// Gl_template.c

#include <windows.h>            // Window defines
#include <gl\gl.h>              // OpenGL
#include <gl\glu.h>             // GLU library
#include <math.h>               // Define for sqrt
#include <stdio.h>
#include "resource.h"           // About box resource identifiers.

#define glRGB(x, y, z)  glColor3ub((GLubyte)x, (GLubyte)y, (GLubyte)z)
#define BITMAP_ID 0x4D42        // identyfikator formatu BMP
#define GL_PI 3.14

// Color Palette handle
HPALETTE hPalette = NULL;

// Application name and instance storeage
static LPCTSTR lpszAppName = "GL Template";
static HINSTANCE hInstance;

// Rotation amounts
static GLfloat xRot = 0.0f;
static GLfloat yRot = 0.0f;


static GLsizei lastHeight;
static GLsizei lastWidth;

// Opis tekstury
BITMAPINFOHEADER    bitmapInfoHeader;   // nag³ówek obrazu
unsigned char*      bitmapData;         // dane tekstury
unsigned int        texture[2];         // obiekt tekstury


// Declaration for Window procedure
LRESULT CALLBACK WndProc(   HWND    hWnd,
                            UINT    message,
                            WPARAM  wParam,
                            LPARAM  lParam);

// Dialog procedure for about box
BOOL APIENTRY AboutDlgProc (HWND hDlg, UINT message, UINT wParam, LONG lParam);

// Set Pixel Format function - forward declaration
void SetDCPixelFormat(HDC hDC);



// Reduces a normal vector specified as a set of three coordinates,
// to a unit normal vector of length one.
void ReduceToUnit(float vector[3])
    {
    float length;

    // Calculate the length of the vector
    length = (float)sqrt((vector[0]*vector[0]) +
                        (vector[1]*vector[1]) +
                        (vector[2]*vector[2]));

    // Keep the program from blowing up by providing an exceptable
    // value for vectors that may calculated too close to zero.
    if(length == 0.0f)
        length = 1.0f;

    // Dividing each element by the length will result in a
    // unit normal vector.
    vector[0] /= length;
    vector[1] /= length;
    vector[2] /= length;
    }


// Points p1, p2, & p3 specified in counter clock-wise order
void calcNormal(float v[3][3], float out[3])
    {
    float v1[3],v2[3];
    static const int x = 0;
    static const int y = 1;
    static const int z = 2;

    // Calculate two vectors from the three points
    v1[x] = v[0][x] - v[1][x];
    v1[y] = v[0][y] - v[1][y];
    v1[z] = v[0][z] - v[1][z];

    v2[x] = v[1][x] - v[2][x];
    v2[y] = v[1][y] - v[2][y];
    v2[z] = v[1][z] - v[2][z];

    // Take the cross product of the two vectors to get
    // the normal vector which will be stored in out
    out[x] = v1[y]*v2[z] - v1[z]*v2[y];
    out[y] = v1[z]*v2[x] - v1[x]*v2[z];
    out[z] = v1[x]*v2[y] - v1[y]*v2[x];

    // Normalize the vector (shorten length to one)
    ReduceToUnit(out);
    }



// Change viewing volume and viewport.  Called when window is resized
void ChangeSize(GLsizei w, GLsizei h)
    {
    GLfloat nRange = 100.0f;
    GLfloat fAspect;
    // Prevent a divide by zero
    if(h == 0)
        h = 1;

    lastWidth = w;
    lastHeight = h;

    fAspect=(GLfloat)w/(GLfloat)h;
    // Set Viewport to window dimensions
    glViewport(0, 0, w, h);

    // Reset coordinate system
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();

    // Establish clipping volume (left, right, bottom, top, near, far)
    if (w <= h)
        glOrtho (-nRange, nRange, -nRange*h/w, nRange*h/w, -nRange, nRange);
    else
        glOrtho (-nRange*w/h, nRange*w/h, -nRange, nRange, -nRange, nRange);

    // Establish perspective:
    /*
    gluPerspective(60.0f,fAspect,1.0,400);
    */

