Microsoft Multimedia Jumpstart 1.1a/CD_ROM.BIN/develpmt/source/lava/lava.c

C/C++ Source or Header | 1992-11-12 | 40.9 KB | 1,347 lines

/*----------------------------------------------------------------------------*\
|   Lava.c - A Lava Flow Simulator for Windows application                    |
|                                                                              |
|                                                                              |
\*----------------------------------------------------------------------------*/
/*
     (C) Copyright Microsoft Corp. 1991.  All rights reserved.

     You have a royalty-free right to use, modify, reproduce and
     distribute the Sample Files (and/or any modified version) in
     any way you find useful, provided that you agree that
     Microsoft has no warranty obligations or liability for any
     Sample Application Files which are modified.
 */

#define PUBLIC far pascal
#define PRIVATE near pascal
#include <windows.h>

#define WinAssert(x)

#include <math.h>

#include "lava.h"

#define    PC_NOCOLLAPSE    0x04       // non-collapsing flag

#define rgbBlack    RGB(0,0,0)
#define rgbWhite    RGB(255,255,255)
//#define rgbRed      RGB(255,0,0)
//#define rgbGreen    RGB(0,255,0)
//#define rgbBlue     RGB(0,0,255)
#define rgbMenu     GetSysColor(COLOR_MENU)
#define rgbMenuText GetSysColor(COLOR_MENUTEXT)

#define MAXCOLORS   256

#define wDibUsage  (fPalColors ? DIB_PAL_COLORS : DIB_RGB_COLORS)

typedef struct CHARGE
{
    POINT pt;
    int value;
}CHARGE;

/*----------------------------------------------------------------------------*\
|                                                                              |
|   g l o b a l   v a r i a b l e s                                            |
|                                                                              |
\*----------------------------------------------------------------------------*/
static  char    szAppName[]="LavaFlow";

static  HANDLE  hInstApp;
static  HWND    hwndApp;

/*----------------------------------------------------------------------------*\
|                                                                              |
|   f u n c t i o n   d e f i n i t i o n s                                    |
|                                                                              |
\*----------------------------------------------------------------------------*/

LONG FAR PASCAL AppWndProc (HWND hwnd, unsigned uiMessage, WORD wParam, LONG lParam);
int  ErrMsg (LPSTR sz,...);
BOOL fDialog(int id,HWND hwnd,FARPROC fpfn);

HMENU   hmenuPopup;

BOOL    fSetDIBits = TRUE;
BOOL    fPalColors = TRUE;
BOOL    fPalette;
BOOL    fFastCycle;
short   fSinPalette=FALSE;
short   fCrossFade=FALSE;
short   fColorCycle=TRUE;
short   fNoCollapse=FALSE;
short   paletteval[MAXCOLORS];

//
//  A brush for every color in the palette, for use on non palette devices.
//
HBRUSH  hbrPalette[MAXCOLORS];

HPALETTE hpalLava;
LOGPALETTE *pLogPal;
int      nColors  = 128;
int     NumCenters = 4;
int      nBandScale = 1;

short       nColorPhase = 0;
RGBQUAD     rgbLava     = {0,0,255};

//
//  TRUE if a Lava computation is in progress
//
BOOL    fLavaSem;

//
//  if set to a non zero value will cause lava calculation to abort
//
BOOL    fStopLava;
#define F_LAVAOK    0
#define F_LAVASTOP  1
#define F_LAVADIE   2

HBITMAP hbmLava;
BITMAP    bmLava;
BYTE    abScanLine[2048];

BITMAPINFOHEADER *pbiLava;

LONG  PRIVATE AppOwnerDraw(HWND hwnd, WORD msg, WORD wParam, LONG lParam);
LONG  PRIVATE AppCommand(HWND hwnd, unsigned msg, WORD wParam, LONG lParam);
HBITMAP CopyBitmap (HBITMAP hbm);
HPALETTE CopyPalette(HPALETTE hpal);
HANDLE CreateLogicalDib(HBITMAP hbm, HPALETTE hpal);

extern LONG LavaFlowXY386(int nCenter, CHARGE *aptCenter, int x, int y);
void LavaFlow(HDC hdc, int nCenter, CHARGE aptCenter[], PRECT prc);
void CyclePalette(HDC hdc);
void InitPalette();
void SetPalette(PALETTEENTRY * pPal, int nPhase, RGBQUAD rgb);

#define MAXI (16*1024)

/*----------------------------------------------------------------------------*\
|                                                                              |
|   Random functions                                                           |
|                                                                              |
\*----------------------------------------------------------------------------*/

#define RAND(x)  (rand() % (x))

DWORD dwRand = 1L;
void PASCAL srand(DWORD dwSeed)
{
    dwRand = dwSeed;
}

WORD PASCAL rand(void)
{
    dwRand = dwRand * 214013L + 2531011L;
    return (WORD)((dwRand >> 16) & 0xffff);
}

POINT PASCAL PtRand(int x, int y)
{
    POINT pt;

    pt.x = RAND(x);
    pt.y = RAND(y);

    return pt;
}

VOID WinYield()
{
    MSG msg;

    while(PeekMessage(&msg,NULL,0,0,PM_REMOVE))
    {
    TranslateMessage(&msg);
    DispatchMessage(&msg);
    }
}

