Category: Memoirs of James Pate Williams Jr

// NASAGeopotentialAltitude.cpp : Defines the entry point for the application.
// Copyright (c) Friday, May 23, 2025 by James Pate Williams, Jr.
// BA, BS, MSWE, PhD All Applicable Rights Reserved

#include "stdafx.h"
#include "GeopotentialAltitude.h"
#include "Integration1d.h"
#include "NASAGeopotentialAltitude.h"
#include <math.h>
#include <stdio.h>
#include <tchar.h>
#include <string.h>
#include <vector>
using namespace std;

#define MAX_LOADSTRING 100

// Global Variables:
HINSTANCE hInst;								// current instance
TCHAR szTitle[MAX_LOADSTRING];					// The title bar text
TCHAR 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);

int APIENTRY _tWinMain(HINSTANCE hInstance,
                     HINSTANCE hPrevInstance,
                     LPTSTR    lpCmdLine,
                     int       nCmdShow)
{
	UNREFERENCED_PARAMETER(hPrevInstance);
	UNREFERENCED_PARAMETER(lpCmdLine);

 	// TODO: Place code here.
	MSG msg;
	HACCEL hAccelTable;

	// Initialize global strings
	LoadString(hInstance, IDS_APP_TITLE, szTitle, MAX_LOADSTRING);
	LoadString(hInstance, IDC_NASAGEOPOTENTIALALTITUDE, szWindowClass, MAX_LOADSTRING);
	MyRegisterClass(hInstance);

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

	hAccelTable = LoadAccelerators(hInstance, MAKEINTRESOURCE(IDC_NASAGEOPOTENTIALALTITUDE));

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

	return (int) msg.wParam;
}

//
//  FUNCTION: MyRegisterClass()
//
//  PURPOSE: Registers the window class.
//
//  COMMENTS:
//
//    This function and its usage are only necessary if you want this code
//    to be compatible with Win32 systems prior to the 'RegisterClassEx'
//    function that was added to Windows 95. It is important to call this function
//    so that the application will get 'well formed' small icons associated
//    with it.
//
ATOM MyRegisterClass(HINSTANCE hInstance)
{
	WNDCLASSEX 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_NASAGEOPOTENTIALALTITUDE));
	wcex.hCursor		= LoadCursor(NULL, IDC_ARROW);
	wcex.hbrBackground	= (HBRUSH)(COLOR_WINDOW+1);
	wcex.lpszMenuName	= MAKEINTRESOURCE(IDC_NASAGEOPOTENTIALALTITUDE);
	wcex.lpszClassName	= szWindowClass;
	wcex.hIconSm		= LoadIcon(wcex.hInstance, MAKEINTRESOURCE(IDI_SMALL));

	return RegisterClassEx(&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)
{
   HWND hWnd;

   hInst = hInstance; // Store instance handle in our global variable

   hWnd = CreateWindow(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW,
      CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, NULL, NULL, hInstance, NULL);

   if (!hWnd)
   {
      return FALSE;
   }

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

   return TRUE;
}

//
//  FUNCTION: WndProc(HWND, UINT, WPARAM, LPARAM)
//
//  PURPOSE:  Processes messages for the main window.
//
//  WM_CREATE   - creates a multiple line edit control
//  WM_COMMAND	- process the application menu
//  WM_PAINT	- Paint the main window
//  WM_DESTROY	- post a quit message and return
//
//

#define ID_EDITCHILD 100
char asciiData[16384];
char asciiLine[16384];
TCHAR textData[16384];

void ConvertCharToTChar(const char* charArray, TCHAR* tcharArray, size_t tcharSize) {
#ifdef _UNICODE
	MultiByteToWideChar(CP_ACP, 0, charArray, -1, tcharArray, (int)tcharSize);
#else
    strncpy(tcharArray, charArray, tcharSize - 1);
    tcharArray[tcharSize - 1] = '\0'; // Ensure null-termination
#endif
}

