X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/45e6e6f8ab806b337dffeb3b52fec7eba3c845ef..c0e69d720d8b15f788fe0998806f18c46f7d5d8b:/samples/opengl/isosurf/isosurf.cpp?ds=sidebyside

diff --git a/samples/opengl/isosurf/isosurf.cpp b/samples/opengl/isosurf/isosurf.cpp
index f602caeeb4..471942b637 100644
--- a/samples/opengl/isosurf/isosurf.cpp
+++ b/samples/opengl/isosurf/isosurf.cpp
@@ -2,7 +2,7 @@
 // Name:        isosurf.cpp
 // Purpose:     wxGLCanvas demo program
 // Author:      Brian Paul (original gltk version), Wolfram Gloger
-// Modified by: Julian Smart
+// Modified by: Julian Smart, Francesco Montorsi
 // Created:     04/01/98
 // RCS-ID:      $Id$
 // Copyright:   (c) Julian Smart
@@ -27,244 +27,87 @@
 #include "wx/timer.h"
 #include "wx/glcanvas.h"
 #include "wx/math.h"
-
-#if defined(__WXMAC__) || defined(__WXCOCOA__)
-#   ifdef __DARWIN__
-#       include <OpenGL/gl.h>
-#       include <OpenGL/glu.h>
-#   else
-#       include <gl.h>
-#       include <glu.h>
-#   endif
-#else
-#   include <GL/gl.h>
-#   include <GL/glu.h>
-#endif
-
-// disabled because this has apparently changed in OpenGL 1.2, so doesn't link
-// correctly if this is on...
-#ifdef GL_EXT_vertex_array
-#undef GL_EXT_vertex_array
-#endif
+#include "wx/log.h"
+#include "wx/cmdline.h"
+#include "wx/wfstream.h"
+#include "wx/zstream.h"
+#include "wx/txtstrm.h"
 
 #include "isosurf.h"
-
 #include "../../sample.xpm"
 
-// The following part is taken largely unchanged from the original C Version
-
-GLboolean speed_test = GL_FALSE;
-GLboolean use_vertex_arrays = GL_FALSE;
-
-GLboolean doubleBuffer = GL_TRUE;
 
-GLboolean smooth = GL_TRUE;
-GLboolean lighting = GL_TRUE;
+// global options which can be set through command-line options
+GLboolean g_use_vertex_arrays = GL_FALSE;
+GLboolean g_doubleBuffer = GL_TRUE;
+GLboolean g_smooth = GL_TRUE;
+GLboolean g_lighting = GL_TRUE;
 
 
-#define MAXVERTS 10000
 
-static GLfloat verts[MAXVERTS][3];
-static GLfloat norms[MAXVERTS][3];
-static GLint numverts;
-
-static GLfloat xrot;
-static GLfloat yrot;
-
-
-static void read_surface( const wxChar *filename )
-{
-    FILE *f = wxFopen(filename,_T("r"));
-    if (!f)
-    {
-        wxString msg = _T("Couldn't read ");
-        msg += filename;
-        wxMessageBox(msg);
-        return;
-    }
-
-    numverts = 0;
-    while (!feof(f) && numverts<MAXVERTS)
-    {
-        fscanf( f, "%f %f %f  %f %f %f",
-            &verts[numverts][0], &verts[numverts][1], &verts[numverts][2],
-            &norms[numverts][0], &norms[numverts][1], &norms[numverts][2] );
-        numverts++;
-    }
-
-    numverts--;
-
-    wxPrintf(_T("%d vertices, %d triangles\n"), numverts, numverts-2);
-
-    fclose(f);
-}
-
-
-static void draw_surface()
-{
-    GLint i;
-
-#ifdef GL_EXT_vertex_array
-    if (use_vertex_arrays)
-    {
-        glDrawArraysEXT( GL_TRIANGLE_STRIP, 0, numverts );
-    }
-    else
-#endif
-    {
-        glBegin( GL_TRIANGLE_STRIP );
-        for (i=0;i<numverts;i++)
-        {
-            glNormal3fv( norms[i] );
-            glVertex3fv( verts[i] );
-        }
-        glEnd();
-    }
-}
-
-
-static void draw1()
-{
-    glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
-    glPushMatrix();
-    glRotatef( yrot, 0.0f, 1.0f, 0.0f );
-    glRotatef( xrot, 1.0f, 0.0f, 0.0f );
-
-    draw_surface();
-
-    glPopMatrix();
-
-    glFlush();
-}
+//---------------------------------------------------------------------------
+// MyApp
+//---------------------------------------------------------------------------
 
