saints row iv · how the game works

How Saints Row IV Works

The game's life cycle in order: start-up, menus, loading, and what happens every frame.

How the Game Works19 rows

The game's life from double-click to quit. Each step names the function where it happens.

Step	What happens	Key function	Address	Notes
Start-up
1	Windows starts the exe; the C runtime sets up and calls WinMain.	WinMain	`007250a0`
2	Reads the command line, creates the 'dumps' and 'mods' folders next to the exe, turns off the screensaver.	init_mods_dir	`00722a60`	The mods folder is real 2017 mod support - see Files & Mods.
3	Creates the window ('Saints Row IV') and the Direct3D 11 graphics device. If that fails you get 'Failed to create graphics device'.	game_create_window_and_device	`00722f50`	Also registers where files are searched for, mods folder first.
4	Registers the BOOT game state and enters it.	gamestate_register	`00865f20`	The whole game is a stack of states - see Game States.
5	BOOT: reserves memory pools, mounts the core packfiles, starts a small loading-screen render thread, loads all data tables (animation, gameplay constants, effects...).	game_init_callback / boot_load_game_data	`00724d70` / `00723bd0`	Memory sizes: see Memory Budgets.
6	Starts the worker threads (rendering, file loading, audio, job scheduler).	thread_create	`010c1a10`	See Threads.
The main loop (runs until you quit)
7	Handle Windows messages (keyboard, focus, close button).	platform_pump_messages	`010befe0`
8	Run one frame: input, the current game state's update, audio, UI, network, then apply any queued state changes (e.g. menu -> loading).	game_frame_tick	`00724f40`	Returns 'quit' when the state stack reaches QUIT (10).
9	Meanwhile the render thread draws the previous frame: shadows, lighting, effects, UI, then presents it.	render_thread_main	`00729ce0`	See Rendering.
Going from the menu into the city
10	MAIN_MENU state shows the menu and handles save selection.	gs_main_menu_enter	`008ca950`
11	CITY_LOAD state loads the city on its own thread while a loading screen plays.	gs_city_load_enter	`008c8d20`	Also starts Havok's physics job threads.
12	IN_GAME state: the world simulates every frame - humans, cars, AI, physics, Lua mission scripts, HUD.	gs_in_game_enter	`00861f70`
13	Streaming: as you move, nearby city zones and assets load in the background and far ones unload.	stream2_container_create	`010dd670`	Files are read by the 'hdd thread', unpacked by the 'mem thread'.
Inside one in-game frame (simplified)
14	Each AI character picks what to do: goals are checked in priority order, and each goal's actions are tried until one succeeds.	ai_select_action	`00532300`	See AI tab.
15	Damage of any kind (bullets, explosions, powers, scripts) goes through one function that lowers health and handles death.	human_take_damage	`00adeb60`	Health is at human`+0x1E20`.
16	Mission logic runs as Lua scripts that call ~1,900 engine commands.	lua_gameplay_vm_init	`00bbd970`	See Lua Commands.
17	In co-op, changes are sent to the other player as small compressed messages.	net_register_msg	`009a85d0`	98 message types.
Saving and quitting
18	Saves are written only to Steam Cloud on a background thread.	gamesave_platform_write_begin	`00d93540`	Files: sr4save_N.sr4s_pc + savedir.sr3d_pc.
19	Quitting pushes the QUIT state; the loop ends and every system shuts down in reverse order.	game_shutdown_all_states	`00866ff0`

Built from SR4_Game_Explained.xlsx (650 KB), if you'd rather filter it in Excel. SaintsRowIV.exe v1.0.6.1 (Steam). Names are ours unless they're Volition's own Lua or C++ class names.