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
	int wmId, wmEvent;
	PAINTSTRUCT ps;
	HDC hdc;
	static HWND hwndEdit;
	static double zArray[] = {
		80000, 80500, 81000, 81500, 82000, 82500,
		83000, 83500, 84000, 84500, 85000, 85500 };
	static vector<double> z(12);
	static vector<double> potential1(12);
	static vector<double> potential2(12);
	static vector<double> potential3(12);
	static vector<double> potential4(12);
	size_t numberPoints = z.size();

	for (size_t i = 0; i < z.size(); i++)
	{
		z[i] = zArray[i];
	}

	switch (message)
	{
	case WM_CREATE:
	GeopotentialAltitude::GaussianLegendre(
		numberPoints, z, potential1);
	GeopotentialAltitude::SimpsonsRule(
		numberPoints, z, potential2);
	GeopotentialAltitude::TrapezoidalRule(
		numberPoints, z, potential3);

	strcpy_s(asciiData, 16384, "H\tZ1\tZ2\tZ3\tg\r\n");

	for (size_t i = 0; i < z.size(); i++)
	{
		double zi = z[i];
		double p1 = potential1[i];
		double p2 = potential2[i];
		double p3 = potential3[i];
		double g = g0 * pow(r0 / (r0 + p1), 2.0);

		sprintf_s(
			asciiLine, 16384,
			"%5.0lf\t%5.1lf\t%5.1lf\t%5.1lf\t%7.5lf\r\n",
			zi, p1, p2, p3, g);
		strcat_s(asciiData, 16384, asciiLine);
	}

	strcat_s(asciiData, "H Geopotential Altitude\r\n");
	strcat_s(asciiData, "Z1 Geopotential Gauss-Legendre 128 Steps\r\n");
	strcat_s(asciiData, "Z2 Geopotential Simpson's Rule 256 Steps\r\n");
	strcat_s(asciiData, "Z3 Geopotential Trapezoidal Rule 512 Steps\r\n");
	strcat_s(asciiData, "g gravitational acceleration in m/s/s\r\n");
	strcat_s(asciiData, "https://ntrs.nasa.gov/api/citations/19770009539/downloads/19770009539.pdf\r\n");
	strcat_s(asciiData, "See Table 8. Page 9\r\n");

	ConvertCharToTChar(asciiData, textData, sizeof(textData));

	// https://learn.microsoft.com/en-us/windows/win32/controls/use-a-multiline-edit-control

	hwndEdit = CreateWindowEx(
		0, L"EDIT",   // predefined class 
        NULL,         // no window title 
        WS_CHILD | WS_VISIBLE | WS_VSCROLL | 
        ES_LEFT | ES_MULTILINE | ES_AUTOVSCROLL, 
        0, 0, 0, 0,   // set size in WM_SIZE message 
        hWnd,         // parent window 
        (HMENU) ID_EDITCHILD,   // edit control ID 
		hInst,
        /*(HINSTANCE) GetWindowLongPtr(hWnd, GWLP_HINSTANCE),*/ 
		NULL);        // pointer not needed 
    // Add text to the window. 
	SendMessage(hwndEdit, WM_SETTEXT, 0, (LPARAM) textData); 
    return 0; 
	case WM_COMMAND:
		wmId    = LOWORD(wParam);
		wmEvent = HIWORD(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:
		hdc = BeginPaint(hWnd, &ps);
		// TODO: Add any drawing code here...
		EndPaint(hWnd, &ps);
		break;
	case WM_SIZE: 
            // Make the edit control the size of the window's client area. 
		MoveWindow(hwndEdit, 
			0, 0,                  // starting x- and y-coordinates 
            LOWORD(lParam),        // width of client area 
            HIWORD(lParam),        // height of client area 
            TRUE);                 // repaint window 
        return 0; 
	case WM_DESTROY:
		PostQuitMessage(0);
		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;
}