Create a openGl context (new version) - windows

Question

i was trying to create a win32 that could handle openGl ( the new version). It doesnt seem to be mutch info about win32/opengl(new version, most examples are in the old version ) on the net.
The few info that i found lead me to this code. But it doesnt display the square.
Does any one know if this is the proper way to do it, and if so what is wrong with it(it doesnt display square).
Ps. i know that the part of the vbo, vao ,shader.. are working cause i already did that with sdl.
Thank a lot.... :)
Here is the Code:
#include <iostream>
#include <windows.h>
#include <stdlib.h>
#include <string.h>
#include <tchar.h>
#include <glew.h>
#include <wglew.h>
using namespace std;
void display(){
// display square
}
bool progRun = false;
//-------------------------------------------------------------------
//#####################################################################
//-------------------------------------------------------------------
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
int CALLBACK WinMain(
HINSTANCE hInstance,
HINSTANCE hPrevInstance,
LPSTR lpCmdLine,
int nCmdShow
){
WNDCLASSEX wcex;
///////////////////////////LOAD GLEW///////////////////////////////////////////
//////////////////////////////////////////////////////////////////////
wcex.cbSize = sizeof(WNDCLASSEX);
wcex.style = CS_HREDRAW | CS_VREDRAW | CS_OWNDC | CS_DBLCLKS ;
wcex.lpfnWndProc = WndProc;
wcex.cbClsExtra = 0;
wcex.cbWndExtra = 0;
wcex.hInstance = hInstance;
wcex.hIcon = LoadIcon(NULL, IDI_APPLICATION);
wcex.hCursor = LoadCursor(NULL, IDC_ARROW);
wcex.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
wcex.lpszMenuName = NULL;
wcex.lpszClassName = szWindowClass;
wcex.hIconSm = NULL;
if (!RegisterClassEx(&wcex))
{
MessageBox(NULL,"RegisterClassEx","ERROR",MB_OK|MB_ICONSTOP);
return 0;
}
HWND hWnd = CreateWindow(
szWindowClass,
szTitle,
WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, CW_USEDEFAULT,
500, 500,
NULL,
NULL,
hInstance,
NULL
);
if (!hWnd)
{
MessageBox(NULL,"hWnd","ERROR",MB_OK|MB_ICONSTOP);
return -1;
}
HDC hdc = GetDC(hWnd);
PIXELFORMATDESCRIPTOR pfd;
memset(&pfd, 0, sizeof(PIXELFORMATDESCRIPTOR));
pfd.nSize= sizeof(PIXELFORMATDESCRIPTOR);
pfd.nVersion = 1;
pfd.dwFlags = PFD_DOUBLEBUFFER | PFD_SUPPORT_OPENGL | PFD_DRAW_TO_WINDOW;
pfd.iPixelType = PFD_TYPE_RGBA;
pfd.cColorBits = 32;
pfd.cDepthBits = 32;
pfd.iLayerType = PFD_MAIN_PLANE;
int pf = ChoosePixelFormat(hdc, &pfd);
if(pf == 0){
MessageBox(NULL,"pf == 0","ERROR",MB_OK|MB_ICONSTOP);
return -1;
}
if(SetPixelFormat(hdc, pf, &pfd) == false){
MessageBox(NULL,"SetPixelFormat","ERROR",MB_OK|MB_ICONSTOP);
return -1;
}
DescribePixelFormat(hdc, pf, sizeof(PIXELFORMATDESCRIPTOR), &pfd);
HGLRC hrc = wglCreateContext(hdc);
wglMakeCurrent(hdc, hrc);
glewExperimental = true;
if(glewInit() != GLEW_OK){
MessageBox(NULL, "Couldn't initialize GLEW!", "Fatal Error", MB_ICONERROR);
}
wglMakeCurrent(NULL, NULL);
ReleaseDC(hWnd, hdc);
wglDeleteContext(hrc);
DestroyWindow(hWnd);
///////////////////////////////TO_CREATE A OPENGL CONTEXT WITH LATER VERSION///////////////////////////////////////
//////////////////////////////////////////////////////////////////////
#define iMajorVersion 3
#define iMinorVersion 1
hWnd = CreateWindow(
szWindowClass,
szTitle,
WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, CW_USEDEFAULT,
500, 500,
NULL,
NULL,
hInstance,
NULL
);
if (!hWnd)
{
MessageBox(NULL,"hWnd","ERROR",MB_OK|MB_ICONSTOP);
return -1;
}
hdc = GetDC(hWnd);
bool bError = false;
if(iMajorVersion <= 2)
{
cout << "version 2" <<endl;
memset(&pfd, 0, sizeof(PIXELFORMATDESCRIPTOR));
