VideoCommon: Make Presenter aware of the next swap time to eliminate unsafe usage of GetTicks() with ImmediateXFB + DualCore.

1 files changed, 24 insertions, 3 deletions

diff --git a/Source/Core/VideoCommon/VideoBackendBase.cpp b/Source/Core/VideoCommon/VideoBackendBase.cpp
index 676349b65b..23d9d6e7f4 100644
--- a/Source/Core/VideoCommon/VideoBackendBase.cpp
+++ b/Source/Core/VideoCommon/VideoBackendBase.cpp
@@ -21,6 +21,8 @@
 #include "Core/Core.h"
 #include "Core/CoreTiming.h"
 #include "Core/DolphinAnalytics.h"
+#include "Core/HW/SystemTimers.h"
+#include "Core/HW/VideoInterface.h"
 #include "Core/System.h"
 
 // TODO: ugly
@@ -93,16 +95,35 @@ std::string VideoBackendBase::BadShaderFilename(const char* shader_stage, int co
 void VideoBackendBase::Video_OutputXFB(u32 xfb_addr, u32 fb_width, u32 fb_stride, u32 fb_height,
                                        u64 ticks)
 {
-  if (m_initialized && g_presenter && !g_ActiveConfig.bImmediateXFB)
+  if (!m_initialized || !g_presenter)
+    return;
+
+  auto& system = Core::System::GetInstance();
+  auto& core_timing = system.GetCoreTiming();
+
+  if (!g_ActiveConfig.bImmediateXFB)
   {
-    auto& system = Core::System::GetInstance();
     system.GetFifo().SyncGPU(Fifo::SyncGPUReason::Swap);
 
-    const TimePoint presentation_time = system.GetCoreTiming().GetTargetHostTime(ticks);
+    const TimePoint presentation_time = core_timing.GetTargetHostTime(ticks);
     AsyncRequests::GetInstance()->PushEvent([=] {
       g_presenter->ViSwap(xfb_addr, fb_width, fb_stride, fb_height, ticks, presentation_time);
     });
   }
+
+  // Inform the Presenter of the next estimated swap time.
+
+  auto& vi = system.GetVideoInterface();
+  const s64 refresh_rate_den = vi.GetTargetRefreshRateDenominator();
+  const s64 refresh_rate_num = vi.GetTargetRefreshRateNumerator();
+
+  const auto next_swap_estimated_ticks =
+      ticks + (system.GetSystemTimers().GetTicksPerSecond() * refresh_rate_den / refresh_rate_num);
+  const auto next_swap_estimated_time = core_timing.GetTargetHostTime(next_swap_estimated_ticks);
+
+  AsyncRequests::GetInstance()->PushEvent([=] {
+    g_presenter->SetNextSwapEstimatedTime(next_swap_estimated_ticks, next_swap_estimated_time);
+  });
 }
 
 u32 VideoBackendBase::Video_GetQueryResult(PerfQueryType type)