我一直在为游戏制作一个Window类，而我在使用消息泵方面遇到了麻烦。
我从Windows提供的消息队列中提取事件并将它们发送到它们所属的窗口。这是Translates和Dispatches的功能。
根据我对Win32编程的记忆，翻译和调度消息会使用消息的参数内容调用指定的WindowProc。所以这是我指定的WindowProc ......
currWin，currhwnd和winMap被定义为Window.cpp的本地变量，位于顶部......
无论如何，调用distributeSystemMessages（）似乎会导致无限循环。
重要提示：游戏循环不在消息处理循环内，而且不是消息处理代码。消息处理循环应该是每个帧的消息队列，每个消息都会发送给它所在的窗口。
这是Window.h ...
#ifndef WINDOW_H_INCLUDED
#define WINDOW_H_INCLUDED
#include "SystemMessage.h"
#include <queue>
#include <windows.h>
using namespace std;
///THIS FUNCTION MUST BE CALLED TO GET MESSAGES INTO WINDOW QUEUES
void distributeSystemMessages();
class Window
{
protected:
HDC hDC;
HWND hWnd;
HINSTANCE hInst;
HGLRC hRC;
public:
queue<SystemMessage> messages;
Window(unsigned int width, unsigned int height, const char* name, unsigned int colorBits = 24, unsigned int depthBits = 24, unsigned int stencilBits = 0);
~Window();
void makeContextCurrent();
void swapBuffers();
unsigned int getHeight();
unsigned int getWidth();
int getMouseX();
int getMouseY();
void setSize(unsigned int width, unsigned int height);
};
#endif // WINDOW_H_INCLUDED
这是Window.cpp ......
#include "Window.h"
#include <map>
#include <cstdio>
#include <GLee.h>
#include <GL/gl.h>
#include <GL/glu.h>
using namespace std;
HWND currhwnd;
Window* currWin;
map<HWND, Window*> winMap = map<HWND, Window*>();
LRESULT CALLBACK MainWndProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
if(currhwnd != hwnd)
{
map<HWND, Window*>::iterator i = winMap.find(hwnd);
if(i != winMap.end())
{
currWin = (*i).second;
currhwnd = hwnd;
}
else return DefWindowProc(hwnd, uMsg, wParam, lParam);
}
SystemMessage msg(hwnd, uMsg, wParam, lParam);
currWin->messages.push(msg);
return 0;
}
Window::Window(unsigned int width, unsigned int height, const char* name, unsigned int colorBits, unsigned int depthBits, unsigned int stencilBits)
{
//TODO: ADD TIME FUNCTIONS TO A TIMER CLASS
//QueryPerformanceCounter(&startTime);
//lastTime = startTime;
messages = queue<SystemMessage>();
hInst = GetModuleHandle(NULL);
WNDCLASSEX wincl; /* Data structure for the windowclass */
/* The Window structure */
wincl.hInstance = hInst;
wincl.lpszClassName = "Squirrel Engine Window";
wincl.lpfnWndProc = MainWndProc; /* This function is called by windows */
wincl.style = CS_DBLCLKS; /* Catch double-clicks */
wincl.cbSize = sizeof (WNDCLASSEX);
/* Use default icon and mouse-pointer */
wincl.hIcon = LoadIcon (NULL, IDI_APPLICATION);
wincl.hIconSm = LoadIcon (NULL, IDI_APPLICATION);
wincl.hCursor = LoadCursor (NULL, IDC_ARROW);
wincl.lpszMenuName = NULL; /* No menu */
wincl.cbClsExtra = 0; /* No extra bytes after the window class */
wincl.cbWndExtra = 0; /* structure or the window instance */
/* Use Windows's default colour as the background of the window */
wincl.hbrBackground = (HBRUSH) COLOR_BACKGROUND;
/* Register the window class, and if it fails quit the program */
if (!RegisterClassEx (&wincl))
{
printf("Could not register window class.\n");
return;
}
/* The class is registered, let's create the program*/
hWnd = CreateWindowEx (
0, /* Extended possibilites for variation */
"Squirrel Engine Window",/* Classname */
name, /* Title Text */
WS_OVERLAPPEDWINDOW, /* default window */
CW_USEDEFAULT, /* Windows decides the position */
CW_USEDEFAULT, /* where the window ends after on the screen */
10, /* The programs width */
10, /* and height in pixels */
HWND_DESKTOP, /* The window is a child-window to desktop */
NULL, /* No menu */
hInst, /* Program Instance handler */
