// Gl_template.c
//Wyłšczanie błędów przed "fopen"
#define  _CRT_SECURE_NO_WARNINGS

// Ładowanie bibliotek:
#ifdef _MSC_VER                         // Check if MS Visual C compiler
#  pragma comment(lib, "opengl32.lib")  // Compiler-specific directive to avoid manually configuration
#  pragma comment(lib, "glu32.lib")     // Link libraries
#endif

// Ustalanie trybu tekstowego:
#ifdef _MSC_VER        // Check if MS Visual C compiler
#   ifndef _MBCS
#      define _MBCS    // Uses Multi-byte character set
#   endif
#   ifdef _UNICODE     // Not using Unicode character set
#      undef _UNICODE
#   endif
#   ifdef UNICODE
#      undef UNICODE
#   endif
#endif


#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;       // nagłówek 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); // Włącz 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); // Wyłącz 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: ładuje mapę bitową z pliku i zwraca jej adres.
//       Wypełnia strukturę nagłówka.
//       Nie obsługuje map 8-bitowych.
unsigned char *LoadBitmapFile(char *filename, BITMAPINFOHEADER *bitmapInfoHeader)
{
	FILE *filePtr;                                                  // wskaźnik pozycji pliku
	BITMAPFILEHEADER        bitmapFileHeader;               // nagłówek pliku
	unsigned char           *bitmapImage;                   // dane obrazu
	int                                     imageIdx = 0;           // licznik pikseli
	unsigned char           tempRGB;                                // zmienna zamiany składowych

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

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

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

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

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

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

	// sprawdza, czy udało się przydzielić pamięć
	if (!bitmapImage)
	{
		free(bitmapImage);
		fclose(filePtr);
		return NULL;
	}

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

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

	// zamienia miejscami składowe 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 wskaźnik bufora zawierającego wczytany obraz
	fclose(filePtr);
	return bitmapImage;
}

void szescian(void)
{
	glBegin(GL_QUADS);
	glColor3d(1, 0.5, 0);
	glVertex3d(20, 20, 20);
	glVertex3d(-20, 20, 20);
	glVertex3d(-20, -20, 20);
	glVertex3d(20, -20, 20);
	glColor3d(0, 0.5, 1);
	glVertex3d(20, 20, 20);
	glVertex3d(20, -20, 20);
	glVertex3d(20, -20, -20);
	glVertex3d(20, 20, -20);
	glColor3d(0.5, 1, 0);
	glVertex3d(20, 20, -20);
	glVertex3d(-20, 20, -20);
	glVertex3d(-20, 20, 20);
	glVertex3d(20, 20, 20);
	glEnd();
}

void walec(double r, double h)
{
	double angle, x, y;
	glColor3d(1, 0.5, 0);
	glBegin(GL_TRIANGLE_FAN);
	glVertex3d(0.0f, 0.0f, 0.0f);
	for (angle = 0.0f; angle <= (2.0f*GL_PI); angle += (GL_PI / 8.0f))
	{
		x = r*sin(angle);
		y = r*cos(angle);
		glVertex3d(x, y, 0.0);
	}
	glEnd();
	glBegin(GL_QUAD_STRIP);
	for (angle = 0.0f; angle <= (2.0f*GL_PI); angle += (GL_PI / 8.0f))
	{
		x = r*sin(angle);
		y = r*cos(angle);
		glVertex3d(x, y, 0);
		glVertex3d(x, y, h);
	}
	glEnd();
	glBegin(GL_TRIANGLE_FAN);
	glVertex3d(0.0f, 0.0f, h);
	for (angle = 0.0f; angle >= (-2.0f*GL_PI); angle -= (GL_PI / 8.0f))
	{
		x = r*sin(angle);
		y = r*cos(angle);
		glVertex3d(x, y, h);
	}
	glEnd();

}

void ramie(double r1, double r2, double h, double d)
{
	double angle, x, y;
	glColor3d(1, 0.5, 0);
	glBegin(GL_TRIANGLE_FAN);
	glVertex3d(0.0f, 0.0f, 0.0f);
	for (angle = GL_PI; angle <= (2.0f*GL_PI); angle += (GL_PI / 8.0f))
	{
		x = r1*sin(angle);
		y = r1*cos(angle);
		glVertex3d(x, y, 0.0);
	}
	glEnd();
	glBegin(GL_QUAD_STRIP);
	for (angle = GL_PI; angle <= (2.0f*GL_PI); angle += (GL_PI / 8.0f))
	{
		x = r1*sin(angle);
		y = r1*cos(angle);
		glVertex3d(x, y, 0);
		glVertex3d(x, y, h);
	}
	glEnd();
	glBegin(GL_TRIANGLE_FAN);
	glVertex3d(0.0f, 0.0f, h);
	for (angle = 0.0f; angle >= (-GL_PI); angle -= (GL_PI / 8.0f))
	{
		x = r1*sin(angle);
		y = r1*cos(angle);
		glVertex3d(x, y, h);
	}
	glEnd();

	glColor3d(1, 0.5, 0);
	glBegin(GL_TRIANGLE_FAN);
	glVertex3d(0.0f + d, 0.0f, 0.0f);
	for (angle = 0.0f; angle <= (GL_PI); angle += (GL_PI / 8.0f))
	{
		x = r2*sin(angle);
		y = r2*cos(angle);
		glVertex3d(x + d, y, 0.0);
	}
	glEnd();
	glBegin(GL_QUAD_STRIP);
	for (angle = 0.0f; angle <= (GL_PI); angle += (GL_PI / 8.0f))
	{
		x = r2*sin(angle);
		y = r2*cos(angle);
		glVertex3d(x + d, y, 0);
		glVertex3d(x + d, y, h);
	}
	glEnd();
	glBegin(GL_TRIANGLE_FAN);
	glVertex3d(0.0f + d, 0.0f, h);
	for (angle = -GL_PI; angle >= (-2.0f*GL_PI); angle -= (GL_PI / 8.0f))
	{
		x = r2*sin(angle);
		y = r2*cos(angle);
		glVertex3d(x + d, y, h);
	}
	glEnd();
	glColor3d(0, 0.5, 1);
	glBegin(GL_QUADS);
	glVertex3d(0, r1, 0);
	glVertex3d(d, r2, 0);
	glVertex3d(d, -r2, 0);
	glVertex3d(0, -r1, 0);

	glVertex3d(0, -r1, 0);
	glVertex3d(d, -r2, 0);
	glVertex3d(d, -r2, h);
	glVertex3d(0, -r1, h);

	glVertex3d(0, -r1, h);
	glVertex3d(d, -r2, h);
	glVertex3d(d, r2, h);
	glVertex3d(0, r1, h);

	glVertex3d(d, r2, h);
	glVertex3d(d, r2, 0);
	glVertex3d(0, r1, 0);
	glVertex3d(0, r1, h);
	glEnd();
}

// 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 odróźnienie "przedniej" i "tylniej" ściany wielokąta:
	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);
	ramie(15, 10, 5, 30);
	/////////////////////////////////////////////////////////////////
	/////////////////////////////////////////////////////////////////
	/////////////////////////////////////////////////////////////////
	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_MENU1);
	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

														// ładuje 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);

		// ładuje 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 tłem
		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;
		}
	}
	break;


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

	}

	return (0L);
}