redo use PeekMessage instead of GetMessage

StudyDx/App.cpp

 #include "App.h"
+#include <sstream>
+#include <iomanip>
 
 App::App()
 	:
@@ -7,28 +9,24 @@ App::App()
 
 int App::Go()
 {
-	MSG msg;
-	BOOL gResult;
-	while( (gResult = GetMessage( &msg,nullptr,0,0 )) > 0 )
+	while (true)
 	{
-		// TranslateMessage will post auxilliary WM_CHAR messages from key msgs
-		TranslateMessage( &msg );
-		DispatchMessage( &msg );
-
-		DoFrame();
-	}
-
-	// check if GetMessage call itself borked
-	if( gResult == -1 )
+		// process all messages pending, but to not block for new messages
+		if (const auto ecode = Window::ProcessMessages())
 		{
-		throw CHWND_LAST_EXCEPT();
+			// if return optional has value, means we're quitting so return exit code
+			return *ecode;
+		}
+		DoFrame();
+		// ȴ10룬ֹ
+		Sleep(10);
 	}
-
-	// wParam here is the value passed to PostQuitMessage
-	return msg.wParam;
 }
 
 void App::DoFrame()
 {
-
+	const float t = timer.Peek();
+	std::ostringstream oss;
+	oss << "Time elapsed: " << std::setprecision(1) << std::fixed << t << "s";
+	wnd.SetTitle(oss.str());
 }
\ No newline at end of file

StudyDx/App.h

 #pragma once
 #include "Window.h"
+#include "ChiliTimer.h"
 
 class App
 {
@@ -11,4 +12,5 @@ private:
 	void DoFrame();
 private:
 	Window wnd;
+	ChiliTimer timer;
 };
\ No newline at end of file

StudyDx/ChiliTimer.cpp

+#include "ChiliTimer.h"
+
+using namespace std::chrono;
+
+ChiliTimer::ChiliTimer() noexcept
+{
+	last = steady_clock::now();
+}
+
+float ChiliTimer::Mark() noexcept
+{
+	const auto old = last;
+	last = steady_clock::now();
+	const duration<float> frameTime = last - old;
+	return frameTime.count();
+}
+
+float ChiliTimer::Peek() const noexcept
+{
+	return duration<float>( steady_clock::now() - last ).count();
+}

StudyDx/ChiliTimer.h

+#pragma once
+#include <chrono>
+
+class ChiliTimer
+{
+public:
+	ChiliTimer() noexcept;
+	float Mark() noexcept;
+	float Peek() const noexcept;
+private:
+	std::chrono::steady_clock::time_point last;
+};
\ No newline at end of file

StudyDx/StudyDx.vcxproj

@@ -139,6 +139,7 @@
   <ItemGroup>
     <ClCompile Include="App.cpp" />
     <ClCompile Include="ChiliException.cpp" />
+    <ClCompile Include="ChiliTimer.cpp" />
     <ClCompile Include="Keyboard.cpp" />
     <ClCompile Include="Mouse.cpp" />
     <ClCompile Include="Window.cpp" />
@@ -148,6 +149,7 @@
   <ItemGroup>
     <ClInclude Include="App.h" />
     <ClInclude Include="ChiliException.h" />
+    <ClInclude Include="ChiliTimer.h" />
     <ClInclude Include="ChiliWin.h" />
     <ClInclude Include="Keyboard.h" />
     <ClInclude Include="Mouse.h" />

StudyDx/StudyDx.vcxproj.filters

@@ -36,6 +36,9 @@
     <ClCompile Include="App.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="ChiliTimer.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="ChiliException.h">
@@ -62,6 +65,9 @@
     <ClInclude Include="App.h">
       <Filter>Header Files</Filter>
     </ClInclude>
+    <ClInclude Include="ChiliTimer.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <ResourceCompile Include="StudyDx.rc">

