From 013624c9bc654a314e04ea18e58f168b8be0c3ca Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Sat, 14 Feb 2026 23:54:07 +0000
Subject: Refactor test-instancing so the data is generated in a common fixture

Includes exposure of InstanceVertices::reserve because why not.
---
 gfx/gl/instanceVertices.h |  7 +++++--
 test/perf-instancing.cpp  | 38 +++++++++++++++++++++++---------------
 2 files changed, 28 insertions(+), 17 deletions(-)

diff --git a/gfx/gl/instanceVertices.h b/gfx/gl/instanceVertices.h
index de20871..2417a91 100644
--- a/gfx/gl/instanceVertices.h
+++ b/gfx/gl/instanceVertices.h
@@ -48,13 +48,15 @@ public:
 		}
 
 		// NOLINTNEXTLINE)hicpp-explicit-conversions
-		[[nodiscard]] operator T &()
+		[[nodiscard]]
+		operator T &()
 		{
 			return instances->lookup(index);
 		}
 
 		// NOLINTNEXTLINE)hicpp-explicit-conversions
-		[[nodiscard]] operator const T &() const
+		[[nodiscard]]
+		operator const T &() const
 		{
 			return instances->lookup(index);
 		}
@@ -119,6 +121,7 @@ public:
 	}
 
 	using base::bufferName;
+	using base::reserve;
 
 	[[nodiscard]] auto
 	size() const
diff --git a/test/perf-instancing.cpp b/test/perf-instancing.cpp
index f3d16a8..4373e5a 100644
--- a/test/perf-instancing.cpp
+++ b/test/perf-instancing.cpp
@@ -9,30 +9,41 @@ namespace {
 		glm::mat3 rot;
 	};
 
-	struct Data {
-		explicit Data(size_t n)
+	const TestMainWindowAppBase _;
+
+	class Data : public benchmark::Fixture {
+	public:
+		void
+		SetUp(::benchmark::State & state) override
 		{
+			auto count = static_cast<size_t>(state.range());
 			std::mt19937 gen(std::random_device {}());
 			std::uniform_int_distribution<GlobalDistance> xyDistrib(0, 1000000);
 			std::uniform_int_distribution<GlobalDistance> zDistrib(0, 10000);
-			while (n--) {
+			proxies.reserve(count);
+			instances.reserve(count);
+
+			while (count--) {
 				proxies.emplace_back(instances.acquire(
 						GlobalPosition3D {xyDistrib(gen), xyDistrib(gen), zDistrib(gen)}, glm::mat3 {}));
 			}
 		}
 
+		void
+		TearDown(::benchmark::State &) override
+		{
+			proxies.clear();
+		}
+
 		InstanceVertices<Instance> instances;
 		std::vector<InstanceVertices<Instance>::InstanceProxy> proxies;
 	};
 
-	void
-	partition1(benchmark::State & state)
+	BENCHMARK_DEFINE_F(Data, partition1)(benchmark::State & state)
 	{
-		TestMainWindowAppBase window;
-		Data data(static_cast<size_t>(state.range()));
 		GlobalPosition2D pos {};
 		for (auto loop : state) {
-			data.instances.partition([&pos](const auto & instance) {
+			instances.partition([&pos](const auto & instance) {
 				return std::abs(instance.pos.x - pos.x) < 5 && std::abs(instance.pos.y - pos.y) < 5;
 			});
 			pos += GlobalPosition2D {33, 17};
@@ -40,14 +51,11 @@ namespace {
 		}
 	}
 
-	void
-	partition2(benchmark::State & state)
+	BENCHMARK_DEFINE_F(Data, partition2)(benchmark::State & state)
 	{
-		TestMainWindowAppBase window;
-		Data data(static_cast<size_t>(state.range()));
 		GlobalPosition2D pos {};
 		for (auto loop : state) {
-			data.instances.partition(
+			instances.partition(
 					[&pos](const auto & instance) {
 						return std::abs(instance.pos.x - pos.x) < 5;
 					},
@@ -60,7 +68,7 @@ namespace {
 	}
 }
 
-BENCHMARK(partition1)->Range(0, 1 << 20);
-BENCHMARK(partition2)->Range(0, 1 << 20);
+BENCHMARK_REGISTER_F(Data, partition1)->Range(0, 1 << 20);
+BENCHMARK_REGISTER_F(Data, partition2)->Range(0, 1 << 20);
 
 BENCHMARK_MAIN();
-- 
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