outdated: 46.Fullscreen AntiAliasing

bool WGLisExtensionSupported(const char* extension)
{
    const size_t extlen = strlen(extension);
    const char* supported = NULL;

    // Try to use wglGetExtensionStringARB on cureent DC
    PROC wglGetExtString = wglGetProcAddress("wglGetExtensionsStringARB");

    if (wglGetExtString) {
        supported = ((char*(__stdcall*)(HDC))wglGetExtString)(wglGetCurrentDC());
    }

    // If that failed, try standard OpenGL extension string
    if (supported == NULL) {
        supported = (char*)glGetString(GL_EXTENSIONS);
    }

    // If that failed too, must be no extension supported
    if (supported == NULL) {
        return false;
    }
    // Begin examination at start of string, increment by 1 on false match
    for (const char* p = supported; ; ++p) {
        p = strstr(p, extension);
        if (p == NULL) {
            return false;
        }

        if ((p == supported || p[-1] == ‘ ‘) || (p[extlen] == ‘\0‘ || p[extlen] == ‘ ‘)) {
            return true;
        }
    }
}

bool InitMultisample(HINSTANCE hInstance, HWND hWnd, PIXELFORMATDESCRIPTOR pdf)
{
    // The string exists in WGL
    if (!WGLisExtensionSupported("WGL_ARB_multisample")) {
        arbMultisampleSupported = false;
        return false;
    }
    // Get pixel format
    PFNWGLCHOOSEPIXELFORMATARBPROC wglChoosePixelFormatARB =
        (PFNWGLCHOOSEPIXELFORMATARBPROC)wglGetProcAddress("wglChoosePixelFormatARB");

    if (!wglChoosePixelFormatARB) {
        arbMultisampleSupported = false;
        return false;
    }
    // Get current device context
    HDC hDC = GetDC(hWnd);
    int pixelFormat;
    BOOL valid;
    UINT numFormats;
    float fAttributes[] = { 0, 0 };

    // These attributes are the bits we want to test for in our sample
    int iAttributes[] = { WGL_DRAW_TO_WINDOW_ARB, GL_TRUE, WGL_SUPPORT_OPENGL_ARB,GL_TRUE,
        WGL_ACCELERATION_ARB,WGL_FULL_ACCELERATION_ARB,
        WGL_COLOR_BITS_ARB,24,
        WGL_ALPHA_BITS_ARB,8,
        WGL_DEPTH_BITS_ARB,16,
        WGL_STENCIL_BITS_ARB,0,
        WGL_DOUBLE_BUFFER_ARB,GL_TRUE,
        WGL_SAMPLE_BUFFERS_ARB,GL_TRUE,
        WGL_SAMPLES_ARB, 4 ,
        0,0 };
    
    // Get a pixel format for 4 samples
    valid = wglChoosePixelFormatARB(hDC, iAttributes, fAttributes, 1, &pixelFormat, &numFormats);

    if (valid && numFormats >= 1) {
        arbMultisampleSupported = true;
        arbMultisampleFormat = pixelFormat;
        return arbMultisampleSupported;
    }

    iAttributes[19] = 2;
    valid = wglChoosePixelFormatARB(hDC, iAttributes, fAttributes, 1, &pixelFormat, &numFormats);
    if (valid && numFormats >= 1) {
        arbMultisampleSupported = true;
        arbMultisampleFormat = pixelFormat;
        return arbMultisampleSupported;
    }

    return arbMultisampleSupported;
}

#ifndef GL_FRAMEWORK_INCLUDED
#define GL_FRAMEWORK_INCLUDED

#include <windows.h>

typedef struct {                                   // Structure for keyboard stuff
    BOOL keyDown[256];
} Keys;

typedef struct {                                   // Contains information vital to applications 
    HMODULE hInstance;                             // Application Instance
    const char* className;
} Application;

typedef struct {                                   // Window creation info
    Application* application;
    char* title;
    int width;
    int height;
    int bitsPerPixel;
    BOOL isFullScreen;
} GL_WindowInit;

typedef struct {                                   // Contains information vital to a window
    Keys* keys;
    HWND hWnd;                                     // Windows handle
    HDC hDC;                                       // Device context
    HGLRC hRC;                                     // Rendering context
    GL_WindowInit init;
    BOOL isVisible;                                // Window visiable?
    DWORD lastTickCount;                           // Tick counter
} GL_Window;

void TerminateApplication(GL_Window* window);      // Terminate the application

void ToggleFullscreen(GL_Window* window);          // Toggle fullscreen / Windowed mode

