Re: Segmentation fault using OpenGL

[Tron Thomas <tron dot thomas at verizon dot net>]

Here is the code:
#include <windows.h>
#include <GL/gl.h>
#include <GL/glu.h>
#include <math.h>
#include <il/il.h>

void SetupOpenGL();
void SetupRenderingContext();
void SetupTexture();
void SetProjection();

LRESULT WINAPI WinProc(HWND hWnd, UINT nMsg, WPARAM wParam, LPARAM lParam);
void Render();
void FreeResources();

HWND g_hWnd = NULL;
HGLRC g_hContext = NULL;

GLuint g_nTexture = 0;

int WINAPI WinMain(HINSTANCE, HINSTANCE, LPSTR, int)
{
   char szClassName[] = "TestIL";
   char szTitle[] = "Test DevIL";

   WNDCLASS wndClass;
   wndClass.style = CS_HREDRAW | CS_VREDRAW;
   wndClass.lpfnWndProc = reinterpret_cast<WNDPROC>(WinProc);
   wndClass.cbClsExtra = 0;
   wndClass.cbWndExtra = 0;
   wndClass.hInstance = ::GetModuleHandle(NULL);
   wndClass.hIcon = ::LoadIcon(NULL, IDI_APPLICATION);
   wndClass.hCursor = ::LoadCursor(NULL, IDC_ARROW);
   wndClass.hbrBackground = reinterpret_cast<HBRUSH>(COLOR_WINDOW + 1);
   wndClass.lpszMenuName = NULL;
   wndClass.lpszClassName = szClassName;

   if(!::RegisterClass(&wndClass)){
       return 0;
   }

   g_hWnd = ::CreateWindow(szClassName, szTitle, WS_OVERLAPPEDWINDOW,
       CW_USEDEFAULT, CW_USEDEFAULT, 640, 480, NULL, NULL, 
wndClass.hInstance,
       NULL);

   if(NULL == g_hWnd){
       return 0;
   }
  
   ::SetupOpenGL();

   ::SetupTexture();

   ::ShowWindow(g_hWnd, SW_SHOWNORMAL);
   ::UpdateWindow(g_hWnd);

   MSG msg;
   ZeroMemory(&msg, sizeof(msg));
   while(WM_QUIT != msg.message){
       if(::PeekMessage(&msg, NULL, 0, 0, PM_REMOVE)){
           ::TranslateMessage(&msg);
           ::DispatchMessage(&msg);
       }
       else{
           ::Render();
       }
   }

   ::FreeResources();

   ::UnregisterClass(szClassName, wndClass.hInstance);

   return static_cast<int>(msg.wParam);
}

void SetupOpenGL()
{
   ::SetupRenderingContext();

   ::SetProjection();

   ::glClearColor(0.0, 0.0, 0.0, 0.0);
   ::glEnable(GL_TEXTURE_2D);
}

void SetupRenderingContext()
{
   HDC hDC = ::GetDC(g_hWnd);

   PIXELFORMATDESCRIPTOR thePixelFormat;
   ZeroMemory(&thePixelFormat, sizeof(thePixelFormat));
   thePixelFormat.nSize = sizeof(thePixelFormat);
   thePixelFormat.nVersion = 1;
   thePixelFormat.dwFlags =
       PFD_DRAW_TO_WINDOW | PFD_SUPPORT_OPENGL | PFD_DOUBLEBUFFER;
   thePixelFormat.iPixelType = PFD_TYPE_RGBA;
   thePixelFormat.cColorBits = 16;
   thePixelFormat.cDepthBits = 16;
   thePixelFormat.iLayerType = PFD_MAIN_PLANE;

   int nFormat = ::ChoosePixelFormat(hDC, &thePixelFormat);
   ::SetPixelFormat(hDC, nFormat, &thePixelFormat);

   g_hContext = ::wglCreateContext(hDC);
   ::wglMakeCurrent(hDC, g_hContext);

   ::ReleaseDC(g_hWnd, hDC);
}

void SetupTexture()
{
   ::ilInit();

   ILuint nImage;
   ::ilGenImages(1, &nImage);
   ::ilBindImage(nImage);

   ::ilLoadImage("BARK4.JPG");