    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    }



// This function does any needed initialization on the rendering
// context.  Here it sets up and initializes the lighting for
// the scene.
void SetupRC()
    {
    // Light values and coordinates
    //GLfloat  ambientLight[] = { 0.3f, 0.3f, 0.3f, 1.0f };
    //GLfloat  diffuseLight[] = { 0.7f, 0.7f, 0.7f, 1.0f };
    //GLfloat  specular[] = { 1.0f, 1.0f, 1.0f, 1.0f};
    //GLfloat    lightPos[] = { 0.0f, 150.0f, 150.0f, 1.0f };
    //GLfloat  specref[] =  { 1.0f, 1.0f, 1.0f, 1.0f };


    glEnable(GL_DEPTH_TEST);    // Hidden surface removal
    glFrontFace(GL_CCW);        // Counter clock-wise polygons face out
    //glEnable(GL_CULL_FACE);       // Do not calculate inside of jet

    // Enable lighting
    //glEnable(GL_LIGHTING);

    // Setup and enable light 0
    //glLightfv(GL_LIGHT0,GL_AMBIENT,ambientLight);
    //glLightfv(GL_LIGHT0,GL_DIFFUSE,diffuseLight);
    //glLightfv(GL_LIGHT0,GL_SPECULAR,specular);
    //glLightfv(GL_LIGHT0,GL_POSITION,lightPos);
    //glEnable(GL_LIGHT0);

    // Enable color tracking
    //glEnable(GL_COLOR_MATERIAL);

    // Set Material properties to follow glColor values
    //glColorMaterial(GL_FRONT, GL_AMBIENT_AND_DIFFUSE);

    // All materials hereafter have full specular reflectivity
    // with a high shine
    //glMaterialfv(GL_FRONT, GL_SPECULAR,specref);
    //glMateriali(GL_FRONT,GL_SHININESS,128);


    // White background
    glClearColor(1.0f, 1.0f, 1.0f, 1.0f );
    // Black brush
    glColor3f(0.0,0.0,0.0);
    }

void skrzynka(void)
{
    glColor3d(0.8,0.7,0.3);


    glEnable(GL_TEXTURE_2D); // W³¹cz teksturowanie

    glBindTexture(GL_TEXTURE_2D,texture[0]);
    glBegin(GL_QUADS);
        glNormal3d(0,0,1);
        glTexCoord2d(1.0,1.0); glVertex3d(25,25,25);
        glTexCoord2d(0.0,1.0); glVertex3d(-25,25,25);
        glTexCoord2d(0.0,0.0); glVertex3d(-25,-25,25);
        glTexCoord2d(1.0,0.0); glVertex3d(25,-25,25);
    glEnd();
    glBindTexture(GL_TEXTURE_2D,texture[1]);
    glBegin(GL_QUADS);
        glNormal3d(1,0,0);
        glTexCoord2d(1.0,1.0); glVertex3d(25,25,25);
        glTexCoord2d(0.0,1.0); glVertex3d(25,-25,25);
        glTexCoord2d(0.0,0.0); glVertex3d(25,-25,-25);
        glTexCoord2d(1.0,0.0); glVertex3d(25,25,-25);
    glEnd();

    glDisable(GL_TEXTURE_2D); // Wy³¹cz teksturowanie



    glBegin(GL_QUADS);
        glNormal3d(0,0,-1);
        glVertex3d(25,25,-25);
        glVertex3d(25,-25,-25);
        glVertex3d(-25,-25,-25);
        glVertex3d(-25,25,-25);

        glNormal3d(-1,0,0);
        glVertex3d(-25,25,-25);
        glVertex3d(-25,-25,-25);
        glVertex3d(-25,-25,25);
        glVertex3d(-25,25,25);

        glNormal3d(0,1,0);
        glVertex3d(25,25,25);
        glVertex3d(25,25,-25);
        glVertex3d(-25,25,-25);
        glVertex3d(-25,25,25);

        glNormal3d(0,-1,0);
        glVertex3d(25,-25,25);
        glVertex3d(-25,-25,25);
        glVertex3d(-25,-25,-25);
        glVertex3d(25,-25,-25);
    glEnd();
}

void walec01(void)
{
GLUquadricObj*obj;
obj=gluNewQuadric();
gluQuadricNormals(obj,GLU_SMOOTH);
glColor3d(1,0,0);
glPushMatrix();
gluCylinder(obj,20,20,30,15,7);
gluCylinder(obj,0,20,0,15,7);
glTranslated(0,0,60);
glRotated(180.0,0,1,0);
gluCylinder(obj,0,20,30,15,7);
glPopMatrix();
}

void kula(void)
{   GLUquadricObj*obj;
    obj=gluNewQuadric();
    gluQuadricTexture(obj,GL_TRUE);
    glBindTexture(GL_TEXTURE_2D,texture[0]);
    glTexEnvi(GL_TEXTURE_ENV,GL_TEXTURE_ENV_MODE,GL_MODULATE);
    glColor3d(1.0,0.8,0.8);
    glEnable(GL_TEXTURE_2D);
    gluSphere(obj,40,15,7);
    glDisable(GL_TEXTURE_2D);
}




