Move client code out of ItemDefManager (#15967)

src/client/item_visuals_manager.h

@@ -0,0 +1,68 @@
+// Luanti
+// SPDX-License-Identifier: LGPL-2.1-or-later
+// Copyright (C) 2025 cx384
+
+#pragma once
+
+#include <string>
+#include <map>
+#include <thread>
+#include "wieldmesh.h" // ItemMesh
+#include "util/basic_macros.h"
+
+class Client;
+class ItemStack;
+typedef std::vector<video::SColor> Palette; // copied from src/client/texturesource.h
+namespace irr::video { class ITexture; }
+
+// Caches data needed to draw an itemstack
+
+struct ItemVisualsManager
+{
+	ItemVisualsManager()
+	{
+		m_main_thread = std::this_thread::get_id();
+	}
+
+	void clear() {
+		m_cached_item_visuals.clear();
+	}
+
+	// Get item inventory texture
+	video::ITexture* getInventoryTexture(const ItemStack &item, Client *client) const;
+
+	// Get item wield mesh
+	// Once said to return nullptr if there is an inventory image, but this is wrong
+	ItemMesh* getWieldMesh(const ItemStack &item, Client *client) const;
+
+	// Get item palette
+	Palette* getPalette(const ItemStack &item, Client *client) const;
+
+	// Returns the base color of an item stack: the color of all
+	// tiles that do not define their own color.
+	video::SColor getItemstackColor(const ItemStack &stack, Client *client) const;
+
+private:
+	struct ItemVisuals
+	{
+		video::ITexture *inventory_texture;
+		ItemMesh wield_mesh;
+		Palette *palette;
+
+		ItemVisuals():
+			inventory_texture(nullptr),
+			palette(nullptr)
+		{}
+
+		~ItemVisuals();
+
+		DISABLE_CLASS_COPY(ItemVisuals);
+	};
+
+	// The id of the thread that is allowed to use irrlicht directly
+	std::thread::id m_main_thread;
+	// Cached textures and meshes
+	mutable std::unordered_map<std::string, std::unique_ptr<ItemVisuals>> m_cached_item_visuals;
+
+	ItemVisuals* createItemVisuals(const ItemStack &item, Client *client) const;
+};