/*----------------------------------------------------------------------------*\
|   AppAbout( hDlg, uiMessage, wParam, lParam )                    |
|                                           |
|   Description:                                   |
|    This function handles messages belonging to the "About" dialog box.    |
|    The only message that it looks for is WM_COMMAND, indicating the use   |
|    has pressed the "OK" button.  When this happens, it takes down           |
|    the dialog box.                                |
|                                           |
|   Arguments:                                       |
|    hDlg        window handle of about dialog window               |
|    uiMessage    message number                           |
|    wParam        message-dependent                       |
|    lParam        message-dependent                       |
|                                           |
|   Returns:                                       |
|    TRUE if message has been processed, else FALSE                   |
|                                           |
\*----------------------------------------------------------------------------*/
BOOL FAR PASCAL AppAbout( hDlg, uiMessage, wParam, lParam )
    HWND     hDlg;
    unsigned uiMessage;
    WORD     wParam;
    long     lParam;
{
    switch (uiMessage) {
        case WM_COMMAND:
            if (wParam == IDOK)
                EndDialog(hDlg,TRUE);
        break;

    case WM_INITDIALOG:
        return TRUE;
    }
    return FALSE;
}

VOID SetupPalette()
{
    int i;
    WORD *pw;
    RGBQUAD *prgb;
    PALETTEENTRY *ppe;

    if (hpalLava)
    {
    DeleteObject(hpalLava);
    hpalLava = NULL;
    }
    //hpalLava = CreateWashPalette(rgbBlue,rgbBlack,-nColors);
    if(pLogPal == NULL)
    {
       pLogPal = (VOID *)LocalAlloc(LPTR,sizeof(LOGPALETTE) + MAXCOLORS * sizeof(PALETTEENTRY));
    }
    WinAssert(pLogPal);

    pLogPal->palVersion = 0x300;
    pLogPal->palNumEntries = nColors;

    SetPalette(pLogPal->palPalEntry,nColorPhase,rgbLava);

    if (!fPalette)
    {
        for(i=0,ppe=pLogPal->palPalEntry;i<nColors;i++,ppe++)
        {
            if (hbrPalette[i])
                DeleteObject(hbrPalette[i]);

            hbrPalette[i] = CreateSolidBrush(RGB(ppe->peRed,ppe->peGreen,ppe->peBlue));
        }
    }

    hpalLava = CreatePalette(pLogPal);

    if (pbiLava == NULL)
    {
        pbiLava = (VOID *)LocalAlloc(LPTR,sizeof(BITMAPINFOHEADER) + MAXCOLORS * sizeof(RGBQUAD));

        pbiLava->biSize     = sizeof(BITMAPINFOHEADER);
        pbiLava->biWidth    = 0;
        pbiLava->biHeight   = 0;
        pbiLava->biPlanes   = 1;
        pbiLava->biBitCount = 8;

        pbiLava->biCompression   = BI_RGB;
        pbiLava->biSizeImage     = 0;
        pbiLava->biXPelsPerMeter = 0;
        pbiLava->biYPelsPerMeter = 0;
        pbiLava->biClrUsed       = nColors;
        pbiLava->biClrImportant  = 0;
    }
    WinAssert(pbiLava);

    if (fPalColors)
    {
        pw = (WORD*)((BYTE*)pbiLava+pbiLava->biSize);
        for (i=0; i<nColors; i++)
        {
            *pw++ = i;
        }
    }
    else
    {
        prgb = (RGBQUAD*)((BYTE*)pbiLava+pbiLava->biSize);
        for (i=0; i<nColors; i++)
        {
            prgb[i].rgbRed   = pLogPal->palPalEntry[i].peRed;
            prgb[i].rgbGreen = pLogPal->palPalEntry[i].peGreen;
            prgb[i].rgbBlue  = pLogPal->palPalEntry[i].peBlue;
            prgb[i].rgbReserved = 0;
        }
    }
}

/*----------------------------------------------------------------------------*\
|   AppExit()                                                                  |
|                                                                              |
|   Description:                                   |
|       This is called when the application is removed from memory             |
|       It free all global objects and other things                            |
|                                                                              |
|   Returns:                                       |
|       Exit code to be returned to KERNEL                                     |
|                                           |
\*----------------------------------------------------------------------------*/
WORD AppExit()
{
    int i;

    for (i=0; i<nColors; i++)
    {
        if (hbrPalette[i])
            DeleteObject(hbrPalette[i]);
    }

    if (hbmLava)
        DeleteObject(hbmLava);

    if (hpalLava)
        DeleteObject(hpalLava);

    //if (hmenuPopup)
    //    DeleteMenu(hmenuPopup);

    return 0;
}

/*----------------------------------------------------------------------------*\
|   AppInit( hInst, hPrev)                               |
|                                           |
|   Description:                                   |
|    This is called when the application is first loaded into           |
|    memory.  It performs all initialization that doesn't need to be done   |
|    once per instance.                               |
|                                           |
|   Arguments:                                       |
|    hInstance    instance handle of current instance               |
|    hPrev        instance handle of previous instance               |
|                                           |
|   Returns:                                       |
|    TRUE if successful, FALSE if not                       |
|                                           |
\*----------------------------------------------------------------------------*/
BOOL AppInit(hInst,hPrev,sw,szCmd)
    HANDLE hInst;
    HANDLE hPrev;
    WORD   sw;
    LPSTR  szCmd;
{
    WNDCLASS rClass;
    int      dx,dy;
    char     ach[80];
    HMENU    hmenu;
    HPALETTE hpal;
    HDC      hdc;

    if (LOWORD(GetWinFlags()) & (WF_CPU086|WF_CPU186|WF_CPU286))
    {
        MessageBox(NULL,"Lava requires a 386 or better","Lava",MB_OK|MB_ICONEXCLAMATION|MB_TASKMODAL);
        return FALSE;
    }

