Patches¶

This page lists the runtime hooks and byte patches DttR installs.

DttR resolves most sites against the loaded game module with DTTR_Core_HookSigscan(), which accepts signatures in space-separated hexadecimal byte format with ? bytes as mask wildcards.

Terminology¶

IAT hooks replace an import-address-table slot. Future calls through that import go directly to DttR's replacement function; the call site itself is unchanged, and the hook may call the saved original import when needed.
Jump hooks replace the first five bytes at the match with E9 <rel32>. Execution that reaches the patched address branches immediately to DttR's callback instead of continuing through the original function body.
Trampoline hooks use the same jump patch and keep a callable copy of the original prologue. The callback can run custom code, call the trampoline to resume the displaced original instructions and continue into the game code, then return or adjust control flow as needed.

Bootstrap¶

Site	Signature	Target	Effect
`dttr_hook_win_main`	Signature `83 EC 40 53 8B 5C 24`, jump hook at the matched function entry	Game `Window_RunWinMain`-style entrypoint	Installs before sidecar setup. The callback initializes config, SDL, graphics, data pointers, hooks, movies, audio, and mods, then drives the original game loop.

Game Data and Process Fixes¶

Site	Signature	Target	Effect
`DTTR_PCDOGS_F_File_OpenWithMode`	Signature `E8 ?? ?? ?? ?? 85 C0 75 ?? C3`, resolve the matched `CALL rel32` target	Game lower-level CRT-style open routine	Hands resolved paths back to the original file opener.
`dttr_crt_hook_open_file`	Signature `6A 40 FF 74 24 0C FF 74 24 0C E8`, jump hook at match	Game file-open wrapper	Routes file reads through DttR path resolution: case-insensitive lookup, ISO paths, and safe failure handling.
`dttr_hook_resolve_pcdogs_path`	Signature `51 8D 44 24 ?? 57`, optional jump hook at match	Game directory resolver	Fixes later releases that mis-detect the game directory when an earlier path segment contains `p`.
`dttr_hook_cleanup_title_resources`	Signature `6A 01 E8 ?? ?? ?? ?? E8 ?? ?? ?? ?? A1 ?? ?? ?? ?? 50 E8 ?? ?? ?? ?? 8B 0D ?? ?? ?? ?? 51 E8 ?? ?? ?? ?? 8B 15 ?? ?? ?? ?? 52 E8 ?? ?? ?? ?? A1 ?? ?? ?? ?? 50 E8 ?? ?? ?? ?? 8B 0D ?? ?? ?? ?? 51 E8 ?? ?? ?? ?? 83 ?? ??`, trampoline hook at match	Original cleanup-title-resources routine, captured as `dttr_hook_cleanup_title_resources_original`	Runs the original cleanup, then clears stale title resource pointers.

Graphics¶

DirectDraw Import Hooks¶

Site	Signature	Target	Effect
`dttr_hook_directdraw_create_ex`	`DDraw_CreateEx` import-thunk symbol, trampoline hook on import thunk	`ddraw!DirectDrawCreateEx` thunk body (`FF 25 <IAT slot>`)	Returns DttR's DirectDraw 7 translator and stores it in the game-side DirectDraw pointer.
`dttr_hook_directdraw_enumerate_ex_a`	`DDraw_EnumerateExA` import-thunk symbol, trampoline hook on import thunk	`ddraw!DirectDrawEnumerateExA` thunk body (`FF 25 <IAT slot>`)	Enumerates DttR's virtual display device.

Subpixel Vertex Precision Byte Patches¶

DttR installs these patches only when vertex_precision is subpixel. When logical scaling is active, the sidecar also expands transformed opaque triangle meshes slightly on the CPU before backend submission. That small overlap hides subpixel cracks between adjacent mesh pieces.

