Plusieurs fenêtres dans OpenGL?

Question

Est-il possible d'avoir OpenGL dans 2 fenêtres? comme dans 2 fenêtres différentes (disons que la première est 640x480 et l'autre 1024x768) rendant différentes choses (disons qu'une fenêtre est un éditeur et l'autre est l'affichage principal / normal)

Answer 1

Si vous utilisez GLUT, vous pouvez utiliser les appels glutSetWindow () / glutGetWindow () pour sélectionner la fenêtre appropriée (après les avoir créées avec glutCreateSubWindow ()). Cependant, parfois, GLUT peut ne pas être le bon outil pour ce travail.

Si vous travaillez sous Windows, vous voudrez vous pencher sur wglMakeCurrent () et wglCreateContext (). Sous OS X, il y a aglSetCurrentContext (), etc., et X11 requiert glXMakeCurrent ().

Ces fonctions activent le contexte OpenGL actuel dans lequel vous pouvez effectuer le rendu. Chaque bibliothèque spécifique à une plate-forme a ses propres moyens de créer une fenêtre et de lui lier un contexte OpenGL.

Sous Windows, une fois que vous avez acquis votre HWND et votre HDC pour une fenêtre (après un appel à CreateWindow et GetDC). Vous faites généralement quelque chose comme ceci pour configurer OpenGL:

GLuint l_PixelFormat = 0;

// some pixel format descriptor that I generally use:
static PIXELFORMATDESCRIPTOR l_Pfd = { sizeof(PIXELFORMATDESCRIPTOR), 1, 
    PFD_DRAW_TO_WINDOW + PFD_SUPPORT_OPENGL + PFD_DOUBLEBUFFER, 
    PFD_TYPE_RGBA, m_BitsPerPixel, 0, 0, 0, 0, 0, 0, 
    0, 0, 0, 0, 0, 0, 0, 16, 0, 0, PFD_MAIN_PLANE, 0, 0, 0, 0};

if(!(l_PixelFormat = ChoosePixelFormat(m_hDC, &l_Pfd))){
    throw std::runtime_error("No matching pixel format descriptor");
}

if(!SetPixelFormat(m_hDC, l_PixelFormat, &l_Pfd)){
    throw std::runtime_error("Can't set the pixel format");
}

if(!(m_hRC = wglCreateContext(m_hDC))){
    throw std::runtime_error("Can't create rendering context");
}

wglMakeCurrent(m_hDC, m_hRC);

Vous utilisez ce code pour créer plusieurs fenêtres et y lier OpenGL. Chaque fois que vous souhaitez afficher une fenêtre spécifique, vous devez appeler wglMakeCurrent avant de faire quoi que ce soit et de transmettre les paramètres. correspondant à cette fenêtre.

En guise de remarque, OpenGL vous permet de partager certaines données entre différents contextes. Toutefois, selon les spécifications, les données que vous pouvez partager sont assez limitées. Cependant, la plupart des systèmes d’exploitation vous permettent de partager plus de données que ce qui est spécifié dans la spécification.

Answer 2

Oui, c'est possible. Pour chaque fenêtre, vous devez créer un contexte de périphérique et un contexte de rendu uniques.

HDC hDC = GetDC( hWnd ); /* get the device context for a particular window */
/* snip */
HGLRC hRC;
hRC = wglCreateContext( hDC ); /* get a render context for the same window */
/* repeat with hDC2 and hRC2 with another window handle*/

Avant de passer des appels GL à la fenêtre, vous devez appeler wglMakeCurrent comme suit:

wglMakeCurrent( hDC, hRC );
/* GL calls for first window */
wglMakeCurrent( NULL, NULL);

wglMakeCurrent( hDC2, hRC2 );
/* GL calls for second window */
wglMakeCurrent( NULL, NULL);

Answer 3

Sous Windows, vous pouvez partager des objets OpenGL tels que des textures et des shaders avec wglShareLists () . Il partage généralement tout ce qui vous intéresse, malgré ce que dit MSDN.

