Несколько окон в OpenGL?

Если вы используете GLUT, вы можете использовать вызовы glutSetWindow() / glutGetWindow() для выбора правильного окна (после их создания с помощью glutCreateSubWindow()). Однако иногда GLUT может оказаться неподходящим инструментом для работы.

Если вы работаете в Windows, вам следует изучить функции wglMakeCurrent() и wglCreateContext(). В OS X есть aglSetCurrentContext() и так далее, а для X11 требуется glXMakeCurrent().

Эти функции активируют текущий контекст OpenGL, в который вы можете выполнять рендеринг. Каждая специфичная для платформы библиотека имеет свои собственные способы создания окна и привязки к нему контекста OpenGL.

В Windows после того, как вы получили HWND и HDC для окна (после вызова CreateWindow и GetDC). Обычно вы делаете что-то вроде этого для настройки 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);

Вы используете этот код для создания нескольких окон и привязки к нему OpenGL, затем каждый раз, когда вы хотите рисовать в определенном окне, вы должны вызывать wglMakeCurrent прежде чем что-либо делать, и вы передаете параметры, соответствующие этому окно.

В качестве примечания, OpenGL позволяет вам обмениваться определенными данными между различными контекстами, однако согласно спецификации данные, которыми вы можете обмениваться, довольно ограничены. Однако большинство операционных систем позволяют обмениваться большим количеством данных, чем указано в спецификации.

Да, это возможно. Для каждого окна вам нужно будет создать уникальный контекст устройства и контекст рендеринга.

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*/

Прежде чем делать вызовы GL к окну, вы должны вызвать wglMakeCurrent следующим образом:

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

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

В Windows вы можете совместно использовать объекты OpenGL, такие как текстуры и шейдеры, с помощью wglShareLists(). Обычно он делится всем, что вам нужно, несмотря на то, что говорит MSDN.

Раньше я делал несколько окон OpenGL в приложении MFC. Вот класс, который может оказаться полезным: поскольку в каждый момент времени в потоке пользовательского интерфейса может быть только один текущий контекст рендеринга, я написал оболочку класса, чтобы упростить управление им.

СохранитьRestoreRC.h

// this class helps to manage multiple RCs using an RAII design pattern

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 );    
}

Now derive a class from CWnd and add these member variables:

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 );

Then in every member function where you call ANY OpenGL commands, use CSaveRestoreRC so that your current render context doesn't get screwed up.

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.
} 

Если вам нравится использовать только библиотеку Glut, посмотрите код Эрика Стрингера.

// 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;
}

Я запустил пример кода в Windows 7, но мне пришлось заменить одну строку glutIntit на

glutInit(&argc, argv);