+IMPLEMENT_APP(MyApp)
 
-static void InitMaterials()
+bool MyApp::OnInit()
 {
-    static const GLfloat ambient[4] = {0.1f, 0.1f, 0.1f, 1.0f};
-    static const GLfloat diffuse[4] = {0.5f, 1.0f, 1.0f, 1.0f};
-    static const GLfloat position0[4] = {0.0f, 0.0f, 20.0f, 0.0f};
-    static const GLfloat position1[4] = {0.0f, 0.0f, -20.0f, 0.0f};
-    static const GLfloat front_mat_shininess[1] = {60.0f};
-    static const GLfloat front_mat_specular[4] = {0.2f, 0.2f, 0.2f, 1.0f};
-    static const GLfloat front_mat_diffuse[4] = {0.5f, 0.28f, 0.38f, 1.0f};
-    /*
-    static const GLfloat back_mat_shininess[1] = {60.0f};
-    static const GLfloat back_mat_specular[4] = {0.5f, 0.5f, 0.2f, 1.0f};
-    static const GLfloat back_mat_diffuse[4] = {1.0f, 1.0f, 0.2f, 1.0f};
-    */
-    static const GLfloat lmodel_ambient[4] = {1.0f, 1.0f, 1.0f, 1.0f};
-    static const GLfloat lmodel_twoside[1] = {GL_FALSE};
-
-    glLightfv(GL_LIGHT0, GL_AMBIENT, ambient);
-    glLightfv(GL_LIGHT0, GL_DIFFUSE, diffuse);
-    glLightfv(GL_LIGHT0, GL_POSITION, position0);
-    glEnable(GL_LIGHT0);
-
-    glLightfv(GL_LIGHT1, GL_AMBIENT, ambient);
-    glLightfv(GL_LIGHT1, GL_DIFFUSE, diffuse);
-    glLightfv(GL_LIGHT1, GL_POSITION, position1);
-    glEnable(GL_LIGHT1);
+    if ( !wxApp::OnInit() )
+        return false;
 
-    glLightModelfv(GL_LIGHT_MODEL_AMBIENT, lmodel_ambient);
-    glLightModelfv(GL_LIGHT_MODEL_TWO_SIDE, lmodel_twoside);
-    glEnable(GL_LIGHTING);
+    // Create the main frame window
+    SetTopWindow(new MyFrame(NULL, wxT("wxWidgets OpenGL Isosurf Sample")));
 
-    glMaterialfv(GL_FRONT_AND_BACK, GL_SHININESS, front_mat_shininess);
-    glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, front_mat_specular);
-    glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, front_mat_diffuse);
+    return true;
 }
 
-
-static void Init(void)
+void MyApp::OnInitCmdLine(wxCmdLineParser& parser)
 {
-    glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
+    parser.AddSwitch("", "sb", "Do not use double buffering");
+    parser.AddSwitch("", "db", "Use double buffering");
+    parser.AddSwitch("", "va", "Use vertex arrays");
 
-    glShadeModel(GL_SMOOTH);
-    glEnable(GL_DEPTH_TEST);
-
-    InitMaterials();
-
-    glMatrixMode(GL_PROJECTION);
-    glLoadIdentity();
-    glFrustum( -1.0, 1.0, -1.0, 1.0, 5.0, 25.0 );
-
-    glMatrixMode(GL_MODELVIEW);
-    glLoadIdentity();
-    glTranslatef( 0.0, 0.0, -6.0 );
-
-#ifdef GL_EXT_vertex_array
-    if (use_vertex_arrays)
-    {
-        glVertexPointerEXT( 3, GL_FLOAT, 0, numverts, verts );
-        glNormalPointerEXT( GL_FLOAT, 0, numverts, norms );
-        glEnable( GL_VERTEX_ARRAY_EXT );
-        glEnable( GL_NORMAL_ARRAY_EXT );
-    }
-#endif
+    wxApp::OnInitCmdLine(parser);
 }
 
-static GLenum Args(int argc, wxChar **argv)
+bool MyApp::OnCmdLineParsed(wxCmdLineParser& parser)
 {
-    GLint i;
+    if (parser.Found("sb"))
+        g_doubleBuffer = GL_FALSE;
+    else if (parser.Found("db"))
+        g_doubleBuffer = GL_TRUE;
 