Answer 4

J'ai déjà utilisé plusieurs fenêtres OpenGL dans une application MFC. Voici une classe qui pourrait vous être utile: puisqu'il ne peut y avoir qu'un seul contexte de rendu actuel dans le thread d'interface utilisateur à la fois, j'ai écrit un wrapper de classe pour faciliter sa gestion.

SaveRestoreRC.h

// cette classe permet de gérer plusieurs contrôleurs de périphérique à l'aide d'un modèle de conception RAII

class CSaveRestoreRC
{
public:
HDC   oldDC;            
HGLRC oldRC;            

CSaveRestoreRC(HDC hDC, HGLRC hRC);
~CSaveRestoreRC(void);
};

SaveRestoreRC.cpp:

CSaveRestoreRC::CSaveRestoreRC(HDC hDC, HGLRC hRC)
{
ASSERT( hDC );
ASSERT( hRC );

oldDC = wglGetCurrentDC();
oldRC = wglGetCurrentContext();

BOOL result = wglMakeCurrent( hDC, hRC );
ASSERT( result );
}

CSaveRestoreRC::~CSaveRestoreRC(void)
{
if( !oldRC )
    return;
ASSERT( oldDC );
BOOL result = wglMakeCurrent( oldDC, oldRC );
ASSERT( result );    
}

Maintenant, dérivez une classe de CWnd et ajoutez ces variables de membre:

class COpenGLControl : public CWnd
{
    // used to interface OpenGL with Windows
    HDC   hdc;          
    HGLRC hrc;          
// ...

int COpenGLControl::OnCreate(LPCREATESTRUCT lpCreateStruct)
{
if (CWnd::OnCreate(lpCreateStruct) == -1)
    return -1;
// Get device context only once.
hdc = GetDC()->m_hDC;

// ... ChoosePixelFormat, SetPixelFormat, etc. here.

// Create the OpenGL Rendering Context.
hrc = wglCreateContext(hdc);
ASSERT( hrc );

Ensuite, dans chaque fonction membre où vous appelez N'IMPORTE QUELLE commande OpenGL, utilisez CSaveRestoreRC afin que votre contexte de rendu actuel ne soit pas gâché.

void COpenGLControl::UpdateCamera()
{
CSaveRestoreRC c(hdc, hrc);

// Map the OpenGL device coordinates.
glViewport(0, 0, renderingWindow.Width(), renderingWindow.Height());

// Do your other OpenGL stuff here
// ... 

// the CSaveRestoreRC destructor will automatically put the correct render context back, 
// even if you call other functions. Of course, put another CSaveRestoreRC there too.
} 

Answer 5

Si vous préférez utiliser uniquement la bibliothèque Glut, consultez un code d'Eric Stringer .

// Glutdualwindow.c
// By Eric Stringer 2002
// Simple examples of OpenGL and Glut usage.
// Keyboard input
// 'v' = view ortho/perspective
// 'l' = lighting on/off


#include <windows.h>  // This header file will be needed for some windows compilers
//#include <GL/gl.h>   // gl.h and glu.h also maybe needed for some compilers
//#include <GL/glu.h>
#include <GL/glut.h>  // glut (gl utility toolkit) basic windows functions, keyboard, mouse.
#include <stdio.h>    // standard (I/O library)
#include <stdlib.h>   // standard library (set of standard C functions
#include <math.h>     // Math library (Higher math functions )


// lighting
GLfloat LightAmbient[]= { 0.2f, 0.2f, 0.2f, 1.0f };
GLfloat LightDiffuse[]= { 0.5f, 0.5f, 0.5f, 1.0f };
GLfloat LightPosition[]= { 5.0f, 5.0f, -10.0f, 1.0f };
GLfloat mat_specular[] = { 0.2, 0.2, 0.2, 1.0 };

int window_1, window_2;

static int view_state = 0, light_state = 0;

int spin;

int shape;

