Merge pull request #840 from FearlessTobi/port-3353

Port #3353 from Citra: "citra-qt: Add customizable speed limit target "

1 files changed, 13 insertions, 4 deletions

diff --git a/src/core/perf_stats.cpp b/src/core/perf_stats.cpp
index 4e5633edbe..93d23de210 100644
--- a/src/core/perf_stats.cpp
+++ b/src/core/perf_stats.cpp
@@ -78,20 +78,29 @@ void FrameLimiter::DoFrameLimiting(microseconds current_system_time_us) {
     // values increase the time needed to recover and limit framerate again after spikes.
     constexpr microseconds MAX_LAG_TIME_US = 25000us;
 
-    if (!Settings::values.toggle_framelimit) {
+    if (!Settings::values.use_frame_limit) {
         return;
     }
 
     auto now = Clock::now();
 
-    frame_limiting_delta_err += current_system_time_us - previous_system_time_us;
+    const double sleep_scale = Settings::values.frame_limit / 100.0;
+
+    // Max lag caused by slow frames. Shouldn't be more than the length of a frame at the current
+    // speed percent or it will clamp too much and prevent this from properly limiting to that
+    // percent. High values means it'll take longer after a slow frame to recover and start
+    // limiting
+    const microseconds max_lag_time_us = duration_cast<microseconds>(
+        std::chrono::duration<double, std::chrono::microseconds::period>(25ms / sleep_scale));
+    frame_limiting_delta_err += duration_cast<microseconds>(
+        std::chrono::duration<double, std::chrono::microseconds::period>(
+            (current_system_time_us - previous_system_time_us) / sleep_scale));
     frame_limiting_delta_err -= duration_cast<microseconds>(now - previous_walltime);
     frame_limiting_delta_err =
-        std::clamp(frame_limiting_delta_err, -MAX_LAG_TIME_US, MAX_LAG_TIME_US);
+        std::clamp(frame_limiting_delta_err, -max_lag_time_us, max_lag_time_us);
 
     if (frame_limiting_delta_err > microseconds::zero()) {
         std::this_thread::sleep_for(frame_limiting_delta_err);
-
         auto now_after_sleep = Clock::now();
         frame_limiting_delta_err -= duration_cast<microseconds>(now_after_sleep - now);
         now = now_after_sleep;