// LoadBitmapFile
// opis: ³aduje mapê bitow¹ z pliku i zwraca jej adres.
//       Wype³nia strukturê nag³ówka.
//   Nie obs³uguje map 8-bitowych.
unsigned char *LoadBitmapFile(char *filename, BITMAPINFOHEADER *bitmapInfoHeader)
{
    FILE *filePtr;                          // wskaŸnik pozycji pliku
    BITMAPFILEHEADER    bitmapFileHeader;       // nag³ówek pliku
    unsigned char       *bitmapImage;           // dane obrazu
    int                 imageIdx = 0;       // licznik pikseli
    unsigned char       tempRGB;                // zmienna zamiany sk³adowych

    // otwiera plik w trybie "read binary"
    filePtr = fopen(filename, "rb");
    if (filePtr == NULL)
        return NULL;

    // wczytuje nag³ówek pliku
    fread(&bitmapFileHeader, sizeof(BITMAPFILEHEADER), 1, filePtr);

    // sprawdza, czy jest to plik formatu BMP
    if (bitmapFileHeader.bfType != BITMAP_ID)
    {
        fclose(filePtr);
        return NULL;
    }

    // wczytuje nag³ówek obrazu
    fread(bitmapInfoHeader, sizeof(BITMAPINFOHEADER), 1, filePtr);

    // ustawia wskaŸnik pozycji pliku na pocz¹tku danych obrazu
    fseek(filePtr, bitmapFileHeader.bfOffBits, SEEK_SET);

    // przydziela pamiêæ buforowi obrazu
    bitmapImage = (unsigned char*)malloc(bitmapInfoHeader->biSizeImage);

    // sprawdza, czy uda³o siê przydzieliæ pamiêæ
    if (!bitmapImage)
    {
        free(bitmapImage);
        fclose(filePtr);
        return NULL;
    }

    // wczytuje dane obrazu
    fread(bitmapImage, 1, bitmapInfoHeader->biSizeImage, filePtr);

    // sprawdza, czy dane zosta³y wczytane
    if (bitmapImage == NULL)
    {
        fclose(filePtr);
        return NULL;
    }

    // zamienia miejscami sk³adowe R i B
    for (imageIdx = 0; imageIdx < bitmapInfoHeader->biSizeImage; imageIdx+=3)
    {
        tempRGB = bitmapImage[imageIdx];
        bitmapImage[imageIdx] = bitmapImage[imageIdx + 2];
        bitmapImage[imageIdx + 2] = tempRGB;
    }

    // zamyka plik i zwraca wskaŸnik bufora zawieraj¹cego wczytany obraz
    fclose(filePtr);
    return bitmapImage;
}


// Called to draw scene
void RenderScene(void)
    {
    //float normal[3];  // Storeage for calculated surface normal

    // Clear the window with current clearing color
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    // Save the matrix state and do the rotations
    glPushMatrix();
    glRotatef(xRot, 1.0f, 0.0f, 0.0f);
    glRotatef(yRot, 0.0f, 1.0f, 0.0f);

    /////////////////////////////////////////////////////////////////
    // MIEJSCE NA KOD OPENGL DO TWORZENIA WLASNYCH SCEN:           //
    /////////////////////////////////////////////////////////////////

    //Sposób na odróŸnienie "przedniej" i "tylniej" œciany wielok¹ta:
    glPolygonMode(GL_BACK,GL_LINE);

    //Uzyskanie siatki:
    //glPolygonMode(GL_FRONT_AND_BACK,GL_LINE);

    //Wyrysowanie prostokata:
    glRectd(-10.0,-10.0,20.0,20.0);

    /////////////////////////////////////////////////////////////////
    /////////////////////////////////////////////////////////////////
    /////////////////////////////////////////////////////////////////
    glPopMatrix();
    glMatrixMode(GL_MODELVIEW);