// I use this to put text on the screen
void Sprint( int x, int y, char *st)
{
    int l,i;

    l=strlen( st ); // see how many characters are in text string.
    glRasterPos2i( x, y); // location to start printing text
    for( i=0; i < l; i++)  // loop until i is greater then l
        {
        glutBitmapCharacter(GLUT_BITMAP_TIMES_ROMAN_24, st[i]); // Print a character on the screen
    }

}


// This creates the spinning of the cube.
static void TimeEvent(int te)
{

    spin++;  // increase cube rotation by 1
    if (spin > 360) spin = 0; // if over 360 degress, start back at zero.

    glutSetWindow( window_1 );
    glutPostRedisplay();  // Update screen with new rotation data

    glutSetWindow( window_2 );
    glutPostRedisplay();  // Update screen with new rotation data

    glutTimerFunc( 100, TimeEvent, 1);  // Reset our timmer.
}


// Setup our Opengl world, called once at startup.
void init(void)
{


   glClearColor (0.0, 0.0, 0.0, 0.0);  // When screen cleared, use black.
   glShadeModel (GL_SMOOTH);  // How the object color will be rendered smooth or flat
   glEnable(GL_DEPTH_TEST);   // Check depth when rendering
   // Lighting is added to scene
   glLightfv(GL_LIGHT1 ,GL_AMBIENT, LightAmbient);
   glLightfv(GL_LIGHT1 ,GL_DIFFUSE, LightDiffuse);
   glLightfv(GL_LIGHT1 ,GL_POSITION, LightPosition);
   glEnable(GL_LIGHTING);  // Turn on lighting
   glEnable(GL_LIGHT1);    // Turn on light 1


}


// Draw our world
void display_1(void)
{
char *p;

glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);  //Clear the screen

glMatrixMode (GL_PROJECTION);  // Tell opengl that we are doing project matrix work
glLoadIdentity();  // Clear the matrix
glOrtho(-8.0, 8.0, -8.0, 8.0, 0.0, 30.0);  // Setup an Ortho view
glMatrixMode(GL_MODELVIEW);  // Tell opengl that we are doing model matrix work. (drawing)
glLoadIdentity(); // Clear the model matrix


glColor3f(1.0, 1.0, 1.0);
if (shape == 0) Sprint(-3, -7 ,"Solid Cube");
if (shape == 1) Sprint(-3, -7 ,"Solid Cone");
if (shape == 2) Sprint(-3, -7 ,"Solid Sphere");
if (shape == 3) Sprint(-3, -7 ,"Solid Torus");
if (shape == 4) Sprint(-3, -7 ,"Solid Dodecahedron");
if (shape == 5) Sprint(-3, -7 ,"Solid Octahedron");
if (shape == 6) Sprint(-3, -7 ,"Solid Tetrahedron");
if (shape == 7) Sprint(-3, -7 ,"Solid Icosahedron");
if (shape == 8) Sprint(-3, -7 ,"Solid Teapot");

// Setup view, and print view state on screen
if (view_state == 1)
    {
    glColor3f( 1.0, 1.0, 1.0);
    Sprint(-2, 4, "Perspective view");
    glMatrixMode (GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(60, 1, 1, 30);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    }else
    {
    glColor3f( 1.0, 1.0, 1.0);
    Sprint(-2, 4, "Ortho view");
    }

glColor3f( 0.0, 0.0, 1.0);  // Cube color

// Lighting on/off
if (light_state == 1)
    {
    glDisable(GL_LIGHTING);  // Turn off lighting
    glDisable(GL_COLOR_MATERIAL); // Turn off material, which needs lighting to work
    }else
    {
    glEnable(GL_LIGHTING); // Turn on lighting
    glEnable(GL_COLOR_MATERIAL); // Turn on material settings
    glColorMaterial(GL_FRONT, GL_AMBIENT);
    glColor4f(0.65, 0.65, 0.65, 0.4);
    glColorMaterial(GL_FRONT, GL_EMISSION);
    glColor4f(0.10, 0.10, 0.10, 0.0);
    glColorMaterial(GL_FRONT, GL_SPECULAR);
    glColor4f(0.5, 0.5, 0.5, 0.4);
    glColorMaterial(GL_FRONT, GL_DIFFUSE);
    glColor4f(0.85, 0.85, 0.85, 0.4);
    }

gluLookAt( 0, 0, 20, 0, 0, 0, 0, 1, 0);

