crown-engine/src/device/device.h

/*
 * Copyright (c) 2012-2025 Daniele Bartolini et al.
 * SPDX-License-Identifier: MIT
 */

#pragma once

#include "config.h"
#include "core/filesystem/types.h"
#include "core/list.h"
#include "core/memory/allocator.h"
#include "core/memory/linear_allocator.h"
#include "core/strings/string_id.h"
#include "core/types.h"
#include "device/boot_config.h"
#include "device/console_server.h"
#include "device/delta_time_filter.h"
#include "device/device_options.h"
#include "device/display.h"
#include "device/input_types.h"
#include "device/pipeline.h"
#include "device/types.h"
#include "device/window.h"
#include "lua/types.h"
#include "resource/types.h"
#include "world/types.h"
#include <atomic>

/// @defgroup Device Device
namespace crown
{
struct BgfxAllocator;
struct BgfxCallback;

/// This is the place where to look for accessing all of
/// the engine subsystems and related stuff.
///
/// @ingroup Device
struct Device
{
	LinearAllocator _allocator;

	const DeviceOptions &_options;
	BootConfig _boot_config;
	ConsoleServer *_console_server;
	Filesystem *_data_filesystem;
	ResourceLoader *_resource_loader;
	ResourceManager *_resource_manager;
	BgfxAllocator *_bgfx_allocator;
	BgfxCallback *_bgfx_callback;
	ShaderManager *_shader_manager;
	MaterialManager *_material_manager;
	InputManager *_input_manager;
	UnitManager *_unit_manager;
	LuaEnvironment *_lua_environment;
	Pipeline *_pipeline;
	Display *_display;
	Window *_window;
	ListNode _worlds;
	TimestepPolicy::Enum _timestep_policy;
	DeltaTimeFilter _delta_time_filter;

	u16 _width;
	u16 _height;
	u16 _prev_width;
	u16 _prev_height;
	s64 _last_time;

	bool _quit;
	bool _paused;
	std::atomic_int _needs_draw;

	///
	bool process_events();

	///
	Device(const DeviceOptions &opts, ConsoleServer &cs);

	///
	Device(const Device &) = delete;

	///
	Device &operator=(const Device &) = delete;

	/// Sets the timestep policy:
	/// * TimestepPolicy::VARIABLE: the timestep is the time it took for the previous frame to
	/// simulate. This is the default;
	/// * TimestepPolicy::SMOOTHED: the timestep is computed as an average of the previous delta
	/// times.
	void set_timestep_policy(TimestepPolicy::Enum policy);

	/// Sets the smoothed timestep parameters.
	/// @see DeltaTimeFilter::set_timestep_smoothing()
	void set_timestep_smoothing(u32 num_samples, u32 num_outliers, f32 average_cap);

	/// Simulate one frame.
	bool frame();

	/// Runs the engine.
	void run();

	/// Returns the number of command line parameters.
	int argc() const;

	/// Returns command line parameters.
	const char **argv() const;

	/// Quits the application.
	void quit();

	/// Pauses the engine.
	void pause();

	/// Unpauses the engine.
	void unpause();

	/// Returns the main window resolution.
	void resolution(u16 &width, u16 &height);

	/// Renders @a world using @a camera.
	void render(World &world, UnitId camera_unit);

	/// Creates a new world.
	World *create_world();

	/// Destroys the @a world.
	void destroy_world(World &world);

	/// Returns the resource package @a id.
	ResourcePackage *create_resource_package(StringId64 id);

	/// Destroys the resource package @a rp.
	/// @note
	/// Resources are not automatically unloaded.
	/// You have to call ResourcePackage::unload() before destroying a package.
	void destroy_resource_package(ResourcePackage &rp);

	/// Reloads all the resources listed in the @a json message.
	void refresh(const char *json);

	/// Captures a screenshot of the main window's backbuffer and saves it at @a path in PNG format.
	void screenshot(const char *path);
};

/// Runs the engine.
void run(const DeviceOptions &opts);

/// Returns the device.
Device *device();

} // namespace crown