-    for (i = 1; i < argc; i++)
-    {
-        if (wxStrcmp(argv[i], _T("-sb")) == 0)
-        {
-            doubleBuffer = GL_FALSE;
-        }
-        else if (wxStrcmp(argv[i], _T("-db")) == 0)
-        {
-            doubleBuffer = GL_TRUE;
-        }
-        else if (wxStrcmp(argv[i], _T("-speed")) == 0)
-        {
-            speed_test = GL_TRUE;
-            doubleBuffer = GL_TRUE;
-        }
-        else if (wxStrcmp(argv[i], _T("-va")) == 0)
-        {
-            use_vertex_arrays = GL_TRUE;
-        }
-        else
-        {
-            wxString msg = _T("Bad option: ");
-            msg += argv[i];
-            wxMessageBox(msg);
-            return GL_FALSE;
-        }
-    }
+    if (parser.Found("va"))
+        g_use_vertex_arrays = GL_TRUE;
 
-    return GL_TRUE;
+    return wxApp::OnCmdLineParsed(parser);
 }
 
-// The following part was written for wxWidgets 1.66
-MyFrame *frame = NULL;
+//---------------------------------------------------------------------------
+// MyFrame
+//---------------------------------------------------------------------------
 
-IMPLEMENT_APP(MyApp)
+BEGIN_EVENT_TABLE(MyFrame, wxFrame)
+    EVT_MENU(wxID_EXIT, MyFrame::OnExit)
+END_EVENT_TABLE()
 
-// `Main program' equivalent, creating windows and returning main app frame
-bool MyApp::OnInit()
+MyFrame::MyFrame(wxFrame *frame, const wxString& title, const wxPoint& pos,
+                 const wxSize& size, long style)
+    : wxFrame(frame, wxID_ANY, title, pos, size, style),
+      m_canvas(NULL)
 {
-    if ( !wxApp::OnInit() )
-        return false;
+    SetIcon(wxICON(sample));
 
-    Args(argc, argv);
-
-    // Create the main frame window
-    frame = new MyFrame(NULL, wxT("wxWidgets OpenGL Isosurf Sample"),
-        wxDefaultPosition, wxDefaultSize);
-
-    // Give it an icon
-    frame->SetIcon(wxIcon(_T("mondrian")));
 
     // Make a menubar
     wxMenu *fileMenu = new wxMenu;
 
-    fileMenu->Append(wxID_EXIT, _T("E&xit"));
+    fileMenu->Append(wxID_EXIT, wxT("E&xit"));
     wxMenuBar *menuBar = new wxMenuBar;
-    menuBar->Append(fileMenu, _T("&File"));
-    frame->SetMenuBar(menuBar);
+    menuBar->Append(fileMenu, wxT("&File"));
+    SetMenuBar(menuBar);
+
 
   // Make a TestGLCanvas
 
@@ -272,7 +115,8 @@ bool MyApp::OnInit()
 #ifdef __WXMSW__
     int *gl_attrib = NULL;
 #else
-    int gl_attrib[20] = { WX_GL_RGBA, WX_GL_MIN_RED, 1, WX_GL_MIN_GREEN, 1,
+    int gl_attrib[20] =
+        { WX_GL_RGBA, WX_GL_MIN_RED, 1, WX_GL_MIN_GREEN, 1,
         WX_GL_MIN_BLUE, 1, WX_GL_DEPTH_SIZE, 1,
         WX_GL_DOUBLEBUFFER,
 #  if defined(__WXMAC__) || defined(__WXCOCOA__)
@@ -282,40 +126,20 @@ bool MyApp::OnInit()
 #  endif
 #endif
 
-    if(!doubleBuffer)
+    if (!g_doubleBuffer)
     {
-        printf("don't have double buffer, disabling\n");
+        wxLogWarning("Disabling double buffering");
+
 #ifdef __WXGTK__
         gl_attrib[9] = None;
 #endif
-        doubleBuffer = GL_FALSE;
+        g_doubleBuffer = GL_FALSE;
     }
 