//glRotatef( 45, 1.0, 1.0, 0.0); // rotate cube
glRotatef( spin++, 1.0, 1.0, 1.0); // spin cube

if (shape == 0) glutSolidCube(10); // Draw a cube
if (shape == 1) glutSolidCone(5,10, 16,16);  // Draw a Cone
if (shape == 2) glutSolidSphere(5, 16,16 );  // Draw a Sphere
if (shape == 3) glutSolidTorus( 2.5, 5, 16, 16);
if (shape == 4)
   {
    glScalef( 3.5, 3.5, 3.5);
    glutSolidDodecahedron();
   }

if (shape == 5)
   {
    glScalef( 5.0, 5.0, 5.0);
    glutSolidOctahedron();
   }
if (shape == 6)
   {
    glScalef( 5.0, 5.0, 5.0);
    glutSolidTetrahedron();
   }

if (shape == 7)
   {
    glScalef( 5.0, 5.0, 5.0);
    glutSolidIcosahedron();
   }
if (shape == 8) glutSolidTeapot( 5 );

glutSwapBuffers();
}

void display_2(void)
{
char *p;

glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);  //Clear the screen

glMatrixMode (GL_PROJECTION);  // Tell opengl that we are doing project matrix work
glLoadIdentity();  // Clear the matrix
glOrtho(-8.0, 8.0, -8.0, 8.0, 0.0, 30.0);  // Setup an Ortho view
glMatrixMode(GL_MODELVIEW);  // Tell opengl that we are doing model matrix work. (drawing)
glLoadIdentity(); // Clear the model matrix


glColor3f(1.0, 1.0, 1.0);
if (shape == 0) Sprint(-3, -7 ,"Wire Cube");
if (shape == 1) Sprint(-3, -7 ,"Wire Cone");
if (shape == 2) Sprint(-3, -7 ,"Wire Sphere");
if (shape == 3) Sprint(-3, -7 ,"Wire Torus");
if (shape == 4) Sprint(-3, -7 ,"Wire Dodecahedron");
if (shape == 5) Sprint(-3, -7 ,"Wire Octahedron");
if (shape == 6) Sprint(-3, -7 ,"Wire Tetrahedron");
if (shape == 7) Sprint(-3, -7 ,"Wire Icosahedron");
if (shape == 8) Sprint(-3, -7 ,"Wire Teapot");

// Setup view, and print view state on screen
if (view_state == 1)
    {
    glColor3f( 1.0, 1.0, 1.0);
    Sprint(-2, 4, "Perspective view");
    glMatrixMode (GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(60, 1, 1, 30);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    }else
    {
    glColor3f( 1.0, 1.0, 1.0);
    Sprint(-2, 4, "Ortho view");
    }

glColor3f( 0.0, 0.0, 1.0);  // Cube color

// Lighting on/off
if (light_state == 1)
    {
    glDisable(GL_LIGHTING);  // Turn off lighting
    glDisable(GL_COLOR_MATERIAL); // Turn off material, which needs lighting to work
    }else
    {
    glEnable(GL_LIGHTING); // Turn on lighting
    glEnable(GL_COLOR_MATERIAL); // Turn on material settings
    glColorMaterial(GL_FRONT, GL_AMBIENT);
    glColor4f(0.65, 0.65, 0.65, 0.4);
    glColorMaterial(GL_FRONT, GL_EMISSION);
    glColor4f(0.10, 0.10, 0.10, 0.0);
    glColorMaterial(GL_FRONT, GL_SPECULAR);
    glColor4f(0.5, 0.5, 0.5, 0.4);
    glColorMaterial(GL_FRONT, GL_DIFFUSE);
    glColor4f(0.85, 0.85, 0.85, 0.4);
    }

gluLookAt( 0, 0, 20, 0, 0, 0, 0, 1, 0);