    // Flush drawing commands
    glFlush();
    }


// Select the pixel format for a given device context
void SetDCPixelFormat(HDC hDC)
    {
    int nPixelFormat;

    static PIXELFORMATDESCRIPTOR pfd = {
        sizeof(PIXELFORMATDESCRIPTOR),  // Size of this structure
        1,                                                              // Version of this structure
        PFD_DRAW_TO_WINDOW |                    // Draw to Window (not to bitmap)
        PFD_SUPPORT_OPENGL |                    // Support OpenGL calls in window
        PFD_DOUBLEBUFFER,                       // Double buffered
        PFD_TYPE_RGBA,                          // RGBA Color mode
        24,                                     // Want 24bit color
        0,0,0,0,0,0,                            // Not used to select mode
        0,0,                                    // Not used to select mode
        0,0,0,0,0,                              // Not used to select mode
        32,                                     // Size of depth buffer
        0,                                      // Not used to select mode
        0,                                      // Not used to select mode
        PFD_MAIN_PLANE,                         // Draw in main plane
        0,                                      // Not used to select mode
        0,0,0 };                                // Not used to select mode

    // Choose a pixel format that best matches that described in pfd
    nPixelFormat = ChoosePixelFormat(hDC, &pfd);

    // Set the pixel format for the device context
    SetPixelFormat(hDC, nPixelFormat, &pfd);
    }



// If necessary, creates a 3-3-2 palette for the device context listed.
HPALETTE GetOpenGLPalette(HDC hDC)
    {
    HPALETTE hRetPal = NULL;    // Handle to palette to be created
    PIXELFORMATDESCRIPTOR pfd;  // Pixel Format Descriptor
    LOGPALETTE *pPal;           // Pointer to memory for logical palette
    int nPixelFormat;           // Pixel format index
    int nColors;                // Number of entries in palette
    int i;                      // Counting variable
    BYTE RedRange,GreenRange,BlueRange;
                                // Range for each color entry (7,7,and 3)


    // Get the pixel format index and retrieve the pixel format description
    nPixelFormat = GetPixelFormat(hDC);
    DescribePixelFormat(hDC, nPixelFormat, sizeof(PIXELFORMATDESCRIPTOR), &pfd);

    // Does this pixel format require a palette?  If not, do not create a
    // palette and just return NULL
    if(!(pfd.dwFlags & PFD_NEED_PALETTE))
        return NULL;

    // Number of entries in palette.  8 bits yeilds 256 entries
    nColors = 1 << pfd.cColorBits;

    // Allocate space for a logical palette structure plus all the palette entries
    pPal = (LOGPALETTE*)malloc(sizeof(LOGPALETTE) +nColors*sizeof(PALETTEENTRY));

    // Fill in palette header
    pPal->palVersion = 0x300;       // Windows 3.0
    pPal->palNumEntries = nColors; // table size

    // Build mask of all 1's.  This creates a number represented by having
    // the low order x bits set, where x = pfd.cRedBits, pfd.cGreenBits, and
    // pfd.cBlueBits.
    RedRange = (1 << pfd.cRedBits) -1;
    GreenRange = (1 << pfd.cGreenBits) - 1;
    BlueRange = (1 << pfd.cBlueBits) -1;

    // Loop through all the palette entries
    for(i = 0; i < nColors; i++)
        {
        // Fill in the 8-bit equivalents for each component
        pPal->palPalEntry[i].peRed = (i >> pfd.cRedShift) & RedRange;
        pPal->palPalEntry[i].peRed = (unsigned char)(
            (double) pPal->palPalEntry[i].peRed * 255.0 / RedRange);

        pPal->palPalEntry[i].peGreen = (i >> pfd.cGreenShift) & GreenRange;
        pPal->palPalEntry[i].peGreen = (unsigned char)(
            (double)pPal->palPalEntry[i].peGreen * 255.0 / GreenRange);

        pPal->palPalEntry[i].peBlue = (i >> pfd.cBlueShift) & BlueRange;
        pPal->palPalEntry[i].peBlue = (unsigned char)(
            (double)pPal->palPalEntry[i].peBlue * 255.0 / BlueRange);

        pPal->palPalEntry[i].peFlags = (unsigned char) NULL;
        }


    // Create the palette
    hRetPal = CreatePalette(pPal);

    // Go ahead and select and realize the palette for this device context
    SelectPalette(hDC,hRetPal,FALSE);
    RealizePalette(hDC);

    // Free the memory used for the logical palette structure
    free(pPal);

