[os.input] add tz::os::is_key_pressed to query if a keyboard key is c…

…urrently pressed

include/tz/os/input.hpp

@@ -16,16 +16,64 @@ namespace tz::os
 	 **/
 	enum class key
 	{
-		// Letters
-		a, b, c, d, e, f, g,
-		h, i, j, k, l, m, n,
-		o, p, q, r, s, t, u,
-		v, w, x, y, z,
-
-		// Numbers
-		num_0, num_1, num_2, num_3, num_4,
-		num_5, num_6, num_7, num_8, num_9,
-		undefined
+		backspace,
+		tab,
+		enter,
+
+		left_shift,
+		left_control,
+		left_alt,
+
+		pause,
+		caps_lock,
+		escape,
+
+		spacebar,
+		page_down,
+		page_up,
+
+		end,
+		home,
+
+		left_arrow,
+		up_arrow,
+		right_arrow,
+		down_arrow,
+
+		select,
+		print,
+		printsc,
+		ins,
+		del,
+		n0,n1,n2,n3,n4,n5,n6,n7,n8,n9,
+		a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,
+
+		left_winkey,
+		right_winkey,
+		apps,
+		sleep,
+
+		np0,np1,np2,np3,np4,np5,np6,np7,np8,np9,
+		npmul,npadd,npsep,npsub,npdec,npdiv,
+		f1,f2,f3,f4,f5,f6,f7,f8,f9,f10,f11,f12,f13,f14,f15,f16,f17,f18,f19,f20,f21,f22,f23,f24,
+		num_lock,
+		scroll_lock,
+
+		right_shift,
+		right_control,
+		right_alt,
+		semicol,
+		period,
+		plus,
+		minus,
+
+		obrack,
+		cbrack,
+		forward_slash,
+		back_slash,
+		apostrophe,
+		grave,
+		_count
 	};
 
 	using char_type_callback = void(*)(char);
@@ -36,6 +84,13 @@ namespace tz::os
 	 * @return - @ref error_code::precondition_failure if a window has not yet been opened.
 	 **/
 	tz::error_code install_char_typed_callback(char_type_callback callback);
+	/**
+	 * @ingroup tz_os_input
+	 * @brief Query as to whether a specific key is pressed right now.
+	 * @param k Keyboard key to query
+	 * @return True if the given key is currently pressed, otherwise false.
+	 */
+	bool is_key_pressed(key k);
 }
 
 #endif // TOPAZ_OS_INPUT_HPP

src/tz/os/impl_win32.cpp

@@ -164,6 +164,141 @@ namespace tz::os
 		return tz::error_code::success;
 	}
 
+	bool key_pressed(key k)
+	{
+		std::array<int, static_cast<int>(key::_count)> key_mappings
+		{
+			VK_BACK,
+			VK_TAB,
+			VK_RETURN,
+
+			VK_LSHIFT,
+			VK_LCONTROL,
+			VK_LMENU,
+
+			VK_PAUSE,
+			VK_CAPITAL,
+			VK_ESCAPE,
+
+			VK_SPACE,
+			VK_NEXT,
+			VK_PRIOR,
+
+			VK_END,
+			VK_HOME,
+
+			VK_LEFT,
+			VK_UP,
+			VK_RIGHT,
+			VK_DOWN,
+
+			VK_SELECT,
+			VK_PRINT,
+			VK_SNAPSHOT,
+			VK_INSERT,
+			VK_DELETE,
+			'0',
+			'1',
+			'2',
+			'3',
+			'4',
+			'5',
+			'6',
+			'7',
+			'8',
+			'9',
+			'A',
+			'B',
+			'C',
+			'D',
+			'E',
+			'F',
+			'G',
+			'H',
+			'I',
+			'J',
+			'K',
+			'L',
+			'M',
+			'N',
+			'O',
+			'P',
+			'Q',
+			'R',
+			'S',
+			'T',
+			'U',
+			'V',
+			'W',
+			'X',
+			'Y',
+			'Z',
+			VK_LWIN,
+			VK_RWIN,
+			VK_APPS,
+			VK_SLEEP,
+
+			VK_NUMPAD0,
+			VK_NUMPAD1,
+			VK_NUMPAD2,
+			VK_NUMPAD3,
+			VK_NUMPAD4,
+			VK_NUMPAD5,
+			VK_NUMPAD6,
+			VK_NUMPAD7,
+			VK_NUMPAD8,
+			VK_NUMPAD9,
+			VK_MULTIPLY,
+			VK_ADD,
+			VK_SEPARATOR,
+			VK_SUBTRACT,
+			VK_DECIMAL,
+			VK_DIVIDE,
+			VK_F1,
+			VK_F2,
+			VK_F3,
+			VK_F4,
+			VK_F5,
+			VK_F6,
+			VK_F7,
+			VK_F8,
+			VK_F9,
+			VK_F10,
+			VK_F11,
+			VK_F12,
+			VK_F13,
+			VK_F14,
+			VK_F15,
+			VK_F16,
+			VK_F17,
+			VK_F18,
+			VK_F19,
+			VK_F20,
+			VK_F21,
+			VK_F22,
+			VK_F23,
+			VK_F24,
+			VK_NUMLOCK,
+			VK_SCROLL,
+
+			VK_RSHIFT,
+			VK_RCONTROL,
+			VK_RMENU,
+			VK_OEM_1,
+			VK_OEM_PERIOD,
+			VK_OEM_PLUS,
+			VK_OEM_MINUS,
+
+			VK_OEM_4,
+			VK_OEM_6,
+			VK_OEM_2,
+			VK_OEM_5,
+			VK_OEM_7,
+			VK_OEM_3
+		};
+		return GetAsyncKeyState(key_mappings[static_cast<int>(k)]) & 0x8000;
+	}
+
 	std::expected<std::string, tz::error_code> read_file(std::filesystem::path path)
 	{
 		HANDLE file = CreateFileA(path.string().c_str(), GENERIC_READ, FILE_SHARE_READ, nullptr, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, nullptr);