//glRotatef( 45, 1.0, 1.0, 0.0); // rotate cube
glRotatef( spin++, 1.0, 1.0, 1.0); // spin cube

if (shape == 0) glutWireCube(10); // Draw a cube
if (shape == 1) glutWireCone(5,10, 16,16);  // Draw a Cone
if (shape == 2) glutWireSphere(5, 16,16 );  // Draw a Sphere
if (shape == 3) glutWireTorus( 2.5, 5, 16, 16);
if (shape == 4)
   {
    glScalef( 3.5, 3.5, 3.5);
    glutSolidDodecahedron();
   }

if (shape == 5)
   {
    glScalef( 5.0, 5.0, 5.0);
    glutWireOctahedron();
   }
if (shape == 6)
   {
    glScalef( 5.0, 5.0, 5.0);
    glutWireTetrahedron();
   }

if (shape == 7)
   {
    glScalef( 5.0, 5.0, 5.0);
    glutWireIcosahedron();
   }
if (shape == 8) glutWireTeapot( 5 );

glutSwapBuffers();
}


// This is called when the window has been resized.
void reshape_1 (int w, int h)
{
   glViewport (0, 0, (GLsizei) w, (GLsizei) h);
   glMatrixMode (GL_PROJECTION);
   glLoadIdentity ();
}

// This is called when the window has been resized.
void reshape_2 (int w, int h)
{
   glViewport (0, 0, (GLsizei) w, (GLsizei) h);
   glMatrixMode (GL_PROJECTION);
   glLoadIdentity ();
}

// Read the keyboard
void keyboard (unsigned char key, int x, int y)
{
   switch (key)
   {

      case 'v':
      case 'V':
          view_state = abs(view_state -1);
          break;
      case 'l':
      case 'L':
          light_state = abs(light_state -1);
          break;
      case 's':
      case 'S':
          shape++;
          break;
      case 27:
         exit(0); // exit program when [ESC] key presseed
         break;
      default:
         break;
   }

if (shape > 8) shape = 0;

}


// Main program
int main(int argc, char** argv)
{
   glutInit(&amp;argc, argv);
   glutInitDisplayMode (GLUT_DOUBLE | GLUT_RGB);
   glutInitWindowSize (500, 500);
   glutInitWindowPosition (10, 10);
   glutTimerFunc( 10, TimeEvent, 1);
   window_1 = glutCreateWindow (argv[0]);
   glutSetWindowTitle("GlutWindow 1");
   init ();
   glutDisplayFunc(display_1);
   glutReshapeFunc(reshape_1);
   glutKeyboardFunc(keyboard);

   window_2 = glutCreateWindow (argv[0]);
   glutSetWindowTitle("GlutWindow 2");
   init ();
   glutDisplayFunc(display_2);
   glutReshapeFunc(reshape_2);
   glutMainLoop();
   return 0;
}



// Glutdualwindow.c
// By Eric Stringer 2002
// Simple examples of OpenGL and Glut usage.
// Keyboard input
// 'v' = view ortho/perspective
// 'l' = lighting on/off


#include <windows.h>  // This header file will be needed for some windows compilers
//#include <GL/gl.h>   // gl.h and glu.h also maybe needed for some compilers
//#include <GL/glu.h>
#include <GL/glut.h>  // glut (gl utility toolkit) basic windows functions, keyboard, mouse.
#include <stdio.h>    // standard (I/O library)
#include <stdlib.h>   // standard library (set of standard C functions
#include <math.h>     // Math library (Higher math functions )