BOOL Initialize(GL_Window* window, Keys* keys);

void Deinitialize(void);

void Update(DWORD milliseconds);

void Draw(void);

#endif

#include <Windows.h>
#include <GL\glew.h>
#include <GL\glut.h>
#include "Previous.h"

#define WM_TOGGLEFULLSCREEN (WM_USER+1)                   // Application define message for toggling 
// between fulscreen / windowed mode
static BOOL g_isProgramLooping;                           // Window creation loop, for fullscreen / windowed mode
static BOOL g_createFullScreen;                           // If true, then create window

void TerminateApplication(GL_Window* window)              // Terminate the application
{
    PostMessage(window->hWnd, WM_QUIT, 0, 0);             // Send a WM_QUIT message
    g_isProgramLooping = FALSE;                           // Stop looping of the program
}

void ToggleFullscreen(GL_Window* window)                  // Toggle fullscreen /windowed mode
{
    PostMessage(window->hWnd, WM_TOGGLEFULLSCREEN, 0, 0); // Send a WM_TOGGLEFULLSCREEN message
}

void ReshapeGL(int width, int height)                     // Reshape the window  when it‘s moved or resized
{
    glViewport(0, 0, (GLsizei)(width), (GLsizei)(height)); // Reset the current viewport
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    // Calcutate the aspect ratio of the window
    gluPerspective(45.0f, (GLfloat)(width) / (GLfloat)(height), 1.0, 1000.0f);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
}

BOOL ChangeScreenResolution(int width, int height, int bitsPerPixel)     // Change the screen resolution
{
    DEVMODE dmScreenSettings;                              // Device mode
    ZeroMemory(&dmScreenSettings, sizeof(DEVMODE));        // Make sure memory is cleared
    dmScreenSettings.dmSize = sizeof(DEVMODE);             // Size of the devmode structure
    dmScreenSettings.dmPelsWidth = width;
    dmScreenSettings.dmPelsHeight = height;
    dmScreenSettings.dmBitsPerPel = bitsPerPixel;
    dmScreenSettings.dmFields = DM_BITSPERPEL | DM_PELSWIDTH | DM_PELSHEIGHT;
    if (ChangeDisplaySettings(&dmScreenSettings, CDS_FULLSCREEN) != DISP_CHANGE_SUCCESSFUL) {
        return FALSE;                                      // Display change failed
    }
    return TRUE;
}

BOOL CreateWindowGL(GL_Window* window)
{
    DWORD windowStyle = WS_OVERLAPPEDWINDOW;                // Define window style
    DWORD windowExtendedStyle = WS_EX_APPWINDOW;            // Define the window‘s extended style

    PIXELFORMATDESCRIPTOR pdf = {
        sizeof(PIXELFORMATDESCRIPTOR),                      // Size of this pixel format descriptor
        1,                                                  // Version Number
        PFD_DRAW_TO_WINDOW |                                // Format must support window
        PFD_SUPPORT_OPENGL |                                // Format must support openGL
        PFD_DOUBLEBUFFER,                                   // Must support double buffering
        PFD_TYPE_RGBA,                                      // Request an RGBA format
        window->init.bitsPerPixel,                          // Select color depth
        0, 0, 0, 0, 0, 0,                                   // Color bits ignored
        0,                                                  // No alpha buffer
        0,                                                  // Shift bit ignored
        0,                                                  // No accumulation buffer
        0, 0, 0, 0,                                         // Accumulation bits ignored
        16,                                                 // 16bits Z-buffer (depth buffer)
        0,                                                  // No stencil buffer
        0,                                                  // No auxiliary buffer
        PFD_MAIN_PLANE,                                     // Main drawing layer
        0,                                                  // Reserved
        0, 0, 0                                             // Layer masks ignored
    };
    RECT windowRect = { 0, 0, window->init.width, window->init.height };   // Window coordiantes