-    frame->m_canvas = new TestGLCanvas(frame, wxID_ANY, wxDefaultPosition,
-        wxDefaultSize, 0, _T("TestGLCanvas"), gl_attrib );
-
-  // Show the frame
-    frame->Show(true);
-
-    frame->m_canvas->SetCurrent();
-    read_surface( _T("isosurf.dat") );
-
-    Init();
+    // Show the frame
+    Show(true);
 
-    return true;
-}
-
-BEGIN_EVENT_TABLE(MyFrame, wxFrame)
-    EVT_MENU(wxID_EXIT, MyFrame::OnExit)
-END_EVENT_TABLE()
-
-// My frame constructor
-MyFrame::MyFrame(wxFrame *frame, const wxString& title, const wxPoint& pos,
-    const wxSize& size, long style)
-    : wxFrame(frame, wxID_ANY, title, pos, size, style)
-{
-    m_canvas = NULL;
-    SetIcon(wxIcon(sample_xpm));
+    m_canvas = new TestGLCanvas(this, wxID_ANY, gl_attrib);
 }
 
 MyFrame::~MyFrame()
@@ -330,34 +154,89 @@ void MyFrame::OnExit( wxCommandEvent& WXUNUSED(event) )
     Close(true);
 }
 
-/*
- * TestGLCanvas implementation
- */
+
+//---------------------------------------------------------------------------
+// TestGLCanvas
+//---------------------------------------------------------------------------
 
 BEGIN_EVENT_TABLE(TestGLCanvas, wxGLCanvas)
     EVT_SIZE(TestGLCanvas::OnSize)
     EVT_PAINT(TestGLCanvas::OnPaint)
     EVT_CHAR(TestGLCanvas::OnChar)
     EVT_MOUSE_EVENTS(TestGLCanvas::OnMouseEvent)
-    EVT_ERASE_BACKGROUND(TestGLCanvas::OnEraseBackground)
 END_EVENT_TABLE()
 
-TestGLCanvas::TestGLCanvas(wxWindow *parent, wxWindowID id,
-    const wxPoint& pos, const wxSize& size, long style,
-    const wxString& name, int* gl_attrib)
-    : wxGLCanvas(parent, id, pos, size, style|wxFULL_REPAINT_ON_RESIZE, name, gl_attrib)
+TestGLCanvas::TestGLCanvas(wxWindow *parent,
+                           wxWindowID id,
+                           int* gl_attrib)
+    : wxGLCanvas(parent, id, gl_attrib)
 {
-    parent->Show(true);
-    SetCurrent();
+    m_xrot = 0;
+    m_yrot = 0;
+    m_numverts = 0;
+
+    // Explicitly create a new rendering context instance for this canvas.
+    m_glRC = new wxGLContext(this);
+
+    // Make the new context current (activate it for use) with this canvas.
+    SetCurrent(*m_glRC);
 
-    /* Make sure server supports the vertex array extension */
-    char* extensions = (char *) glGetString( GL_EXTENSIONS );
-    if (!extensions || !strstr( extensions, "GL_EXT_vertex_array" ))
+    InitGL();
+    InitMaterials();
+    LoadSurface("isosurf.dat.gz");
+}
+
+TestGLCanvas::~TestGLCanvas()
+{
+    delete m_glRC;
+}
+
+void TestGLCanvas::LoadSurface(const wxString& filename)
+{
+    // FIXME
+    // we need to set english locale to force wxTextInputStream's calls to
+    // wxStrtod to use the point and not the comma as decimal separator...
+    // (the isosurf.dat contains points and not commas)...
+    wxLocale l(wxLANGUAGE_ENGLISH);
+
+    wxZlibInputStream* stream =
+        new wxZlibInputStream(new wxFFileInputStream(filename));
+    if (!stream || !stream->IsOk())
     {
-        use_vertex_arrays = GL_FALSE;
+        wxLogError("Cannot load '%s' type of files!", filename.c_str());
+        delete stream;
+        return;
     }
-}
 
