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WiseElben

Wha?... Blank Screen

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WiseElben    250
/*
 *		This Code Was Created By Jeff Molofee 2000
 *		A HUGE Thanks To Fredric Echols For Cleaning Up
 *		And Optimizing This Code, Making It More Flexible!
 *		If You''ve Found This Code Useful, Please Let Me Know.
 *		Visit My Site At nehe.gamedev.net
 *		Conversion to Visual Studio.NET done by Grant James (ZEUS)
 */

#include <windows.h>		// Header File For Windows

#include <gl\gl.h>			// Header File For The OpenGL32 Library

#include <gl\glu.h>			// Header File For The GLu32 Library

#include <gl\glaux.h>		// Header File For The Glaux Library


HDC			hDC=NULL;		// Private GDI Device Context

HGLRC		hRC=NULL;		// Permanent Rendering Context

HWND		hWnd=NULL;		// Holds Our Window Handle

HINSTANCE	hInstance;		// Holds The Instance Of The Application


bool	keys[256];			// Array Used For The Keyboard Routine

bool	active=TRUE;		// Window Active Flag Set To TRUE By Default

bool	fullscreen=TRUE;	// Fullscreen Flag Set To Fullscreen Mode By Default


LRESULT	CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);	// Declaration For WndProc


GLvoid ReSizeGLScene(GLsizei width, GLsizei height)		// Resize And Initialize The GL Window

{
	if (height==0)										// Prevent A Divide By Zero By

	{
		height=1;										// Making Height Equal One

	}

	glViewport(0,0,width,height);						// Reset The Current Viewport


	glMatrixMode(GL_PROJECTION);						// Select The Projection Matrix

	glLoadIdentity();									// Reset The Projection Matrix


	// Calculate The Aspect Ratio Of The Window

	gluPerspective(45.0f,(GLfloat)width/(GLfloat)height,0.1f,100.0f);

	glMatrixMode(GL_MODELVIEW);							// Select The Modelview Matrix

	glLoadIdentity();									// Reset The Modelview Matrix

}

int InitGL(GLvoid)										// All Setup For OpenGL Goes Here

{
	glShadeModel(GL_SMOOTH);							// Enable Smooth Shading

	glClearColor(0.0f, 0.0f, 0.0f, 0.5f);				// Black Background

	glClearDepth(1.0f);									// Depth Buffer Setup

	glEnable(GL_DEPTH_TEST);							// Enables Depth Testing

	glDepthFunc(GL_LEQUAL);								// The Type Of Depth Testing To Do

	glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);	// Really Nice Perspective Calculations

	return TRUE;										// Initialization Went OK

}
//*********************************************************************************************
int DrawGLScene()
{
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
	glLoadIdentity();
	glTranslatef(0.0f, 0.0f, 6.0f);

	glBegin(GL_TRIANGLES);
		glVertex3f(0.0f, 1.0f, 0.0f);
		glVertex3f(-1.0f, -1.0f, 0.0f);
		glVertex3f(1.0f, -1.0f, 0.0f);
	glEnd();

	glFlush();

	return TRUE;
}

GLvoid KillGLWindow(GLvoid)								// Properly Kill The Window
{
	if (fullscreen)										// Are We In Fullscreen Mode?
	{
		ChangeDisplaySettings(NULL,0);					// If So Switch Back To The Desktop
		ShowCursor(TRUE);								// Show Mouse Pointer
	}

	if (hRC)											// Do We Have A Rendering Context?
	{
		if (!wglMakeCurrent(NULL,NULL))					// Are We Able To Release The DC And RC Contexts?
		{
			MessageBox(NULL,"Release Of DC And RC Failed.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
		}

		if (!wglDeleteContext(hRC))						// Are We Able To Delete The RC?
		{
			MessageBox(NULL,"Release Rendering Context Failed.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
		}
		hRC=NULL;										// Set RC To NULL
	}

