/*
       OpenGL描画テスト

    2001/ 4/10　宍戸　輝光
*/

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

LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);

HINSTANCE hInst;
HWND hwMain;
HGLRC hRC;

int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
                    PSTR szCmdLine, int iCmdShow){

	MSG  msg;
	WNDCLASS wndclass ;

	hInst=hInstance; /* プロセスのハンドルを保存 */

	wndclass.style         = CS_HREDRAW | CS_VREDRAW;
	wndclass.lpfnWndProc   = WndProc;
	wndclass.cbClsExtra    = 0;
	wndclass.cbWndExtra    = 0;
	wndclass.hInstance     = hInstance;
	wndclass.hIcon         = LoadIcon(NULL,IDI_APPLICATION);
	wndclass.hCursor       = LoadCursor(NULL,IDC_ARROW);
	wndclass.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
	wndclass.lpszMenuName  = NULL;
	wndclass.lpszClassName = "CWindow";

	RegisterClass(&wndclass);

	hwMain=CreateWindow ("CWindow","OpenGL表示テスト",WS_OVERLAPPEDWINDOW,
               CW_USEDEFAULT,CW_USEDEFAULT,320,240,
               NULL,NULL,hInstance,NULL);

	ShowWindow(hwMain,iCmdShow); /* ウインドウを表示 */
	UpdateWindow (hwMain);        /* 再描画 */

	while (GetMessage(&msg,NULL,0,0)) { /* メッセージループ */

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

	}

	return msg.wParam ;

}

LRESULT CALLBACK WndProc (HWND hwnd, UINT iMsg, WPARAM wParam, LPARAM lParam) {

	static HDC WinDC;
	int pixelFormat;

	PIXELFORMATDESCRIPTOR pfd = { 
		sizeof(PIXELFORMATDESCRIPTOR),   // size of this pfd 
		1,                     // version number 
		PFD_DRAW_TO_WINDOW |   // support window 
		PFD_SUPPORT_OPENGL |   // support OpenGL 
		PFD_DOUBLEBUFFER,      // double buffered 
		PFD_TYPE_RGBA,         // RGBA type 
		24,                    // 24-bit color depth 
		0, 0, 0, 0, 0, 0,      // color bits ignored 
		0,                     // no alpha buffer 
		0,                     // shift bit ignored 
		0,                     // no accumulation buffer 
		0, 0, 0, 0,            // accum bits ignored 
		32,                    // 32-bit z-buffer 
		0,                     // no stencil buffer 
		0,                     // no auxiliary buffer 
		PFD_MAIN_PLANE,        // main layer 
		0,                     // reserved 
		0, 0, 0                // layer masks ignored 
	}; 

	switch (iMsg) {

	case WM_CREATE:

		WinDC=GetDC(hwnd);

		pixelFormat = ChoosePixelFormat(WinDC,&pfd);
		SetPixelFormat(WinDC,pixelFormat,&pfd);

		hRC=wglCreateContext(WinDC);
		wglMakeCurrent(WinDC,hRC);

		return 0;

	case WM_PAINT:

		glClearColor(0.0, 0.4, 0.0, 0.0);
		glClear(GL_COLOR_BUFFER_BIT);

		glRectd(-0.5,-0.5,0.5,0.5);

		glFlush();
		SwapBuffers(WinDC);

		return 0;

	case WM_DESTROY :

		wglMakeCurrent(WinDC, 0);
		wglDeleteContext(hRC);

		PostQuitMessage(0);
		return 0;

	}

	return DefWindowProc (hwnd, iMsg, wParam, lParam) ;

}