From 730fce4b1ce494f28449e84f7783837f44b21b6b Mon Sep 17 00:00:00 2001
From: ns6089 <61738816+ns6089@users.noreply.github.com>
Date: Fri, 12 May 2023 17:07:22 +0300
Subject: [PATCH] Move client frame interval to local variable

---
 src/platform/windows/display.h        |  6 ++++--
 src/platform/windows/display_base.cpp | 14 ++++++++++----
 2 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/src/platform/windows/display.h b/src/platform/windows/display.h
index 238a87c2..5c77aa0d 100644
--- a/src/platform/windows/display.h
+++ b/src/platform/windows/display.h
@@ -132,14 +132,16 @@ namespace platf::dxgi {
     capture_e
     capture(const push_captured_image_cb_t &push_captured_image_cb, const pull_free_image_cb_t &pull_free_image_cb, bool *cursor) override;
 
-    std::chrono::nanoseconds delay;
-
     factory1_t factory;
     adapter_t adapter;
     output_t output;
     device_t device;
     device_ctx_t device_ctx;
     duplication_t dup;
+    DXGI_RATIONAL display_refresh_rate;
+    int display_refresh_rate_rounded;
+
+    int client_frame_rate;
 
     DXGI_FORMAT capture_format;
     D3D_FEATURE_LEVEL feature_level;
diff --git a/src/platform/windows/display_base.cpp b/src/platform/windows/display_base.cpp
index c016514a..4382ef0a 100644
--- a/src/platform/windows/display_base.cpp
+++ b/src/platform/windows/display_base.cpp
@@ -119,6 +119,7 @@ namespace platf::dxgi {
   capture_e
   display_base_t::capture(const push_captured_image_cb_t &push_captured_image_cb, const pull_free_image_cb_t &pull_free_image_cb, bool *cursor) {
     auto next_frame = std::chrono::steady_clock::now();
+    const auto client_frame_interval = std::chrono::nanoseconds { 1s } / client_frame_rate;
 
     // Keep the display awake during capture. If the display goes to sleep during
     // capture, best case is that capture stops until it powers back on. However,
@@ -142,14 +143,14 @@ namespace platf::dxgi {
       auto wait_time = next_frame - std::chrono::steady_clock::now();
       if (wait_time > 0s && wait_time < 1s) {
         high_precision_sleep(wait_time);
-        next_frame += delay;
+        next_frame += client_frame_interval;
       }
       else {
         // If the wait time is negative (meaning the frame is past due) or the
         // computed wait time is beyond a second (meaning possible clock issues),
         // just capture the frame now and resynchronize the frame interval with
         // the current time.
-        next_frame = std::chrono::steady_clock::now() + delay;
+        next_frame = std::chrono::steady_clock::now() + client_frame_interval;
       }
 
       std::shared_ptr<img_t> img_out;
@@ -334,8 +335,6 @@ namespace platf::dxgi {
     // Ensure we can duplicate the current display
     syncThreadDesktop();
 
-    delay = std::chrono::nanoseconds { 1s } / config.framerate;
-
     // Get rectangle of full desktop for absolute mouse coordinates
     env_width = GetSystemMetrics(SM_CXVIRTUALSCREEN);
     env_height = GetSystemMetrics(SM_CYVIRTUALSCREEN);
@@ -595,6 +594,13 @@ namespace platf::dxgi {
     BOOST_LOG(info) << "Desktop resolution ["sv << dup_desc.ModeDesc.Width << 'x' << dup_desc.ModeDesc.Height << ']';
     BOOST_LOG(info) << "Desktop format ["sv << dxgi_format_to_string(dup_desc.ModeDesc.Format) << ']';
 
+    display_refresh_rate = dup_desc.ModeDesc.RefreshRate;
+    display_refresh_rate_rounded = lround((double) display_refresh_rate.Numerator / display_refresh_rate.Denominator);
+    BOOST_LOG(info) << "Display refresh rate [" << display_refresh_rate_rounded << "Hz]";
+
+    client_frame_rate = config.framerate;
+    BOOST_LOG(info) << "Requested frame rate [" << client_frame_rate << "fps]";
+
     dxgi::output6_t output6 {};
     status = output->QueryInterface(IID_IDXGIOutput6, (void **) &output6);
     if (SUCCEEDED(status)) {