From b8838794e135c1b849ac7a8638ca8e948042ef86 Mon Sep 17 00:00:00 2001
From: Frederico Linhares <fred@linhares.blue>
Date: Mon, 8 Aug 2022 11:12:51 -0300
Subject: refa Replace SDL timer with C++ timer

---
 src/core.cpp |  5 ++++-
 src/core.hpp |  3 ++-
 src/main.cpp | 19 +++++++++++--------
 3 files changed, 17 insertions(+), 10 deletions(-)

diff --git a/src/core.cpp b/src/core.cpp
index 30acbf9..a1c996f 100644
--- a/src/core.cpp
+++ b/src/core.cpp
@@ -54,6 +54,8 @@ vk_debug_callback(
 static void
 load_variables(void *obj)
 {
+  using namespace std::chrono;
+
   YAML::Node root = YAML::LoadFile(cg_core.config_file);
 
   std::string game_name = root["name"].as<std::string>().c_str();
@@ -70,7 +72,8 @@ load_variables(void *obj)
   cg_core.game_version_patch = 0;
 
   cg_core.fps = 30;
-  cg_core.max_frame_duration_ms = 1000 / cg_core.fps;
+  cg_core.max_frame_duration =
+    duration<long long, std::milli>(1000 / cg_core.fps);
 }
 
 static void
diff --git a/src/core.hpp b/src/core.hpp
index a51d2b4..d9e68e8 100644
--- a/src/core.hpp
+++ b/src/core.hpp
@@ -23,6 +23,7 @@
 
 #define DATA_DIR "/usr/local/share/candy_gear"
 
+#include <chrono>
 #include <random>
 
 #include <mruby.h>
@@ -87,7 +88,7 @@ struct cg_sCore
   int game_version_major, game_version_minor, game_version_patch;
 
   Uint32 fps;
-  Uint32 max_frame_duration_ms;
+  std::chrono::duration<long long, std::milli> max_frame_duration;
 
   SDL_Window *window;
 
diff --git a/src/main.cpp b/src/main.cpp
index 34cbcb4..5155f60 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -14,6 +14,9 @@
  * limitations under the License.
  */
 
+#include <chrono>
+#include <thread>
+
 #include "camera.hpp"
 #include "candy_gear.hpp"
 #include "core.hpp"
@@ -33,8 +36,10 @@ static void handle_error(mrb_state *mrb)
 
 int main(int argc, char *argv[])
 {
+  using namespace std::chrono;
+  using namespace std::this_thread;
+
   SDL_Event event;
-  Uint32 frame_start;
 
   // Random numbers
   random_number_generator.seed(random_seed());
@@ -79,7 +84,7 @@ int main(int argc, char *argv[])
     if (cg_core.mrb->exc) handle_error(cg_core.mrb);
   }
 
-  frame_start = SDL_GetTicks();
+  auto frame_start = steady_clock::now();
 
   // Game main loop.
   while(!cg_core.quit_game)
@@ -118,14 +123,12 @@ int main(int argc, char *argv[])
 
     // Timer
     {
-      Uint32 frame_stop, frame_duration;
-
-      frame_stop = SDL_GetTicks();
-      frame_duration = frame_stop - frame_start;
+      auto frame_stop = steady_clock::now();
+      auto frame_duration = frame_stop - frame_start;
 
       // If frame take less time than maximum allowed.
-      if(cg_core.max_frame_duration_ms > frame_duration)
-	SDL_Delay(cg_core.max_frame_duration_ms - frame_duration);
+      if(cg_core.max_frame_duration > frame_duration)
+	sleep_for(cg_core.max_frame_duration - frame_duration);
 
       frame_start = frame_stop;
     }
-- 
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