StudyDx/Window.cpp

@@ -129,6 +129,29 @@ void Window::SetTitle(const std::string& title)
 	}
 }
 
+std::optional<int> Window::ProcessMessages()
+{
+	MSG msg;
+	// while queue has messages, remove and dispatch them (but do not block on empty queue)
+	// 检查一下消息队列，如果有的话就循环取出所有消息，如果没有的话直接返回，不阻塞
+	while (PeekMessage(&msg, nullptr, 0, 0, PM_REMOVE))
+	{
+		// check for quit because peekmessage does not signal this via return val
+		if (msg.message == WM_QUIT)
+		{
+			// return optional wrapping int (arg to PostQuitMessage is in wparam) signals quit
+			return (int)msg.wParam;
+		}
+
+		// TranslateMessage will post auxilliary WM_CHAR messages from key msgs
+		TranslateMessage(&msg);
+		DispatchMessage(&msg);
+	}
+
+	// return empty optional when not quitting app
+	return {};
+}
+
 LRESULT CALLBACK Window::HandleMsgSetup( HWND hWnd,UINT msg,WPARAM wParam,LPARAM lParam ) noexcept
 {
 	// use create parameter passed in from CreateWindow() to store window class pointer at WinAPI side

StudyDx/Window.h

@@ -22,6 +22,7 @@
 #include "ChiliException.h"
 #include "Keyboard.h"
 #include "Mouse.h"
+#include <optional>
 
 
 class Window
@@ -61,6 +62,7 @@ public:
 	Window(const Window&) = delete;
 	Window& operator=(const Window&) = delete;
 	void SetTitle(const std::string& title);
+	static std::optional<int> ProcessMessages();
 private:
 	static LRESULT CALLBACK HandleMsgSetup(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam) noexcept;
 	static LRESULT CALLBACK HandleMsgThunk(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam) noexcept;

StudyDx/WindowsMessageMap.cpp

@@ -33,7 +33,7 @@
 
 #define REGISTER_MESSAGE(msg){msg,#msg}
 
-WindowsMessageMap::WindowsMessageMap()
+WindowsMessageMap::WindowsMessageMap() noexcept
 	:
 	map({
 		REGISTER_MESSAGE(WM_CREATE),
@@ -168,15 +168,6 @@ WindowsMessageMap::WindowsMessageMap()
 		REGISTER_MESSAGE(WM_QUERYNEWPALETTE),
 		REGISTER_MESSAGE(WM_PALETTEISCHANGING),
 		REGISTER_MESSAGE(WM_PALETTECHANGED),
-		REGISTER_MESSAGE(WM_DDE_INITIATE),
-		REGISTER_MESSAGE(WM_DDE_TERMINATE),
-		REGISTER_MESSAGE(WM_DDE_ADVISE),
-		REGISTER_MESSAGE(WM_DDE_UNADVISE),
-		REGISTER_MESSAGE(WM_DDE_ACK),
-		REGISTER_MESSAGE(WM_DDE_DATA),
-		REGISTER_MESSAGE(WM_DDE_REQUEST),
-		REGISTER_MESSAGE(WM_DDE_POKE),
-		REGISTER_MESSAGE(WM_DDE_EXECUTE),
 		REGISTER_MESSAGE(WM_DROPFILES),
 		REGISTER_MESSAGE(WM_POWER),
 		REGISTER_MESSAGE(WM_WINDOWPOSCHANGED),
@@ -219,7 +210,7 @@ WindowsMessageMap::WindowsMessageMap()
 		})
 {}
 
-std::string WindowsMessageMap::operator()(DWORD msg, LPARAM lp, WPARAM wp) const
+std::string WindowsMessageMap::operator()(DWORD msg, LPARAM lp, WPARAM wp) const noexcept
 {
 	constexpr int firstColWidth = 25;
 	const auto i = map.find(msg);

StudyDx/WindowsMessageMap.h

@@ -21,12 +21,13 @@
 #include <unordered_map>
 #include <Windows.h>
 #include <string>
+#include "ChiliWin.h"
 
 class WindowsMessageMap
 {
 public:
-	WindowsMessageMap();
-	std::string operator()(DWORD msg, LPARAM lp, WPARAM wp) const;
+	WindowsMessageMap() noexcept;
+	std::string operator()(DWORD msg, LPARAM lp, WPARAM wp) const noexcept;
 private:
 	std::unordered_map<DWORD, std::string> map;
 };
\ No newline at end of file