From e97baa503a0f386dc4a2413d7937a6d8bdd0d0fb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Henrik=20Rydg=C3=A5rd?= <hrydgard@gmail.com>
Date: Sat, 10 Oct 2020 19:01:40 +0200
Subject: [PATCH] Avoid a division in time_now_d(). Minor optimizations.

---
 Common/TimeUtil.cpp     | 8 ++------
 Core/HLE/sceDisplay.cpp | 3 +++
 UI/OnScreenDisplay.cpp  | 3 ++-
 Windows/MainWindow.cpp  | 2 +-
 4 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/Common/TimeUtil.cpp b/Common/TimeUtil.cpp
index 2cb375c9a0..8f0ce379ed 100644
--- a/Common/TimeUtil.cpp
+++ b/Common/TimeUtil.cpp
@@ -42,18 +42,14 @@ double time_now_d() {
 
 #else
 
-static uint64_t _frequency = 0;
-static uint64_t _starttime = 0;
-
 double time_now_d() {
 	static time_t start;
 	struct timeval tv;
-	gettimeofday(&tv, NULL);
+	gettimeofday(&tv, nullptr);
 	if (start == 0) {
 		start = tv.tv_sec;
 	}
-	tv.tv_sec -= start;
-	return (double)tv.tv_sec + (double)tv.tv_usec / 1000000.0;
+	return (double)(tv.tv_sec - start) + (double)tv.tv_usec * (1.0 / 1000000.0);
 }
 
 #endif
diff --git a/Core/HLE/sceDisplay.cpp b/Core/HLE/sceDisplay.cpp
index 1b97a35336..a8cb651a8b 100644
--- a/Core/HLE/sceDisplay.cpp
+++ b/Core/HLE/sceDisplay.cpp
@@ -619,6 +619,9 @@ static void DoFrameTiming(bool &throttle, bool &skipFrame, float timestep) {
 			skipFrame = true;
 	}
 
+	// TODO: This is NOT where we should wait, really! We should mark each outgoing frame with the desired
+	// timestamp to push it to display, and sleep in the render thread to achieve that.
+
 	if (curFrameTime < nextFrameTime && throttle) {
 		// If time gap is huge just jump (somebody unthrottled)
 		if (nextFrameTime - curFrameTime > 2*scaledTimestep) {
diff --git a/UI/OnScreenDisplay.cpp b/UI/OnScreenDisplay.cpp
index 5b89f78b57..e63eb37d08 100644
--- a/UI/OnScreenDisplay.cpp
+++ b/UI/OnScreenDisplay.cpp
@@ -22,8 +22,9 @@ void OnScreenMessagesView::Draw(UIContext &dc) {
 	float y = 10.0f;
 	// Then draw them all. 
 	const std::list<OnScreenMessages::Message> &messages = osm.Messages();
+	double now = time_now_d();
 	for (auto iter = messages.begin(); iter != messages.end(); ++iter) {
-		float alpha = (iter->endTime - time_now_d()) * 4.0f;
+		float alpha = (iter->endTime - now) * 4.0f;
 		if (alpha > 1.0) alpha = 1.0f;
 		if (alpha < 0.0) alpha = 0.0f;
 		// Messages that are wider than the screen are left-aligned instead of centered.
diff --git a/Windows/MainWindow.cpp b/Windows/MainWindow.cpp
index 439791544e..f925f05fe8 100644
--- a/Windows/MainWindow.cpp
+++ b/Windows/MainWindow.cpp
@@ -622,7 +622,7 @@ namespace MainWindow
 					}
 					lastMouseDown = 0.0;
 				} else {
-					lastMouseDown = time_now_d();
+					lastMouseDown = now;
 				}
 			}
 			break;