opengl-win32.cpp

opengl-win32.cpp

// Opengltest01.cpp : Defines the entry point for the application.
//

#include "stdafx.h"
#include <windows.h>

#define GLEW_STATIC

#include <GL/glew.h>
#include <GL/gl.h>
#include <vector>
#include <stdexcept>
#include "Opengltest01.h"

#pragma comment(lib, "opengl32.lib")
#pragma comment(lib, "glew32s.lib")

#define MAX_LOADSTRING 100

// Global Variables:
HINSTANCE hInst;                                // current instance
WCHAR szTitle[MAX_LOADSTRING];                  // The title bar text
WCHAR szWindowClass[MAX_LOADSTRING];            // the main window class name

// Forward declarations of functions included in this code module:
ATOM                MyRegisterClass(HINSTANCE hInstance);
BOOL                InitInstance(HINSTANCE, int);
LRESULT CALLBACK    WndProc(HWND, UINT, WPARAM, LPARAM);
INT_PTR CALLBACK    About(HWND, UINT, WPARAM, LPARAM);

HWND hOGLWnd = NULL;
HGLRC hOGLRenderContext = NULL;

int APIENTRY wWinMain(_In_ HINSTANCE hInstance,
                     _In_opt_ HINSTANCE hPrevInstance,
                     _In_ LPWSTR    lpCmdLine,
                     _In_ int       nCmdShow)
{
    UNREFERENCED_PARAMETER(hPrevInstance);
    UNREFERENCED_PARAMETER(lpCmdLine);

    // TODO: Place code here.

    // Initialize global strings
    LoadStringW(hInstance, IDS_APP_TITLE, szTitle, MAX_LOADSTRING);
    LoadStringW(hInstance, IDC_OPENGLTEST01, szWindowClass, MAX_LOADSTRING);
    MyRegisterClass(hInstance);

    // Perform application initialization:
    if (!InitInstance (hInstance, nCmdShow))
    {
        return FALSE;
    }

	if (glewInit() != GLEW_OK)
		throw std::runtime_error("error initializing glew");

	static const std::vector<float> varray
	{
		-0.707f, -0.75f,    1.0f, 0.0f, 0.0f, 1.0f,
		0.707f, -0.75f,    1.0f, 1.0f, 0.0f, 1.0f,
		0.0f,    0.75f,    0.0f, 0.0f, 1.0f, 1.0f
	};

	GLuint vbo;
	glGenBuffers(1, &vbo);
	glBindBuffer(GL_ARRAY_BUFFER, vbo);
	glBufferData(GL_ARRAY_BUFFER, varray.size() * sizeof(*varray.data()), varray.data(), GL_STATIC_DRAW);

	GLuint vao;
	glGenVertexArrays(1, &vao);
	glBindVertexArray(vao);
	glVertexPointer(2, GL_FLOAT, 6 * sizeof(*varray.data()), 0);
	glEnableClientState(GL_VERTEX_ARRAY);
	glColorPointer(4, GL_FLOAT, 6 * sizeof(*varray.data()), (void*)(2 * sizeof(*varray.data())));
	glEnableClientState(GL_COLOR_ARRAY);
	glBindBuffer(GL_ARRAY_BUFFER, 0);

    HACCEL hAccelTable = LoadAccelerators(hInstance, MAKEINTRESOURCE(IDC_OPENGLTEST01));

    MSG msg;

    // Main message loop:
    while (GetMessage(&msg, nullptr, 0, 0))
    {
        if (!TranslateAccelerator(msg.hwnd, hAccelTable, &msg))
        {
            TranslateMessage(&msg);
            DispatchMessage(&msg);
        }
    }

    return (int) msg.wParam;
}



//
//  FUNCTION: MyRegisterClass()
//
//  PURPOSE: Registers the window class.
//
ATOM MyRegisterClass(HINSTANCE hInstance)
{
    WNDCLASSEXW wcex;

    wcex.cbSize = sizeof(WNDCLASSEX);

    wcex.style          = CS_HREDRAW | CS_VREDRAW;
    wcex.lpfnWndProc    = WndProc;
    wcex.cbClsExtra     = 0;
    wcex.cbWndExtra     = 0;
    wcex.hInstance      = hInstance;
    wcex.hIcon          = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_OPENGLTEST01));
    wcex.hCursor        = LoadCursor(nullptr, IDC_ARROW);
    wcex.hbrBackground  = (HBRUSH)(COLOR_WINDOW+1);
    wcex.lpszMenuName   = MAKEINTRESOURCEW(IDC_OPENGLTEST01);
    wcex.lpszClassName  = szWindowClass;
    wcex.hIconSm        = LoadIcon(wcex.hInstance, MAKEINTRESOURCE(IDI_SMALL));

    return RegisterClassExW(&wcex);
}

//
//   FUNCTION: InitInstance(HINSTANCE, int)
//
//   PURPOSE: Saves instance handle and creates main window
//
//   COMMENTS:
//
//        In this function, we save the instance handle in a global variable and
//        create and display the main program window.
//
BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
{
   hInst = hInstance; // Store instance handle in our global variable

   hOGLWnd = CreateWindowW(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW,
      CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, nullptr, nullptr, hInstance, nullptr);

   if (!hOGLWnd)
   {
      return FALSE;
   }

   // Get device context
   HDC hDC = ::GetDC(hOGLWnd);

