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System messages — the structured client-message service

The client's structured-message ("SysMsg") service — ENGINE\Source\Services\SysMessage.cpp — is the diagnostic/system-message facility that roughly 35 producer sites emit through (e.g. "NOSPELLIDFOUND|%d", "Camera view %s", object-cache traces). It is small: it formats a message string, validates and classifies it by a small type code, and looks up that type's colour and on-screen duration. The actual on-screen message store, display, and fade are delegated to an external store; in the retail 5875 build the print path formats the string and then discards it (display compiled out).

Translation unit and startup

The translation unit is [0x44cb20, 0x44cd80) (~19 functions), with __FILE__ at 0x835934. Its init is wired during startup at 0x402ad0, immediately after the console (0x402350).

Note that the lower band [0x44c040, 0x44cb20) is a separate Texture.cpp TSExplicitList<CTextureHash> TU with zero call edges into sysmsg — it is not part of this subsystem.

The producer path

sys_msg(type, channel, fmt, ...)   0x44cbd0
    → format    0x44cb90   vsnprintf into a 256-byte buffer
    → validate  0x44cb20   accept only if  text != 0 && type < 4

The type < 4 gate matches the four records in the colour table below.

The colour primitive

The one look-defining computation the service owns is the per-type colour normalize, color_lookup (0x44cca0). For a given type index it converts the table's stored 8-bit channels to normalized floats:

*{r, g, b} = (float)(u8) colorTable[idx].{R, G, B} · (1/255)

In the binary this is fild ; fmul [0x8026c8] ; fstp, repeated for each of R, G, B, where 0x8026c8 holds the reciprocal 0.0039215689 (= 1/255 as f32).

The result is consumed by the external glue status renderer (0x40924f), which re-packs the floats back ×255 into BGRA. The round-trip through floats is the binary's actual path; an implementer reproducing the on-screen colour should follow it rather than passing the bytes through directly.

The SYSMSGCOLOR table

The colour/duration data is a 4-record table at 0x835908. Each record is 8 bytes: {u8 R, u8 G, u8 B, u8 pad, f32 duration}.

idx R G B duration (s) colour
0 255 255 255 10.0 white
1 255 255 127 15.0 yellow
2 255 127 127 15.0 red
3 127 255 255 20.0 cyan

The duration field is read by the f32-duration getter 0x44cd00. The idx < 4 validation gate corresponds exactly to these four records.

The scalar state machine

The remaining state is plain integer bookkeeping — loaded, stored, and clamped, with no look-defining arithmetic:

State Address Init Notes
enabled 0x835928 1
window lo 0xb05d30 0 set with a lo ≤ hi clamp
window hi 0x83592c 3 set with a lo ≤ hi clamp
sel 0x835930 -1

Entry points: init 0x44cd10 (called from startup 0x402ad0); disable 0x44cd40.

Delegated work

  • Storm runtime: vsnprintf (0x73f6ad), SErrSetLastError (0x64e850), SMemFree (0x646430).
  • The on-screen message store, display, and fade: a 268-byte ring buffer at 0x882e28, owned by the later CGlue/world TU around 0x409xxx. The sysmsg service's color_lookup output feeds this store; the store itself, and the duration/fade rendering that consume the colour/duration table, live in the glue layer. In the retail 5875 build the print path formats the message and then discards it — the display side is compiled out.