    GLuint PixelFormat;

    if (window->init.isFullScreen == TRUE) {
        if (ChangeScreenResolution(window->init.width, window->init.height, window->init.bitsPerPixel) == FALSE)
        {
            // Fullscreen mode failed, run in windowed mode instead
            MessageBox(HWND_DESKTOP, "Mode Switch Failed.\nRuning In Windowed Mode.",
                "Error", MB_OK | MB_ICONEXCLAMATION);
            window->init.isFullScreen = FALSE;
        }
        else {
            ShowCursor(FALSE);
            windowStyle = WS_POPUP;                         // Popup window
            windowExtendedStyle |= WS_EX_TOPMOST;
        }
    }
    else {
        // Adjust window, account for window borders
        AdjustWindowRectEx(&windowRect, windowStyle, 0, windowExtendedStyle);
    }
    // Create Opengl window
    window->hWnd = CreateWindowEx(windowExtendedStyle,      // Extended style
        window->init.application->className,                // Class name
        window->init.title,                                 // Window title
        windowStyle,                                        // Window style
        0, 0,                                               // Window X,Y position
        windowRect.right - windowRect.left,                 // Window width
        windowRect.bottom - windowRect.top,                 // Window height
        HWND_DESKTOP,                                       // Desktop is window‘s parent
        0,                                                  // No menu
        window->init.application->hInstance,                // Pass the window instance
        window);

    if (window->hWnd == 0) {                                // Was window creation a success?
        return FALSE;
    }
    window->hDC = GetDC(window->hWnd);
    if (window->hDC == 0) {
        DestroyWindow(window->hWnd);
        window->hWnd = 0;
        return FALSE;
    }
    PixelFormat = ChoosePixelFormat(window->hDC, &pdf);     // Find a compatible pixel format
    if (PixelFormat == 0) {
        ReleaseDC(window->hWnd, window->hDC);               // Release device context
        window->hDC = 0;
        DestroyWindow(window->hWnd);
        window->hWnd = 0;
        return FALSE;
    }
    if (SetPixelFormat(window->hDC, PixelFormat, &pdf) == FALSE) {   // Try to set the pixel format
        ReleaseDC(window->hWnd, window->hDC);
        window->hDC = 0;
        DestroyWindow(window->hWnd);
        window->hWnd = 0;
        return FALSE;
    }
    window->hRC = wglCreateContext(window->hDC);            // Try to get a rendering context
    if (window->hRC == 0) {
        ReleaseDC(window->hWnd, window->hDC);
        window->hDC = 0;
        DestroyWindow(window->hWnd);
        window->hWnd = 0;
        return FALSE;
    }
    // Make the rendering context our current rendering context
    if (wglMakeCurrent(window->hDC, window->hRC) == FALSE) {
        wglDeleteContext(window->hRC);                      //  Delete the rendering context
        window->hRC = 0;
        ReleaseDC(window->hWnd, window->hDC);
        window->hDC = 0;
        DestroyWindow(window->hWnd);
        window->hWnd = 0;
        return FALSE;
    }
    ShowWindow(window->hWnd, SW_NORMAL);                    // Make the window visiable
    window->isVisible = TRUE;
    ReshapeGL(window->init.width, window->init.height);     // Reshape our GL window
    ZeroMemory(window->keys, sizeof(Keys));                 // Clear all keys
    window->lastTickCount = GetTickCount();
    return TRUE;
}

BOOL DestroyWindowGL(GL_Window* window)
{
    if (window->hWnd != 0) {
        if (window->hDC != 0) {
            wglMakeCurrent(window->hDC, 0);                 // Setting current active rendering context to zero
            if (window->hRC != 0) {
                wglDeleteContext(window->hRC);
                window->hRC = 0;
            }
            ReleaseDC(window->hWnd, window->hDC);
            window->hDC = 0;
        }
        DestroyWindow(window->hWnd);
        window->hWnd = 0;
    }
    if (window->init.isFullScreen) {
        ChangeDisplaySettings(NULL, 0);                     // Switch back to desktop resolution
        ShowCursor(TRUE);
    }
    return TRUE;
}

