docs/re-notes/frontend-screens.md

Frontend Navigation State Machine

Overview

The WA frontend uses MFC CDialog modal dialogs driven by a main navigation loop. The loop is at 0x4E6440 (Frontend__MainNavigationLoop), which is the CWinApp::Run() virtual method override — a 19KB function that handles initialization and screen dispatch.

Architecture

g_CurrentScreen (0x6B3504)
        │
        ▼
┌──────────────────────┐
│ Main Navigation Loop │  (0x4E6440)
│ do {                 │
│   switch(screenId) { │
│     case 10: ...     │──► Create dialog ──► DoModal() ──► result
│     case 11: ...     │                                       │
│     ...              │                                       │
│   }                  │◄──── store result in g_CurrentScreen ─┘
│ } while(true);       │
│                      │
│ case 15: EXIT        │──► cleanup, return
└──────────────────────┘

Each iteration:

1. Reads g_CurrentScreen (0x6B3504)
2. Dispatches to the matching case → allocates dialog → calls constructor → DoModal
3. FrontendChangeScreen(screen_id) inside the dialog calls EndDialog(screen_id)
4. DoModal returns the result code → stored back into g_CurrentScreen
5. Previous dialog destroyed via Frontend__PostScreenCleanup (0x4EB450)
6. Loop continues

FrontendChangeScreen (0x447A20)

stdcall(screen_id) with ESI = dialog this pointer (MSVC __usercall).

Two modes based on g_FrontendFrame (0x6B3908):

• Normal (g_FrontendFrame != 0): Disable window → palette transition (0x422180) → call vtable[0x15C] twice (args 1, 2) → re-enable window → CDialog::EndDialog(screen_id)
• Init (g_FrontendFrame == 0): Store screen_id at dialog+0x44, clear flag bit 0x10 at dialog+0x3C

Screen Dispatch Table

Valid main-loop screens (10–30)

ID	Hex	Name	Constructor	Notes
10	0x0A	Deathmatch	0x440F40	PreTransitionCleanup before
11	0x0B	LocalMultiplayer	0x49C420	PreTransitionCleanup before
12	0x0C	Training	0x4E0880	Palette load before
14	0x0E	Missions	0x499190	Palette load before
15	0x0F	Exit	—	Cleanup + return from CWinApp::Run
16	0x10	PostInitMenu	0x4C91B0	Calls 0x4E4BD0 after
17	0x11	MainMenuRedirect	—	Sets g_CurrentScreen = 18
18	0x12	MainMenu	0x4866C0	Primary menu dialog
21	0x15	SinglePlayer	0x4D69F0	Palette load before
22	0x16	CampaignA	0x4A2B70	PreTransitionCleanup after
23	0x17	CampaignB	0x4A24D0	PreTransitionCleanup after
24	0x18	AdvancedSettings	0x4279E0	Calls 0x4E4BD0 after
25	0x19	IntroMovie	0x470870	Hardcodes next=18, sets g_SkipToMainMenu
27	0x1B	NetworkHostSetup	0x4ADCA0	PreTransitionCleanup after
28	0x1C	NetworkOnlineSetup	0x4ACBC0	PreTransitionCleanup after
29	0x1D	NetworkDialogA	0x4BC970	PreTransitionCleanup after
30	0x1E	NetworkDialogB	0x4BBC00	PreTransitionCleanup after

Network/lobby screens (1700–1707)

ID	Hex	Name	Constructor	Notes
1700	0x6A4	NetworkProviderSelect	0x4A7990	Special post-DoModal logic
1701	0x6A5	NetworkSettings	0x4C23C0
1702	0x6A6	LAN	0x480A80
1703	0x6A7	WormNet	0x472400
1704	0x6A8	LobbyHost	0x4B0160	Fall-through from setup
1705	0x6A9	LobbyHostContinued	(fall-through)
1706	0x6AA	LobbyClient	(fall-through)
1707	0x6AB	LobbyGameStart	0x4BDBE0

Dialog result codes (NOT dispatched by main loop)

These are returned by EndDialog from sub-dialogs (button handlers, options screens). If they reach the main loop, they hit the default case → g_CurrentScreen = 0x0F → exit. By that point, the game has already launched or the action has been taken.

ID	Hex	Name	Meaning
0	0x00	Cancel	Return to previous / back
1	0x01	Splash	Splash/intro trigger
2	0x02	NetworkOptionA	Network option result
4	0x04	SinglePlayerPrep	SP prep result
5	0x05	SinglePlayerConfirm	SP confirm result
32	0x20	SchemeEditorDone	Return from scheme/weapon editor
35	0x23	StartGameOffline	Start game, no network
36	0x24	StartGameOnline	Start game, network available
37	0x25	MultiplayerLocal	Multiplayer, no network
38	0x26	MultiplayerOnline	Multiplayer, network available
39	0x27	OptionsAccepted	Return after applying options + saving theme
50	0x32	InGameA	In-game state
52	0x34	InGameB	In-game state
58	0x3A	InGameC	In-game state

Offline/Online pairs

The "Start Game" and "Multiplayer" paths each check a network availability flag and branch to an offline/online result code:

• Start Game (this+0x244 flag): 35 (offline) / 36 (online)
• Multiplayer (this+0x140 flag): 37 (offline) / 38 (online)

Both paths use 0 (Cancel) as the "back to main menu" value.

