Use chrono steady_clock for time measurement

Descent3/init.cpp

@@ -1461,7 +1461,6 @@ void InitIOSystems(bool editor) {
 
   //	do io init stuff
   io_info.obj = Descent;
-  io_info.use_lo_res_time = (bool)(FindArg("-lorestimer") != 0);
   io_info.joy_emulation = (bool)((FindArg("-alternatejoy") == 0) && (FindArg("-directinput") == 0));
   io_info.key_emulation = true; //(bool)(FindArg("-slowkey")!=0); WIN95: DirectInput is flaky for some keys.
   INIT_MESSAGE(("Initializing DDIO systems."));
@@ -2229,7 +2228,6 @@ void RestartD3() {
 
   // startup io
   io_info.obj = Descent;
-  io_info.use_lo_res_time = (bool)(FindArg("-lorestimer") != 0);
   io_info.key_emulation = true; //(bool)(FindArg("-slowkey")!=0);
   io_info.joy_emulation = (bool)((FindArg("-alternatejoy") == 0) && (FindArg("-directinput") == 0));
   if (!ddio_Init(&io_info)) {

ddio/CMakeLists.txt

@@ -1,4 +1,5 @@
 set(CPPS
+  chrono_timer.cpp
   ddio.cpp
   key.cpp
   $<$<PLATFORM_ID:Darwin,Linux>:
@@ -9,7 +10,6 @@ set(CPPS
     lnxkey.cpp
     lnxkey_null.cpp
     lnxmouse.cpp
-    lnxtimer.cpp
     lnxcdrom.cpp
     lnxkey_sdl.cpp
   >
@@ -20,7 +20,6 @@ set(CPPS
     winjoy.cpp
     winkey.cpp
     winmouse.cpp
-    wintimer.cpp
   >
 )
 add_library(ddio STATIC ${CPPS})

ddio/chrono_timer.cpp

@@ -0,0 +1,36 @@
+/*
+ * Descent 3
+ * Copyright (C) 2024 Descent Developers
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <chrono>
+#include "chrono_timer.h"
+
+namespace D3 {
+
+void ChronoTimer::Initialize() { m_start_tstamp = std::chrono::steady_clock::now(); }
+
+float ChronoTimer::GetTime() {
+  return std::chrono::duration_cast<std::chrono::duration<float>>(std::chrono::steady_clock::now() - m_start_tstamp)
+      .count();
+}
+
+int64_t ChronoTimer::GetTimeMS() {
+  return std::chrono::duration_cast<std::chrono::milliseconds>(std::chrono::steady_clock::now() - m_start_tstamp)
+      .count();
+}
+
+} // namespace D3

ddio/chrono_timer.h

@@ -0,0 +1,44 @@
+/*
+ * Descent 3
+ * Copyright (C) 2024 Descent Developers
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <chrono>
+
+namespace D3 {
+
+static std::chrono::time_point<std::chrono::steady_clock> m_start_tstamp;
+
+/**
+ * Static class for handling timers and time durations
+ */
+class ChronoTimer {
+public:
+
+  /// Initialize internal timestamp
+  static void Initialize();
+
+  /// Get time in seconds after class initialization (i.e. application start)
+  static float GetTime();
+
+  /// Get time in milliseconds after class initialization (i.e. application start)
+  static int64_t GetTimeMS();
+
+};
+
+}

ddio/ddio.cpp

@@ -107,7 +107,7 @@ bool ddio_Init(ddio_init_info *init_info) {
   res = ddio_InternalInit(init_info);
   if (res) {
     if (first_time) { // initialize once and only once.
-      timer_Init(0, init_info->use_lo_res_time);
+      timer_Init();
     }
     if (!ddio_KeyInit(init_info))
       Error("Failed to initialize keyboard system.");

ddio/ddio.h

@@ -193,8 +193,9 @@
 #include <cstdio>
 #include <cstdint>
 
-#include "pstypes.h"
+#include "chrono_timer.h"
 #include "ddio_common.h"
+#include "pstypes.h"
 
 // ----------------------------------------------------------------------------
 //	Initialization and destruction functions
@@ -230,20 +231,9 @@ void ddio_InternalResetKey(uint8_t key);
 //	Device Dependent Timer Interface
 // ----------------------------------------------------------------------------
 
-bool timer_Init(int preemptive, bool force_lores);
-void timer_Close();
-
-//	returns time in seconds
-float timer_GetTime();
-
-// returns time in milliseconds
-int64_t timer_GetMSTime();
-
-//	hook in timer function at certain period.  returns a handle to this function
-//@@int timer_HookFunction(void (*fncptr)(), int period);
-
-//	clears function from hook list specified by a handle returned from HookFunction
-//@@void timer_ReleaseFunction(int func);
+#define timer_Init D3::ChronoTimer::Initialize
+#define timer_GetTime D3::ChronoTimer::GetTime
+#define timer_GetMSTime D3::ChronoTimer::GetTimeMS
 
 // ----------------------------------------------------------------------------
 //	Device Dependent Mouse Interface

ddio/ddio_common.h

@@ -124,7 +124,6 @@
 
 typedef struct ddio_init_info {
   oeApplication *obj; // App object used to initialize to IO system
-  bool use_lo_res_time;
   bool key_emulation; // keyboard emulation
   bool joy_emulation; // joystick emulation
 } ddio_init_info;