int *attribList,
	180	const wxPalette& palette )
	181	: wxScrolledWindow(parent, id, pos, size, style, name)
	182	{
	183	Create( parent, NULL, NULL, id, pos, size, style, name, attribList, palette );
	184	}
	185
	186	wxGLCanvas::wxGLCanvas( wxWindow *parent,
	187	const wxGLContext *shared,
	188	wxWindowID id,
	189	const wxPoint& pos, const wxSize& size,
	190	long style, const wxString& name,
	191	int *attribList,
	192	const wxPalette& palette )
	193	: wxScrolledWindow(parent, id, pos, size, style, name)
	194	{
	195	Create( parent, shared, NULL, id, pos, size, style, name, attribList, palette );
	196	}
	197
	198	wxGLCanvas::wxGLCanvas( wxWindow *parent,
	199	const wxGLCanvas *shared,
	200	wxWindowID id,
	201	const wxPoint& pos, const wxSize& size,
	202	long style, const wxString& name,
	203	int *attribList,
	204	const wxPalette& palette )
	205	: wxScrolledWindow(parent, id, pos, size, style, name)
	206	{
	207	Create( parent, NULL, shared, id, pos, size, style, name, attribList, palette );
	208	}
	209
	210
	211	/*
	212	bool wxGLCanvas::Create(wxWindow *parent,
	213	const wxGLContext shared, const wxGLCanvas shared_context_of,
	214	wxWindowID id = -1, const wxPoint& pos,
	215	const wxSize& size, long style,
	216	const wxString& name, int *attribList, const wxPalette& palette):
	217	wxScrolledWindow(parent, id, pos, size, style, name)
	218	*/
	219
	220	bool wxGLCanvas::Create( wxWindow *parent,
	221	const wxGLContext *shared,
	222	const wxGLCanvas *shared_context_of,
	223	wxWindowID id,
	224	const wxPoint& pos, const wxSize& size,
	225	long style, const wxString& name,
	226	int *attribList,
	227	const wxPalette& palette)
	228	{
	229	XVisualInfo *vi, vi_templ;
	230	XWindowAttributes xwa;
	231	int val, n;
	232
	233	m_sharedContext = (wxGLContext*)shared; // const_cast
	234	m_sharedContextOf = (wxGLCanvas*)shared_context_of; // const_cast
	235	m_glContext = (wxGLContext*) NULL;
	236
	237	Display* display = (Display*) wxGetDisplay();
	238
	239	// Check for the presence of the GLX extension
	240	if(!glXQueryExtension(display, NULL, NULL)) {
	241	wxLogDebug("wxGLCanvas: GLX extension is missing\n");
	242	return FALSE;
	243	}
	244
	245	if(attribList) {
	246	int data[512], arg=0, p=0;
	247
	248	while( (attribList[arg]!=0) && (p<512) )
	249	{
	250	switch( attribList[arg++] )
	251	{
	252	case WX_GL_RGBA: data[p++] = GLX_RGBA; break;
	253	case WX_GL_BUFFER_SIZE:
	254	data[p++]=GLX_BUFFER_SIZE; data[p++]=attribList[arg++]; break;
	255	case WX_GL_LEVEL:
	256	data[p++]=GLX_LEVEL; data[p++]=attribList[arg++]; break;
	257	case WX_GL_DOUBLEBUFFER: data[p++] = GLX_DOUBLEBUFFER; break;
	258	case WX_GL_STEREO: data[p++] = GLX_STEREO; break;
	259	case WX_GL_AUX_BUFFERS:
	260	data[p++]=GLX_AUX_BUFFERS; data[p++]=attribList[arg++]; break;
	261	case WX_GL_MIN_RED:
	262	data[p++]=GLX_RED_SIZE; data[p++]=attribList[arg++]; break;
	263	case WX_GL_MIN_GREEN:
	264	data[p++]=GLX_GREEN_SIZE; data[p++]=attribList[arg++]; break;
	265	case WX_GL_MIN_BLUE:
	266	data[p++]=GLX_BLUE_SIZE; data[p++]=attribList[arg++]; break;
	267	case WX_GL_MIN_ALPHA:
	268	data[p++]=GLX_ALPHA_SIZE; data[p++]=attribList[arg++]; break;
	269	case WX_GL_DEPTH_SIZE:
	270	data[p++]=GLX_DEPTH_SIZE; data[p++]=attribList[arg++]; break;
	271	case WX_GL_STENCIL_SIZE:
	272	data[p++]=GLX_STENCIL_SIZE; data[p++]=attribList[arg++]; break;
	273	case WX_GL_MIN_ACCUM_RED:
	274	data[p++]=GLX_ACCUM_RED_SIZE; data[p++]=attribList[arg++]; break;
	275	case WX_GL_MIN_ACCUM_GREEN:
	276	data[p++]=GLX_ACCUM_GREEN_SIZE; data[p++]=attribList[arg++]; break;
	277	case WX_GL_MIN_ACCUM_BLUE:
	278	data[p++]=GLX_ACCUM_BLUE_SIZE; data[p++]=attribList[arg++]; break;
	279	case WX_GL_MIN_ACCUM_ALPHA:
	280	data[p++]=GLX_ACCUM_ALPHA_SIZE; data[p++]=attribList[arg++]; break;
	281	default:
	282	break;
	283	}
	284	}
	285	data[p] = 0;
	286
	287	attribList = (int*) data;
	288	// Get an appropriate visual
	289	vi = glXChooseVisual(display, DefaultScreen(display), attribList);
	290	if(!vi) return FALSE;
	291
	292	// Here we should make sure that vi is the same visual as the
	293	// one used by the xwindow drawable in wxCanvas. However,
	294	// there is currently no mechanism for this in wx_canvs.cc.
