From b43f8fcff763acc5b2445339ec2bdd56795945a2 Mon Sep 17 00:00:00 2001
From: 23rd <23rd@vivaldi.net>
Date: Thu, 22 Dec 2022 18:57:46 +0300
Subject: [PATCH] Slightly optimized drawing of ministars in premium settings.

---
 .../SourceFiles/settings/settings_premium.cpp |  6 +--
 .../SourceFiles/ui/effects/premium_stars.cpp  | 45 ++++++++++++-------
 .../SourceFiles/ui/effects/premium_stars.h    |  5 ++-
 3 files changed, 34 insertions(+), 22 deletions(-)

diff --git a/Telegram/SourceFiles/settings/settings_premium.cpp b/Telegram/SourceFiles/settings/settings_premium.cpp
index 6eb7d375a..31d9ef839 100644
--- a/Telegram/SourceFiles/settings/settings_premium.cpp
+++ b/Telegram/SourceFiles/settings/settings_premium.cpp
@@ -1359,6 +1359,9 @@ void Premium::setupContent() {
 					box->closeBox();
 				}, box->lifetime());
 
+				box->boxClosing(
+				) | rpl::start_with_next(hidden, box->lifetime());
+
 				if (controller->session().premium()) {
 					box->addButton(tr::lng_close(), [=] {
 						box->closeBox();
@@ -1370,9 +1373,6 @@ void Premium::setupContent() {
 						[] { return u"double_limits"_q; }
 					});
 
-					box->boxClosing(
-					) | rpl::start_with_next(hidden, box->lifetime());
-
 					box->setShowFinishedCallback([=] {
 						button->startGlareAnimation();
 					});
diff --git a/Telegram/SourceFiles/ui/effects/premium_stars.cpp b/Telegram/SourceFiles/ui/effects/premium_stars.cpp
index 3de000481..3efe9a2dc 100644
--- a/Telegram/SourceFiles/ui/effects/premium_stars.cpp
+++ b/Telegram/SourceFiles/ui/effects/premium_stars.cpp
@@ -36,7 +36,6 @@ MiniStars::MiniStars(Fn<void(const QRect &r)> updateCallback, bool opaque)
 , _animation([=](crl::time now) {
 	if (now > _nextBirthTime && !_paused) {
 		createStar(now);
-		_nextBirthTime = now + randomInterval(_lifeLength);
 	}
 	if (_rectToUpdate.isValid()) {
 		updateCallback(base::take(_rectToUpdate));
@@ -44,7 +43,10 @@ MiniStars::MiniStars(Fn<void(const QRect &r)> updateCallback, bool opaque)
 }) {
 	if (anim::Disabled()) {
 		const auto from = _deathTime.from + _deathTime.length;
-		for (auto i = -from; i < 0; i += randomInterval(_lifeLength)) {
+		auto r = bytes::vector(from);
+		base::RandomFill(r.data(), r.size());
+
+		for (auto i = -from; i < 0; i += randomInterval(_lifeLength, r[-i])) {
 			createStar(i);
 		}
 		updateCallback(_rectToUpdate);
@@ -53,8 +55,10 @@ MiniStars::MiniStars(Fn<void(const QRect &r)> updateCallback, bool opaque)
 	}
 }
 
-int MiniStars::randomInterval(const Interval &interval) const {
-	return interval.from + base::RandomIndex(interval.length);
+int MiniStars::randomInterval(
+		const Interval &interval,
+		const bytes::type &random) const {
+	return interval.from + (uchar(random) % interval.length);
 }
 
 crl::time MiniStars::timeNow() const {
@@ -64,8 +68,9 @@ crl::time MiniStars::timeNow() const {
 void MiniStars::paint(QPainter &p, const QRectF &rect) {
 	const auto center = rect.center();
 	const auto opacity = p.opacity();
+	const auto now = timeNow();
 	for (const auto &ministar : _ministars) {
-		const auto progress = (timeNow() - ministar.birthTime)
+		const auto progress = (now - ministar.birthTime)
 			/ float64(ministar.deathTime - ministar.birthTime);
 		if (progress > 1.) {
 			continue;
@@ -122,21 +127,27 @@ void MiniStars::setPaused(bool paused) {
 	_paused = paused;
 }
 
-int MiniStars::angle() const {
-	const auto &interval = _availableAngles[
-		base::RandomIndex(_availableAngles.size())];
-	return base::RandomIndex(interval.length) + interval.from;
-}
-
 void MiniStars::createStar(crl::time now) {
+	constexpr auto kRandomSize = 8;
+	auto random = bytes::vector(kRandomSize);
+	base::RandomFill(random.data(), random.size());
+
+	auto i = 0;
+	auto next = [&] { return random[i++]; };
+
+	_nextBirthTime = now + randomInterval(_lifeLength, next());
+
+	const auto &angleInterval = _availableAngles[
+		uchar(next()) % _availableAngles.size()];
+
 	auto ministar = MiniStar{
 		.birthTime = now,
-		.deathTime = now + randomInterval(_deathTime),
-		.angle = angle(),
-		.size = float64(randomInterval(_size)),
-		.alpha = float64(randomInterval(_alpha)) / 100.,
-		.sinFactor = randomInterval(_sinFactor) / 100.
-			* (base::RandomIndex(2) == 1 ? 1. : -1.),
+		.deathTime = now + randomInterval(_deathTime, next()),
+		.angle = randomInterval(angleInterval, next()),
+		.size = float64(randomInterval(_size, next())),
+		.alpha = float64(randomInterval(_alpha, next())) / 100.,
+		.sinFactor = randomInterval(_sinFactor, next()) / 100.
+			* ((uchar(next()) % 2) == 1 ? 1. : -1.),
 	};
 	for (auto i = 0; i < _ministars.size(); i++) {
 		if (ministar.birthTime > _ministars[i].deathTime) {
diff --git a/Telegram/SourceFiles/ui/effects/premium_stars.h b/Telegram/SourceFiles/ui/effects/premium_stars.h
index cb0b88acb..52feb589d 100644
--- a/Telegram/SourceFiles/ui/effects/premium_stars.h
+++ b/Telegram/SourceFiles/ui/effects/premium_stars.h
@@ -39,9 +39,10 @@ private:
 	};
 
 	void createStar(crl::time now);
-	[[nodiscard]] int angle() const;
 	[[nodiscard]] crl::time timeNow() const;
-	[[nodiscard]] int randomInterval(const Interval &interval) const;
+	[[nodiscard]] int randomInterval(
+		const Interval &interval,
+		const gsl::byte &random) const;
 
 	const std::vector<Interval> _availableAngles;
 	const Interval _lifeLength;