我正在创建一个游戏,其中在WM_PAINT消息期间完成了大量绘图.窗口失效有几个不同的地方,迫使它重绘.我把所有东西画到了一个屏幕外的DC,然后把它绘制到窗口 – 创建非闪烁的“帧”.
然而,每隔一段时间,一切都突然开始被错误地绘制.在我使用的五个位图中,前三个正在或多或少(但不完全)正确绘制.同样,所有颜色信息对于这三个都是正确的.在这三个之后绘制的另外两个是用错误的颜色绘制的 – 我认为白色仍然是白色的,但其他一切都被绘制为灰色.我不是说灰度,我的意思是除了白色之外的所有东西都是相同的颜色 – 灰色.
此外,当这种情况开始发生时,通常情况下所有内容都被绘制得太高 – 大约20到30个像素.此外,字体和消息框停止工作 – 所有文本都以默认字体绘制(但奇怪的是,正确的颜色),消息框只出现短暂,没有文字,然后消失 – 但必须像常规一样被解雇(你必须按回车键,否则如果你点击主窗口,它会按照正常情况执行,当有一个消息框打开时输入 – 闪烁并拨打错误音.所以一切都被皇家搞砸了.
我一直在研究这个项目已经有一段时间了,我最近才开始看到这个错误 – 尽管我根本没有修改下面的代码片段.很难测试可能会做什么,因为它似乎偶尔会发生.
这是WndProc中WM_CREATE和WM_PAINT中的代码：
case WM_CREATE:
{
hdc = GetDC(hWnd);
hdcmem = CreateCompatibleDC(hdc);
RECT rc;
GetClientRect(hWnd,&rc);
hdcbm = CreateCompatibleBitmap(hdc,rc.right,rc.bottom);
hbcmem = CreateCompatibleDC(hdcmem);
hdcbmold = (HBITMAP)SelectObject(hdcmem,hdcbm);
// Load bitmaps
bg = LoadBitmap(hInst,MAKEINTRESOURCE(IDB_BACKGROUND));
mainCont = LoadBitmap(hInst,MAKEINTRESOURCE(IDB_GAME_CONT));
if(bg == NULL || mainCont == NULL)
ThrowError("A bitmap failed to load.");
}
break;
case WM_PAINT:
{
PAINTSTRUCT ps;
BeginPaint(hWnd,&ps);
// Background
hdcold = (HBITMAP)SelectObject(hbcmem,bg);
BitBlt(hdcmem,237,196,hbcmem,SRCCOPY);
BitBlt(hdcmem,237 * 2,SRCCOPY);
// Main Game Container
hdcold = (HBITMAP)SelectObject(hbcmem,mainCont);
BitBlt(hdcmem,26,300,SRCCOPY);
// Side Info
HBITMAP side = LoadBitmap(hInst,MAKEINTRESOURCE(IDB_SIDEINFO));
hdcold = (HBITMAP)SelectObject(hbcmem,side);
BitBlt(hdcmem,339,154,SRCCOPY);
DrawLevelNumber(game.map.levelnumber);
if (color)
sprites = LoadBitmap(hInst,MAKEINTRESOURCE(IDB_COLOR_SPRITES));
else sprites = LoadBitmap(hInst,MAKEINTRESOURCE(IDB_BLACKWHITE_SPRITES));
hdcold = (HBITMAP)SelectObject(hbcmem,sprites);
// Find x and y coordinate for the top left of the visible screen
int x = game.player.x,y = game.player.y,ypos = 0;
if (x < 4) x = 4;
if (x > 27) x = 27;
if (y < 4) y = 4;
if (y > 27) y = 27;
x -= 4;
y -= 4;
// Draw lower layer
for (int i = 0; i < 9; i++)
{
for (int j = 0; j < 9; j++)
{
if (game.map.Layer_Two[x + i][y + j] != 0)
{
int xpos = game.get_pos(game.map.Layer_Two[x + i][y + j].get(),ypos,false);
BitBlt(hdcmem,(i * 32) + 32,(j * 32) + 32,32,xpos,SRCCOPY);
}
}
}
// Draw upper layer
for (int i = 0; i < 9; i++)
{
for (int j = 0; j < 9; j++)
{
if ((game.map.Layer_Two[x + i][y + j] != 0 && game.map.Layer_One[x + i][y + j] >= 64 && game.map.Layer_One[x + i][y + j] <= 111))
{
int xpos = game.get_pos(game.map.Layer_One[x + i][y + j].get(),true);
BitBlt(hdcmem,xpos + 96,SRCPAINT);
