Linien in OpenGL: Schlechte Qualität

hellihjb

Alphablending aktivieren.

http://img684.imageshack.us/img684/5492/badcy.png

Aktiviert sind:

glEnable(GL_LINE_SMOOTH)
glHint(GL_LINE_SMOOTH_HINT, GL_DONT_CARE)
glShadeModel(GL_SMOOTH)
glEnable(GL_BLEND)
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA)

rapso

das sieht an sich seltsam aus, dass manche linien pixelbreit sind, andere wiederrum mehrere pixel bedecken und graeulich sind. es sieht nicht danach aus als ob es viel code waere, vielleicht kannst du das ja hier posten (mit code tags) oder pastebin und verlinken, dann gibt es bessere chancen dass wir sehen was vor sich geht.

gary1195

rapso schrieb:

das sieht an sich seltsam aus, dass manche linien pixelbreit sind, andere wiederrum mehrere pixel bedecken und graeulich sind.

Das passiert wenn eine Linie nicht direkt unter einem Pixelstreifen liegt sondern zwischen zwei Pixelstreifen.

rapso

opengl an sich zeichnet linien aber nur pixelweise, das sub-pixel zeichnen koennte ich mir nur vorstellen, wenn anti aliasing an waere, dann waere aber auch eine intensiverere farbe an kreuzungsstellen offensichtlich (gibt ja mehr schwarze pixel).

hustbaer

Komische sind doch die seltsamen "Verdickungen" "um" die Schnittpunkten rum, die wesentlich mehr als nur 1 Pixel hoch/breit sind. Die können niemals vom "Überblenden" zweier Linien im Schnittpunkt kommen, dafür sind sie viel zu weit vom Schnittpunkt entfernt.

Deswegen meine ich auch dass das vielleicht JPEG Artefakte sind. Das PNG sieht zwar genau so aus, aber pfuh... vielleicht hat der OP ja irgendwas komisches mit dem PNG gemacht, wie z.B. nen Screenshot als JPEG zu nehmen und dann zu PNG zu konvertieren

Ich habe mein Problem mal in ein Tutorial aus dem Internet implementiert, da ich für OpenGL meine eigene Klasse verwende; ändert aber nichts an meinem Problem:

#include <windows.h>
#include <gl\gl.h>
#include <gl\glu.h>
#include <gl\glaux.h>

HDC			hDC=NULL;
HGLRC		hRC=NULL;
HWND		hWnd=NULL;
HINSTANCE	hInstance;

bool	keys[256];
bool	active=TRUE;

LRESULT	CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);

GLvoid ReSizeGLScene(GLsizei width, GLsizei height)
{
	if (height==0)
	{
		height=1;
	}

	glViewport(0,0,width,height);

	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();

	gluOrtho2D(0, 10, 10, 0);

	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
}

int InitGL(GLvoid)
{
	glClearColor(1.0f, 1.0f, 1.0f, 0.0f);
	glEnable(GL_LINE_SMOOTH);
	glHint(GL_LINE_SMOOTH_HINT, GL_DONT_CARE);
	glShadeModel(GL_SMOOTH);
	glEnable(GL_BLEND);
	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
	return TRUE;
}

int DrawGLScene(GLvoid)
{
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
	glLoadIdentity();

	glColor3ub(0, 0, 0);

	glBegin(GL_LINES);
	for(float x = 0; x <= 10; x += 1)
	{
		glVertex2f(x, 0);
		glVertex2f(x, 10);
	}

	for(float y = 0; y <= 10; y += 0.5f)
	{
		glVertex2f(0, y);
		glVertex2f(10, y);
	}
	glEnd();
	return TRUE;
}

GLvoid KillGLWindow(GLvoid)								// Properly Kill The Window
{
	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 (8/16/24/32)			*
 *	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

	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
	}

	dwExStyle=WS_EX_APPWINDOW | WS_EX_WINDOWEDGE;			// Window Extended Style
	dwStyle=WS_OVERLAPPEDWINDOW;

	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
								title,								// 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
		16,											// 16Bit 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:
		{
			switch (wParam)
			{
				case SC_SCREENSAVE:
				case SC_MONITORPOWER:
					return 0;
			}
			break;
		}

		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

	// Create Our OpenGL Window
	if (!CreateGLWindow("NeHe's First Polygon Tutorial",768,864,16,false))
	{
		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
		{
			if((active && !DrawGLScene()) || keys[VK_ESCAPE])	// Active?  Was There A Quit Received?
			{
				done=TRUE;							// ESC or DrawGLScene Signalled A Quit
			}
			else									// Not Time To Quit, Update Screen
			{
				SwapBuffers(hDC);					// Swap Buffers (Double Buffering)
			}
		}
	}

	KillGLWindow();
	return (msg.wParam);
}

Dobi

Hab deinen Code grad mal hier ausgeführt, und die Linien sahen ok aus: http://s16.postimage.org/z0zg50vad/oglll.png

Achja, falls du keine Lust hast, weiterhin die veraltete fixed-pipeline-variante von OpenGL zu lernen, kannst du ja mal hier reinschauen. http://www.c-plusplus.net/forum/285147-full

Alles klar, hatte FXAA aktiviert.
http://www.pcgameshardware.de/aid,832856/FXAA-fuer-Geforce-Grafikkarten-So-aktivieren-Sie-den-neuen-Immer-AA-Modus-Update-mit-Geforce-29518/Grafikkarte/Test/

rapso

wie zu erwarten war