	if (hDC && !ReleaseDC(hWnd,hDC))					// Are We Able To Release The DC
	{
		MessageBox(NULL,"Release Device Context Failed.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
		hDC=NULL;										// Set DC To NULL
	}

	if (hWnd && !DestroyWindow(hWnd))					// Are We Able To Destroy The Window?
	{
		MessageBox(NULL,"Could Not Release hWnd.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
		hWnd=NULL;										// Set hWnd To NULL
	}

	if (!UnregisterClass("OpenGL",hInstance))			// Are We Able To Unregister Class
	{
		MessageBox(NULL,"Could Not Unregister Class.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
		hInstance=NULL;									// Set hInstance To NULL
	}
}

/*	This Code Creates Our OpenGL Window.  Parameters Are:					*
 *	title			- Title To Appear At The Top Of The Window				*
 *	width			- Width Of The GL Window Or Fullscreen Mode				*
 *	height			- Height Of The GL Window Or Fullscreen Mode			*
 *	bits			- Number Of Bits To Use For Color (8/32/24/32)			*
 *	fullscreenflag	- Use Fullscreen Mode (TRUE) Or Windowed Mode (FALSE)	*/
 
BOOL CreateGLWindow(char* title, int width, int height, int bits, bool fullscreenflag)
{
	GLuint		PixelFormat;			// Holds The Results After Searching For A Match

	WNDCLASS	wc;						// Windows Class Structure

	DWORD		dwExStyle;				// Window Extended Style

	DWORD		dwStyle;				// Window Style

	RECT		WindowRect;				// Grabs Rectangle Upper Left / Lower Right Values

	WindowRect.left=(long)0;			// Set Left Value To 0

	WindowRect.right=(long)width;		// Set Right Value To Requested Width

	WindowRect.top=(long)0;				// Set Top Value To 0

	WindowRect.bottom=(long)height;		// Set Bottom Value To Requested Height


	fullscreen=fullscreenflag;			// Set The Global Fullscreen Flag


	hInstance			= GetModuleHandle(NULL);				// Grab An Instance For Our Window

	wc.style			= CS_HREDRAW | CS_VREDRAW | CS_OWNDC;	// Redraw On Size, And Own DC For Window.

	wc.lpfnWndProc		= (WNDPROC) WndProc;					// WndProc Handles Messages

	wc.cbClsExtra		= 0;									// No Extra Window Data

	wc.cbWndExtra		= 0;									// No Extra Window Data

	wc.hInstance		= hInstance;							// Set The Instance

	wc.hIcon			= LoadIcon(NULL, IDI_WINLOGO);			// Load The Default Icon

	wc.hCursor			= LoadCursor(NULL, IDC_ARROW);			// Load The Arrow Pointer

	wc.hbrBackground	= NULL;									// No Background Required For GL

	wc.lpszMenuName		= NULL;									// We Don''t Want A Menu

	wc.lpszClassName	= "OpenGL";								// Set The Class Name


	if (!RegisterClass(&wc))									// Attempt To Register The Window Class

	{
		MessageBox(NULL,"Failed To Register The Window Class.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		return FALSE;											// Return FALSE

	}
	
	if (fullscreen)												// Attempt Fullscreen Mode?

	{
		DEVMODE dmScreenSettings;								// Device Mode

		memset(&dmScreenSettings,0,sizeof(dmScreenSettings));	// Makes Sure Memory''s Cleared

		dmScreenSettings.dmSize=sizeof(dmScreenSettings);		// Size Of The Devmode Structure

		dmScreenSettings.dmPelsWidth	= width;				// Selected Screen Width

		dmScreenSettings.dmPelsHeight	= height;				// Selected Screen Height

		dmScreenSettings.dmBitsPerPel	= bits;					// Selected Bits Per Pixel

		dmScreenSettings.dmFields=DM_BITSPERPEL|DM_PELSWIDTH|DM_PELSHEIGHT;