    /* Save instance handle for DialogBoxs */
    hInstApp = hInst;

    if (!hPrev) {
    /*
     *  Register a class for the main application window
     */
    rClass.hCursor          = LoadCursor(NULL,IDC_ARROW);
    rClass.hIcon          = LoadIcon(hInst,"AppIcon");
        rClass.lpszMenuName   = NULL;
        rClass.lpszClassName  = szAppName;
    rClass.hbrBackground  = (HBRUSH)COLOR_WINDOW + 1;
    rClass.hInstance      = hInst;
    rClass.style          = CS_BYTEALIGNCLIENT | CS_VREDRAW | CS_HREDRAW | CS_DBLCLKS;
    rClass.lpfnWndProc    = AppWndProc;
    rClass.cbWndExtra     = 0;
    rClass.cbClsExtra     = 0;

    if (!RegisterClass(&rClass))
        return FALSE;
    }

    dx = GetSystemMetrics (SM_CXSCREEN);
    dy = GetSystemMetrics (SM_CYSCREEN);

    hwndApp = CreateWindow (szAppName,szAppName,
                WS_OVERLAPPEDWINDOW,
                CW_USEDEFAULT, 0,dx/2,dy/2,
                            (HWND)NULL,        /* no parent */
                            (HMENU)NULL,       /* use class menu */
                (HANDLE)hInst,     /* handle to window instance */
                            (LPSTR)NULL        /* no params to pass on */
                           );
    WinAssert(hwndApp);
    ShowWindow (hwndApp,sw);

    hmenu = LoadMenu(hInst,"AppMenu");
    WinAssert(hmenu);
    hmenuPopup = GetSubMenu(hmenu, 0);
    WinAssert(hmenuPopup);

    CheckMenuItem(hmenuPopup,MENU_NUMCENTERS+NumCenters,MF_CHECKED);
    CheckMenuItem(hmenuPopup,MENU_NUMCOLORS+nColors,MF_CHECKED);
    CheckMenuItem(hmenuPopup,MENU_BANDSCALE+nBandScale,MF_CHECKED);

    InitPalette();
    SetupPalette();

    SetTimer(hwndApp,1,10,NULL);

    srand(GetCurrentTime());

    hdc = GetDC(NULL);
    fPalette = fSetDIBits = (GetDeviceCaps(hdc,RASTERCAPS) & RC_PALETTE);
    ReleaseDC(NULL,hdc);

    return TRUE;
}

/*----------------------------------------------------------------------------*\
|   WinMain( hInst, hPrev, lpszCmdLine, cmdShow )                   |
|                                                                              |
|   Description:                                                               |
|       The main procedure for the App.  After initializing, it just goes      |
|       into a message-processing loop until it gets a WM_QUIT message         |
|       (meaning the app was closed).                                          |
|                                                                              |
|   Arguments:                                                                 |
|    hInst        instance handle of this instance of the app           |
|    hPrev        instance handle of previous instance, NULL if first    |
|       lpszCmdLine     ->null-terminated command line                         |
|       cmdShow         specifies how the window is initially displayed        |
|                                                                              |
|   Returns:                                                                   |
|       The exit code as specified in the WM_QUIT message.                     |
|                                                                              |
\*----------------------------------------------------------------------------*/
int PASCAL WinMain( hInst, hPrev, fpcCmdLine, iCmdShow )
    HANDLE  hInst, hPrev;
    LPSTR   fpcCmdLine;
    int     iCmdShow;
{
    MSG     msg;

    /* Call initialization procedure */
    if (!AppInit(hInst,hPrev,iCmdShow,fpcCmdLine))
        return FALSE;

    for (;;)
    {
        /* Polling messages from event queue */
        while (PeekMessage(&msg, NULL, 0, 0,PM_REMOVE))
        {
            if (msg.message == WM_QUIT)
                goto exit;

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

        if (fFastCycle)
            SendMessage(hwndApp,WM_TIMER,0,0L);
        else
            WaitMessage();
    }
exit:
    return AppExit();
}

/*----------------------------------------------------------------------------*\
|   AppPaint(hwnd, hdc)                                |
|                                                                              |
|   Description:                                                               |
|       The paint function.  Right now this does nothing.                      |
|                                                                              |
|   Arguments:                                       |
|    hwnd         window painting into                       |
|    hdc         display context to paint to                   |
|                                                                              |
|   Returns:                                                                   |
|       nothing                                                                |
|                                                                              |
\*----------------------------------------------------------------------------*/
AppPaint (HWND hwnd, HDC hdc)
{
    RECT    rc;
    HBITMAP hbmT;
    HDC     hdcBits;

    if (hbmLava == NULL)
    return FALSE;

    if (hpalLava)
    {
    SelectPalette(hdc,hpalLava,FALSE);
        RealizePalette(hdc);
    }

    hdcBits = CreateCompatibleDC(hdc);

    GetClientRect(hwnd,&rc);

    hbmT = SelectObject(hdcBits,hbmLava);
    BitBlt(hdc,0,0,bmLava.bmWidth,bmLava.bmHeight,hdcBits,0,0,SRCCOPY);
    SelectObject(hdcBits,hbmT);

    DeleteDC(hdcBits);
    return TRUE;
}

/*----------------------------------------------------------------------------*\
|                                                                              |
|   w i n d o w   p r o c s                                                    |
|                                                                              |
\*----------------------------------------------------------------------------*/

