Stop memory allocations by keeping the RectPacker around

src/common/rendering/hwrenderer/data/hw_rectpacker.cpp

@@ -16,6 +16,23 @@ RectPacker::RectPacker(int width, int height, int padding) : PageWidth(width), P
 {
 }
 
+void RectPacker::Clear()
+{
+	Pages.clear();
+	ItemFreeList.resize(Items.size());
+	size_t i = Items.size();
+	for (auto& item : Items)
+	{
+		item->Shelf = nullptr;
+		item->PrevItem = nullptr;
+		item->NextItem = nullptr;
+		item->IsAvailable = false;
+		item->PrevAvailable = nullptr;
+		item->NextAvailable = nullptr;
+		ItemFreeList[--i] = item.get();
+	}
+}
+
 RectPackerItem* RectPacker::Alloc(int width, int height)
 {
 	width += Padding * 2;

src/common/rendering/hwrenderer/data/hw_rectpacker.h

@@ -56,6 +56,8 @@ class RectPacker
 public:
 	RectPacker(int width, int height, int padding);
 
+	void Clear();
+
 	RectPackerItem* Alloc(int width, int height);
 	void Free(RectPackerItem* item);
 

src/common/rendering/vulkan/vk_lightmapper.cpp

@@ -133,7 +133,10 @@ void VkLightmapper::SelectTiles(const TArray<LightmapTile*>& tiles)
 	selectedTiles.Clear();
 
 	// We use a 3 texel spacing between rectangles so that the blur pass will not pick up anything from a neighbour tile.
-	RectPacker packer(bakeImageSize, bakeImageSize, 3);
+	if (!packer)
+		packer = std::make_unique<RectPacker>(bakeImageSize, bakeImageSize, 3);
+	else
+		packer->Clear();
 
 	for (int i = 0, count = tiles.Size(); i < count; i++)
 	{
@@ -143,7 +146,7 @@ void VkLightmapper::SelectTiles(const TArray<LightmapTile*>& tiles)
 			continue;
 
 		// Only grab surfaces until our bake texture is full
-		auto result = packer.Alloc(tile->AtlasLocation.Width, tile->AtlasLocation.Height);
+		auto result = packer->Alloc(tile->AtlasLocation.Width, tile->AtlasLocation.Height);
 		if (result->PageIndex == 0)
 		{
 			SelectedTile selected;

src/common/rendering/vulkan/vk_lightmapper.h

@@ -6,6 +6,7 @@
 class VulkanRenderDevice;
 class FString;
 class ShaderIncludeResult;
+class RectPacker;
 
 struct Uniforms
 {
@@ -232,4 +233,5 @@ private:
 
 	LightmapBakeImage bakeImage;
 	static const int bakeImageSize = 2048;
+	std::unique_ptr<RectPacker> packer;
 };