From f4ec69021db51dc801fb928971a2c1c01a498d74 Mon Sep 17 00:00:00 2001
From: WerWolv <werwolv98@gmail.com>
Date: Thu, 14 Mar 2024 21:18:57 +0100
Subject: [PATCH] impr: Manually implement VSync because GPU manufacturers are
 terrible at writing drivers

---
 main/gui/source/window/window.cpp | 30 ++++++++++++++++++++++--------
 1 file changed, 22 insertions(+), 8 deletions(-)

diff --git a/main/gui/source/window/window.cpp b/main/gui/source/window/window.cpp
index d8372c795..3f6311a04 100644
--- a/main/gui/source/window/window.cpp
+++ b/main/gui/source/window/window.cpp
@@ -208,7 +208,6 @@ namespace hex {
                 // Long sleep mode is enabled automatically after a few frames if the window content hasn't changed
                 // and no events have been received
                 if (shouldLongSleep) {
-                    std::this_thread::sleep_for(std::chrono::milliseconds(1));
                     // Calculate the time until the next frame
                     constexpr static auto LongSleepFPS = 5.0;
                     const double timeout = std::max(0.0, (1.0 / LongSleepFPS) - (glfwGetTime() - m_lastStartFrameTime));
@@ -236,15 +235,28 @@ namespace hex {
 
             // Limit frame rate
             // If the target FPS are below 15, use the monitor refresh rate, if it's above 200, don't limit the frame rate
-            const auto targetFPS = ImHexApi::System::getTargetFPS();
-            if (targetFPS < 15) {
-                glfwSwapInterval(1);
-            } else if (targetFPS > 200) {
-                glfwSwapInterval(0);
+            auto targetFPS = ImHexApi::System::getTargetFPS();
+            if (targetFPS >= 200) {
+                // Let it rip
             } else {
+                // If the target frame rate is below 15, use the current monitor's refresh rate
+                if (targetFPS < 15) {
+                    // Fall back to 60 FPS if the monitor refresh rate cannot be determined
+                    targetFPS = 60;
+
+                    if (auto monitor = glfwGetWindowMonitor(m_window); monitor != nullptr) {
+                        if (auto videoMode = glfwGetVideoMode(monitor); videoMode != nullptr) {
+                            targetFPS = videoMode->refreshRate;
+                        }
+                    }
+                }
+
+                // Sleep if we're not in long sleep mode
                 if (!shouldLongSleep) {
-                    glfwSwapInterval(0);
+                    // If anything goes wrong with these checks, make sure that we're sleeping for at least 1ms
                     std::this_thread::sleep_for(std::chrono::milliseconds(1));
+
+                    // Sleep for the remaining time if the frame rate is above the target frame rate
                     const auto frameTime = glfwGetTime() - m_lastStartFrameTime;
                     const auto targetFrameTime = 1.0 / targetFPS;
                     if (frameTime < targetFrameTime) {
@@ -718,7 +730,9 @@ namespace hex {
         glfwSetWindowOpacity(m_window, 1.0F);
 
         glfwMakeContextCurrent(m_window);
-        glfwSwapInterval(1);
+
+        // Disable VSync. Not like any graphics driver actually cares
+        glfwSwapInterval(0);
 
         // Center window
         GLFWmonitor *monitor = glfwGetPrimaryMonitor();