/*----------------------------------------------------------------------------*\
|   AppWndProc( hwnd, uiMessage, wParam, lParam )                   |
|                                                                              |
|   Description:                                                               |
|       The window proc for the app's main (tiled) window.  This processes all |
|       of the parent window's messages.                                       |
|                                                                              |
|   Arguments:                                                                 |
|    hwnd        window handle for the window                   |
|       uiMessage       message number                                         |
|       wParam          message-dependent                                      |
|       lParam          message-dependent                                      |
|                                                                              |
|   Returns:                                                                   |
|       0 if processed, nonzero if ignored                                     |
|                                                                              |
\*----------------------------------------------------------------------------*/
LONG FAR PASCAL AppWndProc(hwnd, msg, wParam, lParam)
    HWND     hwnd;
    unsigned msg;
    WORD     wParam;
    long     lParam;
{
    PAINTSTRUCT ps;
    BOOL        f;
    HDC         hdc;
    RECT        rc;

    switch (msg) {
    case WM_CREATE:
            break;

        case WM_QUERYNEWPALETTE:
            if (hpalLava)
            {
                hdc = GetDC(hwnd);
        SelectPalette(hdc,hpalLava,FALSE);
                f = RealizePalette(hdc);
                ReleaseDC(hwnd,hdc);
                return (LONG)f;
            }
            return FALSE;

        case WM_PALETTECHANGED:
            if (wParam != hwnd && hpalLava)
                InvalidateRect(hwnd,NULL,TRUE);
            break;

        case WM_LBUTTONDOWN:
            ClientToScreen(hwnd, (LPPOINT)&lParam);
            TrackPopupMenu(hmenuPopup, 0, LOWORD(lParam)-30, HIWORD(lParam)+4, 0, hwnd, NULL);
            break;

        case WM_DRAWITEM:
        case WM_MEASUREITEM:
        case WM_DELETEITEM:
            return AppOwnerDraw(hwnd,msg,wParam,lParam);

        case WM_INITMENU:
            EnableMenuItem(wParam,MENU_GO,
                fLavaSem ? MF_GRAYED : MF_ENABLED);
            EnableMenuItem(wParam,MENU_STOP,
                !fLavaSem ? MF_GRAYED : MF_ENABLED);
            EnableMenuItem(wParam,MENU_PASTE,
                IsClipboardFormatAvailable(CF_BITMAP) ? MF_ENABLED : MF_GRAYED);
            EnableMenuItem(wParam,MENU_COPY,
                hbmLava ? MF_ENABLED : MF_GRAYED);
            EnableMenuItem(wParam,MENU_PALCOLORS,
                fSetDIBits ? MF_ENABLED : MF_GRAYED);
            CheckMenuItem(wParam,MENU_PALETTE,
                fPalette ? MF_CHECKED : MF_UNCHECKED);
        CheckMenuItem(wParam,MENU_SATIN,
        fSinPalette ? MF_CHECKED : MF_UNCHECKED);
        CheckMenuItem(wParam,MENU_CROSSFADE,
        fCrossFade ? MF_CHECKED : MF_UNCHECKED);
            CheckMenuItem(wParam,MENU_SETDIBITS,
                fSetDIBits ? MF_CHECKED : MF_UNCHECKED);
            CheckMenuItem(wParam,MENU_PALCOLORS,
                (fPalColors && fSetDIBits)? MF_CHECKED : MF_UNCHECKED);
            CheckMenuItem(wParam,MENU_FASTCYCLE,
                fFastCycle ? MF_CHECKED : MF_UNCHECKED);
            CheckMenuItem(wParam,MENU_COLORCYCLE,
                fColorCycle ? MF_CHECKED : MF_UNCHECKED);
            CheckMenuItem(wParam,MENU_NOCOLLAPSE,
                fNoCollapse ? MF_CHECKED : MF_UNCHECKED);
            break;

        case WM_COMMAND:
            return AppCommand(hwnd,msg,wParam,lParam);

    case WM_DESTROY:
        PostQuitMessage(0);
        break;

        case WM_CLOSE:
            //
            // if a lava calculation is under way stop it before closing
            //
            if (fLavaSem)
            {
                fStopLava = F_LAVADIE;
                return 0L;
            }
        break;

        case WM_TIMER:
            if (fPalette && hpalLava)
            {
                hdc = GetDC(hwnd);

                SelectPalette(hdc,hpalLava,FALSE);
                RealizePalette(hdc);

                CyclePalette(hdc);

                ReleaseDC(hwnd,hdc);
            }
            break;

        case WM_PAINT:
            BeginPaint(hwnd,&ps);
            AppPaint (hwnd,ps.hdc);
            EndPaint(hwnd,&ps);
        return 0L;
    }
    return DefWindowProc(hwnd,msg,wParam,lParam);
}


/*----------------------------------------------------------------------------*\
|   ErrMsg - Opens a Message box with a error message in it.  The user can     |
|         select the OK button to continue or the CANCEL button to kill     |
|         the parent application.                           |
\*----------------------------------------------------------------------------*/
int ErrMsg (LPSTR sz,...)
{
    char ach[128];

    wsprintf (ach,sz,(LPSTR)(&sz+1));     /* Format the string */
    MessageBox(NULL,ach,NULL,MB_YESNO|MB_ICONEXCLAMATION|MB_DEFBUTTON2|MB_SYSTEMMODAL);
    return FALSE;
}

/*----------------------------------------------------------------------------*\
|   fDialog(id,hwnd,fpfn)                               |
|                                           |
|   Description:                                                               |
|    This function displays a dialog box and returns the exit code.           |
|    the function passed will have a proc instance made for it.           |
|                                           |
|   Arguments:                                                                 |
|    id        resource id of dialog to display               |
|    hwnd        parent window of dialog                    |
|    fpfn        dialog message function                    |
|                                                                              |
|   Returns:                                                                   |
|    exit code of dialog (what was passed to EndDialog)               |
|                                                                              |
\*----------------------------------------------------------------------------*/
BOOL fDialog(int id,HWND hwnd,FARPROC fpfn)
{
    BOOL    f;
    HANDLE    hInst;

    hInst = GetWindowWord(hwnd,GWW_HINSTANCE);
    fpfn  = MakeProcInstance(fpfn,hInst);
    f = DialogBox(hInst,MAKEINTRESOURCE(id),hwnd,fpfn);
    FreeProcInstance (fpfn);
    return f;
}

void PRIVATE WinSetCursor(HWND hwnd, HCURSOR hcur)
{
    SetCursor(hcur);
    SetClassWord(hwnd,GCW_HCURSOR,(WORD)hcur);
}