// Process window message callback
LRESULT CALLBACK WindowProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
    // Get the window context
    GL_Window* window = (GL_Window*)(GetWindowLong(hWnd, GWL_USERDATA));
    switch (uMsg) {                                         // Evaluate window message
    case WM_SYSCOMMAND:                                     // Intercept system commands
    {
        switch (wParam) {                                   // Check system calls
        case SC_SCREENSAVE:                                 // Screensaver trying to start?
        case SC_MONITORPOWER:                               // Mointer trying to enter powersave?
            return 0;                                           // Prevent form happening
        }
        break;
    }
    return 0;
    case WM_CREATE:
    {
        CREATESTRUCT* creation = (CREATESTRUCT*)(lParam);   // Store window structure pointer
        window = (GL_Window*)(creation->lpCreateParams);
        SetWindowLong(hWnd, GWL_USERDATA, (LONG)(window));
    }
    return 0;

    case WM_CLOSE:
        TerminateApplication(window);
        return 0;

    case WM_SIZE:
        switch (wParam) {
        case SIZE_MINIMIZED:                                 // Was window minimized?
            window->isVisible = FALSE;
            return 0;
        case SIZE_MAXIMIZED:
            window->isVisible = TRUE;
            ReshapeGL(LOWORD(lParam), HIWORD(lParam));
            return 0;
        case SIZE_RESTORED:
            window->isVisible = TRUE;
            ReshapeGL(LOWORD(lParam), HIWORD(lParam));
            return 0;
        }
        break;

    case WM_KEYDOWN:
        if ((wParam >= 0) && (wParam <= 255)) {
            window->keys->keyDown[wParam] = TRUE;            // Set the selected key(wParam) to true
            return 0;
        }
        break;

    case WM_KEYUP:
        if ((wParam >= 0) && (wParam <= 255)) {
            window->keys->keyDown[wParam] = FALSE;
            return 0;
        }
        break;

    case WM_TOGGLEFULLSCREEN:
        g_createFullScreen = (g_createFullScreen == TRUE) ? FALSE : TRUE;
        PostMessage(hWnd, WM_QUIT, 0, 0);
        break;
    }
    return DefWindowProc(hWnd, uMsg, wParam, lParam);        // Pass unhandle message to DefWindowProc
}

BOOL RegisterWindowClass(Application* application)
{
    WNDCLASSEX windowClass;
    ZeroMemory(&windowClass, sizeof(WNDCLASSEX));            // Make sure memory is cleared
    windowClass.cbSize = sizeof(WNDCLASSEX);                 // Size of the windowClass structure
    windowClass.style = CS_HREDRAW | CS_VREDRAW | CS_OWNDC;  // Redraws the window for any movement / resizing
    windowClass.lpfnWndProc = (WNDPROC)(WindowProc);         // WindowProc handles message
    windowClass.hInstance = application->hInstance;          // Set the instance
    windowClass.hbrBackground = (HBRUSH)(COLOR_APPWORKSPACE);// Class background brush color
    windowClass.hCursor = LoadCursor(NULL, IDC_ARROW);       // Load the arrow pointer
    windowClass.lpszClassName = application->className;      // Sets the application className
    if (RegisterClassEx(&windowClass) == 0) {
        MessageBox(HWND_DESKTOP, "RegisterClassEx Failed!", "Error", MB_OK | MB_ICONEXCLAMATION);
        return FALSE;
    }
    return TRUE;
}

int WINAPI WinMain(HINSTANCE hIstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
    Application application;
    GL_Window window;
    Keys keys;
    BOOL isMessagePumpActive;
    MSG msg;
    DWORD tickCount;

    application.className = "OpenGL";
    application.hInstance = hIstance;

    ZeroMemory(&window, sizeof(GL_Window));
    window.keys = &keys;                                     // Window key structure
    window.init.application = &application;                  // Window application
    window.init.title = "Resource File";                     // Window title
    window.init.width = 640;                                 // Window width
    window.init.height = 480;                                // Window height
    window.init.bitsPerPixel = 16;                           // Bits per pixel
    window.init.isFullScreen = TRUE;                         // Fullscreen? (set to TRUE)

