na gut, dann probiere ich es eben so: ich hab hier ein programm, welches grafik zeichnet. was ich wissen muss, ist wie man diese grafik mit double-buffering zeichnet, d.h. grafik wird erst berechnet, und dann, wenn alles fertig ist, alles auf einmal auf den bildschirm gezeichnet wird. so sind die übergänge sauber. könnt ihr mir helfen? ihr könntet ja den folgenden quelltext entsprechend ergänzen? ich wäre euch sehr dankbar!
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#include <windows.h>
static char g_szClassName[] = "MyWindowClass";
static HINSTANCE g_hInst = NULL;
const UINT idTimer1 = 1;
UINT nTimerDelay = 10;
HBITMAP hbmBall, hbmMask;
BITMAP bm;
int ballX, ballY;
int deltaX, deltaY;
int deltaValue = 4;
void EraseBall(HDC hdc)
{
RECT rc;
rc.left = ballX;
rc.top = ballY;
rc.right = ballX + bm.bmWidth;
rc.bottom = ballY + bm.bmHeight;
FillRect(hdc, &rc, (HBRUSH)(COLOR_BTNFACE+1));
}
void DrawBall(HDC hdc)
{
HDC hdcMemory;
hdcMemory = CreateCompatibleDC(hdc);
SelectObject(hdcMemory, hbmMask);
BitBlt(hdc, ballX, ballY, bm.bmWidth, bm.bmHeight, hdcMemory, 0, 0, SRCAND);
SelectObject(hdcMemory, hbmBall);
BitBlt(hdc, ballX, ballY, bm.bmWidth, bm.bmHeight, hdcMemory, 0, 0, SRCPAINT);
DeleteDC(hdcMemory);
}
void UpdateBall(HWND hwnd)
{
RECT rc;
GetClientRect(hwnd, &rc);
ballX += deltaX;
ballY += deltaY;
if(ballX < 0){
ballX = 0;
deltaX = deltaValue;
}
else if(ballX + bm.bmWidth > rc.right){
ballX = rc.right - bm.bmWidth;
deltaX = -deltaValue;
}
if(ballY < 0){
ballY = 0;
deltaY = deltaValue;
}
else if(ballY + bm.bmHeight > rc.bottom){
ballY = rc.bottom - bm.bmHeight;
deltaY = -deltaValue;
}
}
LRESULT CALLBACK WndProc(HWND hwnd, UINT Message, WPARAM wParam, LPARAM lParam)
{
switch(Message)
{
case WM_CREATE:
hbmBall = LoadBitmap(g_hInst, "BALLBMP");
hbmMask = LoadBitmap(g_hInst, "MASKBMP");
if(!hbmBall || !hbmMask){
MessageBox(hwnd, "Load of resources failed.", "Error",
MB_OK | MB_ICONEXCLAMATION);
return -1;
}
GetObject(hbmBall, sizeof(bm), &bm);
SetTimer(hwnd, idTimer1, nTimerDelay, NULL);
ballX = 0;
ballY = 0;
deltaX = deltaValue;
deltaY = deltaValue;
break;
case WM_TIMER:
if(hbmBall && hbmMask)
{
HDC hdcWindow;
hdcWindow = GetDC(hwnd);
EraseBall(hdcWindow);
UpdateBall(hwnd);
DrawBall(hdcWindow);
ReleaseDC(hwnd, hdcWindow);
}
break;
case WM_PAINT:
if(hbmBall && hbmMask)
{
PAINTSTRUCT ps;
HDC hdcWindow;
hdcWindow = BeginPaint(hwnd, &ps);
DrawBall(hdcWindow);
EndPaint(hwnd, &ps);
}
break;
case WM_CLOSE:
DestroyWindow(hwnd);
break;
case WM_DESTROY:
KillTimer(hwnd, idTimer1);
DeleteObject(hbmBall);
DeleteObject(hbmMask);
PostQuitMessage(0);
break;
default:
return DefWindowProc(hwnd, Message, wParam, lParam);
}
return 0;
}
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
LPSTR lpCmdLine, int nCmdShow)
{
WNDCLASSEX WndClass;
HWND hwnd;
MSG Msg;
g_hInst = hInstance;
WndClass.cbSize = sizeof(WNDCLASSEX);
WndClass.style = 0;
WndClass.lpfnWndProc = WndProc;
WndClass.cbClsExtra = 0;
WndClass.cbWndExtra = 0;
WndClass.hInstance = g_hInst;
WndClass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
WndClass.hCursor = LoadCursor(NULL, IDC_ARROW);
WndClass.hbrBackground = (HBRUSH)(COLOR_BTNFACE+1);
WndClass.lpszMenuName = NULL;
WndClass.lpszClassName = g_szClassName;
WndClass.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
if(!RegisterClassEx(&WndClass))
{
MessageBox(0, "Window Registration Failed!", "Error!",
MB_ICONEXCLAMATION | MB_OK | MB_SYSTEMMODAL);
return 0;
}
hwnd = CreateWindowEx(
WS_EX_CLIENTEDGE,
g_szClassName,
"A Bitmap Program",
WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, CW_USEDEFAULT, 320, 240,
NULL, NULL, g_hInst, NULL);
if(hwnd == NULL)
{
MessageBox(0, "Window Creation Failed!", "Error!",
MB_ICONEXCLAMATION | MB_OK | MB_SYSTEMMODAL);
return 0;
}
ShowWindow(hwnd, nCmdShow);
UpdateWindow(hwnd);
while(GetMessage(&Msg, NULL, 0, 0))
{
TranslateMessage(&Msg);
DispatchMessage(&Msg);
}
return Msg.wParam;
}