Key Functions

Address	Name	Purpose
0x4E6440	Frontend__MainNavigationLoop	CWinApp::Run override — main dispatch loop
0x447A20	FrontendChangeScreen	Ends current dialog via EndDialog(screen_id)
0x447960	Frontend__DoModalWrapper	Palette transition + custom DoModal
0x40FD60	CDialog__DoModal_Custom	Custom MFC DoModal
0x40FBE0	CDialog__CustomMsgPump	Custom message pump (replaces RunModalLoop)
0x40FF90	FrontendDialog__OnIdle	Per-frame idle: cursor, mouse, paint dispatch
0x40BF60	FrontendDialog__PaintControlTree	Traverse control tree, paint dirty controls
0x4EB450	Frontend__PostScreenCleanup	Destroys previous dialog
0x4E4AE0	Frontend__PreTransitionCleanup	Cleanup before certain transitions
0x422180	Frontend__PaletteAnimation	Palette transition effect
0x446BA0	FrontendDialog__Constructor	Base frontend dialog constructor
0x44E850	Frontend__OnMultiplayerButton	Multiplayer button handler
0x44EC10	Frontend__OnNetworkButton	Network button handler
0x48DAB0	Frontend__OnOptionsAccept	Options accept handler
0x4F14A0	Frontend__OnStartGameButton	Start game button handler
0x4D4920	Network__IsAvailable	Check network availability

Key Globals

Address	Name	Type	Description
0x6B3504	g_CurrentScreen	u32	Screen ID driving the main dispatch loop
0x6B3908	g_FrontendFrame	CFrameWnd*	Main frame window
0x6B390C	g_FrontendHwnd	HWND	Main window handle
0x79D6D4	g_DDDisplayWrapper	void*	Display backend wrapper (valid during entire frontend)
0x7A083D	g_SkipToMainMenu	u8	Skip splash, go directly to main menu
0x7A083F	g_AutoNetworkFlag	u8	Auto-network mode flag
0x7C0A20	g_MainMenuActive	u8	0xFF during screen 18
0x7C03D0	g_CWinApp	CWinApp*	MFC application singleton
0x7C0D40	g_NetworkMode	u32	0=LAN, nonzero=WormNET
0x7C0D68	g_NetworkSubtype	u32	Network sub-type selector

Bitmap Font System

WA uses a custom bitmap font renderer, NOT GDI, for all game/frontend text.

Font files

• Graphics\Font.bmp + Data\Gfx\FontExt\%s2.fex (extended glyphs)
• Four sizes: SmlFont2.bmp (12px), StdFont2.bmp (17px), MedFont2.bmp (25px), BigFont2.bmp (33px)

Key structures

• Font array at 0x7A0F58, each font is 0x241C bytes
• Glyph table: 256 entries at font+0x14, each 0x24 bytes
• Character width table at 0x6B2DD9 (256 bytes)
• Registry options: LargerFonts (font+0x20), FrontendFontDynamicAntialiasing (font+0x70)

Key functions

Address	Name	Description
0x414680	Font__LoadFonts	Loads all four font sizes from BMP files
0x4143D0	Font__RenderGlyphs	Core glyph renderer: iterates chars, blits from sprite sheet
0x427830	Font__DrawText	Higher-level: measures string, creates surface, renders
0x5236B0	DDDisplay__DrawTextOnBitmap	thiscall(font_id, bitmap, hAlign, vAlign, msg, a7, a8)
0x4FAF00	DDDisplay__ConstructTextbox	thiscall(dst, length, fontid)
0x4FB070	SetTextboxText	stdcall(textbox, msg, textcolor, color1, color2, a6, a7, opacity)
0x542200	DrawTextboxLocal	Draws textbox at screen position

Rendering pipeline

1. Create surface via g_DDDisplayWrapper->vtable[22] (CreateSurface factory)
2. Font__RenderGlyphs iterates characters, looks up glyph data in font table
3. Each glyph is blitted from the font sprite sheet onto the surface
4. Surface blitted to screen via Surface__Blit (0x403BF0 → surface->vtable[11])

Display backends

The display wrapper at 0x79D6D4 (vtable 0x662EC8, size 0x1C) delegates to one of 6 backends: DirectDraw legacy, DirectDraw classic, D3D9 basic, D3D9 shader, OpenGL CPU, OpenGL GPU. Concrete backend stored at wrapper+0x18. Initialized in the main navigation loop before any dialog is created.