pfd.nSize = sizeof(PIXELFORMATDESCRIPTOR);
pfd.nVersion = 1;
pfd.dwFlags = PFD_DOUBLEBUFFER | PFD_SUPPORT_OPENGL | PFD_DRAW_TO_WINDOW;
pfd.iPixelType = PFD_TYPE_RGBA;
pfd.cColorBits = 32;
pfd.cDepthBits = 32;
pfd.iLayerType = PFD_MAIN_PLANE;
pf = ChoosePixelFormat(hdc, &pfd);
if (pf == 0){
MessageBox(NULL,"pf == 0","ERROR",MB_OK|MB_ICONSTOP);
return false;
}
if(!SetPixelFormat(hdc, pf, &pfd)){
MessageBox(NULL,"SetPixelFormat 1","ERROR",MB_OK|MB_ICONSTOP);
return false;
}
// Create the old style context (OpenGL 2.1 and before)
hrc = wglCreateContext(hdc);
if(hrc)wglMakeCurrent(hdc, hrc);
else bError = true;
}
else if(WGLEW_ARB_create_context && WGLEW_ARB_pixel_format)
{
cout << "version 3" <<endl;
const int iPixelFormatAttribList[] =
{
WGL_DRAW_TO_WINDOW_ARB, GL_TRUE,
WGL_SUPPORT_OPENGL_ARB, GL_TRUE,
WGL_DOUBLE_BUFFER_ARB, GL_TRUE,
WGL_PIXEL_TYPE_ARB, WGL_TYPE_RGBA_ARB,
WGL_COLOR_BITS_ARB, 32,
WGL_DEPTH_BITS_ARB, 24,
WGL_STENCIL_BITS_ARB, 8,
0 // End of attributes list
};
int iContextAttribs[] =
{
WGL_CONTEXT_MAJOR_VERSION_ARB, iMajorVersion,
WGL_CONTEXT_MINOR_VERSION_ARB, iMinorVersion,
WGL_CONTEXT_FLAGS_ARB, WGL_CONTEXT_FORWARD_COMPATIBLE_BIT_ARB,
0 // End of attributes list
};
int iNumFormats;
if(!wglChoosePixelFormatARB(hdc, iPixelFormatAttribList, NULL, 1, &pf, (UINT*)&iNumFormats)){
MessageBox(NULL,"wglChoosePixelFormatARB","ERROR",MB_OK|MB_ICONSTOP);
return 0;
}
// PFD seems to be only redundant parameter now
if(!SetPixelFormat(hdc, pf, &pfd)){
MessageBox(NULL,"SetPixelFormat 2","ERROR",MB_OK|MB_ICONSTOP);
return false;
}
hrc = wglCreateContextAttribsARB(hdc, 0, iContextAttribs);
// If everything went OK
if(hrc) wglMakeCurrent(hdc, hrc);
else bError = true;
//glewInit();
}else{
bError = true;
}
if(bError)
{
// Generate error messages
char sErrorMessage[255], sErrorTitle[255];
sprintf(sErrorMessage, "OpenGL %d.%d is not supported! Please download latest GPU drivers!", iMajorVersion, iMinorVersion);
sprintf(sErrorTitle, "OpenGL %d.%d Not Supported", iMajorVersion, iMinorVersion);
MessageBox(hWnd, sErrorMessage, sErrorTitle, MB_ICONINFORMATION);
return false;
}
//////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////
MSG msg;
progRun = true;
ShowWindow(hWnd,SW_SHOW);
UpdateWindow(hWnd);
//-----------Setup shader and objects
setupShader();
setupObject();
//-------
glClearDepth(1.0f); // Depth Buffer Setup
glEnable(GL_DEPTH_TEST); // Enables Depth Testing
glDepthFunc(GL_LEQUAL);
glClearColor(1,0,0,1);
while(progRun){
if (PeekMessage (&msg, NULL, 0, 0, PM_REMOVE)){
TranslateMessage(&msg);
DispatchMessage(&msg);
}
glClear(GL_COLOR_BUFFER_BIT);
display();
SwapBuffers(hdc);
}
return (int) msg.wParam;
}
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
PAINTSTRUCT ps;
HDC hdc;
switch (message){
case WM_ERASEBKGND:
display();
break;
case WM_PAINT:
BeginPaint(hWnd, &ps);
EndPaint(hWnd, &ps);
break;
case WM_SIZE:
glViewport(0, 0, LOWORD(lParam), HIWORD(lParam));
break;
case WM_DESTROY:
PostQuitMessage(0);
progRun = false;
break;
default:
return DefWindowProc(hWnd, message, wParam, lParam);
break;
}
return 0;
}

Answer 1

If you use wglCreateContext then you get old context (<= 2.1).
You need wglCreateContextAttribsARB instead. But this first you need to get a pointer to this function, which requires using a context.
So:
Create a normal, old context, and set it current. Any pixelformat is
valid.
Get the pointers to wglCreateContextAttribsARB (and perhaps also for wglChoosePixelFormatARB), by using
wglGetProcAddress. Now you can delete the old context.
Set the pixelformat you wish and the context attributes you wish.
Create the context by that pointer.
Useful links from the wiki OpenGL are here and here and here