Complete timing functions

src/engine.cc

@@ -61,6 +61,7 @@ namespace openrayman
         {
             double current_timer_value = m_backend_specifics.get_time();
             m_current_delta_time = current_timer_value - m_last_timer_value;
+            m_accumulated_time += m_current_delta_time;
             m_total_time += m_current_delta_time;
             m_last_timer_value = current_timer_value;
 
@@ -73,9 +74,25 @@ namespace openrayman
             if(m_current_input.command(input_command::toggle_fullscreen) && !m_last_input.command(input_command::toggle_fullscreen))
                 m_config.fullscreen = !m_config.fullscreen;
 
+            std::cout << "Update: " << m_current_delta_time * 1000 << "ms, " << m_total_frames << std::endl;
+            m_total_frames++;
+            while(m_accumulated_time >= 1 / m_static_info.updates_per_second)
+            {
+                std::cout << "Fixed update: " << m_total_fixed_updates << std::endl;
+                m_total_fixed_updates++;
+                m_accumulated_time -= 1 / m_static_info.updates_per_second;
+            }
+
+            m_window.present();
+
+            if(m_config.max_fps > 0)
+            {
+                while(m_backend_specifics.get_time() - m_last_timer_value < 1 / m_config.max_fps)
+                    m_backend_specifics.yield_cpu();
+            }
+
             m_window.set_vsync(m_config.vsync);
             m_window.set_fullscreen(m_config.fullscreen);
-            m_window.present();
 
             m_exit_requested = m_exit_requested || m_window.wants_close();
         }

src/engine.h

@@ -7,6 +7,7 @@
 #include <GL/gl3w.h>
 #include <config/info.h>
 #include <config/config.h>
+#include <cstdint>
 
 #ifdef LIBRETRO_CORE
 #error Building as a libretro core is not yet supported!
@@ -35,6 +36,9 @@ public:
             m_last_timer_value(0),
             m_current_delta_time(0),
             m_total_time(0),
+            m_accumulated_time(0),
+            m_total_frames(0),
+            m_total_fixed_updates(0),
             m_static_info(m_backend_specifics),
             m_config(m_static_info, m_backend_specifics)
             { };
@@ -95,6 +99,18 @@ public:
             return m_current_delta_time;
         }
 
+        // Returns the total amount of frames that have passed since the start of the game.
+        inline std::uint64_t get_total_frames() const
+        {
+            return m_total_frames;
+        }
+
+        // Returns the total amount of fixed updates that have passed since the start of the game.
+        inline std::uint64_t get_total_fixed_updates() const
+        {
+            return m_total_fixed_updates;
+        }
+
         // Returns a reference to the active static engine info.
         inline const info& get_static_info() const
         {
@@ -112,7 +128,8 @@ private:
         backend_specifics& m_backend_specifics;
         input_state m_current_input;
         input_state m_last_input;
-        double m_last_timer_value, m_current_delta_time, m_total_time;
+        double m_last_timer_value, m_current_delta_time, m_total_time, m_accumulated_time;
+        std::uint64_t m_total_frames, m_total_fixed_updates;
         info m_static_info;
         config m_config;
         bool m_exit_requested;

src/main.cc

@@ -2,9 +2,6 @@
 #include <iostream>
 #include <info.h>
 #include <engine.h>
-#ifndef _WIN32
-#include <gtk/gtk.h>
-#endif
 
 int main(int argc, char** argv)
 {
@@ -30,7 +27,7 @@ int main(int argc, char** argv)
             std::cout << "Options:" << std::endl;
             std::cout << "  --version  Display version information" << std::endl;
             std::cout << "  --game     Specifies what game to run" << std::endl;
-            std::cout << "             This will default to the game set in \"info.json\" if no game is specified." << std::endl;
+            std::cout << "             This will default to the game set in \"config.json\" if no game is specified." << std::endl;
             return EXIT_SUCCESS;
         }
         if(str == "--version")

src/platform/backend_specifics.h

@@ -2,6 +2,7 @@
 #define BACKEND_SPECIFICS_H
 
 #include <string>
+#include <cstdint>
 
 namespace openrayman
 {
@@ -19,6 +20,9 @@ public:
 
         // Returns a high-resolution timer value in seconds.
         virtual double get_time() const = 0;
+
+        // Yields CPU using the most efficient method possible.
+        virtual void yield_cpu() const = 0;
     };
 }
 

src/platform/standalone_backend_specifics.cc

@@ -103,4 +103,15 @@ namespace openrayman
         // we use GLFW when we are run standalone.
         return glfwGetTime();
     }
+
+    void standalone_backend_specifics::yield_cpu() const
+    {
+#ifdef _WIN32
+        // might consume 100% cpu? who cares lmao
+        Sleep(0);
+#else
+        // usleep has the same effect as sched_yield, but does not consume 100% CPU.
+        usleep(0);
+#endif
+    }
 }

src/platform/standalone_backend_specifics.h

@@ -24,6 +24,8 @@ public:
         const std::string& get_storage_path() const override;
 
         double get_time() const override;
+
+        void yield_cpu() const override;
 private:
         void initialize_data_path();
         void initialize_storage_path();