+    {
+        // we suppose to have in input a text file containing floating numbers
+        // space/newline-separed... first 3 numbers are the coordinates of a
+        // vertex and the following 3 are the relative vertex normal and so on...
+
+        wxTextInputStream inFile(*stream);
+        m_numverts = 0;
+
+        while (!stream->Eof() && m_numverts < MAXVERTS)// && m_numverts<MAXVERTS)
+        {
+            inFile >> m_verts[m_numverts][0] >> m_verts[m_numverts][1] >> m_verts[m_numverts][2];
+            inFile >> m_norms[m_numverts][0] >> m_norms[m_numverts][1] >> m_norms[m_numverts][2];
+
+            m_numverts++;
+        }
+
+        // discard last vertex; it is a zero caused by the EOF
+        m_numverts--;
+    }
+
+    delete stream;
+
+    wxLogMessage(wxT("Loaded %d vertices, %d triangles from '%s'"),
+                 m_numverts, m_numverts-2, filename.c_str());
+                 
+    // NOTE: for some reason under wxGTK the following is required to avoid that
+    //       the surface gets rendered in a small rectangle in the top-left corner of the frame
+    PostSizeEventToParent();
+}
 
 void TestGLCanvas::OnPaint( wxPaintEvent& WXUNUSED(event) )
 {
@@ -365,31 +244,50 @@ void TestGLCanvas::OnPaint( wxPaintEvent& WXUNUSED(event) )
     // OnPaint handlers must always create a wxPaintDC.
     wxPaintDC dc(this);
 
-#ifndef __WXMOTIF__
-    if (!GetContext()) return;
-#endif
+    // This is normally only necessary if there is more than one wxGLCanvas
+    // or more than one wxGLContext in the application.
+    SetCurrent(*m_glRC);
+
+    glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
+    glPushMatrix();
+    glRotatef( m_yrot, 0.0f, 1.0f, 0.0f );
+    glRotatef( m_xrot, 1.0f, 0.0f, 0.0f );
+
+    // draw the surface
+    if (g_use_vertex_arrays)
+    {
+        glDrawArrays( GL_TRIANGLE_STRIP, 0, m_numverts );
+    }
+    else
+    {
+        glBegin( GL_TRIANGLE_STRIP );
 
-    SetCurrent();
+        for (int i=0;i<m_numverts;i++)
+        {
+            glNormal3fv( m_norms[i] );
+            glVertex3fv( m_verts[i] );
+        }
+
+        glEnd();
+    }
+
+    glPopMatrix();
+    glFlush(); // Not really necessary: buffer swapping below implies glFlush()
 
-    draw1();
     SwapBuffers();
 }
 
 void TestGLCanvas::OnSize(wxSizeEvent& event)
 {
-    // this is also necessary to update the context on some platforms
-    wxGLCanvas::OnSize(event);
-
-    // set GL viewport (not called by wxGLCanvas::OnSize on all platforms...)
-    int w, h;
-    GetClientSize(&w, &h);
-#ifndef __WXMOTIF__
-    if (GetContext())
-#endif
-    {
-        SetCurrent();
-        glViewport(0, 0, (GLint) w, (GLint) h);
-    }
+    // This is normally only necessary if there is more than one wxGLCanvas
+    // or more than one wxGLContext in the application.
+    SetCurrent(*m_glRC);
+
+    // It's up to the application code to update the OpenGL viewport settings.
+    // This is OK here only because there is only one canvas that uses the
+    // context. See the cube sample for that case that multiple canvases are
+    // made current with one context.
+    glViewport(0, 0, event.GetSize().x, event.GetSize().y);
 }
 
 void TestGLCanvas::OnChar(wxKeyEvent& event)
@@ -401,43 +299,35 @@ void TestGLCanvas::OnChar(wxKeyEvent& event)
         return;
 
     case WXK_LEFT:
-        yrot -= 15.0;
+        m_yrot -= 15.0;
         break;
 
     case WXK_RIGHT:
-        yrot += 15.0;
+        m_yrot += 15.0;
         break;
 
     case WXK_UP:
-        xrot += 15.0;
+        m_xrot += 15.0;
         break;
 
     case WXK_DOWN:
-        xrot -= 15.0;
+        m_xrot -= 15.0;
         break;
 
     case 's': case 'S':
-        smooth = !smooth;
-        if (smooth)
-        {
+        g_smooth = !g_smooth;
+        if (g_smooth)
             glShadeModel(GL_SMOOTH);
-        }
         else
-        {
             glShadeModel(GL_FLAT);
-        }
         break;
 
     case 'l': case 'L':
-        lighting = !lighting;
-        if (lighting)
-        {
+        g_lighting = !g_lighting;
+        if (g_lighting)
             glEnable(GL_LIGHTING);
-        }
         else
-        {
             glDisable(GL_LIGHTING);
-        }
         break;
 
     default:
@@ -453,29 +343,90 @@ void TestGLCanvas::OnMouseEvent(wxMouseEvent& event)
     static int dragging = 0;
     static float last_x, last_y;
 
