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

LRESULT CALLBACK WndProc(HWND,UINT,WPARAM,LPARAM);
HINSTANCE g_hInst;
HWND hWndMain;
LPSTR lpszClass="Heart";

int APIENTRY WinMain(HINSTANCE hInstance,HINSTANCE hPrevInstance
                  ,LPSTR lpszCmdParam,int nCmdShow)
{
        HWND hWnd;
        MSG Message;
        WNDCLASS WndClass;
        g_hInst=hInstance;
        
        WndClass.cbClsExtra=0;
        WndClass.cbWndExtra=0;
        WndClass.hbrBackground=(HBRUSH)GetStockObject(WHITE_BRUSH);
        WndClass.hCursor=LoadCursor(NULL,IDC_ARROW);
        WndClass.hIcon=LoadIcon(NULL,IDI_APPLICATION);
        WndClass.hInstance=hInstance;
        WndClass.lpfnWndProc=(WNDPROC)WndProc;
        WndClass.lpszClassName=lpszClass;
        WndClass.lpszMenuName=NULL;
        WndClass.style=CS_HREDRAW | CS_VREDRAW;
        RegisterClass(&WndClass);

        hWnd=CreateWindow(lpszClass,lpszClass,WS_OVERLAPPEDWINDOW,
                  CW_USEDEFAULT,CW_USEDEFAULT,800,600,
                  NULL,(HMENU)NULL,hInstance,NULL);
        ShowWindow(hWnd,nCmdShow);
        
        while(GetMessage(&Message,0,0,0)) {
                TranslateMessage(&Message);
                DispatchMessage(&Message);
        }
        return Message.wParam;
}

#ifdef STRESS
#else
#endif
#define MANSPEED 5
int cx;
const int cy=480;

HBITMAP hBit;
enum {STOP,RUN} Status;
int nStage;
int nLife;
int nScore;

void DrawBitmap(HDC hdc, int x, int y, HBITMAP hBit);
void OnTimer(HWND hWnd);


LRESULT CALLBACK WndProc(HWND hWnd,UINT iMessage,WPARAM wParam,LPARAM lParam)
{
        HDC hdc;
        PAINTSTRUCT ps;
        TCHAR *Mes="PRESS BUTTON ENTER";

        switch(iMessage) {
        case WM_CREATE:
                hWndMain=hWnd;
                hBit=LoadBitmap(g_hInst,MAKEINTRESOURCE(IDB_HERO1));
                return 0;
        case WM_KEYDOWN:
                switch (wParam){
        case VK_RETURN:
                if(Status == STOP){
                        Status=RUN;
#ifdef STRESS
                        nStage=10;
#else
                        nStage=1;
#endif
                        nLife=5;
                        nScore=0;
                        SetTimer(hWnd,1,20,NULL);
                }
                break;
                }
                return 0;
        case WM_TIMER:
                OnTimer(hWnd);
                return 0;
        case WM_PAINT:
                hdc=BeginPaint(hWnd, &ps);
                if(Status == RUN){
                        DrawBitmap(hdc,0,0,hBit);
                }
                EndPaint(hWnd, &ps);
                return 0;
        case WM_DESTROY:
                KillTimer(hWnd,1);
                DeleteObject(hBit);
                PostQuitMessage(0);
                return 0;
        }
        return(DefWindowProc(hWnd,iMessage,wParam,lParam));
}

void OnTimer(HWND hWnd)
{
        HDC hdc;
        RECT crt;
        HDC hMemDC;
        HBITMAP OldBit;

        hdc=GetDC(hWnd);
        GetClientRect(hWnd,&crt);
        if(hBit==NULL){
                hBit=CreateCompatibleBitmap(hdc,crt.right,crt.bottom);
        }
        hMemDC=CreateCompatibleDC(hdc);
        OldBit=(HBITMAP)SelectObject(hMemDC,hBit);

        if(GetKeyState(VK_LEFT) < 0){
                if(cx > 10) cx-=MANSPEED;
        }
        if(GetKeyState(VK_RIGHT) < 0){
                if(cx < 780) cx+=MANSPEED;
        }

        

        TransparentBlt(hdc, cx, cy, 30, 60, hMemDC, 0, 0, 30, 60, RGB(255,0,0));

        SelectObject(hMemDC,OldBit);
        DeleteDC(hMemDC);
        ReleaseDC(hWnd,hdc);
        InvalidateRect(hWnd,NULL,FALSE);
}

void DrawBitmap(HDC hdc, int x, int y, HBITMAP hBit)
{
        HDC MemDC;
        HBITMAP OldBitmap;
        int bx,by;
        BITMAP bit;

        MemDC=CreateCompatibleDC(hdc);
        OldBitmap=(HBITMAP)SelectObject(MemDC,hBit);

        GetObject(hBit,sizeof(BITMAP),&bit);
        bx=bit.bmWidth;
        by=bit.bmHeight;

        TransparentBlt(hdc, cx, cy, 30, 60, MemDC, 0, 0, 30, 60, RGB(255,0,0));

        SelectObject(MemDC,OldBitmap);
        DeleteDC(MemDC);
}

책 보고 여러 기능 넣어볼려고 이것저것 쳐놨는데 일단 캐릭터 좌우 이동만 해볼려고 합니다.
그런데 캐릭터가 지나가면 뒤에 잔상이 안 생겨야 되는데, 잔상이 안 사라지고 계속 남아있네요.
OnTimer 함수에서 메모리 DC에 그림을 그리고 Invalidate라는 함수로 인수 FALSE로 해주면 초기화 안된상태에서
DrawBitmap으로 다시 그려주면 더블버퍼링이 되서 화면이 깜빡이지 않고 빨리 그려지면서 잔상도 안남아야 되는데;;;
뭐가 문제인지 모르겠습니다. 지적 좀 부탁드립니다.