BitBlt(hdcmem,SRCAND);
} else {
int xpos = game.get_pos(game.map.Layer_One[x + i][y + j].get(),SRCCOPY);
}
}
}
// If it isn't started,show title
if (!game.started)
{
HDC tmphdc = CreateCompatibleDC(hdcmem);
HDC tmp = CreateCompatibleDC(tmphdc);
RECT rc;
GetClientRect(hWnd,&rc);
string str = game.map.leveltitle.substr(0,game.map.leveltitle.length() - 1);
TCHAR* tch = new TCHAR[str.length()];
mbstowcs_s(NULL,tch,_tcslen(tch),str.c_str(),str.length());
HFONT font = CreateFont(25,FW_BOLD,false,ANSI_CHARSET,OUT_DEFAULT_PRECIS,CLIP_DEFAULT_PRECIS,DEFAULT_QUALITY,FF_DONTCARE,NULL);
SelectObject(tmp,font);
DrawText(tmp,str.length(),&rc,DT_CALCRECT);
rc.right += 16;
HBITMAP tmpbm = CreateCompatibleBitmap(hdcmem,rc.bottom);
HBITMAP tmpold = (HBITMAP)SelectObject(tmphdc,tmpbm);
HBRUSH hbr = CreateSolidBrush(RGB(255,255,255));
HPEN pen = CreatePen(PS_SOLID,1,RGB(255,255));
SelectObject(hdcmem,pen);
SelectObject(hdcmem,hbr);
Rectangle(hdcmem,176 - (rc.right / 2),243,177 + (rc.right / 2),248);
hbr = CreateSolidBrush(RGB(128,128,128));
pen = CreatePen(PS_SOLID,RGB(128,128));
SelectObject(hdcmem,294,299);
HBITMAP left = LoadBitmap(hInst,MAKEINTRESOURCE(IDB_LEFT));
hdcold = (HBITMAP)SelectObject(hbcmem,left);
BitBlt(hdcmem,176 - (rc.right / 2) - 4,4,56,SRCCOPY);
HBITMAP right = LoadBitmap(hInst,MAKEINTRESOURCE(IDB_RIGHT));
hdcold = (HBITMAP)SelectObject(hbcmem,right);
BitBlt(hdcmem,176 + (rc.right / 2) + ((rc.right % 2) != 0),SRCCOPY);
SelectObject(tmphdc,font);
SetTextColor(tmphdc,0));
SetBkColor(tmphdc,RGB(0,0));
DrawText(tmphdc,DT_CENTER);
BITMAP structBitmapHeader;
memset( &structBitmapHeader,sizeof(BITMAP) );
HGDIOBJ hBitmap = GetCurrentObject(tmphdc,OBJ_BITMAP);
GetObject(hBitmap,sizeof(BITMAP),&structBitmapHeader);
BitBlt(hdcmem,247,structBitmapHeader.bmWidth,structBitmapHeader.bmHeight,tmphdc,SRCCOPY);
DeleteDC(tmphdc);
DeleteDC(tmp);
}
// If paused
if (game.paused)
{
RECT rc;
rc.top = 32;
rc.left = 32;
rc.bottom = 330;
rc.right = 330;
BitBlt(hdcmem,288,NULL,BLACKNESS);
HFONT font = CreateFont(50,FW_NORMAL,NULL);
SelectObject(hdcmem,font);
SetTextColor(hdcmem,0));
SetBkColor(hdcmem,0));
DrawText(hdcmem,L"PAUSED",6,(DT_CENTER + DT_SINGLELINE + DT_VCENTER));
}
nums = LoadBitmap(hInst,MAKEINTRESOURCE(IDB_NUMBERS));
hdcold = (HBITMAP)SelectObject(hbcmem,nums);
for (int i = 100; i > 0; i /= 10) // coins and time left
{
int tmp;
if (i == 100)
tmp = game.coinsleft / 100;
if (i == 10)
tmp = ((game.coinsleft % 100) - (game.coinsleft % 10)) / 10;