    ZeroMemory(&keys, sizeof(Keys));
    if (MessageBox(HWND_DESKTOP, "Would You Like To Run In Fullscreen Mode?", "Start FullScreen?",
        MB_YESNO | MB_ICONQUESTION) == IDNO)
    {
        window.init.isFullScreen = FALSE;
    }
    if (RegisterWindowClass(&application) == FALSE)
    {
        MessageBox(HWND_DESKTOP, "Error Registering Window Class!", "Error", MB_OK | MB_ICONEXCLAMATION);
        return -1;
    }
    g_isProgramLooping = TRUE;
    g_createFullScreen = window.init.isFullScreen;
    while (g_isProgramLooping) {                             // Loop until WM_QUIT is received
        window.init.isFullScreen = g_createFullScreen;       // Set init param of window creation to fullscreen?
        if (CreateWindowGL(&window) == TRUE) {               // Was window creation successful?
                                                             // At this point we should have a window that is setup to render OpenGL
            if (Initialize(&window, &keys) == FALSE) {
                TerminateApplication(&window);               // Close window, this will handle the shutdown
            }
            else {
                isMessagePumpActive = TRUE;
                while (isMessagePumpActive == TRUE) {
                    // Success creating window. Check for window messages
                    if (PeekMessage(&msg, window.hWnd, 0, 0, PM_REMOVE) != 0) {
                        if (msg.message != WM_QUIT) {
                            DispatchMessage(&msg);
                        }
                        else {
                            isMessagePumpActive = FALSE;     // Terminate the message pump
                        }
                    }
                    else {
                        if (window.isVisible == FALSE) {
                            WaitMessage();                   // Application is minimized wait for a message
                        }
                        else {
                            // Process application loop
                            tickCount = GetTickCount();      // Get the tick count
                            Update(tickCount - window.lastTickCount); // Update the counter
                            window.lastTickCount = tickCount;// Set last count to current count
                            Draw();                          // Draw screen
                            SwapBuffers(window.hDC);
                        }
                    }
                }
            }
            // Application is finished
            Deinitialize();
            DestroyWindowGL(&window);
        }
        else {
            MessageBox(HWND_DESKTOP, "Error Creating OpenGL Window", "Error", MB_OK | MB_ICONEXCLAMATION);
            g_isProgramLooping = FALSE;
        }
    }
    UnregisterClass(application.className, application.hInstance);    // UnRegister window class
    return 0;
}

#ifndef __ARB_MULTISAMPLE_H__
#define __ARB_MULTISAMPLE_H__

#include <GL\wglext.h>     // WGL extensions
#include <GL\glext.h>      // GL extwnsions

// Globals
extern bool arbMultisampleSupported;
extern int arbMultisampleFormat;

// If you don‘t want multisampling, set this to 0
#define CHECK_FOR_MULTISAMPLE 1

// To heck for our sampling
bool InitMultisample(HINSTANCE hInstance, HWND hWnd, PIXELFORMATDESCRIPTOR pdf);

#endif // !__ARB_MULTISAMPLE_H__

#include <Windows.h>
#include <GL\glew.h>
#include <GL\glut.h>
#include "arbMultiSample.h"

#define WGL_SAMPLE_BUFFERS_ARB 0X2041
#define WGL_SAMPLES_ARB 0x2042

bool arbMultisampleSupported = false;
int arbMultisampleFormat = 0;

bool WGLisExtensionSupported(const char* extension)
{
    const size_t extlen = strlen(extension);
    const char* supported = NULL;

    // Try to use wglGetExtensionStringARB on cureent DC
    PROC wglGetExtString = wglGetProcAddress("wglGetExtensionStringARB");

    if (wglGetExtString) {
        supported = ((char*(__stdcall*)(HDC))wglGetExtString)(wglGetCurrentDC());
    }

    // If that failed, try standard OpenGL extension string
    if (supported == NULL) {
        supported = (char*)glGetString(GL_EXTENSIONS);
    }

    // If that failed too, must be no extension supported
    if (supported == NULL) {
        return false;
    }
    // Begin examination at start of string, increment by 1 on false match
    for (const char* p = supported; ; ++p) {
        p = strstr(p, extension);
        if (p == NULL) {
            return false;
        }

        if ((p == supported || p[-1] == ‘ ‘) || (p[extlen] == ‘\0‘ || p[extlen] == ‘ ‘)) {
            return true;
        }
    }
}

bool InitMultisample(HINSTANCE hInstance, HWND hWnd, PIXELFORMATDESCRIPTOR pdf)
{
    // The string exists in WGL
    if (!WGLisExtensionSupported("WGL_ARB_multisample")) {
        arbMultisampleSupported = false;
        return false;
    }
    // Get pixel format
    PFNWGLCHOOSEPIXELFORMATARBPROC wglChoosePixelFormatARB =
        (PFNWGLCHOOSEPIXELFORMATARBPROC)wglGetProcAddress("wglChoosePixelFormatARB");

    if (!wglChoosePixelFormatARB) {
        arbMultisampleSupported = false;
        return false;
    }
    // Get current device context
    HDC hDC = GetDC(hWnd);
    int pixelFormat;
    BOOL valid;
    UINT numFormats;
    float fAttributes[] = { 0, 0 };