Site	Signature	Bytes	Effect
`dttr_hook_precision_fast_path`	Signature `83 F8 ?? 7C ?? D9 43 ?? D8 1D ?? ?? ?? ?? DF E0 F6 C4 41 0F 85 ?? ?? ?? ??`, offset `+19`	`E9 BA 00 00 00 90` (`jmp +0xBA` plus `nop`)	Skips the original fast-path conditional branch that collapses vertex precision.
`dttr_hook_precision_batch_limit_a`	Signature `8B 08 EB ?? A1 ?? ?? ?? ?? 8B 0D ?? ?? ?? ?? 3B C1`, offset `+17`	`90 90` (two `nop`s)	Keeps the precision path from leaving through the original batch-limit check.
`dttr_hook_precision_batch_limit_b`	Signature `83 C1 14 4E 75 ?? A1 ?? ?? ?? ?? 8B 0D ?? ?? ?? ?? 3B C1`, offset `+19`	`90 90` (two `nop`s)	Applies the same batch-limit fix for the second matched loop.
`dttr_hook_precision_ftol_x`	Signature `DB 44 24 30 D9 1F`, offset `-15`	`D9 1F 90 90 90` (`fstp dword ptr [edi]` plus three `nop`s)	Stores the x coordinate directly as float, preserving subpixel precision.
`dttr_hook_precision_mov_x`	Signature `DB 44 24 30 D9 1F`, offset `-10`	`90 90 90 90` (`nop` x4)	Removes the integer move paired with the original x conversion.
`dttr_hook_precision_fstp2_x`	Signature `8D AE ?? ?? ?? ?? DB 44 24 30 D9 1F`, offset `+10`	`90 90` (two `nop`s)	Removes the second store from the original x conversion sequence.
`dttr_hook_precision_fild_x`	Signature `8D AE ?? ?? ?? ?? DB 44 24 30`, offset `+6`	`90 90 90 90` (`nop` x4)	Removes the integer reload for x.
`dttr_hook_precision_ftol_y`	Signature `8B 54 24 18 89 44 24 30`, offset `-5`	`D9 5D 00 90 90` (`fstp dword ptr [ebp+0]` plus two `nop`s)	Stores the y coordinate directly as float.
`dttr_hook_precision_mov_y`	Signature `8B 54 24 18 89 44 24 30`, offset `+4`	`90 90 90 90` (`nop` x4)	Removes the integer move paired with the original y conversion.
`dttr_hook_precision_fstp2_y`	Signature `83 C0 14 50 55 D9 5D 00`, offset `+5`	`90 90 90` (`nop` x3)	Removes the second store from the original y conversion sequence.
`dttr_hook_precision_fild_y`	Signature `52 DB 44 24 34`, offset `+1`	`90 90 90 90` (`nop` x4)	Removes the integer reload for y.
`dttr_hook_render_quad_snap`	Signature `53 8B 5C 24 14 55 33 C9 56 57 85 DB`, offset `+0`	`C3` (`ret`)	Optional compatibility patch for the subpixel path that stops the original render-quad snap helper.

Input¶

Site	Signature	Target	Effect
`dttr_inputs_hook_dinput_poll`	Signature `56 8B 74 24 ?? 56 8B 06`, jump hook at match	Game DirectInput joystick poll function	Maps SDL gamepad state into the game's joystick layout.
`dttr_inputs_hook_get_async_key_state`	`Video_PlayMovieLoop_GetAsyncKeyStateThunk->PatchSpec()` in the `sidecar/inputs` patch group	IAT-style slot loaded by `mov ebx, [GetAsyncKeyStateSlot]`	Routes keyboard state through SDL and limits input to the SDL window.

Audio¶

Audio Trampolines¶

These hooks keep game audio paths safe while DttR routes MSS through SDL.

Site	Signature	Target	Effect
`DTTR_PCDOGS_F_Audio_InitializeSystem`	Signature `81 EC 90 ?? ?? ?? 55 56 57 FF 15`, `PatchSpec()` in the `sidecar/audio` patch group	Game audio system init, captured as `audio_init_system_original`	Skips MSS init when SDL reports no playback devices.
`DTTR_PCDOGS_F_Audio_StopAllSounds`	Signature `A1 ?? ?? ?? ?? 6A ?? 50 FF 15`, `PatchSpec()` in the `sidecar/audio` patch group	Game stop-all-sounds routine, captured as `audio_stop_all_sounds_original`	Stops DttR's SDL samples first, then calls the original only if a digital driver exists.
`DTTR_PCDOGS_F_Audio_InitializeLevelAudio`	Signature `A1 ?? ?? ?? ?? 6A 7F 50 FF 15`, `PatchSpec()` in the `sidecar/audio` patch group	Game level-audio init routine, captured as `audio_init_level_audio_original`	Guards level audio init when no driver is active.
`DTTR_PCDOGS_F_Audio_StopAllSamples`	Signature `56 57 8B 3D ?? ?? ?? ?? BE`, `PatchSpec()` in the `sidecar/audio` patch group	Game stop-all-samples routine, captured as `audio_stop_all_samples_original`	Stops DttR's SDL samples first, then calls the original only if a digital driver exists.