LONG PRIVATE AppCommand (hwnd, msg, wParam, lParam)
    HWND     hwnd;
    unsigned msg;
    WORD     wParam;
    long     lParam;
{
    switch(wParam)
    {
        case MENU_COPY:
            if (!OpenClipboard(hwnd))
                break;

            EmptyClipboard();

            rgbLava.rgbRed = rgbLava.rgbGreen = rgbLava.rgbBlue = 255;
            SetPalette(pLogPal->palPalEntry,0,rgbLava);
            SetPaletteEntries(hpalLava,0,nColors,pLogPal->palPalEntry);

            if (hbmLava)
                SetClipboardData(CF_BITMAP,CopyBitmap(hbmLava));

            if (hpalLava)
                SetClipboardData(CF_PALETTE,CopyPalette(hpalLava));

            if (hbmLava)
                SetClipboardData(CF_DIB,CreateLogicalDib(hbmLava,hpalLava));

            CloseClipboard();
            break;

    case MENU_ABOUT:
            fDialog(ABOUTBOX,hwnd,AppAbout);
            break;

        case MENU_EXIT:
        PostMessage(hwnd,WM_CLOSE,0,0L);
            break;
    case MENU_SATIN:
        fSinPalette = !fSinPalette;
            InitPalette();
        SetupPalette();
        break;
    case MENU_CROSSFADE:
        fCrossFade = !fCrossFade;
        break;
        case MENU_SETDIBITS:
            fSetDIBits = !fSetDIBits;
        break;
        case MENU_COLORCYCLE:
            fColorCycle = !fColorCycle;
        break;
        case MENU_PALCOLORS:
            fPalColors = !fPalColors;
        SetupPalette();
        break;
        case MENU_FASTCYCLE:
            fFastCycle = !fFastCycle;

            KillTimer(hwndApp,1);

            if (!fFastCycle)
                SetTimer(hwndApp,1,10,NULL);

        break;
        case MENU_NOCOLLAPSE:
            fNoCollapse = !fNoCollapse;
        SetupPalette();
        break;
    case MENU_PALETTE:
            fPalette = !fPalette;
        SetupPalette();
        break;
        case MENU_STOP:
            if (fLavaSem)
                fStopLava = F_LAVASTOP;
            break;
        case MENU_GO:
            if (!fLavaSem)
            {
                HDC   hdc;
                CHARGE apt[40];
                RECT  rc;
                int   i;

                //
                // Change the GO menu item to stop
                //
                ChangeMenu(hmenuPopup,MENU_GO,"Stop!",MENU_STOP,MF_CHANGE|MF_BYCOMMAND);

                WinSetCursor(hwnd,LoadCursor(NULL,IDC_WAIT));

                fLavaSem++;
                fStopLava = F_LAVAOK;

                hdc = GetDC(hwnd);
                SelectPalette(hdc,hpalLava,FALSE);
                RealizePalette(hdc);

                //
                // Hack, if the window is maximized generate a SCREEN size
                // bitmap
                //
                if (IsZoomed(hwnd))
                    SetRect(&rc,0,0,GetSystemMetrics(SM_CXSCREEN),GetSystemMetrics(SM_CYSCREEN));
                else
                    GetClientRect(hwnd,&rc);

                //
                //  Pick random charge centers and weights
                //
                for (i=0; i<NumCenters; i++)
                {
                    apt[i].pt = PtRand(rc.right,rc.bottom);
                    do
                        apt[i].value = RAND(9)-4;
                    while (apt[i].value == 0);
                }

                LavaFlow(hdc, NumCenters, apt, &rc);

                fLavaSem--;
                ReleaseDC(hwnd,hdc);

                WinSetCursor(hwnd,LoadCursor(NULL,IDC_ARROW));

                //
                // Change the STOP menu item back to go
                //
                ChangeMenu(hmenuPopup,MENU_STOP,"Go!",MENU_GO,MF_CHANGE|MF_BYCOMMAND);

                //
                //  If the user tried to close the app while we were working
                //  do it now
                //
                if (fStopLava == F_LAVADIE)
                    PostMessage(hwnd,WM_CLOSE,0,0L);
            }
            break;

        default:
            switch (wParam & 0xFF00)
            {
                int n;

                case MENU_NUMCENTERS:
                    n = wParam & 0xFF;
                    CheckMenuItem(hmenuPopup,MENU_NUMCENTERS+NumCenters,MF_UNCHECKED);
                    CheckMenuItem(hmenuPopup,MENU_NUMCENTERS+n,MF_CHECKED);
                    NumCenters = n;
            break;
        case MENU_NUMCOLORS:
                    n = wParam & 0xFF;
            CheckMenuItem(hmenuPopup,MENU_NUMCOLORS+nColors,MF_UNCHECKED);
            CheckMenuItem(hmenuPopup,MENU_NUMCOLORS+n,MF_CHECKED);
            nColors = n;
            SetupPalette();
            break;
        case MENU_BANDSCALE:
                    n = wParam & 0xFF;
            CheckMenuItem(hmenuPopup,MENU_BANDSCALE+nBandScale,MF_UNCHECKED);
            CheckMenuItem(hmenuPopup,MENU_BANDSCALE+n,MF_CHECKED);
            nBandScale = n;
            break;
        }
            break;
    }
    return 0L;
}

