screensaver.c File Reference

#include <windows.h>
#include <tchar.h>
#include <scrnsave.h>
#include "resource.h"

Include dependency graph for screensaver.c:

Go to the source code of this file.

Classes
struct	star

Macros
#define	RANDOM(min, max)   ((rand() % (int)(((max)+1) - (min))) + (min))
#define	MAX_LOADSTRING   100
#define	MAX_STARS   1000
#define	APPNAME   _T("Starfield")
#define	APP_TIMER   1
#define	APP_TIMER_INTERVAL   20
#define	MAX_STARS   1000

Typedefs
typedef struct star	STAR

Functions
void	DrawStarField (HDC pDC)
BOOL	SetUpStars (int nNumStars)
void	MoveStarField (int nXofs, int nYofs, int nZofs)
void	SetDimensions (int nWidth, int nHeight)
LRESULT WINAPI	ScreenSaverProc (HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
BOOL WINAPI	ScreenSaverConfigureDialog (HWND hWnd, UINT message, WPARAM wparam, LPARAM lparam)
BOOL WINAPI	RegisterDialogClasses (HANDLE hmodule)

Variables
STAR *	stars
int	m_nTotStars
int	m_nCenterX
int	m_nCenterY

Macro Definition Documentation

APP_TIMER

#define APP_TIMER   1

Definition at line 33 of file screensaver.c.

APP_TIMER_INTERVAL

#define APP_TIMER_INTERVAL   20

Definition at line 34 of file screensaver.c.

APPNAME

#define APPNAME   _T("Starfield")

Definition at line 32 of file screensaver.c.

MAX_LOADSTRING

#define MAX_LOADSTRING   100

Definition at line 29 of file screensaver.c.

MAX_STARS [1/2]

#define MAX_STARS   1000

Definition at line 36 of file screensaver.c.

MAX_STARS [2/2]

#define MAX_STARS   1000

Definition at line 36 of file screensaver.c.

RANDOM

#define RANDOM	(		min,
			max
	)		((rand() % (int)(((max)+1) - (min))) + (min))

Definition at line 27 of file screensaver.c.

Typedef Documentation

STAR

typedef struct star STAR

Function Documentation

DrawStarField()

void DrawStarField

(

HDC

pDC

)

Definition at line 50 of file screensaver.c.

{
    int nX, nY;
    int i;
    for (i = 0; i < m_nTotStars; i++)
    {
        // Clear last position of this star
        SetPixel (
            pDC,
            stars[i].m_nOldX,
            stars[i].m_nOldY,
            RGB (0, 0, 0));

        nX = (int)((((long)stars[i].m_nXPos << 7) / (long)stars[i].m_nZPos) + m_nCenterX);
        nY = (int)((((long)stars[i].m_nYPos << 7) / (long)stars[i].m_nZPos) + m_nCenterY);

        // Draw star
        SetPixel (
            pDC,
            nX,
            nY,
            RGB (255, 255, 255));

        // Remember current position for clearing later
        stars[i].m_nOldX = nX;
        stars[i].m_nOldY = nY;
    }
}

Referenced by ScreenSaverProc().

MoveStarField()

void MoveStarField	(	int	nXofs,
		int	nYofs,
		int	nZofs
	)

Definition at line 121 of file screensaver.c.

{
    int i;
    for (i = 0; i < m_nTotStars; i++)
    {
        stars[i].m_nXPos += nXofs;
        stars[i].m_nYPos += nYofs;
        stars[i].m_nZPos += nZofs;

        if (stars[i].m_nZPos > m_nTotStars)
            stars[i].m_nZPos -= m_nTotStars;
        if (stars[i].m_nZPos < 1)
            stars[i].m_nZPos += m_nTotStars;
    }
}

Referenced by ScreenSaverProc().

RegisterDialogClasses()

BOOL WINAPI RegisterDialogClasses

(

HANDLE

hmodule

)

Definition at line 207 of file screensaver.c.