Miles Sound System Import Hooks¶

DttR patches the mss32.dll import address table by name. It keeps the original MSS32 function from each game IAT slot so the hook can be restored.

Hook	Import name / site	Replacement target
`dttr_hook_mss_ail_allocate_sample_handle`	`_AIL_allocate_sample_handle@4`	`dttr_mss_ail_allocate_sample_handle`
`dttr_hook_mss_ail_close_stream`	`_AIL_close_stream@4`	`dttr_mss_ail_close_stream`
`dttr_hook_mss_ail_end_sample`	`_AIL_end_sample@4`	`dttr_mss_ail_end_sample`
`dttr_hook_mss_ail_get_preference`	`_AIL_get_preference@4`	`dttr_mss_ail_get_preference`
`dttr_hook_mss_ail_init_sample`	`_AIL_init_sample@4`	`dttr_mss_ail_init_sample`
`dttr_hook_mss_ail_open_stream`	`_AIL_open_stream@12`	`dttr_mss_ail_open_stream`
`dttr_hook_mss_ail_pause_stream`	`_AIL_pause_stream@8`	`dttr_mss_ail_pause_stream`
`dttr_hook_mss_ail_release_sample_handle`	`_AIL_release_sample_handle@4`	`dttr_mss_ail_release_sample_handle`
`dttr_hook_mss_ail_sample_playback_rate`	`_AIL_sample_playback_rate@4`	`dttr_mss_ail_sample_playback_rate`
`dttr_hook_mss_ail_sample_status`	`_AIL_sample_status@4`	`dttr_mss_ail_sample_status`
`dttr_hook_mss_ail_set_digital_master_volume`	`_AIL_set_digital_master_volume@8`	`dttr_mss_ail_set_digital_master_volume`
`dttr_hook_mss_ail_set_preference`	`_AIL_set_preference@8`	`dttr_mss_ail_set_preference`
`dttr_hook_mss_ail_set_sample_file`	`_AIL_set_sample_file@12`	`dttr_mss_ail_set_sample_file`
`dttr_hook_mss_ail_set_sample_loop_count`	`_AIL_set_sample_loop_count@8`	`dttr_mss_ail_set_sample_loop_count`
`dttr_hook_mss_ail_set_sample_pan`	`_AIL_set_sample_pan@8`	`dttr_mss_ail_set_sample_pan`
`dttr_hook_mss_ail_set_sample_playback_rate`	`_AIL_set_sample_playback_rate@8`	`dttr_mss_ail_set_sample_playback_rate`
`dttr_hook_mss_ail_set_sample_volume`	`_AIL_set_sample_volume@8`	`dttr_mss_ail_set_sample_volume`
`dttr_hook_mss_ail_set_stream_loop_count`	`_AIL_set_stream_loop_count@8`	`dttr_mss_ail_set_stream_loop_count`
`dttr_hook_mss_ail_set_stream_volume`	`_AIL_set_stream_volume@8`	`dttr_mss_ail_set_stream_volume`
`dttr_hook_mss_ail_shutdown`	`_AIL_shutdown@0`	`dttr_mss_ail_shutdown`
`dttr_hook_mss_ail_start_sample`	`_AIL_start_sample@4`	`dttr_mss_ail_start_sample`
`dttr_hook_mss_ail_start_stream`	`_AIL_start_stream@4`	`dttr_mss_ail_start_stream`
`dttr_hook_mss_ail_startup`	`_AIL_startup@0`	`dttr_mss_ail_startup`
`dttr_hook_mss_ail_stop_sample`	`_AIL_stop_sample@4`	`dttr_mss_ail_stop_sample`
`dttr_hook_mss_ail_stream_status`	`_AIL_stream_status@4`	`dttr_mss_ail_stream_status`
`dttr_hook_mss_ail_waveOutClose`	`_AIL_waveOutClose@4`	`dttr_mss_ail_waveOutClose`
`dttr_hook_mss_ail_waveOutOpen`	`_AIL_waveOutOpen@16`	`dttr_mss_ail_waveOutOpen`

Movies¶

Site	Signature	Target	Effect
`dttr_movies_hook_movie_play_file`	`PatchSpec()` in the `sidecar/movie` patch group	Game `Video_PlayMovieFile` routine	Replaces MCI playback with DttR's FFmpeg/SDL-backed movie player.