From d90471adedd805d524bf5f7480fe58c53f7ec919 Mon Sep 17 00:00:00 2001
From: RSDuck <RSDuck@users.noreply.github.com>
Date: Mon, 17 Oct 2022 22:21:24 +0200
Subject: [PATCH] stuff Arisotura said

---
 src/frontend/qt_sdl/VideoSettingsDialog.cpp | 11 +++++++++++
 src/frontend/qt_sdl/VideoSettingsDialog.h   |  3 ++-
 src/frontend/qt_sdl/main.cpp                | 10 +++++++++-
 3 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/src/frontend/qt_sdl/VideoSettingsDialog.cpp b/src/frontend/qt_sdl/VideoSettingsDialog.cpp
index 87129428..95ec7d31 100644
--- a/src/frontend/qt_sdl/VideoSettingsDialog.cpp
+++ b/src/frontend/qt_sdl/VideoSettingsDialog.cpp
@@ -78,6 +78,7 @@ VideoSettingsDialog::VideoSettingsDialog(QWidget* parent) : QDialog(parent), ui(
 
     if (!Config::ScreenVSync)
         ui->sbVSyncInterval->setEnabled(false);
+    setVsyncControlEnable(UsesGL());
 
     if (Config::_3DRenderer == 0)
     {
@@ -124,6 +125,12 @@ void VideoSettingsDialog::on_VideoSettingsDialog_rejected()
     closeDlg();
 }
 
+void VideoSettingsDialog::setVsyncControlEnable(bool hasOGL)
+{
+    ui->cbVSync->setEnabled(hasOGL);
+    ui->sbVSyncInterval->setEnabled(hasOGL);
+}
+
 void VideoSettingsDialog::onChange3DRenderer(int renderer)
 {
     bool old_gl = (Config::ScreenUseGL != 0) || (Config::_3DRenderer != 0);
@@ -154,6 +161,8 @@ void VideoSettingsDialog::on_cbGLDisplay_stateChanged(int state)
 
     Config::ScreenUseGL = (state != 0);
 
+    setVsyncControlEnable(UsesGL());
+
     emit updateVideoSettings(old_gl != UsesGL());
 }
 
@@ -185,6 +194,8 @@ void VideoSettingsDialog::on_cbxGLResolution_currentIndexChanged(int idx)
 
     Config::GL_ScaleFactor = idx+1;
 
+    setVsyncControlEnable(UsesGL());
+
     emit updateVideoSettings(false);
 }
 
diff --git a/src/frontend/qt_sdl/VideoSettingsDialog.h b/src/frontend/qt_sdl/VideoSettingsDialog.h
index 527cc931..7fee5bb8 100644
--- a/src/frontend/qt_sdl/VideoSettingsDialog.h
+++ b/src/frontend/qt_sdl/VideoSettingsDialog.h
@@ -67,8 +67,9 @@ private slots:
     void on_cbBetterPolygons_stateChanged(int state);
 
     void on_cbSoftwareThreaded_stateChanged(int state);
-
 private:
+    void setVsyncControlEnable(bool hasOGL);
+
     Ui::VideoSettingsDialog* ui;
 
     QButtonGroup* grp3DRenderer;
diff --git a/src/frontend/qt_sdl/main.cpp b/src/frontend/qt_sdl/main.cpp
index a8add8ee..cd0ea52d 100644
--- a/src/frontend/qt_sdl/main.cpp
+++ b/src/frontend/qt_sdl/main.cpp
@@ -569,7 +569,10 @@ void EmuThread::run()
             if (EmuRunning == 3) EmuRunning = 2;
 
             // update render settings if needed
-            if (videoSettingsDirty)
+            // HACK:
+            // once the fast forward hotkey is released, we need to update vsync
+            // to the old setting again
+            if (videoSettingsDirty || Input::HotkeyReleased(HK_FastForward))
             {
                 if (oglContext)
                 {
@@ -674,6 +677,11 @@ void EmuThread::run()
 
             bool fastforward = Input::HotkeyDown(HK_FastForward);
 
+            if (fastforward && oglContext && Config::ScreenVSync)
+            {
+                oglContext->SetSwapInterval(0);
+            }
+
             if (Config::AudioSync && !fastforward && audioDevice)
             {
                 SDL_LockMutex(audioSyncLock);