    // Return the handle to the new palette
    return hRetPal;
    }


// Entry point of all Windows programs
int APIENTRY WinMain(   HINSTANCE       hInst,
                        HINSTANCE       hPrevInstance,
                        LPSTR           lpCmdLine,
                        int                     nCmdShow)
    {
    MSG                     msg;            // Windows message structure
    WNDCLASS        wc;                     // Windows class structure
    HWND            hWnd;           // Storeage for window handle

    hInstance = hInst;

    // Register Window style
    wc.style                        = CS_HREDRAW | CS_VREDRAW;
    wc.lpfnWndProc          = (WNDPROC) WndProc;
    wc.cbClsExtra           = 0;
    wc.cbWndExtra           = 0;
    wc.hInstance            = hInstance;
    wc.hIcon                        = NULL;
    wc.hCursor                      = LoadCursor(NULL, IDC_ARROW);

    // No need for background brush for OpenGL window
    wc.hbrBackground        = NULL;

    wc.lpszMenuName         = MAKEINTRESOURCE(IDR_MENU);
    wc.lpszClassName        = lpszAppName;

    // Register the window class
    if(RegisterClass(&wc) == 0)
        return FALSE;


    // Create the main application window
    hWnd = CreateWindow(
                lpszAppName,
                lpszAppName,

                // OpenGL requires WS_CLIPCHILDREN and WS_CLIPSIBLINGS
                WS_OVERLAPPEDWINDOW | WS_CLIPCHILDREN | WS_CLIPSIBLINGS,

                // Window position and size
                50, 50,
                400, 400,
                NULL,
                NULL,
                hInstance,
                NULL);

    // If window was not created, quit
    if(hWnd == NULL)
        return FALSE;


    // Display the window
    ShowWindow(hWnd,SW_SHOW);
    UpdateWindow(hWnd);

    // Process application messages until the application closes
    while( GetMessage(&msg, NULL, 0, 0))
        {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
        }

    return msg.wParam;
    }




// Window procedure, handles all messages for this program
LRESULT CALLBACK WndProc(       HWND    hWnd,
                            UINT    message,
                            WPARAM  wParam,
                            LPARAM  lParam)
    {
    static HGLRC hRC;               // Permenant Rendering context
    static HDC hDC;                 // Private GDI Device context

    switch (message)
        {
        // Window creation, setup for OpenGL
        case WM_CREATE:
            // Store the device context
            hDC = GetDC(hWnd);

            // Select the pixel format
            SetDCPixelFormat(hDC);

            // Create palette if needed
            hPalette = GetOpenGLPalette(hDC);

            // Create the rendering context and make it current
            hRC = wglCreateContext(hDC);
            wglMakeCurrent(hDC, hRC);
            SetupRC();
            glGenTextures(2, &texture[0]);                  // tworzy obiekt tekstury

            // ³aduje pierwszy obraz tekstury:
            bitmapData = LoadBitmapFile("Bitmapy\\checker.bmp", &bitmapInfoHeader);

            glBindTexture(GL_TEXTURE_2D, texture[0]);       // aktywuje obiekt tekstury

            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);

            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP );

            // tworzy obraz tekstury
            glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, bitmapInfoHeader.biWidth,
                         bitmapInfoHeader.biHeight, 0, GL_RGB, GL_UNSIGNED_BYTE, bitmapData);

            if(bitmapData)
            free(bitmapData);

            // ³aduje drugi obraz tekstury:
            bitmapData = LoadBitmapFile("Bitmapy\\crate.bmp", &bitmapInfoHeader);
            glBindTexture(GL_TEXTURE_2D, texture[1]);       // aktywuje obiekt tekstury

            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);

            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP );

            // tworzy obraz tekstury
            glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, bitmapInfoHeader.biWidth,
                         bitmapInfoHeader.biHeight, 0, GL_RGB, GL_UNSIGNED_BYTE, bitmapData);

            if(bitmapData)
            free(bitmapData);

            // ustalenie sposobu mieszania tekstury z t³em
            glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE,GL_MODULATE);
            break;

        // Window is being destroyed, cleanup
        case WM_DESTROY:
            // Deselect the current rendering context and delete it
            wglMakeCurrent(hDC,NULL);
            wglDeleteContext(hRC);

            // Delete the palette if it was created
            if(hPalette != NULL)
                DeleteObject(hPalette);

            // Tell the application to terminate after the window
            // is gone.
            PostQuitMessage(0);
            break;

