Template for win32 OpenGL app.

win32_opengl.cpp

#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <gl/GL.h>

const bool IS_EVENT_DRIVEN = true; // TRUE: Wait for update event. FALSE: 30 fps
bool isRunning = true;
bool needsRefresh = true;

// Window Callback
LRESULT CALLBACK WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);

// Define Pixel format
PIXELFORMATDESCRIPTOR defaultPixelFormatDescriptor = { 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, 24, 0, 0, PFD_MAIN_PLANE };

// Create window class
const wchar_t* WNDCLASSNAME = L"TEST_OPENGL_WNDCLASSEX";
const WNDCLASSEX WINDOW_CLASS_TEMPLATE = { sizeof(WNDCLASSEX), CS_OWNDC, &WndProc, 0, 0, GetModuleHandle(NULL), 0, LoadCursor(NULL , IDC_ARROW), 0, 0, WNDCLASSNAME };
ATOM windowClassAtom = RegisterClassEx(&WINDOW_CLASS_TEMPLATE);

// Create window
HWND hWnd = CreateWindowEx(WS_EX_APPWINDOW, WNDCLASSNAME, L"OpenGL Window", WS_OVERLAPPEDWINDOW | WS_CLIPSIBLINGS | WS_CLIPCHILDREN, CW_USEDEFAULT, CW_USEDEFAULT, 640, 480, 0, 0, GetModuleHandle(NULL), 0);

// Set pixel format
HDC hDC = GetDC(hWnd);
int pixelFormat = ChoosePixelFormat(hDC, &defaultPixelFormatDescriptor);
BOOL result = SetPixelFormat(hDC, pixelFormat, &defaultPixelFormatDescriptor);

// Create Rendering context
HGLRC hRC = wglCreateContext(hDC);

// Get WindowSize
unsigned int GetWindowWidth(HWND hWnd) { RECT rect; GetClientRect(hWnd, &rect); return rect.right - rect.left; }
unsigned int GetWindowHeight(HWND hWnd) { RECT rect; GetClientRect(hWnd, &rect); return rect.bottom - rect.top; }

// Paint
void Paint()
{
    // Set the viewport in case the window size has changed
    glViewport(0,0, GetWindowWidth(hWnd), GetWindowHeight(hWnd));

    glClearDepth(1.0);
    glClearColor(0.5, 0.5, 0.5, 0.0);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    // Set up the drawing surface
    glLoadIdentity();
    glOrtho(0, GetWindowWidth(hWnd), GetWindowHeight(hWnd), 0, 1, 0);

    // OpenGL drawing goes here!
    glColor3d(1.0, 1.0, 1.0);
    glBegin(GL_LINES);
        glVertex3f(0, 0, 0);
        glVertex3f(100, 100, 0);
    glEnd();

    // Swap buffers
    SwapBuffers(hDC);
    needsRefresh = false;
}

LRESULT CALLBACK WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam) 
{ 
    switch (msg) { 
    case WM_PAINT:      needsRefresh = true; break;
    case WM_SIZE:       needsRefresh = true; break;
    case WM_CLOSE:      isRunning = false; break;
    case WM_KEYDOWN:    isRunning = !(wParam == VK_ESCAPE); break;
    } 
    
    return DefWindowProc(hWnd, msg, wParam, lParam); 
}


// Main
int main()
{
    ShowWindow(hWnd, SW_SHOW);
    wglMakeCurrent(hDC, hRC);

    while(isRunning == true)
    {
        if (IS_EVENT_DRIVEN) WaitMessage();
        else Sleep(1000/30);

        // Handle Events
        MSG msg;
        if (PeekMessage(&msg, hWnd, 0, 0, PM_REMOVE))
            DispatchMessage(&msg);

        // Update as needed
        if (!IS_EVENT_DRIVEN || needsRefresh) 
            Paint();
    }

    wglDeleteContext(hRC);
    ReleaseDC(hWnd, hDC);
    DestroyWindow(hWnd);
    UnregisterClass(WNDCLASSNAME, GetModuleHandle(0));
}