// lighting
GLfloat LightAmbient[]= { 0.2f, 0.2f, 0.2f, 1.0f };
GLfloat LightDiffuse[]= { 0.5f, 0.5f, 0.5f, 1.0f };
GLfloat LightPosition[]= { 5.0f, 5.0f, -10.0f, 1.0f };
GLfloat mat_specular[] = { 0.2, 0.2, 0.2, 1.0 };

int window_1, window_2;

static int view_state = 0, light_state = 0;

int spin;

int shape;

// I use this to put text on the screen
void Sprint( int x, int y, char *st)
{
    int l,i;

    l=strlen( st ); // see how many characters are in text string.
    glRasterPos2i( x, y); // location to start printing text
    for( i=0; i < l; i++)  // loop until i is greater then l
        {
        glutBitmapCharacter(GLUT_BITMAP_TIMES_ROMAN_24, st[i]); // Print a character on the screen
    }

}


// This creates the spinning of the cube.
static void TimeEvent(int te)
{

    spin++;  // increase cube rotation by 1
    if (spin > 360) spin = 0; // if over 360 degress, start back at zero.

    glutSetWindow( window_1 );
    glutPostRedisplay();  // Update screen with new rotation data

    glutSetWindow( window_2 );
    glutPostRedisplay();  // Update screen with new rotation data

    glutTimerFunc( 100, TimeEvent, 1);  // Reset our timmer.
}


// Setup our Opengl world, called once at startup.
void init(void)
{


   glClearColor (0.0, 0.0, 0.0, 0.0);  // When screen cleared, use black.
   glShadeModel (GL_SMOOTH);  // How the object color will be rendered smooth or flat
   glEnable(GL_DEPTH_TEST);   // Check depth when rendering
   // Lighting is added to scene
   glLightfv(GL_LIGHT1 ,GL_AMBIENT, LightAmbient);
   glLightfv(GL_LIGHT1 ,GL_DIFFUSE, LightDiffuse);
   glLightfv(GL_LIGHT1 ,GL_POSITION, LightPosition);
   glEnable(GL_LIGHTING);  // Turn on lighting
   glEnable(GL_LIGHT1);    // Turn on light 1


}


// Draw our world
void display_1(void)
{
char *p;

glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);  //Clear the screen

glMatrixMode (GL_PROJECTION);  // Tell opengl that we are doing project matrix work
glLoadIdentity();  // Clear the matrix
glOrtho(-8.0, 8.0, -8.0, 8.0, 0.0, 30.0);  // Setup an Ortho view
glMatrixMode(GL_MODELVIEW);  // Tell opengl that we are doing model matrix work. (drawing)
glLoadIdentity(); // Clear the model matrix


glColor3f(1.0, 1.0, 1.0);
if (shape == 0) Sprint(-3, -7 ,"Solid Cube");
if (shape == 1) Sprint(-3, -7 ,"Solid Cone");
if (shape == 2) Sprint(-3, -7 ,"Solid Sphere");
if (shape == 3) Sprint(-3, -7 ,"Solid Torus");
if (shape == 4) Sprint(-3, -7 ,"Solid Dodecahedron");
if (shape == 5) Sprint(-3, -7 ,"Solid Octahedron");
if (shape == 6) Sprint(-3, -7 ,"Solid Tetrahedron");
if (shape == 7) Sprint(-3, -7 ,"Solid Icosahedron");
if (shape == 8) Sprint(-3, -7 ,"Solid Teapot");