{
    TCHAR szTitle[256];
    TCHAR szText[256];

    LoadString(hmodule,
            IDS_TITLE,
            szTitle,
            256);

    LoadString(hmodule,
            IDS_TEXT,
            szText,
            256);

    MessageBox(0,
            szText,
            szTitle,
            MB_OK | MB_ICONWARNING);
    return FALSE;
}

ScreenSaverConfigureDialog()

BOOL WINAPI ScreenSaverConfigureDialog	(	HWND	hWnd,
		UINT	message,
		WPARAM	wparam,
		LPARAM	lparam
	)

Definition at line 202 of file screensaver.c.

{
    return FALSE;
}

ScreenSaverProc()

LRESULT WINAPI ScreenSaverProc	(	HWND	hwnd,
		UINT	msg,
		WPARAM	wParam,
		LPARAM	lParam
	)

Definition at line 143 of file screensaver.c.

{
    static HDC pDC;

    switch (msg)
    {
        case WM_CREATE:
        {
            SetTimer (
                hwnd,
                APP_TIMER,
                APP_TIMER_INTERVAL,
                NULL);
        }
        break;
        case WM_PAINT:
        {
            PAINTSTRUCT    PtStr;
            HDC pDC = BeginPaint (hwnd, &PtStr);
            DrawStarField (pDC);
            EndPaint (hwnd, &PtStr);
            SetUpStars(250);
            return (0);
        }
        break;
        case WM_TIMER:
        {
            if (wParam == APP_TIMER)
            {
                MoveStarField (0, 0, -3);
                pDC = GetDC(hwnd);
                DrawStarField (pDC);
                ReleaseDC(hwnd, pDC);
            }
        }
        break;
        case WM_SIZE:
        {
            // Change the center point of the starfield
            SetDimensions (
                LOWORD(lParam),
                HIWORD(lParam));
        }
        break;
        case WM_DESTROY:
        {
            KillTimer (hwnd, APP_TIMER);
            free(stars);
            ShowCursor(TRUE);
            PostQuitMessage (0);
            return 0;
        }
        break;
        default:
            return DefScreenSaverProc(hwnd, msg, wParam, lParam);
    }
    return 0;
}

SetDimensions()

void SetDimensions	(	int	nWidth,
		int	nHeight
	)

Definition at line 137 of file screensaver.c.

{
    m_nCenterX = nWidth / 2;
    m_nCenterY = nHeight / 2;
}

Referenced by ScreenSaverProc().

SetUpStars()

BOOL SetUpStars

(

int

nNumStars

)

Definition at line 79 of file screensaver.c.

{
    int i;
    if (nNumStars > MAX_STARS)
    {
        MessageBox (0,
            _T("Too many stars! Aborting!"),
            _T("Error"),
            MB_OK | MB_ICONWARNING);
        return FALSE;
    }

    if (stars)
        free (stars);

    m_nTotStars = nNumStars;

    stars = (STAR*)malloc(nNumStars * sizeof(STAR));

    if (!stars)
    {
        MessageBox (0,
            _T("Unable to allocate memory! Aborting!"),
            _T("Error"),
            MB_OK | MB_ICONWARNING);
        return FALSE;
    }

    for (i = 0; i < m_nTotStars; i++)
    {
        do
        {
            stars[i].m_nXPos = RANDOM (-320, 320);
            stars[i].m_nYPos = RANDOM (-200, 200);
            stars[i].m_nZPos = i+1;
            stars[i].m_nOldX = -1;
            stars[i].m_nOldY = -1;
        } while ((stars[i].m_nXPos == 0) || (stars[i].m_nYPos == 0));
    }
    return TRUE;
}

Referenced by ScreenSaverProc().

Variable Documentation

m_nCenterX

int m_nCenterX

Definition at line 48 of file screensaver.c.

Referenced by DrawStarField(), and SetDimensions().

m_nCenterY

int m_nCenterY

Definition at line 48 of file screensaver.c.

Referenced by DrawStarField(), and SetDimensions().

m_nTotStars

int m_nTotStars

Definition at line 47 of file screensaver.c.

Referenced by DrawStarField(), MoveStarField(), and SetUpStars().

stars

STAR* stars

Definition at line 45 of file screensaver.c.

Referenced by DrawStarField(), MoveStarField(), ScreenSaverProc(), and SetUpStars().