From 32ffd21076bfd0704e3eff0eef3b8bba97e31638 Mon Sep 17 00:00:00 2001
From: ohyzha <oleksii.hyzha.ext@madvoxel.com>
Date: Sun, 25 Aug 2024 16:21:31 +0300
Subject: [PATCH] main loop improvements

---
 openVulkanoCpp/Base/EngineConfiguration.hpp | 14 +++++++--
 openVulkanoCpp/Host/GraphicsAppManager.cpp  | 34 ++++++++++++++++++---
 openVulkanoCpp/Host/GraphicsAppManager.hpp  |  2 ++
 3 files changed, 44 insertions(+), 6 deletions(-)

diff --git a/openVulkanoCpp/Base/EngineConfiguration.hpp b/openVulkanoCpp/Base/EngineConfiguration.hpp
index 347fec7..61ef440 100644
--- a/openVulkanoCpp/Base/EngineConfiguration.hpp
+++ b/openVulkanoCpp/Base/EngineConfiguration.hpp
@@ -9,6 +9,7 @@
 #include <cstdint>
 #include <algorithm>
 #include <array>
+#include "Base/Event.hpp"
 #undef max
 
 namespace OpenVulkano
@@ -34,10 +35,19 @@ namespace OpenVulkano
 		void SetVSync(bool vSync) { m_vSync = vSync; }
 
 		[[nodiscard]] int32_t GetFpsCap() const { return m_fpsCap; }
-		void SetFpsCap(int32_t fpsCap) { m_fpsCap = fpsCap; }
+		void SetFpsCap(int32_t fpsCap)
+		{
+			if (m_fpsCap != fpsCap)
+			{
+				m_fpsCap = fpsCap;
+				OnFpsCapChanged(fpsCap);
+			}
+		}
 
 		[[nodiscard]] uint32_t GetPrefferedSwapChainImageCount() const { return m_preferredImageCount; }
 		void SetPrefferedSwapChainImageCount(uint32_t preferredImageCount) { m_preferredImageCount = preferredImageCount; }
+	public:
+		Event<int32_t> OnFpsCapChanged;
 
 		private:
 		EngineConfiguration();
@@ -48,7 +58,7 @@ namespace OpenVulkano
 		bool m_preferFramebufferFormatSRGB = true;
 		bool m_lazyRendering = false;
 		bool m_vSync = false;
-		int32_t m_fpsCap = 500; // -1 = no fps cap. 0 = fps cap if vsync, no cap otherwise. > 0 = set fps cap
+		int32_t m_fpsCap = -1; // -1 = no fps cap. 0 = fps cap if vsync, no cap otherwise. > 0 = set fps cap
 		#ifdef __APPLE__
 				uint32_t m_preferredImageCount = 3;
 		#else
diff --git a/openVulkanoCpp/Host/GraphicsAppManager.cpp b/openVulkanoCpp/Host/GraphicsAppManager.cpp
index 6d29b66..9377b56 100644
--- a/openVulkanoCpp/Host/GraphicsAppManager.cpp
+++ b/openVulkanoCpp/Host/GraphicsAppManager.cpp
@@ -41,6 +41,12 @@ namespace OpenVulkano
 		window->SetWindowHandler(this);
 		inputManager = Input::InputManager::GetInstance();
 		engineConfig = EngineConfiguration::GetEngineConfiguration();
+		engineConfig->OnFpsCapChanged += EventHandler(this, &GraphicsAppManager::UpdateCappedFpsInfo);
+		// set initial values
+		if (engineConfig->GetFpsCap() > 0)
+		{
+			UpdateCappedFpsInfo(engineConfig->GetFpsCap());
+		}
 	}
 
 	GraphicsAppManager::GraphicsAppManager(IGraphicsApp* app, IWindow* window, RenderAPI::RenderApi renderApi)
@@ -63,19 +69,38 @@ namespace OpenVulkano
 		window->SetWindowHandler(this);
 		inputManager = OpenVulkano::Input::InputManager::GetInstance();
 		engineConfig = OpenVulkano::EngineConfiguration::GetEngineConfiguration();
+		engineConfig->OnFpsCapChanged += EventHandler(this, &GraphicsAppManager::UpdateCappedFpsInfo);
+		// set initial values
+		if (engineConfig->GetFpsCap() > 0)
+		{
+			UpdateCappedFpsInfo(engineConfig->GetFpsCap());
+		}
+	}
+
+	void GraphicsAppManager::UpdateCappedFpsInfo(int32_t newFpsCap)
+	{ 
+		if (newFpsCap < 0)
+		{
+			cappedFrameTime = std::chrono::milliseconds(0);
+		}
+		else
+		{
+			cappedFrameTime = std::chrono::milliseconds(1000 / newFpsCap);
+		}
 	}
 
 	void GraphicsAppManager::OnCappedFPS(const auto& frameStartTime) 
 	{
 		int32_t fpsCap = engineConfig->GetFpsCap();
 		fpsCapRemainder += 1000 % fpsCap;
-		auto frameTime = std::chrono::milliseconds(1000 / fpsCap);
+		auto expectedFrameTime = cappedFrameTime;
 		if (fpsCapRemainder >= fpsCap)
 		{
-			frameTime += std::chrono::milliseconds(1);
+			expectedFrameTime += std::chrono::milliseconds(1);
 			fpsCapRemainder -= fpsCap;
 		}
-		while (clock::now() < frameStartTime + frameTime)
+		auto frameEndTime = frameStartTime + expectedFrameTime;
+		while (clock::now() < frameEndTime)
 		{
 			std::this_thread::yield();
 		}
@@ -84,6 +109,7 @@ namespace OpenVulkano
 	GraphicsAppManager::~GraphicsAppManager() noexcept
 	{
 		if (windowTitleFormat.empty()) return;
+		engineConfig->OnFpsCapChanged -= EventHandler(this, &GraphicsAppManager::UpdateCappedFpsInfo);
 		ShutDown();
 	}
 
@@ -165,7 +191,7 @@ namespace OpenVulkano
 			inputManager->Tick();
 			app->Tick();
 			if (CURRENT_FRAME.needsRedraw) renderer->Tick();
-			if (engineConfig->GetFpsCap() > 0 && !engineConfig->GetVSync())
+			if (cappedFrameTime.count())
 			{
 				OnCappedFPS(start);
 			}
diff --git a/openVulkanoCpp/Host/GraphicsAppManager.hpp b/openVulkanoCpp/Host/GraphicsAppManager.hpp
index d264e1b..d28490b 100644
--- a/openVulkanoCpp/Host/GraphicsAppManager.hpp
+++ b/openVulkanoCpp/Host/GraphicsAppManager.hpp
@@ -38,6 +38,7 @@ namespace OpenVulkano
 		bool paused = false, running = false;
 		float fpsTimer = 0, avgFps = 0, avgFrameTime = 0;
 		uint64_t frameCount = 0, lastFrameCount = 0, fpsCapRemainder = 0;
+		std::chrono::milliseconds cappedFrameTime = std::chrono::milliseconds(0);
 		Timer frameTimer;
 		std::string windowTitleFormat;
 		Input::InputManager* inputManager;
@@ -45,6 +46,7 @@ namespace OpenVulkano
 
 	private:
 		void OnCappedFPS(const auto& frameStartTime);
+		void UpdateCappedFpsInfo(int32_t newFpsCap);
 	public:
 		explicit GraphicsAppManager(IGraphicsApp* app, RenderAPI::RenderApi renderApi = RenderAPI::Vulkan);