if (i == 1)
tmp = game.coinsleft % 10;
if (game.coinsleft < i && i > 1)
tmp = 10;
int ypos = game.get_num_pos(tmp,(game.coinsleft == 0));
BitBlt(hdcmem,417 + ((3 - (int)floor(log10((double)i)) * 17)),215,17,23,SRCCOPY);
if (i == 100)
tmp = game.timeleft / 100;
if (i == 10)
tmp = ((game.timeleft % 100) - (game.timeleft % 10)) / 10;
if (i == 1)
tmp = game.timeleft % 10;
if (game.timeleft < i && i > 1)
tmp = 10;
if (game.map.timelimit == 0)
tmp = 11;
ypos = game.get_num_pos(tmp,(game.timeleft < 16 || game.map.timelimit == 0));
BitBlt(hdcmem,369 + ((3 - (int)floor(log10((double)i))) * 17),125,SRCCOPY);
}
if (game.onhint)
{
HBITMAP sidebg = LoadBitmap(hInst,MAKEINTRESOURCE(IDB_SIDEBG));
hdcold = (HBITMAP)SelectObject(hbcmem,sidebg);
BitBlt(hdcmem,353,165,127,146,SRCCOPY);
HFONT font = CreateFont(18,true,255));
SetBkColor(hdcmem,0));
RECT rc;
rc.top = 168;
rc.left = 356;
rc.bottom = 308;
rc.right = 477;
string str = "Hint: " + game.map.hint;
TCHAR* tch = new TCHAR[str.length()];
mbstowcs_s(NULL,str.length());
DrawText(hdcmem,DT_CENTER + DT_WORDBREAK);
} else {
hdcold = (HBITMAP)SelectObject(hbcmem,sprites); // LOWER SIDE INFO
if (game.player.key1 > 0)
BitBlt(hdcmem,352,192,160,SRCCOPY);
else BitBlt(hdcmem,SRCCOPY);
if (game.player.key2 > 0)
BitBlt(hdcmem,384,SRCCOPY);
if (game.player.key3 > 0)
BitBlt(hdcmem,416,224,SRCCOPY);
if (game.player.key4)
BitBlt(hdcmem,448,SRCCOPY);
if (game.player.mod1)
BitBlt(hdcmem,279,256,SRCCOPY);
if (game.player.mod2)
BitBlt(hdcmem,SRCCOPY);
if (game.player.mod3)
BitBlt(hdcmem,320,SRCCOPY);
if (game.player.mod4)
BitBlt(hdcmem,SRCCOPY);
}
BitBlt(hdc,518,401,hdcmem,SRCCOPY);
EndPaint(hWnd,&ps);
}
break;
case WM_DESTROY:
SelectObject(hdc,hdcold);
DeleteDC(hdcmem);
DeleteDC(hbcmem);
ReleaseDC(hWnd,hdc);
DeleteObject(bg);
PostQuitMessage(0);
break;
我也非常感谢任何人可以提供的关于语法,效率和/或更好的代码处理方式的建议/批评.我是Win32的新手.
解决方法
您正在泄漏GDI对象.
每次创建画笔或加载位图时,都会创建一个GDI对象. Windows限制了您可以创建的GDI对象的数量.如果您反复创建对象而不删除它们,您将达到限制并且其他对象的创建将失败.当发生这种情况时,您的显示器看起来会出错 – 您会看到错误的颜色,默认字体等.
任务管理器将显示进程已分配的GDI对象的数量(在“进程”选项卡中,转到“查看”|“选择列”).价值可能会有一点波动,但不应该随着时间的推移而增长.
使用GDI的标准模式是：
>创建对象(例如,使用CreateSolidBrush的画笔).
>使用SelectObject将对象选择到设备上下文中,并记住原始对象(返回值).
>做你的绘画或其他什么.
>使用SelectObject将原始对象选回设备上下文. (当然,这也会从设备上下文中取消选择您的对象.)
>使用DeleteObject删除对象.
您只执行第2步的一半并跳过第4步和第5步.
然后请注意,在每次喷涂操作中都不需要重复步骤1和5.您可以分别将它们移动到程序初始化和终止.并且可以跳过程序终止时的清理,因为OS无论如何都要这样做.
最后,加载位图是一个适度缓慢的操作,所以你绝对不想重复这样做.这是GDI提供对象句柄的要点.
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