// Setup view, and print view state on screen
if (view_state == 1)
    {
    glColor3f( 1.0, 1.0, 1.0);
    Sprint(-2, 4, "Perspective view");
    glMatrixMode (GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(60, 1, 1, 30);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    }else
    {
    glColor3f( 1.0, 1.0, 1.0);
    Sprint(-2, 4, "Ortho view");
    }

glColor3f( 0.0, 0.0, 1.0);  // Cube color

// Lighting on/off
if (light_state == 1)
    {
    glDisable(GL_LIGHTING);  // Turn off lighting
    glDisable(GL_COLOR_MATERIAL); // Turn off material, which needs lighting to work
    }else
    {
    glEnable(GL_LIGHTING); // Turn on lighting
    glEnable(GL_COLOR_MATERIAL); // Turn on material settings
    glColorMaterial(GL_FRONT, GL_AMBIENT);
    glColor4f(0.65, 0.65, 0.65, 0.4);
    glColorMaterial(GL_FRONT, GL_EMISSION);
    glColor4f(0.10, 0.10, 0.10, 0.0);
    glColorMaterial(GL_FRONT, GL_SPECULAR);
    glColor4f(0.5, 0.5, 0.5, 0.4);
    glColorMaterial(GL_FRONT, GL_DIFFUSE);
    glColor4f(0.85, 0.85, 0.85, 0.4);
    }

gluLookAt( 0, 0, 20, 0, 0, 0, 0, 1, 0);

//glRotatef( 45, 1.0, 1.0, 0.0); // rotate cube
glRotatef( spin++, 1.0, 1.0, 1.0); // spin cube

if (shape == 0) glutSolidCube(10); // Draw a cube
if (shape == 1) glutSolidCone(5,10, 16,16);  // Draw a Cone
if (shape == 2) glutSolidSphere(5, 16,16 );  // Draw a Sphere
if (shape == 3) glutSolidTorus( 2.5, 5, 16, 16);
if (shape == 4)
   {
    glScalef( 3.5, 3.5, 3.5);
    glutSolidDodecahedron();
   }

if (shape == 5)
   {
    glScalef( 5.0, 5.0, 5.0);
    glutSolidOctahedron();
   }
if (shape == 6)
   {
    glScalef( 5.0, 5.0, 5.0);
    glutSolidTetrahedron();
   }

if (shape == 7)
   {
    glScalef( 5.0, 5.0, 5.0);
    glutSolidIcosahedron();
   }
if (shape == 8) glutSolidTeapot( 5 );

glutSwapBuffers();
}

void display_2(void)
{
char *p;

glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);  //Clear the screen

glMatrixMode (GL_PROJECTION);  // Tell opengl that we are doing project matrix work
glLoadIdentity();  // Clear the matrix
glOrtho(-8.0, 8.0, -8.0, 8.0, 0.0, 30.0);  // Setup an Ortho view
glMatrixMode(GL_MODELVIEW);  // Tell opengl that we are doing model matrix work. (drawing)
glLoadIdentity(); // Clear the model matrix


glColor3f(1.0, 1.0, 1.0);
if (shape == 0) Sprint(-3, -7 ,"Wire Cube");
if (shape == 1) Sprint(-3, -7 ,"Wire Cone");
if (shape == 2) Sprint(-3, -7 ,"Wire Sphere");
if (shape == 3) Sprint(-3, -7 ,"Wire Torus");
if (shape == 4) Sprint(-3, -7 ,"Wire Dodecahedron");
if (shape == 5) Sprint(-3, -7 ,"Wire Octahedron");
if (shape == 6) Sprint(-3, -7 ,"Wire Tetrahedron");
if (shape == 7) Sprint(-3, -7 ,"Wire Icosahedron");
if (shape == 8) Sprint(-3, -7 ,"Wire Teapot");