    // These attributes are the bits we want to test for in our sample
    int iAttributes[] = { WGL_DRAW_TO_WINDOW_ARB, GL_TRUE, WGL_SUPPORT_OPENGL_ARB,GL_TRUE,
        WGL_ACCELERATION_ARB,WGL_FULL_ACCELERATION_ARB,
        WGL_COLOR_BITS_ARB,24,
        WGL_ALPHA_BITS_ARB,8,
        WGL_DEPTH_BITS_ARB,16,
        WGL_STENCIL_BITS_ARB,0,
        WGL_DOUBLE_BUFFER_ARB,GL_TRUE,
        WGL_SAMPLE_BUFFERS_ARB,GL_TRUE,
        WGL_SAMPLES_ARB, 4 ,
        0,0 };
    
    // Get a pixel format for 4 samples
    valid = wglChoosePixelFormatARB(hDC, iAttributes, fAttributes, 1, &pixelFormat, &numFormats);

    if (valid && numFormats >= 1) {
        arbMultisampleSupported = true;
        arbMultisampleFormat = pixelFormat;
        return arbMultisampleSupported;
    }

    iAttributes[19] = 2;
    valid = wglChoosePixelFormatARB(hDC, iAttributes, fAttributes, 1, &pixelFormat, &numFormats);
    if (valid && numFormats >= 1) {
        arbMultisampleSupported = true;
        arbMultisampleFormat = pixelFormat;
        return arbMultisampleSupported;
    }

    return arbMultisampleSupported;
}

#include <windows.h>
#include <stdio.h>
#include <math.h>
#include <gl/glew.h>
#include <gl/glut.h>
#include <GL/GLUAX.H>
#include <mmsystem.h>
#include "Previous.h"
#include "arbMultiSample.h"

// Fullscreen AntiAliasing
#pragma comment(lib, "legacy_stdio_definitions.lib")

#ifndef CDS_FULLSCREEN
#define CDS_FULLSCREEN 4
#endif

bool domulti = true;
bool doangle = true;

float angle = 0.0f;

GL_Window*    g_window;
Keys*        g_keys;

BOOL Initialize(GL_Window* window, Keys* keys)
{
    g_window = window;
    g_keys = keys;

    angle = 0.0f;

    glViewport(0, 0, window->init.width, window->init.height);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(50, (float)window->init.width / (float)window->init.height, 5, 2000);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    glEnable(GL_DEPTH_TEST);
    glShadeModel(GL_SMOOTH);
    glClearColor(0.0f, 0.0f, 0.0f, 0.5f);

    return TRUE;
}

void Deinitialize(void) { }

void Update(DWORD milliseconds)
{
    if (g_keys->keyDown[VK_ESCAPE] == TRUE) {
        TerminateApplication(g_window);
    }
    if (g_keys->keyDown[VK_F1] == TRUE) {
        ToggleFullscreen(g_window);
    }
    if (g_keys->keyDown[VK_SPACE] == TRUE) {
        domulti = !domulti;
    }
    if (g_keys->keyDown[‘M‘] == TRUE) {
        doangle = !doangle;
    }
}

void Draw(void)
{
    if (domulti) {
        glEnable(GL_MULTISAMPLE_ARB);
    }

    glClearColor(0.0f, 0.0f, 0.0f, 0.5);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glLoadIdentity();

    for (float i = -10; i < 10; ++i) {
        for (float j = -10; j < 10; ++j) {
            glPushMatrix();
            glTranslatef(i * 2.0f, j * 2.0f, -5.0f);
            glRotatef(angle, 0.0f, 0.0f, 1.0f);
            glBegin(GL_QUADS);
                glColor3f(1.0f, 0.0f, 0.0f); glVertex3f(i, j, 0.0f);
                glColor3f(0.0f, 1.0f, 0.0f); glVertex3f(i + 2.0f, j, 0.0f);
                glColor3f(0.0f, 0.0f, 1.0f); glVertex3f(i + 2.0f, j + 2.0f, 0.0f);
                glColor3f(1.0f, 1.0f, 1.0f); glVertex3f(i, j + 2.0f, 0.0f);
            glEnd();
            glPopMatrix();
        }
    }

    if (doangle) {
        angle += 0.05f;
    }
    glFlush();
    if (domulti) {
        glDisable(GL_MULTISAMPLE_ARB);
    }
}