NULL /* No Window Creation data */
);
RECT rcWindow;
RECT rcClient;
GetWindowRect(hWnd, &rcWindow);
GetClientRect(hWnd, &rcClient);
POINT ptDiff;
ptDiff.x = (rcWindow.right - rcWindow.left) - rcClient.right;
ptDiff.y = (rcWindow.bottom - rcWindow.top) - rcClient.bottom;
MoveWindow(hWnd,rcWindow.left, rcWindow.top, width + ptDiff.x, height + ptDiff.y, TRUE);
ShowWindow (hWnd, SW_SHOW);
hDC = GetDC( hWnd );
PIXELFORMATDESCRIPTOR pfd;
ZeroMemory( &pfd, sizeof( pfd ) );
pfd.nSize = sizeof( pfd );
pfd.nVersion = 1;
pfd.dwFlags = PFD_DRAW_TO_WINDOW | PFD_SUPPORT_OPENGL |
PFD_DOUBLEBUFFER;
pfd.iPixelType = PFD_TYPE_RGBA;
pfd.cColorBits = colorBits;
pfd.cDepthBits = depthBits;
pfd.cStencilBits = stencilBits;
pfd.iLayerType = PFD_MAIN_PLANE;
int iFormat = ChoosePixelFormat( hDC, &pfd );
SetPixelFormat( hDC, iFormat, &pfd );
hRC = wglCreateContext(hDC);
hDC = hDC;
//makeContextCurrent();
winMap[hWnd] = this;
//TODO: Find out what this function does
wglSwapIntervalEXT(0);
}
Window::~Window()
{
wglDeleteContext(hRC);
ReleaseDC(hWnd, hDC);
winMap.erase(hWnd);
PostQuitMessage(0);
}
unsigned int Window::getWidth()
{
RECT rcClient;
GetClientRect(hWnd, &rcClient);
return rcClient.right;
}
unsigned int Window::getHeight()
{
RECT rcClient;
GetClientRect(hWnd, &rcClient);
return rcClient.bottom;
}
void Window::setSize(unsigned int width, unsigned int height)
{
RECT rcWindow;
RECT rcClient;
GetWindowRect(hWnd, &rcWindow);
GetClientRect(hWnd, &rcClient);
POINT ptDiff;
ptDiff.x = (rcWindow.right - rcWindow.left) - rcClient.right;
ptDiff.y = (rcWindow.bottom - rcWindow.top) - rcClient.bottom;
MoveWindow(hWnd,rcWindow.left, rcWindow.top, width + ptDiff.x, height + ptDiff.y, TRUE);
}
void Window::makeContextCurrent()
{
wglMakeCurrent( hDC, hRC );
}
void Window::swapBuffers()
{
SwapBuffers( hDC );
}
int Window::getMouseX()
{
POINT p;
GetCursorPos(&p);
RECT rcWindow;
RECT rcClient;
GetWindowRect(hWnd, &rcWindow);
GetClientRect(hWnd, &rcClient);
POINT ptDiff;
ptDiff.x = (rcWindow.right - rcWindow.left) - rcClient.right;
ptDiff.y = (rcWindow.bottom - rcWindow.top) - rcClient.bottom;
return p.x - (rcWindow.left + ptDiff.x);
}
int Window::getMouseY()
{
POINT p;
GetCursorPos(&p);
RECT rcWindow;
RECT rcClient;
GetWindowRect(hWnd, &rcWindow);
GetClientRect(hWnd, &rcClient);
POINT ptDiff;
ptDiff.x = (rcWindow.right - rcWindow.left) - rcClient.right;
ptDiff.y = (rcWindow.bottom - rcWindow.top) - rcClient.bottom;
return p.y - (rcWindow.top + ptDiff.y);
}
void distributeSystemMessages()
{
MSG messages;
while(PeekMessage (&messages, NULL, 0, 0, PM_REMOVE))
{
printf("MessageLoop\n");
TranslateMessage(&messages);
DispatchMessage(&messages);
}
}
答案 0 :(得分：2)
通常，您使用对象体系结构。 Windows提供对每个hWnd本地空间的访问，这些空间明确保留供您基本上用于此目的。您不需要任何全局变量来完成这项工作。
class Window {
// Can be virtual if necessary
LRESULT WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam) {
// Process the message here
}
static LRESULT WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam) {
if (Window* ptr = reinterpret_cast<Window*>(GetWindowLongPtr(hwnd, GWLP_USERDATA))) {
return ptr->WindowProc(hwnd, uMsg, wParam, lParam);
}
return DefWindowProc(hwnd, uMsg, wParam, lParam);
}
HWND hwnd;
public:
Window() {
hwnd = CreateWindowEx(....);
SetWindowLongPtr(hwnd, GWLP_USERDATA, reinterpret_cast<LONG_PTR>(this));
ShowWindow(...); // update the ptr
}
void ProcessMessages() {
MSG messages;
while(PeekMessage (&messages, hwnd, 0, 0, PM_REMOVE))
{
printf("MessageLoop\n");
TranslateMessage(&messages);
DispatchMessage(&messages);
}
}
};