// Setup view, and print view state on screen
if (view_state == 1)
    {
    glColor3f( 1.0, 1.0, 1.0);
    Sprint(-2, 4, "Perspective view");
    glMatrixMode (GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(60, 1, 1, 30);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    }else
    {
    glColor3f( 1.0, 1.0, 1.0);
    Sprint(-2, 4, "Ortho view");
    }

glColor3f( 0.0, 0.0, 1.0);  // Cube color

// Lighting on/off
if (light_state == 1)
    {
    glDisable(GL_LIGHTING);  // Turn off lighting
    glDisable(GL_COLOR_MATERIAL); // Turn off material, which needs lighting to work
    }else
    {
    glEnable(GL_LIGHTING); // Turn on lighting
    glEnable(GL_COLOR_MATERIAL); // Turn on material settings
    glColorMaterial(GL_FRONT, GL_AMBIENT);
    glColor4f(0.65, 0.65, 0.65, 0.4);
    glColorMaterial(GL_FRONT, GL_EMISSION);
    glColor4f(0.10, 0.10, 0.10, 0.0);
    glColorMaterial(GL_FRONT, GL_SPECULAR);
    glColor4f(0.5, 0.5, 0.5, 0.4);
    glColorMaterial(GL_FRONT, GL_DIFFUSE);
    glColor4f(0.85, 0.85, 0.85, 0.4);
    }

gluLookAt( 0, 0, 20, 0, 0, 0, 0, 1, 0);

//glRotatef( 45, 1.0, 1.0, 0.0); // rotate cube
glRotatef( spin++, 1.0, 1.0, 1.0); // spin cube

if (shape == 0) glutWireCube(10); // Draw a cube
if (shape == 1) glutWireCone(5,10, 16,16);  // Draw a Cone
if (shape == 2) glutWireSphere(5, 16,16 );  // Draw a Sphere
if (shape == 3) glutWireTorus( 2.5, 5, 16, 16);
if (shape == 4)
   {
    glScalef( 3.5, 3.5, 3.5);
    glutSolidDodecahedron();
   }

if (shape == 5)
   {
    glScalef( 5.0, 5.0, 5.0);
    glutWireOctahedron();
   }
if (shape == 6)
   {
    glScalef( 5.0, 5.0, 5.0);
    glutWireTetrahedron();
   }

if (shape == 7)
   {
    glScalef( 5.0, 5.0, 5.0);
    glutWireIcosahedron();
   }
if (shape == 8) glutWireTeapot( 5 );

glutSwapBuffers();
}


// This is called when the window has been resized.
void reshape_1 (int w, int h)
{
   glViewport (0, 0, (GLsizei) w, (GLsizei) h);
   glMatrixMode (GL_PROJECTION);
   glLoadIdentity ();
}

// This is called when the window has been resized.
void reshape_2 (int w, int h)
{
   glViewport (0, 0, (GLsizei) w, (GLsizei) h);
   glMatrixMode (GL_PROJECTION);
   glLoadIdentity ();
}

// Read the keyboard
void keyboard (unsigned char key, int x, int y)
{
   switch (key)
   {

      case 'v':
      case 'V':
          view_state = abs(view_state -1);
          break;
      case 'l':
      case 'L':
          light_state = abs(light_state -1);
          break;
      case 's':
      case 'S':
          shape++;
          break;
      case 27:
         exit(0); // exit program when [ESC] key presseed
         break;
      default:
         break;
   }

if (shape > 8) shape = 0;

}


// Main program
int main(int argc, char** argv)
{
   glutInit(&amp;argc, argv);
   glutInitDisplayMode (GLUT_DOUBLE | GLUT_RGB);
   glutInitWindowSize (500, 500);
   glutInitWindowPosition (10, 10);
   glutTimerFunc( 10, TimeEvent, 1);
   window_1 = glutCreateWindow (argv[0]);
   glutSetWindowTitle("GlutWindow 1");
   init ();
   glutDisplayFunc(display_1);
   glutReshapeFunc(reshape_1);
   glutKeyboardFunc(keyboard);

   window_2 = glutCreateWindow (argv[0]);
   glutSetWindowTitle("GlutWindow 2");
   init ();
   glutDisplayFunc(display_2);
   glutReshapeFunc(reshape_2);
   glutMainLoop();
   return 0;
}

J'ai exécuté l'exemple de code sous Windows 7, mais je devais remplacer une ligne de glutIntit par

.

glutInit(&argc, argv);