        // Window is resized.
        case WM_SIZE:
            // Call our function which modifies the clipping
            // volume and viewport
            ChangeSize(LOWORD(lParam), HIWORD(lParam));
            break;


        // The painting function.  This message sent by Windows
        // whenever the screen needs updating.
        case WM_PAINT:
            {
            // Call OpenGL drawing code
            RenderScene();

            SwapBuffers(hDC);

            // Validate the newly painted client area
            ValidateRect(hWnd,NULL);
            }
            break;

        // Windows is telling the application that it may modify
        // the system palette.  This message in essance asks the
        // application for a new palette.
        case WM_QUERYNEWPALETTE:
            // If the palette was created.
            if(hPalette)
                {
                int nRet;

                // Selects the palette into the current device context
                SelectPalette(hDC, hPalette, FALSE);

                // Map entries from the currently selected palette to
                // the system palette.  The return value is the number
                // of palette entries modified.
                nRet = RealizePalette(hDC);

                // Repaint, forces remap of palette in current window
                InvalidateRect(hWnd,NULL,FALSE);

                return nRet;
                }
            break;


        // This window may set the palette, even though it is not the
        // currently active window.
        case WM_PALETTECHANGED:
            // Don't do anything if the palette does not exist, or if
            // this is the window that changed the palette.
            if((hPalette != NULL) && ((HWND)wParam != hWnd))
                {
                // Select the palette into the device context
                SelectPalette(hDC,hPalette,FALSE);

                // Map entries to system palette
                RealizePalette(hDC);

                // Remap the current colors to the newly realized palette
                UpdateColors(hDC);
                return 0;
                }
            break;

        // Key press, check for arrow keys to do cube rotation.
        case WM_KEYDOWN:
            {
            if(wParam == VK_UP)
                xRot-= 5.0f;

            if(wParam == VK_DOWN)
                xRot += 5.0f;

            if(wParam == VK_LEFT)
                yRot -= 5.0f;

            if(wParam == VK_RIGHT)
                yRot += 5.0f;

            xRot = (const int)xRot % 360;
            yRot = (const int)yRot % 360;

            InvalidateRect(hWnd,NULL,FALSE);
            }
            break;

        // A menu command
        case WM_COMMAND:
            {
            switch(LOWORD(wParam))
                {
                // Exit the program
                case ID_FILE_EXIT:
                    DestroyWindow(hWnd);
                    break;

                // Display the about box
                case ID_HELP_ABOUT:
                    DialogBox (hInstance,
                        MAKEINTRESOURCE(IDD_DIALOG_ABOUT),
                        hWnd,
                        AboutDlgProc);
                    break;
                }
            }
            break;


    default:   // Passes it on if unproccessed
        return (DefWindowProc(hWnd, message, wParam, lParam));

    }

    return (0L);
    }




// Dialog procedure.
BOOL APIENTRY AboutDlgProc (HWND hDlg, UINT message, UINT wParam, LONG lParam)
    {

    switch (message)
    {
        // Initialize the dialog box
        case WM_INITDIALOG:
            {
            int i;
            GLenum glError;

            // glGetString demo
            SetDlgItemText(hDlg,IDC_OPENGL_VENDOR,glGetString(GL_VENDOR));
            SetDlgItemText(hDlg,IDC_OPENGL_RENDERER,glGetString(GL_RENDERER));
            SetDlgItemText(hDlg,IDC_OPENGL_VERSION,glGetString(GL_VERSION));
            SetDlgItemText(hDlg,IDC_OPENGL_EXTENSIONS,glGetString(GL_EXTENSIONS));

            // gluGetString demo
            SetDlgItemText(hDlg,IDC_GLU_VERSION,gluGetString(GLU_VERSION));
            SetDlgItemText(hDlg,IDC_GLU_EXTENSIONS,gluGetString(GLU_EXTENSIONS));


            // Display any recent error messages
            i = 0;
            do {
                glError = glGetError();
                SetDlgItemText(hDlg,IDC_ERROR1+i,gluErrorString(glError));
                i++;
                }
            while(i < 6 && glError != GL_NO_ERROR);


            return (TRUE);
            }
            break;

        // Process command messages
        case WM_COMMAND:
            {
            // Validate and Make the changes
            if(LOWORD(wParam) == IDOK)
                EndDialog(hDlg,TRUE);
            }
            break;

        // Closed from sysbox
        case WM_CLOSE:
            EndDialog(hDlg,TRUE);
            break;
        }

    return FALSE;
    }