// This is a Win32 program,it simply demonstrates how to draw lines in a window
// Basicaly,you draw a line by clicking somehwere on the window and while the button
// is pressed,you simply move the mouse to a new position and then release the button
// @author: Gonzales Cenelia
// homepage: www.ai-search.4t.com
#include <windows.h>
#include <windows.h>

LRESULT CALLBACK WndProc(HWND hWnd, UINT Msg, WPARAM wParam, LPARAM lParam);

int WINAPI WinMain( HINSTANCE hInstance,
				    HINSTANCE hPrevInstance,
					LPSTR lpCmdLine,
					int nShowCmd) {
	HWND hWnd;
	MSG msg;
	WNDCLASSEX wc;
	wc.cbSize = sizeof(WNDCLASSEX);
	wc.cbClsExtra = 0;
	wc.cbWndExtra = 0;
	wc.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
	wc.hCursor = LoadCursor(hInstance, IDC_ARROW);
	wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
	wc.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
	wc.hInstance = hInstance;
	wc.lpfnWndProc = WndProc;
	wc.lpszClassName = "DrawingApp1";
	wc.lpszMenuName = NULL;
	wc.style = CS_HREDRAW | CS_VREDRAW;

    // registering the class
	if(!RegisterClassEx(&wc)) {
		MessageBox(NULL, "Error while registering window", "OPenGL Tutorial", MB_OK );
		return 1;
	}

	// creating the window
	hWnd = CreateWindowEx(
		WS_EX_OVERLAPPEDWINDOW,
		"DrawingApp1",
		"Win32 DrawingApp",
		WS_OVERLAPPEDWINDOW,
		150,
		100,
		640,
		480,
		NULL,
		NULL,
		hInstance,
		NULL );

	if(!hWnd) {
		MessageBox(NULL, "Error while creating window", "OpenGL Tutorial", MB_OK );
		return 1;
	}

	ShowWindow(hWnd, SW_SHOW);
	UpdateWindow(hWnd);

	while( GetMessage( &msg, 0, 0, 0 ) > 0 ) {
		TranslateMessage(&msg);
		DispatchMessage(&msg);
	}

	return msg.wParam;
}

LRESULT CALLBACK WndProc(HWND hWnd, UINT Msg, WPARAM wParam, LPARAM lParam) {
	static BOOL bButtonClicked = 0;
	static int X = 0, Y = 0;
	HDC hDC = NULL;

	switch(Msg) {
	case WM_LBUTTONDOWN:
		bButtonClicked = 1;
		X = LOWORD(lParam);
		Y = HIWORD(lParam);
		break;
	case WM_LBUTTONUP:
		if(bButtonClicked) {
			hDC = GetDC(hWnd);
			MoveToEx( hDC, X, Y, NULL );
			X = LOWORD(lParam);
			Y = HIWORD(lParam);
			LineTo( hDC, X, Y );
			bButtonClicked = 0;
			ReleaseDC( hWnd, hDC );
		}
		break;
	case WM_MOUSEMOVE:
		break;
	case WM_CLOSE:
		DestroyWindow(hWnd);
		break;
	case WM_DESTROY:
		PostQuitMessage(0);
		break;
	}
	return DefWindowProc(hWnd, Msg, wParam, lParam);
}