		// Try To Set Selected Mode And Get Results.  NOTE: CDS_FULLSCREEN Gets Rid Of Start Bar.

		if (ChangeDisplaySettings(&dmScreenSettings,CDS_FULLSCREEN)!=DISP_CHANGE_SUCCESSFUL)
		{
			// If The Mode Fails, Offer Two Options.  Quit Or Use Windowed Mode.

			if (MessageBox(NULL,"The Requested Fullscreen Mode Is Not Supported By\nYour Video Card. Use Windowed Mode Instead?","NeHe GL",MB_YESNO|MB_ICONEXCLAMATION)==IDYES)
			{
				fullscreen=FALSE;		// Windowed Mode Selected.  Fullscreen = FALSE

			}
			else
			{
				// Pop Up A Message Box Letting User Know The Program Is Closing.

				MessageBox(NULL,"Program Will Now Close.","ERROR",MB_OK|MB_ICONSTOP);
				return FALSE;									// Return FALSE

			}
		}
	}

	if (fullscreen)												// Are We Still In Fullscreen Mode?

	{
		dwExStyle=WS_EX_APPWINDOW;								// Window Extended Style

		dwStyle=WS_POPUP;										// Windows Style

		ShowCursor(FALSE);										// Hide Mouse Pointer

	}
	else
	{
		dwExStyle=WS_EX_APPWINDOW | WS_EX_WINDOWEDGE;			// Window Extended Style

		dwStyle=WS_OVERLAPPEDWINDOW;							// Windows Style

	}

	AdjustWindowRectEx(&WindowRect, dwStyle, FALSE, dwExStyle);		// Adjust Window To True Requested Size


	// Create The Window

	if (!(hWnd=CreateWindowEx(	dwExStyle,							// Extended Style For The Window

								"OpenGL",							// Class Name

								"OpenGL 1: A WindowX Project",		// Window Title

								dwStyle |							// Defined Window Style

								WS_CLIPSIBLINGS |					// Required Window Style

								WS_CLIPCHILDREN,					// Required Window Style

								0, 0,								// Window Position

								WindowRect.right-WindowRect.left,	// Calculate Window Width

								WindowRect.bottom-WindowRect.top,	// Calculate Window Height

								NULL,								// No Parent Window

								NULL,								// No Menu

								hInstance,							// Instance

								NULL)))								// Dont Pass Anything To WM_CREATE

	{
		KillGLWindow();								// Reset The Display

		MessageBox(NULL,"Window Creation Error.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		return FALSE;								// Return FALSE

	}

	static	PIXELFORMATDESCRIPTOR pfd=				// pfd Tells Windows How We Want Things To Be

	{
		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

		bits,										// Select Our 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

		32,											// 32Bit 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

	};
	
	if (!(hDC=GetDC(hWnd)))							// Did We Get A Device Context?

	{
		KillGLWindow();								// Reset The Display

		MessageBox(NULL,"Can''t Create A GL Device Context.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		return FALSE;								// Return FALSE

	}

	if (!(PixelFormat=ChoosePixelFormat(hDC,&pfd)))	// Did Windows Find A Matching Pixel Format?

	{
		KillGLWindow();								// Reset The Display

		MessageBox(NULL,"Can''t Find A Suitable PixelFormat.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		return FALSE;								// Return FALSE

	}

	if(!SetPixelFormat(hDC,PixelFormat,&pfd))		// Are We Able To Set The Pixel Format?

	{
		KillGLWindow();								// Reset The Display

		MessageBox(NULL,"Can''t Set The PixelFormat.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		return FALSE;								// Return FALSE

	}

	if (!(hRC=wglCreateContext(hDC)))				// Are We Able To Get A Rendering Context?