   ::glGenTextures(1, &g_nTexture);
   ::glBindTexture(GL_TEXTURE_2D, g_nTexture);

   ILint nWidth = ::ilGetInteger(IL_IMAGE_WIDTH);
   ILint nHeight = ::ilGetInteger(IL_IMAGE_HEIGHT);
   ::ilConvertImage(IL_RGBA, IL_UNSIGNED_BYTE);

   unsigned char* pData = ::ilGetData();
   ::glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, nWidth, nHeight, 0, GL_RGBA,
       GL_UNSIGNED_BYTE, pData);

   ::ilDeleteImages(1, &nImage);
   ::ilShutDown();

   ::glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);    
::glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
   // Specify how to filter the texture when it is stretch or shrunk
   ::glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
   ::glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
}

void SetProjection()
{
   RECT rect;
   ::GetClientRect(g_hWnd, &rect);
   int nWidth = rect.right- rect.left;
   int nHeight = rect.bottom - rect.top;

   ::glViewport(0, 0, nWidth, nHeight);

   ::glMatrixMode(GL_PROJECTION);
   ::glLoadIdentity();
   GLdouble dAspect = static_cast<GLdouble>(nWidth) / nHeight;
   ::gluPerspective(45.0, dAspect, 0.1, 100.0);

   ::gluLookAt(0.0, 0.0, -10.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);
}

LRESULT WINAPI WinProc
(
   HWND hWnd,
   UINT nMsg,
   WPARAM wParam,
   LPARAM lParam
)
{
   switch(nMsg){

       case WM_CREATE:
           return 0;

       case WM_SIZE:
           ::SetProjection();
           return 0;

       case WM_PAINT:
           ::Render();
           ::ValidateRect(hWnd, NULL);
           return 0;

       case WM_DESTROY:
           ::PostQuitMessage(0);
           return 0;
   }

   return ::DefWindowProc(hWnd, nMsg, wParam, lParam);
}         

void Render()
{
   HDC hDC = ::GetDC(g_hWnd);

   ::wglMakeCurrent(hDC, g_hContext);
   ::glClear(GL_COLOR_BUFFER_BIT);

   ::glMatrixMode(GL_MODELVIEW);
   ::glLoadIdentity();

   ::glBindTexture(GL_TEXTURE_2D, g_nTexture);
   ::glBegin(GL_QUADS);

   ::glTexCoord2f(0.0f, 1.0f);
   ::glVertex3f(-2.5f, 2.5f, 0.0f);

   ::glTexCoord2f(0.0f, 0.0f);
   ::glVertex3f(-2.5f, -2.5f, 0.0f);

   ::glTexCoord2f(1.0f, 0.0f);
   ::glVertex3f(2.5f, -2.5f, 0.0f);

   ::glTexCoord2f(1.0f, 1.0f);
   ::glVertex3f(2.5f, 2.5f, 0.0f);

   ::glEnd();

   ::SwapBuffers(hDC);

   ::ReleaseDC(g_hWnd, hDC);
}

void FreeResources()
{
   ::glBindTexture(GL_TEXTURE_2D, 0);

   ::glDeleteTextures(1, &g_nTexture);

   ::wglMakeCurrent(NULL, NULL);
   ::wglDeleteContext(g_hContext);   
}

It is trying to test the DevIL image library.


Reid Thompson wrote:

> posting the code might get someone interested in looking at the issue
>
> --
> thanks,
> reid
>
>
> -----Original Message-----
> From: Tron Thomas [mailto:tron dot thomas at verizon dot net] 
> Sent: Friday, March 21, 2003 3:57 PM
> To: cygwin at cygwin dot com
> Subject: Segmentation fault using OpenGL
>
>
> I have written a Windows OpenGL program which I can successfully build 
> and run using both the Borland and Microsoft compilers.  When I try to 
> run the same program after building it with the Cygwin GCC compiler, I 
> get a segmentation fault.  I'm very puzzled by this as the program works
>
> fine when built with other compilers.
>
> Does anyone have experieince with Cygwin and OpenGL and might know what 
> could be causing this problem?  The fault occur when I call glTexImage2D
>
> to create a 2 dimensional texture.
>
>
>
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>  



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