1 files changed, 36 insertions, 22 deletions

diff --git a/src/core/hw/gpu.cpp b/src/core/hw/gpu.cpp
index 28cb97d8e..1503b45da 100644
--- a/src/core/hw/gpu.cpp
+++ b/src/core/hw/gpu.cpp
@@ -8,7 +8,10 @@
 #include "common/color.h"
 #include "common/common_types.h"
 #include "common/logging/log.h"
+#include "common/math_util.h"
 #include "common/microprofile.h"
+#include "common/thread.h"
+#include "common/timer.h"
 #include "common/vector_math.h"
 #include "core/core_timing.h"
 #include "core/hle/service/gsp_gpu.h"
@@ -29,16 +32,20 @@ namespace GPU {
 
 Regs g_regs;
 
-/// True if the current frame was skipped
-bool g_skip_frame;
 /// 268MHz CPU clocks / 60Hz frames per second
 const u64 frame_ticks = 268123480ull / 60;
 /// Event id for CoreTiming
 static int vblank_event;
 /// Total number of frames drawn
 static u64 frame_count;
-/// True if the last frame was skipped
-static bool last_skip_frame;
+/// Start clock for frame limiter
+static u32 time_point;
+/// Total delay caused by slow frames
+static float time_delay;
+constexpr float FIXED_FRAME_TIME = 1000.0f / 60;
+// Max lag caused by slow frames. Can be adjusted to compensate for too many slow frames. Higher
+// values increases time needed to limit frame rate after spikes
+constexpr float MAX_LAG_TIME = 18;
 
 template <typename T>
 inline void Read(T& var, const u32 raw_addr) {
@@ -480,8 +487,8 @@ inline void Write(u32 addr, const T data) {
             u32* buffer = (u32*)Memory::GetPhysicalPointer(config.GetPhysicalAddress());
 
             if (Pica::g_debug_context && Pica::g_debug_context->recorder) {
-                Pica::g_debug_context->recorder->MemoryAccessed(
-                    (u8*)buffer, config.size * sizeof(u32), config.GetPhysicalAddress());
+                Pica::g_debug_context->recorder->MemoryAccessed((u8*)buffer, config.size,
+                                                                config.GetPhysicalAddress());
             }
 
             Pica::CommandProcessor::ProcessCommandList(buffer, config.size);
@@ -516,23 +523,25 @@ template void Write<u32>(u32 addr, const u32 data);
 template void Write<u16>(u32 addr, const u16 data);
 template void Write<u8>(u32 addr, const u8 data);
 
+static void FrameLimiter() {
+    time_delay += FIXED_FRAME_TIME;
+    time_delay = MathUtil::Clamp(time_delay, -MAX_LAG_TIME, MAX_LAG_TIME);
+    s32 desired_time = static_cast<s32>(time_delay);
+    s32 elapsed_time = static_cast<s32>(Common::Timer::GetTimeMs() - time_point);
+
+    if (elapsed_time < desired_time) {
+        Common::SleepCurrentThread(desired_time - elapsed_time);
+    }
+
+    u32 frame_time = Common::Timer::GetTimeMs() - time_point;
+
+    time_delay -= frame_time;
+}
+
 /// Update hardware
 static void VBlankCallback(u64 userdata, int cycles_late) {
     frame_count++;
-    last_skip_frame = g_skip_frame;
-    g_skip_frame = (frame_count & Settings::values.frame_skip) != 0;
-
-    // Swap buffers based on the frameskip mode, which is a little bit tricky. When
-    // a frame is being skipped, nothing is being rendered to the internal framebuffer(s).
-    // So, we should only swap frames if the last frame was rendered. The rules are:
-    //  - If frameskip == 0 (disabled), always swap buffers
-    //  - If frameskip == 1, swap buffers every other frame (starting from the first frame)
-    //  - If frameskip > 1, swap buffers every frameskip^n frames (starting from the second frame)
-    if ((((Settings::values.frame_skip != 1) ^ last_skip_frame) &&
-         last_skip_frame != g_skip_frame) ||
-        Settings::values.frame_skip == 0) {
-        VideoCore::g_renderer->SwapBuffers();
-    }
+    VideoCore::g_renderer->SwapBuffers();
 
     // Signal to GSP that GPU interrupt has occurred
     // TODO(yuriks): hwtest to determine if PDC0 is for the Top screen and PDC1 for the Sub
@@ -545,6 +554,12 @@ static void VBlankCallback(u64 userdata, int cycles_late) {
     // Check for user input updates
     Service::HID::Update();
 
+    if (!Settings::values.use_vsync && Settings::values.toggle_framelimit) {
+        FrameLimiter();
+    }
+
+    time_point = Common::Timer::GetTimeMs();
+
     // Reschedule recurrent event
     CoreTiming::ScheduleEvent(frame_ticks - cycles_late, vblank_event);
 }
@@ -579,9 +594,8 @@ void Init() {
     framebuffer_sub.color_format.Assign(Regs::PixelFormat::RGB8);
     framebuffer_sub.active_fb = 0;
 
-    last_skip_frame = false;
-    g_skip_frame = false;
     frame_count = 0;
+    time_point = Common::Timer::GetTimeMs();
 
     vblank_event = CoreTiming::RegisterEvent("GPU::VBlankCallback", VBlankCallback);
     CoreTiming::ScheduleEvent(frame_ticks, vblank_event);