	{
		KillGLWindow();								// Reset The Display

		MessageBox(NULL,"Can''t Create A GL Rendering Context.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		return FALSE;								// Return FALSE

	}

	if(!wglMakeCurrent(hDC,hRC))					// Try To Activate The Rendering Context

	{
		KillGLWindow();								// Reset The Display

		MessageBox(NULL,"Can''t Activate The GL Rendering Context.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		return FALSE;								// Return FALSE

	}

	ShowWindow(hWnd,SW_SHOW);						// Show The Window

	SetForegroundWindow(hWnd);						// Slightly Higher Priority

	SetFocus(hWnd);									// Sets Keyboard Focus To The Window

	ReSizeGLScene(width, height);					// Set Up Our Perspective GL Screen


	if (!InitGL())									// Initialize Our Newly Created GL Window

	{
		KillGLWindow();								// Reset The Display

		MessageBox(NULL,"Initialization Failed.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		return FALSE;								// Return FALSE

	}

	return TRUE;									// Success

}

LRESULT CALLBACK WndProc(	HWND	hWnd,			// Handle For This Window

							UINT	uMsg,			// Message For This Window

							WPARAM	wParam,			// Additional Message Information

							LPARAM	lParam)			// Additional Message Information

{
	switch (uMsg)									// Check For Windows Messages

	{
		case WM_ACTIVATE:							// Watch For Window Activate Message

		{
			if (!HIWORD(wParam))					// Check Minimization State

			{
				active=TRUE;						// Program Is Active

			}
			else
			{
				active=FALSE;						// Program Is No Longer Active

			}

			return 0;								// Return To The Message Loop

		}

		case WM_SYSCOMMAND:							// Intercept System Commands

		{
			switch (wParam)							// Check System Calls

			{
				case SC_SCREENSAVE:					// Screensaver Trying To Start?

				case SC_MONITORPOWER:				// Monitor Trying To Enter Powersave?

				return 0;							// Prevent From Happening

			}
			break;									// Exit

		}

		case WM_CLOSE:								// Did We Receive A Close Message?

		{
			PostQuitMessage(0);						// Send A Quit Message

			return 0;								// Jump Back

		}

		case WM_KEYDOWN:							// Is A Key Being Held Down?

		{
			keys[wParam] = TRUE;					// If So, Mark It As TRUE

			return 0;								// Jump Back

		}

		case WM_KEYUP:								// Has A Key Been Released?

		{
			keys[wParam] = FALSE;					// If So, Mark It As FALSE

			return 0;								// Jump Back

		}

		case WM_SIZE:								// Resize The OpenGL Window

		{
			ReSizeGLScene(LOWORD(lParam),HIWORD(lParam));  // LoWord=Width, HiWord=Height

			return 0;								// Jump Back

		}
	}

	// Pass All Unhandled Messages To DefWindowProc

	return DefWindowProc(hWnd,uMsg,wParam,lParam);
}

int WINAPI WinMain(	HINSTANCE	hInstance,			// Instance

					HINSTANCE	hPrevInstance,		// Previous Instance

					LPSTR		lpCmdLine,			// Command Line Parameters

					int			nCmdShow)			// Window Show State

{
	MSG		msg;									// Windows Message Structure

	BOOL	done=FALSE;								// Bool Variable To Exit Loop


	// Ask The User Which Screen Mode They Prefer

	if (MessageBox(NULL,"Would You Like To Run In Fullscreen Mode?", "Start FullScreen?",MB_YESNO|MB_ICONQUESTION)==IDNO)
	{
		fullscreen=FALSE;							// Windowed Mode

	}

	// Create Our OpenGL Window

	if (!CreateGLWindow("NeHe''s OpenGL Framework",1024,768,32,fullscreen))
	{
		return 0;									// Quit If Window Was Not Created

	}

	while(!done)									// Loop That Runs While done=FALSE

	{
		if (PeekMessage(&msg,NULL,0,0,PM_REMOVE))	// Is There A Message Waiting?