LONG PRIVATE AppOwnerDraw(HWND hwnd, WORD msg, WORD wParam, LONG lParam)
{
    #define lpMIS  ((LPMEASUREITEMSTRUCT)lParam)
    #define lpDIS  ((LPDRAWITEMSTRUCT)lParam)

    switch (msg)
    {
        case WM_MEASUREITEM:
            lpMIS->itemHeight = 10;
            lpMIS->itemWidth  = 10;
        return TRUE;

        case WM_DRAWITEM:
            return TRUE;

    case WM_DELETEITEM:
        return TRUE;
    }
    return TRUE;
}

void InitPalette()
{
    int i;
    int j;

    j = 0;
    for(i=0;i<nColors;i++)
    {
        if (fSinPalette)
            paletteval[i] = (int)(MAXI-sin(i*3.14/(nColors-1))*MAXI);
        else
            paletteval[i] = (int)((1-pow(2.0*i/(nColors-1)-1,2.0))*MAXI);
    }
}

/*
 *  llSetPixel(hdc,x,y,n)
 *
 *  Sets a pixel in a HDC, will use dither patterns if fPalette not set
 *
 */
void llSetPixel(HDC hdc, int x, int y, int n)
{
    HBRUSH hbrT;

    if (fPalette)
    {
    SetPixel(hdc,x,y,PALETTEINDEX(n));
    }
    else
    {
    hbrT = SelectObject(hdc,hbrPalette[n]);
    PatBlt(hdc,x,y,1,1,PATCOPY);
    SelectObject(hdc,hbrT);
    }
}

/*
 *  LavaFlow()
 *
 *  calulates the "Lava Lamp" equation for each point in the passed
 *  rectangle.   The Lava equation at any point is defined as the sum
 *  of the distance squared from each center point
 *
 */
void LavaFlow(HDC hdc, int nCenter, CHARGE aptCenter[], PRECT prc)
{
    int      x,y,i,a1;
    static   short a = 0;
    int      dx,dy;
    HDC      hdcBits;
    HBITMAP  hbmT;
    HPALETTE hpalT;

    hdcBits = CreateCompatibleDC(hdc);

    dx = prc->right  - prc->left;
    dy = prc->bottom - prc->top;

    a1 = a;

    if (!hbmLava || bmLava.bmWidth != dx || bmLava.bmHeight != dy)
    {
    if (hbmLava)
        DeleteObject(hbmLava);

    hbmLava = CreateCompatibleBitmap(hdc,dx,dy);

    if (!hbmLava)
         return;

    GetObject(hbmLava,sizeof(bmLava),(LPSTR)&bmLava);

        pbiLava->biWidth    = dx;
        pbiLava->biHeight   = dy;
        pbiLava->biPlanes   = 1;
        pbiLava->biBitCount = 8;

        pbiLava->biClrUsed       = nColors;
        pbiLava->biClrImportant  = 0;

        hbmT = SelectObject(hdcBits,hbmLava);
        PatBlt(hdcBits,0,0,dx,dy,BLACKNESS);
        SelectObject(hdcBits,hbmT);
    }

    for (y=prc->top; y<prc->bottom; y++)
    {
        if (fCrossFade)
        {
             hbmT = SelectObject(hdcBits,hbmLava);
             hpalT = SelectPalette(hdcBits,hpalLava,FALSE);
             RealizePalette(hdcBits);

         a = !a;
         for (x=prc->left+a; x<prc->right; x+=2)
         {
                 i = LavaFlowXY386(nCenter,aptCenter,x,y) / nBandScale % nColors;
                 llSetPixel(hdc,x,y,i);
                 llSetPixel(hdcBits,x,y,i);
             }

             SelectObject(hdcBits,hbmT);
             SelectPalette(hdcBits,hpalT,FALSE);
    }
    else
    {
            for (x=prc->left; x<prc->right; x++)
            {
                 i = LavaFlowXY386(nCenter,aptCenter,x,y) / nBandScale % nColors;
                 abScanLine[x] = (BYTE)i;
            }

            if (fSetDIBits)
            {
                SetDIBits(hdc,hbmLava,dy-1-y,1,abScanLine,(LPBITMAPINFO)pbiLava,wDibUsage);

                hbmT = SelectObject(hdcBits,hbmLava);
                hpalT = SelectPalette(hdcBits,hpalLava,FALSE);
                RealizePalette(hdcBits);

                BitBlt(hdc,0,y,dx,1,hdcBits,0,y,SRCCOPY);

                SelectObject(hdcBits,hbmT);
                SelectPalette(hdcBits,hpalT,FALSE);
            }
            else
            {
                hbmT = SelectObject(hdcBits,hbmLava);
                hpalT = SelectPalette(hdcBits,hpalLava,FALSE);
                RealizePalette(hdcBits);

                for (x=prc->left; x<prc->right; x++)
                {
                    i = abScanLine[x];
                    llSetPixel(hdc,x,y,i);
                    llSetPixel(hdcBits,x,y,i);
                }

                SelectObject(hdcBits,hbmT);
                SelectPalette(hdcBits,hpalT,FALSE);
            }
        }

        if (fPalette)
            CyclePalette(hdc);

        WinYield();

        //
        //  See if we should abort early
        //
        if (fStopLava != F_LAVAOK)
            break;
    }

    a = !a1;