   // Create OpenGL context
   DWORD pixelFormatFlags = PFD_SUPPORT_OPENGL | PFD_SUPPORT_COMPOSITION | PFD_GENERIC_ACCELERATED | PFD_DRAW_TO_WINDOW | PFD_DOUBLEBUFFER;
   PIXELFORMATDESCRIPTOR pfd =
   {
	   sizeof(PIXELFORMATDESCRIPTOR),
	   1,
	   pixelFormatFlags,         //Flags
	   PFD_TYPE_RGBA,            //The kind of framebuffer. RGBA or palette.
	   32,                       //Colordepth of the framebuffer.
	   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	   24,                       //Number of bits for the depthbuffer
	   8,                        //Number of bits for the stencilbuffer
	   0,                        //Number of Aux buffers in the framebuffer.
	   PFD_MAIN_PLANE,
	   0, 0, 0, 0
   };
   int pixelFormat = ::ChoosePixelFormat(hDC, &pfd);
   ::SetPixelFormat(hDC, pixelFormat, &pfd);
   hOGLRenderContext = ::wglCreateContext(hDC);

   // make OpenGL context the current context
   ::wglMakeCurrent(hDC, hOGLRenderContext);

   // release device context
   ::ReleaseDC(hOGLWnd, hDC);

   // show the window
   ::ShowWindow(hOGLWnd, SW_SHOWDEFAULT);

   //ShowWindow(hWnd, nCmdShow);
   //UpdateWindow(hWnd);

   return TRUE;
}

void display(void)
{
	RECT clientRect;
	::GetClientRect(hOGLWnd, &clientRect);
	glViewport(0, 0, clientRect.right - clientRect.left, clientRect.bottom - clientRect.top);
	glClearColor(0.0f, 0.0f, 0.0f, 0.0f);

	glDrawArrays(GL_TRIANGLES, 0, 3);

	// swap buffers
	HDC hDC = ::GetDC(hOGLWnd);
	::SwapBuffers(hDC);
	::ReleaseDC(hOGLWnd, hDC);

	// create message WM_ERASEBKGND
	::InvalidateRect(hOGLWnd, NULL, TRUE);
}

//
//  FUNCTION: WndProc(HWND, UINT, WPARAM, LPARAM)
//
//  PURPOSE:  Processes messages for the main window.
//
//  WM_COMMAND  - process the application menu
//  WM_PAINT    - Paint the main window
//  WM_DESTROY  - post a quit message and return
//
//
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch (message)
    {
    case WM_COMMAND:
        {
            int wmId = LOWORD(wParam);
            // Parse the menu selections:
            switch (wmId)
            {
            case IDM_ABOUT:
                DialogBox(hInst, MAKEINTRESOURCE(IDD_ABOUTBOX), hWnd, About);
                break;
            case IDM_EXIT:
                DestroyWindow(hWnd);
                break;
            default:
                return DefWindowProc(hWnd, message, wParam, lParam);
            }
        }
        break;
    case WM_PAINT:
        {
            PAINTSTRUCT ps;
            HDC hdc = BeginPaint(hWnd, &ps);
            // TODO: Add any drawing code that uses hdc here...
            EndPaint(hWnd, &ps);
        }
        break;
    case WM_DESTROY:
        PostQuitMessage(0);
        break;
	case WM_ERASEBKGND:
		display();
		break;
    default:
        return DefWindowProc(hWnd, message, wParam, lParam);
    }
    return 0;
}

// Message handler for about box.
INT_PTR CALLBACK About(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam)
{
    UNREFERENCED_PARAMETER(lParam);
    switch (message)
    {
    case WM_INITDIALOG:
        return (INT_PTR)TRUE;

    case WM_COMMAND:
        if (LOWORD(wParam) == IDOK || LOWORD(wParam) == IDCANCEL)
        {
            EndDialog(hDlg, LOWORD(wParam));
            return (INT_PTR)TRUE;
        }
        break;
    }
    return (INT_PTR)FALSE;
}