SaveTool: add a frame limiter.

The FPS slider isn't the most accurate, but it just works™.
Closes #10.

src/SaveTool/SaveTool.cpp

@@ -136,6 +136,19 @@ SaveTool::SaveTool(const Arguments& arguments):
 
     initialiseConfiguration();
 
+    switch(_framelimit) {
+        case Framelimit::Vsync:
+            setSwapInterval(1);
+            break;
+        case Framelimit::HalfVsync:
+            setSwapInterval(2);
+            break;
+        case Framelimit::FpsCap:
+            setSwapInterval(0);
+            setMinimalLoopPeriod(1000/_fpsCap);
+            break;
+    }
+
     if(_checkUpdatesOnStartup) {
         _thread = std::thread{[this]{ checkForUpdates(); }};
         _queue.addToast(Toast::Type::Default, "Checking for updates...");
@@ -148,6 +161,19 @@ SaveTool::~SaveTool() {
     _conf.setValue("cheat_mode", _cheatMode);
     _conf.setValue("unsafe_mode", _unsafeMode);
     _conf.setValue("startup_update_check", _checkUpdatesOnStartup);
+
+    switch(_framelimit) {
+        case Framelimit::Vsync:
+            _conf.setValue("frame_limit", "vsync");
+            break;
+        case Framelimit::HalfVsync:
+            _conf.setValue("frame_limit", "half_vsync");
+            break;
+        case Framelimit::FpsCap:
+            _conf.setValue<UnsignedInt>("frame_limit", _fpsCap);
+            break;
+    }
+
     _conf.save();
 }
 
@@ -379,6 +405,23 @@ void SaveTool::initialiseConfiguration() {
         _conf.setValue("startup_update_check", _checkUpdatesOnStartup);
     }
 
+    if(_conf.hasValue("frame_limit")) {
+        std::string frame_limit = _conf.value("frame_limit");
+        if(frame_limit == "vsync") {
+            _framelimit = Framelimit::Vsync;
+        }
+        else if(frame_limit == "half_vsync") {
+            _framelimit = Framelimit::HalfVsync;
+        }
+        else {
+            _framelimit = Framelimit::FpsCap;
+            _fpsCap = std::stoul(frame_limit);
+        }
+    }
+    else {
+        _conf.setValue("frame_limit", "vsync");
+    }
+
     _conf.save();
 }
 

src/SaveTool/SaveTool.h

@@ -197,6 +197,13 @@ class SaveTool: public Platform::Sdl2Application, public efsw::FileWatchListener
         };
         Containers::StaticArray<2, efsw::WatchID> _watchIDs;
 
+        enum class Framelimit: UnsignedByte {
+            Vsync,
+            HalfVsync,
+            FpsCap
+        } _framelimit{Framelimit::Vsync};
+        UnsignedInt _fpsCap{60};
+
         bool _checkUpdatesOnStartup{true};
         bool _unsafeMode{false};
 

src/SaveTool/SaveTool_drawMainMenu.cpp

@@ -55,6 +55,48 @@ void SaveTool::drawMainMenu() {
             ImGui::Separator();
 
             if(ImGui::BeginMenu(ICON_FA_COG " Settings")) {
+                ImGui::AlignTextToFramePadding();
+                ImGui::TextUnformatted("Frame limiter:");
+                ImGui::SameLine();
+
+                static UnsignedByte selection = static_cast<UnsignedByte>(_framelimit);
+                static const char* framelimit_labels[3] = {
+                    "V-sync",
+                    "Half V-sync",
+                    "FPS cap, no V-sync"
+                };
+
+                ImGui::SetNextItemWidth(150.0f);
+                if(ImGui::BeginCombo("##FrameLimit", framelimit_labels[selection])) {
+                    if(ImGui::Selectable(framelimit_labels[0], _framelimit == Framelimit::Vsync)) {
+                        selection = 0;
+                        _framelimit = Framelimit::Vsync;
+                        setSwapInterval(1);
+                    }
+                    if(ImGui::Selectable(framelimit_labels[1], _framelimit == Framelimit::HalfVsync)) {
+                        selection = 1;
+                        _framelimit = Framelimit::HalfVsync;
+                        setSwapInterval(2);
+                    }
+                    if(ImGui::Selectable(framelimit_labels[2], _framelimit == Framelimit::FpsCap)) {
+                        selection = 2;
+                        _framelimit = Framelimit::FpsCap;
+                        setSwapInterval(0);
+                        setMinimalLoopPeriod(1000 / _fpsCap);
+                    }
+
+                    ImGui::EndCombo();
+                }
+
+                if(_framelimit == Framelimit::FpsCap) {
+                    static constexpr UnsignedInt min_fps = 15;
+                    static constexpr UnsignedInt max_fps = 150;
+
+                    if(ImGui::SliderScalar("##FpsSlider", ImGuiDataType_U32, &_fpsCap, &min_fps, &max_fps, "%u FPS", ImGuiSliderFlags_AlwaysClamp)) {
+                        setMinimalLoopPeriod(1000 / _fpsCap);
+                    }
+                }
+
                 ImGui::Checkbox("Cheat mode", &_cheatMode);
                 ImGui::SameLine();
                 ImGui::AlignTextToFramePadding();