    DeleteDC(hdcBits);
}

void SetPalette(PALETTEENTRY * pPal, int nPhase, RGBQUAD rgb)
{
    int i,n;

    for(i=0;i<nColors;i++)
    {
        n = paletteval[(nPhase + i) % nColors];

        pPal[i].peRed   = (BYTE)((long)rgb.rgbRed  * n / MAXI);
        pPal[i].peGreen = (BYTE)((long)rgb.rgbGreen* n / MAXI);
        pPal[i].peBlue  = (BYTE)((long)rgb.rgbBlue * n / MAXI);

        if (fNoCollapse)
            pPal[i].peFlags = (BYTE)PC_NOCOLLAPSE;
        else
            pPal[i].peFlags = (BYTE)PC_RESERVED;
    }
}

void CyclePalette(HDC hdc)
{
    int i;
    PALETTEENTRY peT;

    static short       nLenColorCycle = 0;
    static RGBQUAD     rgbLavaOrg;
    static short       dr,dg,db;

    if (fColorCycle)
    {
        if (nColorPhase >= nLenColorCycle)
        {
            nLenColorCycle = (RAND(4) + 1) * nColors;
            nColorPhase = 0;

            rgbLavaOrg = rgbLava;

            dr = RAND(256) - (int)rgbLava.rgbRed;
            dg = RAND(256) - (int)rgbLava.rgbGreen;
            db = RAND(256) - (int)rgbLava.rgbBlue;
        }

        rgbLava.rgbRed   = (int)rgbLavaOrg.rgbRed   + (long)dr * nColorPhase / nLenColorCycle;
        rgbLava.rgbGreen = (int)rgbLavaOrg.rgbGreen + (long)dg * nColorPhase / nLenColorCycle;
        rgbLava.rgbBlue  = (int)rgbLavaOrg.rgbBlue  + (long)db * nColorPhase / nLenColorCycle;

        nColorPhase++;

        SetPalette(pLogPal->palPalEntry,nColorPhase,rgbLava);
    }
    else
    {
        peT = pLogPal->palPalEntry[0];

        for (i = 0; i < (pLogPal->palNumEntries - 1); i++)
            pLogPal->palPalEntry[i] = pLogPal->palPalEntry[i+1];

        pLogPal->palPalEntry[i] = peT;
    }

    if (fNoCollapse)
    {
        SetPaletteEntries(hpalLava, 0, pLogPal->palNumEntries, pLogPal->palPalEntry);
        RealizePalette(hdc);
    }
    else
    {
        AnimatePalette(hpalLava, 0, pLogPal->palNumEntries, pLogPal->palPalEntry);
    }
}

#define WIDTHBYTES(i)   ((i+31)/32*4)      /* ULONG aligned ! */
#define MAKEP(sel,off)  ((VOID FAR *)MAKELONG(off,sel))

#define PaletteSize(lpbi) (sizeof(RGBQUAD)*DibNumColors(lpbi))

WORD DibNumColors(LPBITMAPINFOHEADER lpbi)
{
    if (lpbi->biClrUsed != 0 || lpbi->biBitCount == 24)
        return (WORD)lpbi->biClrUsed;
    else
        return 1<<lpbi->biBitCount;
}

/*
 *  CreateLogicalDib
 *
 *  Given a DDB and a HPALETTE create a "logical" DIB
 *
 *  if the HBITMAP is NULL create a DIB from the system "stock" bitmap
 *      This is used to save a logical palette to a disk file as a DIB
 *
 *  if the HPALETTE is NULL use the system "stock" palette (ie the
 *      system palette)
 *
 *  a "logical" DIB is a DIB where the DIB color table *exactly* matches
 *  the passed logical palette.  There will be no system colors in the DIB
 *  block, and a pixel value of <n> in the DIB will correspond to logical
 *  palette index <n>.
 *
 *  This is accomplished by doing a GetDIBits() with the DIB_PAL_COLORS
 *  option then converting the palindexes returned in the color table
 *  from palette indexes to logical RGB values.  The entire passed logical
 *  palette is always copied to the DIB color table.
 *
 *  The DIB color table will have exactly the same number of entries as
 *  the logical palette.  Normaly GetDIBits() will always set biClrUsed to
 *  the maximum colors supported by the device regardless of the number of
 *  colors in the logical palette
 *
 *  Why would you want to do this?  The major reason for a "logical" DIB
 *  is so when the DIB is written to a disk file then reloaded the logical
 *  palette created from the DIB color table will be the same as one used
 *  originaly to create the bitmap.  It also will prevent GDI from doing
 *  nearest color matching on PC_RESERVED palettes.
 *
 *  ** What do we do if the logical palette has more than 256 entries!!!!!
 *  ** GetDIBits() may return logical palette index's that are greater than
 *  ** 256, we cant represent these colors in the "logical" DIB
 *  **
 *  ** for now hose the caller?????
 *
 */

HANDLE CreateLogicalDib(HBITMAP hbm, HPALETTE hpal)
{
    BITMAP              bm;
    BITMAPINFOHEADER    bi;
    LPBITMAPINFOHEADER  lpDib;      // pointer to DIB
    LPBITMAPINFOHEADER  lpbi;       // temp pointer to BITMAPINFO
    DWORD               dwLen;
    DWORD               dw;
    int                 n;
    int                 nColors;
    HANDLE              hdib;
    HDC                 hdc;
    BYTE FAR *          lpBits;
    WORD FAR *          lpCT;
    RGBQUAD FAR *       lpRgb;
    PALETTEENTRY        peT;
    HPALETTE            hpalT;
    WORD                biBits;

    if (hpal == NULL)
        hpal = GetStockObject(DEFAULT_PALETTE);

    if (hbm == NULL)
        hbm = NULL; // ????GetStockObject(STOCK_BITMAP);

    GetObject(hpal,sizeof(nColors),(LPSTR)&nColors);
    GetObject(hbm,sizeof(bm),(LPSTR)&bm);

    biBits = nColors > 16 ? 8 : 4;

    if (nColors > 256)      // ACK!
        ;                   // How do we handle this????

