From e2761965720e9f5ea938b23133b508731e37511f Mon Sep 17 00:00:00 2001
From: XProger <xproger@list.ru>
Date: Sat, 18 Jul 2020 17:25:57 +0300
Subject: [PATCH] 30 updates per second (Core::UPS)

---
 src/core.h                |  6 ++++++
 src/game.h                | 26 +++++++++++++-------------
 src/platform/win/main.cpp | 34 ++++++++++++++++++++++------------
 3 files changed, 41 insertions(+), 25 deletions(-)

diff --git a/src/core.h b/src/core.h
index d15f153..e7db117 100644
--- a/src/core.h
+++ b/src/core.h
@@ -176,6 +176,8 @@ extern void  osMutexFree     (void *obj);
 extern void  osMutexLock     (void *obj);
 extern void  osMutexUnlock   (void *obj);
 
+extern int64 osGetCounter    ();
+extern int64 osGetFrequency  ();
 extern int   osGetTimeMS     ();
 
 extern bool  osJoyReady      (int index);
@@ -229,6 +231,10 @@ enum RenderTargetOp {
 
 namespace Core {
 
+    enum {
+        UPS = 30,
+    };
+
     struct Mutex {
         void *obj;
     
diff --git a/src/game.h b/src/game.h
index f909888..46a55f7 100644
--- a/src/game.h
+++ b/src/game.h
@@ -203,17 +203,17 @@ namespace Game {
             if (Input::lastState[1] == cStart) level->addPlayer(1);
         }
 
+        /*
         float dt = Core::deltaTime;
         if (Input::down[ikR]) // slow motion (for animation debugging)
             Core::deltaTime /= 10.0f;
+        */
 
         if (Input::down[ikT]) // fast motion
             for (int i = 0; i < 9; i++)
                 level->update();
 
         level->update();
-
-        Core::deltaTime = dt;
     }
 
     void quickSave() {
@@ -247,17 +247,23 @@ namespace Game {
         }
     }
 
+    int32 lastFrame = -1;
+
     bool update() {
     // async load for settings
         if (Core::settings.version == SETTINGS_READING)
             return true;
 
-        PROFILE_MARKER("UPDATE");
-
         if (!Core::update())
             return false;
 
-        float delta = Core::deltaTime;
+        int32 frame = int32(osGetCounter() * 30L / osGetFrequency());
+        int32 frameDelta = frame - lastFrame;
+        lastFrame = frame;
+
+        if (frameDelta <= 0) {
+            return false;
+        }
 
         if (nextLevel) {
             startLevel(nextLevel);
@@ -293,15 +299,9 @@ namespace Game {
             Input::down[ik9] = false;
         }
 
-        if (!level->level.isCutsceneLevel())
-            delta = min(0.2f, delta);
-
-        while (delta > EPS) {
-            Core::deltaTime = min(delta, 1.0f / 30.0f);
+        Core::deltaTime = 1.0f / Core::UPS;
+        for (int i = 0; i < frameDelta; i++) {
             Game::updateTick();
-            delta -= Core::deltaTime;
-            if (Core::resetState) // resetTime was called
-                break;
         }
 
         return true;
diff --git a/src/platform/win/main.cpp b/src/platform/win/main.cpp
index dc1cf6e..91c70a3 100644
--- a/src/platform/win/main.cpp
+++ b/src/platform/win/main.cpp
@@ -47,18 +47,29 @@ void osMutexUnlock(void *obj) {
 }
 
 // timing
-int osStartTime = 0;
+int64 osCounterStart = 0;
+int64 osCounterFrequency = 0;
+
+int64 osGetCounter() {
+    LARGE_INTEGER value;
+    QueryPerformanceCounter(&value);
+    return value.QuadPart - osCounterStart;
+}
+
+int64 osGetFrequency() {
+    return osCounterFrequency;
+}
 
 int osGetTimeMS() {
-#ifdef DEBUG
-    LARGE_INTEGER Freq, Count;
-    QueryPerformanceFrequency(&Freq);
-    QueryPerformanceCounter(&Count);
-    return int(Count.QuadPart * 1000L / Freq.QuadPart);
-#else
-    timeBeginPeriod(0);
-    return int(timeGetTime()) - osStartTime;
-#endif
+    return int32(osGetCounter() * 1000L / osCounterFrequency);
+}
+
+void initCounter() {
+    LARGE_INTEGER value;
+    QueryPerformanceCounter(&value);
+    osCounterStart = value.QuadPart;
+    QueryPerformanceFrequency(&value);
+    osCounterFrequency = value.QuadPart;
 }
 
 // common input functions
@@ -929,7 +940,6 @@ int main(int argc, char** argv) {
     _CrtSetReportMode(_CRT_WARN, _CRTDBG_MODE_FILE);
     _CrtSetReportFile(_CRT_WARN, _CRTDBG_FILE_STDOUT);
     _CrtMemCheckpoint(&_msBegin);
-//#elif PROFILE
 #elif PROFILE
 int main(int argc, char** argv) {
 #else
@@ -1017,7 +1027,7 @@ int CALLBACK WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLi
 
     Sound::channelsCount = 0;
 
-    osStartTime = Core::getTime();
+    initCounter();
 
     touchInit(hWnd);
     joyInit();