-    //printf("%f %f %d\n", event.GetX(), event.GetY(), (int)event.LeftIsDown());
-    if(event.LeftIsDown())
+    // Allow default processing to happen, or else the canvas cannot gain focus
+    // (for key events).
+    event.Skip();
+
+    if (event.LeftIsDown())
     {
-        if(!dragging)
+        if (!dragging)
         {
             dragging = 1;
         }
         else
         {
-            yrot += (event.GetX() - last_x)*1.0;
-            xrot += (event.GetY() - last_y)*1.0;
+            m_yrot += (event.GetX() - last_x)*1.0;
+            m_xrot += (event.GetY() - last_y)*1.0;
             Refresh(false);
         }
         last_x = event.GetX();
         last_y = event.GetY();
     }
     else
+    {
         dragging = 0;
+    }
+}
 
+void TestGLCanvas::InitMaterials()
+{
+    static const GLfloat ambient[4] = {0.1f, 0.1f, 0.1f, 1.0f};
+    static const GLfloat diffuse[4] = {0.5f, 1.0f, 1.0f, 1.0f};
+    static const GLfloat position0[4] = {0.0f, 0.0f, 20.0f, 0.0f};
+    static const GLfloat position1[4] = {0.0f, 0.0f, -20.0f, 0.0f};
+    static const GLfloat front_mat_shininess[1] = {60.0f};
+    static const GLfloat front_mat_specular[4] = {0.2f, 0.2f, 0.2f, 1.0f};
+    static const GLfloat front_mat_diffuse[4] = {0.5f, 0.28f, 0.38f, 1.0f};
+    /*
+    static const GLfloat back_mat_shininess[1] = {60.0f};
+    static const GLfloat back_mat_specular[4] = {0.5f, 0.5f, 0.2f, 1.0f};
+    static const GLfloat back_mat_diffuse[4] = {1.0f, 1.0f, 0.2f, 1.0f};
+    */
+    static const GLfloat lmodel_ambient[4] = {1.0f, 1.0f, 1.0f, 1.0f};
+    static const GLfloat lmodel_twoside[1] = {GL_FALSE};
+
+    glLightfv(GL_LIGHT0, GL_AMBIENT, ambient);
+    glLightfv(GL_LIGHT0, GL_DIFFUSE, diffuse);
+    glLightfv(GL_LIGHT0, GL_POSITION, position0);
+    glEnable(GL_LIGHT0);
+
+    glLightfv(GL_LIGHT1, GL_AMBIENT, ambient);
+    glLightfv(GL_LIGHT1, GL_DIFFUSE, diffuse);
+    glLightfv(GL_LIGHT1, GL_POSITION, position1);
+    glEnable(GL_LIGHT1);
+
+    glLightModelfv(GL_LIGHT_MODEL_AMBIENT, lmodel_ambient);
+    glLightModelfv(GL_LIGHT_MODEL_TWO_SIDE, lmodel_twoside);
+    glEnable(GL_LIGHTING);
+
+    glMaterialfv(GL_FRONT_AND_BACK, GL_SHININESS, front_mat_shininess);
+    glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, front_mat_specular);
+    glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, front_mat_diffuse);
 }
 
-void TestGLCanvas::OnEraseBackground( wxEraseEvent& WXUNUSED(event) )
+void TestGLCanvas::InitGL()
 {
-    // Do nothing, to avoid flashing.
+    glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
+
+    glShadeModel(GL_SMOOTH);
+    glEnable(GL_DEPTH_TEST);
+
+    InitMaterials();
+
+    glMatrixMode(GL_PROJECTION);
+    glLoadIdentity();
+    glFrustum( -1.0, 1.0, -1.0, 1.0, 5.0, 25.0 );
+
+    glMatrixMode(GL_MODELVIEW);
+    glLoadIdentity();
+    glTranslatef( 0.0, 0.0, -6.0 );
+
+    if (g_use_vertex_arrays)
+    {
+        glVertexPointer( 3, GL_FLOAT, 0, m_verts );
+        glNormalPointer( GL_FLOAT, 0, m_norms );
+        glEnable( GL_VERTEX_ARRAY );
+        glEnable( GL_NORMAL_ARRAY );
+    }
 }