	295	} else {
	296	// By default, we use the visual of xwindow
	297	// NI: is this really senseful ? opengl in e.g. color index mode ?
	298	XGetWindowAttributes(display, (Window) GetClientAreaWindow(), &xwa);
	299	vi_templ.visualid = XVisualIDFromVisual(xwa.visual);
	300	vi = XGetVisualInfo(display, VisualIDMask, &vi_templ, &n);
	301	if(!vi) return FALSE;
	302	glXGetConfig(display, vi, GLX_USE_GL, &val);
	303	if(!val) return FALSE;
	304	// Basically, this is it. It should be possible to use vi
	305	// in glXCreateContext() below. But this fails with Mesa.
	306	// I notified the Mesa author about it; there may be a fix.
	307	#ifdef OLD_MESA
	308	// Construct an attribute list matching the visual
	309	int a_list[32];
	310	n = 0;
	311	if(vi->c_class==TrueColor \|\| vi->c_class==DirectColor) { // RGBA visual
	312	a_list[n++] = GLX_RGBA;
	313	a_list[n++] = GLX_RED_SIZE;
	314	a_list[n++] = bitcount(vi->red_mask);
	315	a_list[n++] = GLX_GREEN_SIZE;
	316	a_list[n++] = bitcount(vi->green_mask);
	317	a_list[n++] = GLX_BLUE_SIZE;
	318	a_list[n++] = bitcount(vi->blue_mask);
	319	glXGetConfig(display, vi, GLX_ALPHA_SIZE, &val);
	320	a_list[n++] = GLX_ALPHA_SIZE;
	321	a_list[n++] = val;
	322	} else { // Color index visual
	323	glXGetConfig(display, vi, GLX_BUFFER_SIZE, &val);
	324	a_list[n++] = GLX_BUFFER_SIZE;
	325	a_list[n++] = val;
	326	}
	327	a_list[n] = None;
	328	// XFree(vi);
	329	vi = glXChooseVisual(display, DefaultScreen(display), a_list);
	330	if(!vi) return FALSE;
	331	#endif /* OLD_MESA */
	332	}
	333
	334	m_vi = vi; // safe for later use
	335
	336	wxCHECK_MSG( m_vi, FALSE, "required visual couldn't be found" );
	337
	338	// Create the GLX context and make it current
	339
	340	wxGLContext *share= m_sharedContext;
	341	if (share==NULL && m_sharedContextOf)
	342	share = m_sharedContextOf->GetContext();
	343
	344	m_glContext = new wxGLContext( TRUE, this, wxNullPalette, share );
	345
	346	#ifndef OLD_MESA
	347	// XFree(vi);
	348	#endif
	349	SetCurrent();
	350
	351	return TRUE;
	352	}
	353
	354	wxGLCanvas::~wxGLCanvas(void)
	355	{
	356	XVisualInfo vi = (XVisualInfo ) m_vi;
	357
	358	if (vi) XFree( vi );
	359	if (m_glContext) delete m_glContext;
	360
	361	// Display* display = (Display*) GetXDisplay();
	362	// if(glx_cx) glXDestroyContext(display, glx_cx);
	363	}
	364
	365	void wxGLCanvas::SwapBuffers()
	366	{
	367	if( m_glContext ) m_glContext->SwapBuffers();
	368
	369	// Display* display = (Display*) GetXDisplay();
	370	// if(glx_cx) glXSwapBuffers(display, (Window) GetClientAreaWindow());
	371	}
	372
	373	void wxGLCanvas::SetCurrent()
	374	{
	375	if( m_glContext ) m_glContext->SetCurrent();
	376
	377	// Display* display = (Display*) GetXDisplay();
	378	// if(glx_cx) glXMakeCurrent(display, (Window) GetClientAreaWindow(), glx_cx);
	379	}
	380
	381	void wxGLCanvas::SetColour(const char *col)
	382	{
	383	if( m_glContext ) m_glContext->SetColour(col);
	384	}
	385
	386	#endif
	387	// wxUSE_GLCANVAS
	388