    bi.biSize               = sizeof(BITMAPINFOHEADER);
    bi.biWidth              = bm.bmWidth;
    bi.biHeight             = bm.bmHeight;
    bi.biPlanes             = 1;
    bi.biBitCount           = biBits;
    bi.biCompression        = BI_RGB;
    bi.biSizeImage          = WIDTHBYTES((DWORD)bm.bmWidth * biBits) * bm.bmHeight;
    bi.biXPelsPerMeter      = 0;
    bi.biYPelsPerMeter      = 0;
    bi.biClrUsed            = nColors;
    bi.biClrImportant       = 0;

    dwLen = bi.biSize + PaletteSize(&bi) + bi.biSizeImage;

    hdib = GlobalAlloc(GMEM_MOVEABLE,dwLen);

    if (!hdib)
        return NULL;

    lpbi = MAKEP(GlobalAlloc(GMEM_FIXED,bi.biSize + 256 * sizeof(RGBQUAD)),0);

    if (!lpbi)
    {
        GlobalFree(hdib);
        return NULL;
    }

    hdc = GetDC(NULL);
    hpalT = SelectPalette(hdc,hpal,FALSE);
    RealizePalette(hdc);  // why is this needed on a MEMORY DC? GDI bug??

    lpDib = (VOID FAR *)GlobalLock(hdib);

    *lpbi  = bi;
    *lpDib = bi;
    lpCT   = (WORD FAR *)((LPSTR)lpbi + (WORD)lpbi->biSize);
    lpRgb  = (RGBQUAD FAR *)((LPSTR)lpDib + (WORD)lpDib->biSize);
    lpBits = (LPSTR)lpDib + (WORD)lpDib->biSize + PaletteSize(lpDib);

    /*
     *  call GetDIBits to get the DIB bits and fill the color table with
     *  logical palette index's
     */
    GetDIBits(hdc, hbm, 0, (WORD)bi.biHeight,
        lpBits,(LPBITMAPINFO)lpbi, DIB_PAL_COLORS);

    /*
     *  Now convert the DIB bits into "real" logical palette index's
     *
     *  lpCT        points to the DIB color table wich is a WORD array of
     *              logical palette index's
     *
     *  lpBits      points to the DIB bits, each DIB pixel is a index into
     *              the DIB color table.
     *
     */

    if (biBits == 8)
    {
        for (dw = 0; dw < bi.biSizeImage; dw++, ((BYTE huge *)lpBits)++)
            *lpBits = (BYTE)lpCT[*lpBits];
    }
    else // biBits == 4
    {
        for (dw = 0; dw < bi.biSizeImage; dw++, ((BYTE huge *)lpBits)++)
            *lpBits = lpCT[*lpBits & 0x0F] | (lpCT[(*lpBits >> 4) & 0x0F] << 4);
    }

    /*
     *  Now copy the RGBs in the logical palette to the dib color table
     */
    for (n=0; n<nColors; n++,lpRgb++)
    {
        GetPaletteEntries(hpal,n,1,&peT);

        lpRgb->rgbRed      = peT.peRed;
        lpRgb->rgbGreen    = peT.peGreen;
        lpRgb->rgbBlue     = peT.peBlue;
        lpRgb->rgbReserved = (BYTE)0;
    }

    GlobalUnlock(hdib);
    GlobalFree(HIWORD((DWORD)lpbi));

    SelectPalette(hdc,hpalT,FALSE);
    ReleaseDC(NULL,hdc);

    return hdib;
}

/*----------------------------------------------------------------------------
  CopyBitmap (hbm) - Returns a copy of the passed bitmap
  ----------------------------------------------------------------------------*/
HBITMAP CopyBitmap (HBITMAP hbm)
{
    HDC     hMemDCsrc;
    HDC     hMemDCdst;
    HDC     hdc;
    HBITMAP hNewBm;
    BITMAP  bm;

    if (!hbm)
         return NULL;

    hdc = GetDC(NULL);
    hMemDCsrc = CreateCompatibleDC(hdc);
    hMemDCdst = CreateCompatibleDC(hdc);

    GetObject(hbm,sizeof(BITMAP),(LPSTR)&bm);

    hNewBm = CreateBitmap(bm.bmWidth,bm.bmHeight,bm.bmPlanes,bm.bmBitsPixel,NULL);

    if (hNewBm)
    {
        SelectObject (hMemDCsrc,hbm);
        SelectObject (hMemDCdst,hNewBm);

        BitBlt (hMemDCdst,0,0,bm.bmWidth,bm.bmHeight,hMemDCsrc,0,0,SRCCOPY);
    }

    ReleaseDC(NULL,hdc);
    DeleteDC(hMemDCsrc);
    DeleteDC(hMemDCdst);
    return hNewBm;
}

/*
 * CopyPalette, makes a copy of a GDI logical palette
 */
HPALETTE CopyPalette(HPALETTE hpal)
{
    PLOGPALETTE ppal;
    int         nNumEntries;

    if (!hpal)
    return NULL;

    GetObject(hpal,sizeof(int),(LPSTR)&nNumEntries);

    if (nNumEntries == 0)
        return NULL;

    ppal = (PLOGPALETTE)LocalAlloc(LPTR,sizeof(LOGPALETTE) +
                nNumEntries * sizeof(PALETTEENTRY));

    if (!ppal)
        return NULL;

    ppal->palVersion    = 0x300;
    ppal->palNumEntries = nNumEntries;

    GetPaletteEntries(hpal,0,nNumEntries,ppal->palPalEntry);

    hpal = CreatePalette(ppal);

    LocalFree((HANDLE)ppal);
    return hpal;
}