		{
			if (msg.message==WM_QUIT)				// Have We Received A Quit Message?

			{
				done=TRUE;							// If So done=TRUE

			}
			else									// If Not, Deal With Window Messages

			{
				TranslateMessage(&msg);				// Translate The Message

				DispatchMessage(&msg);				// Dispatch The Message

			}
		}
		else										// If There Are No Messages

		{
			// Draw The Scene.  Watch For ESC Key And Quit Messages From DrawGLScene()

			if (active)								// Program Active?

			{
				if (keys[VK_ESCAPE])				// Was ESC Pressed?

				{
					done=TRUE;						// ESC Signalled A Quit

				}
				else								// Not Time To Quit, Update Screen

				{
					DrawGLScene();					// Draw The Scene

					SwapBuffers(hDC);				// Swap Buffers (Double Buffering)

				}
			}

			if (keys[VK_F1])						// Is F1 Being Pressed?

			{
				keys[VK_F1]=FALSE;					// If So Make Key FALSE

				KillGLWindow();						// Kill Our Current Window

				fullscreen=!fullscreen;				// Toggle Fullscreen / Windowed Mode

				// Recreate Our OpenGL Window

				if (!CreateGLWindow("NeHe''s OpenGL Framework",1024,768,32,fullscreen))
				{
					return 0;						// Quit If Window Was Not Created

				}
			}
		}
	}

	// Shutdown

	KillGLWindow();									// Kill The Window

	return (msg.wParam);							// Exit The Program

}
Last year, I started working with OpenGL using Dev-C++. Then I decided to learn more of C++ and Win32 progamming first. Now I''m back to NeHe. Ok, this code compiles and runs, but all I see is a blank screen. Help!
WiseElben.com - Game programming tutorials, articles, and community. E-mail:wiseelben@wiseelben.com AIM: WiseElben ICQ: 299127026 [edited by - GameDev Staff on September 27, 1989 9X:58:97 XMS] For violating Article 43 Page 456 Paragraph 251 Line .042]

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clum    217
I don't think it actually is commented out - the source tag probably considers the /* a comment but the compiler doesn't (otherwise it wouldn't even compile).

I'm actually having a similar problem, see my thread here.

[edited by - clum on August 12, 2003 6:30:34 PM]

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Crispy    556
erm - this is just a guess, but if you don''t have your view vector (camera) set up, which way is the camera looking by default? along the minus z axis? anyway, as far as I can tell (I didn''t read most of the code, mind you) your camera might be overlapping with the triangle, making it appear closer than the near plane. try moving it on the z axis or changing the camera parameters.

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WiseElben    250
Actually, I''m stupid. No, I didn''t comment out my code, I just messed up when Copy and Pasting on to the forums.

My problem was that I did not tranlate the screen far back enough. Actually, I didn''t translate it back at all.

I just added glTranslatef(0.0f,0.0f,-6.0f); and it works fine. hehe...




WiseElben.com - Game programming tutorials, articles, and community.

E-mail:wiseelben@wiseelben.com
AIM: WiseElben
ICQ: 299127026

[edited by - GameDev Staff on September 27, 1989 9X:58:97 XMS] For violating Article 43 Page 456 Paragraph 251 Line .042]

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WiseElben    250
quote:
Original post by Crispy
erm - this is just a guess, but if you don''t have your view vector (camera) set up, which way is the camera looking by default? along the minus z axis? anyway, as far as I can tell (I didn''t read most of the code, mind you) your camera might be overlapping with the triangle, making it appear closer than the near plane. try moving it on the z axis or changing the camera parameters.


Yea, thats why.




WiseElben.com - Game programming tutorials, articles, and community.

E-mail:wiseelben@wiseelben.com
AIM: WiseElben
ICQ: 299127026

[edited by - GameDev Staff on September 27, 1989 9X:58:97 XMS] For violating Article 43 Page 456 Paragraph 251 Line .042]

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