RE: Experiencing problems with OpenGL

["Julian Moors" <julianmoors at hotmail dot com>]

Hi everybody,
?
First and foremost I have to say that I am so happy with the concept of
Cygwin and to the Cygwin volunteers ?Keep up with the good work. It is
so much appreciated?. I am having a little problem with compiling an
OpenGL sourcefile.
?
Here's what I've done so far:
?
Installed Cygwin using setup.exe to c:\cygwin using default settings
onto Windows XP SP 2 OS.
Installed make, g++ and nano by running setup.exe again.
Read the readme file located under /usr/share/opengl1-1-0.
Little confused about what switches I should use when compiling .cpp
file and whether to use a makefile or not.
Ran the OpenGL examples to test if it?s possible to run the .exe files
compiled and linked under Cygwin. All examples ran successfully.
Tried to compile the following .cpp file whilst using -lglu32 -lopengl32
switches with g++:

#define WIN32_LEAN_AND_MEAN

#include <windows.h>
#include <gl/glu.h>
#include <gl/gl.h>

HDC   g_hDC;
bool  g_keys[256];

void SetupPixelFormat(HDC hDC)
{
	int nPixelFormat;

	static PIXELFORMATDESCRIPTOR pfd =
	{
		sizeof(PIXELFORMATDESCRIPTOR),
		1,
		PFD_DRAW_TO_WINDOW |
		PFD_SUPPORT_OPENGL |
		PFD_DOUBLEBUFFER,
		PFD_TYPE_RGBA,
		32,
		0,0,0,0,0,0,
		0,
		0,
		0,
		0,0,0,0,
		16,
		0,
		0,
		PFD_MAIN_PLANE,
		0,
		0,0,0
	};

	nPixelFormat = ChoosePixelFormat(hDC,&pfd);
	SetPixelFormat(hDC,nPixelFormat,&pfd);
}

LRESULT CALLBACK WndProc(HWND hWnd,UINT msg,WPARAM wParam,LPARAM lParam)
{
	static HDC   hDC;
	static HGLRC hRC;
	int width,height;

	switch (msg)
	{
		case WM_CREATE:
		{
			hDC   = GetDC(hWnd);
			g_hDC = hDC;
			SetupPixelFormat(hDC);
			hRC   = wglCreateContext(hDC);
			wglMakeCurrent(hDC,hRC);
			return 0;
			break;
		}
		case WM_SIZE:
		{
			width  = LOWORD(lParam);
			height = HIWORD(lParam);

			glViewport(0,0,width,height);
			glMatrixMode(GL_PROJECTION);
			glLoadIdentity();

			gluPerspective(45.0f,(GLfloat)width /
(GLfloat)height,1.0f,1000.0f);

			glMatrixMode(GL_MODELVIEW);
			glLoadIdentity();
			return 0;
			break;
		}
		case WM_CLOSE:
		{
			wglMakeCurrent(hDC,NULL);
			wglDeleteContext(hRC);
			PostQuitMessage(0);
			return 0;
			break;
		}
		case WM_SYSCOMMAND:
		{
			switch (wParam)
			{
				case SC_SCREENSAVE:
				{
					return 0;
					break;
				}
				case SC_MONITORPOWER:
				{
					return 0;
					break;
				}
				default:
				{
					break;
				}
			}
			break;
		}
		case WM_KEYDOWN:
		{
			g_keys[wParam] = TRUE;
			return 0;
			break;
		}
		case WM_KEYUP:
		{
			g_keys[wParam] = FALSE;
			return 0;
			break;
		}
		default:
		{
			break;
		}
	}

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

int WINAPI WinMain(HINSTANCE hInstance,HINSTANCE hPrevInstance,LPSTR
lpCmdLine,int nShowCmd)
{
	RECT       wr;
	WNDCLASSEX wc;
	HWND       hWnd;
	bool       done;
	MSG        msg;

	int width  = 1280;
	int height = 800;
	int bits   = 32;

	wr.left   = (long)0;
	wr.right  = (long)width;
	wr.top    = (long)0;
	wr.bottom = (long)height;

	wc.cbSize        = sizeof(WNDCLASSEX);
	wc.style         = CS_HREDRAW | CS_VREDRAW;
	wc.lpfnWndProc   = WndProc;
	wc.cbClsExtra    = 0;
	wc.cbWndExtra    = 0;
	wc.hInstance     = hInstance;
	wc.hIcon         = LoadIcon(NULL,IDI_APPLICATION);
	wc.hCursor       = LoadCursor(NULL,IDC_ARROW);
	wc.hbrBackground = NULL;
	wc.lpszMenuName  = NULL;
	wc.lpszClassName = "OpenGLWindowClass";
	wc.hIconSm       = LoadIcon(NULL,IDI_APPLICATION);

	if (! RegisterClassEx(&wc))
	{
		return 0;
	}

	DEVMODE dmScreenSettings;
	memset(&dmScreenSettings,0,sizeof(dmScreenSettings));
	dmScreenSettings.dmSize       = sizeof(dmScreenSettings);
	dmScreenSettings.dmPelsWidth  = width;
	dmScreenSettings.dmPelsHeight = height;
	dmScreenSettings.dmBitsPerPel = bits;
	dmScreenSettings.dmFields     = DM_BITSPERPEL | DM_PELSWIDTH |
DM_PELSHEIGHT;

	if (ChangeDisplaySettings(&dmScreenSettings,CDS_FULLSCREEN) !=
DISP_CHANGE_SUCCESSFUL)
	{
		MessageBox(NULL,"Your current graphics card does not
support the selected screen resolution. The application will now
close.","APPLICATION ERROR",MB_OK | MB_ICONEXCLAMATION);
	}

	ShowCursor(FALSE);

	hWnd = CreateWindowEx(NULL,
						  "OpenGLWindowClass",
						  "OpenGL 1.2",
						  WS_POPUP |
						  WS_CLIPCHILDREN |
						  WS_CLIPSIBLINGS,
						  0,0,
						  wr.right  - wr.left,
						  wr.bottom - wr.top,
						  NULL,
						  NULL,
						  hInstance,
						  NULL);

	if (! hWnd)
	{
		return 0;
	}

	ShowWindow(hWnd,SW_SHOW);
	UpdateWindow(hWnd);

	done = false;

	while (! done)
	{
		PeekMessage(&msg,hWnd,NULL,NULL,PM_REMOVE);

		if (msg.message == WM_QUIT || g_keys[VK_ESCAPE])
		{
			done = true;
		}
		else
		{
			glClear(GL_COLOR_BUFFER_BIT |
GL_DEPTH_BUFFER_BIT);
			glLoadIdentity();

			/* game programming code goes here */

			SwapBuffers(g_hDC);

			TranslateMessage(&msg);
			DispatchMessage(&msg);
		}
	}

	ChangeDisplaySettings(NULL,0);
	ShowCursor(TRUE);

	return msg.wParam;
}

This .cpp source file compiles perfectly under Visual Studio 6.0, but as
I don?t have it anymore I?m unable to compile it now. Is there anyway I
can compile this source under Cygwin or will I have to rewrite it and
make use of the GLUI and GLUX libraries. If so could you explain this
process for me with compile/linker command line switches. Thanks for
your help.

Julian

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