From 022446bce75ad9f6e1fa9c0fdb96e4e9e621ca71 Mon Sep 17 00:00:00 2001
From: Leon Styhre <leon@leonstyhre.com>
Date: Sun, 22 Jan 2023 23:24:08 +0100
Subject: [PATCH] Found a better method to limit buffer swaps during splash
 screen rendering.

---
 es-app/src/SystemData.cpp           | 16 +++++++++++++---
 es-app/src/main.cpp                 |  8 --------
 es-app/src/views/ViewController.cpp |  3 +++
 3 files changed, 16 insertions(+), 11 deletions(-)

diff --git a/es-app/src/SystemData.cpp b/es-app/src/SystemData.cpp
index 72fdb29ce..7baa51526 100644
--- a/es-app/src/SystemData.cpp
+++ b/es-app/src/SystemData.cpp
@@ -25,6 +25,8 @@
 #include "views/GamelistView.h"
 #include "views/ViewController.h"
 
+#include <SDL2/SDL_timer.h>
+
 #include <fstream>
 #include <pugixml.hpp>
 #include <random>
@@ -511,6 +513,7 @@ bool SystemData::loadConfig()
         const bool splashScreen {Settings::getInstance()->getBool("SplashScreen")};
         float systemCount {0.0f};
         float loadedSystems {0.0f};
+        long unsigned int lastTime {0};
 
         for (pugi::xml_node system {systemList.child("system")}; system;
              system = system.next_sibling("system")) {
@@ -531,10 +534,17 @@ bool SystemData::loadConfig()
             path = system.child("path").text().get();
 
             if (splashScreen) {
+                const long unsigned int curTime {SDL_GetTicks64()};
+                const long unsigned int deltaTime {curTime - lastTime};
+                lastTime = curTime;
                 ++loadedSystems;
-                const float progress {glm::mix(0.0f, 0.5f, loadedSystems / systemCount)};
-                Window::getInstance()->renderSplashScreen(Window::SplashScreenState::SCANNING,
-                                                          progress);
+                // This prevents Renderer::swapBuffers() from being called excessively which
+                // could lead to significantly longer application startup times.
+                if (deltaTime > 15) {
+                    const float progress {glm::mix(0.0f, 0.5f, loadedSystems / systemCount)};
+                    Window::getInstance()->renderSplashScreen(Window::SplashScreenState::SCANNING,
+                                                              progress);
+                }
             }
 
             auto nameFindFunc = [&] {
diff --git a/es-app/src/main.cpp b/es-app/src/main.cpp
index 7fb8dca4d..d32fc08b6 100644
--- a/es-app/src/main.cpp
+++ b/es-app/src/main.cpp
@@ -707,15 +707,7 @@ int main(int argc, char* argv[])
     AudioManager::getInstance();
     MameNames::getInstance();
     ThemeData::populateThemeSets();
-    // We need to temporarily disable VSync as the splash screen may otherwise slow down
-    // application startup significantly due to excessive swapBuffers() calls.
-    const bool splashScreen {Settings::getInstance()->getBool("SplashScreen")};
-    const bool vSync {Settings::getInstance()->getBool("VSync")};
-    if (splashScreen && vSync)
-        SDL_GL_SetSwapInterval(0);
     loadSystemsReturnCode loadSystemsStatus {loadSystemConfigFile()};
-    if (splashScreen && vSync)
-        SDL_GL_SetSwapInterval(1);
 
     if (loadSystemsStatus) {
         // If there was an issue parsing the es_systems.xml file, display an error message.
diff --git a/es-app/src/views/ViewController.cpp b/es-app/src/views/ViewController.cpp
index 37ca8ee66..fbbd10750 100644
--- a/es-app/src/views/ViewController.cpp
+++ b/es-app/src/views/ViewController.cpp
@@ -1104,6 +1104,9 @@ void ViewController::preload()
 {
     unsigned int systemCount {static_cast<unsigned int>(SystemData::sSystemVector.size())};
 
+    if (Settings::getInstance()->getBool("SplashScreen"))
+        mWindow->renderSplashScreen(Window::SplashScreenState::POPULATING, 0.5f);
+
     // This reduces the amount of texture pop-in when loading theme extras.
     if (!SystemData::sSystemVector.empty())
         getSystemListView();