Feat/wwise file location resolver hook

.github/workflows/build.yml

@@ -99,4 +99,4 @@ jobs:
         with:
           name: 'modengine-${{ github.sha }}'
           path: '${{ env.CMAKE_BUILD_DIR }}/ModEngine-*-win64.*' # FIXME gtierney: run-cmake isn't respecting CMAKE_INSTALL_PREFIX
-        if: ${{ github.event_name == 'push' }}
+        if: ${{ github.event_name == 'push' }}

src/CMakeLists.txt

@@ -50,6 +50,7 @@ add_library(modengine2 SHARED
         modengine/ext/debug_menu/ds3/_DS3GameProperties.asm
         modengine/ext/mod_loader/archive_file_overrides.cpp
         modengine/ext/mod_loader/mod_loader_extension.cpp
+        modengine/ext/mod_loader/wwise_file_overrides.cpp
         modengine/ext/profiling/profiling_extension.cpp
         modengine/ext/profiling/profiler_trampoline.asm
         modengine/ext/profiling/main_loop.cpp

src/modengine/ext/mod_loader/mod_loader_extension.cpp

@@ -1,5 +1,6 @@
 #include "mod_loader_extension.h"
 #include "archive_file_overrides.h"
+#include "wwise_file_overrides.h"
 
 #include "modengine/util/hex_string.h"
 #include "modengine/util/platform.h"
@@ -18,6 +19,8 @@ auto loose_params_aob_2 = util::hex_string("0F 85 C5 00 00 00 48 8D 4C 24 28");
 auto virtual_to_archive_path_er_aob = util::hex_aob("e8 ?? ?? ?? ?? 48 83 7b 20 08 48 8d 4b 08 72 03 48 8b 09 4c 8b 4b 18 41 b8 05 00 00 00 4d 3b c8");
 auto virtual_to_archive_path_ac6_aob = util::hex_aob("cf e8 ?? ?? ?? ?? 48 83 7b 20 08 48 8d 4b 08 72 03 48 8b 09 4c 8b 4b 18 41 b8 05 00 00 00 4d 3b c8");
 
+auto ak_file_location_resolver_open_aob = util::hex_aob("4c 89 74 24 28 48 8b 84 24 90 00 00 00 48 89 44 24 20 4c 8b ce 45 8b c4 49 8b d7 48 8b cd e8 ?? ?? ?? ?? 8b d8");
+
 static fs::path primary_mod_path(const Settings& settings)
 {
     return settings.modengine_local_path();
@@ -60,6 +63,8 @@ void ModLoaderExtension::on_attach()
     register_hook(DS3, &hooked_virtual_to_archive_path_ds3, util::rva2addr(0x7d660), virtual_to_archive_path_ds3);
     register_hook(ELDEN_RING, &hooked_virtual_to_archive_path_eldenring, virtual_to_archive_path_er_aob, 0x0, virtual_to_archive_path_eldenring, SCAN_CALL_INST);
     register_hook(ARMORED_CORE_6, &hooked_virtual_to_archive_path_eldenring, virtual_to_archive_path_ac6_aob, 0x1, virtual_to_archive_path_eldenring, SCAN_CALL_INST);
+    register_hook(ELDEN_RING, &hooked_ak_file_location_resolver_open, ak_file_location_resolver_open_aob, 0x1E, ak_file_location_resolver_open, SCAN_CALL_INST);
+    register_hook(ARMORED_CORE_6, &hooked_ak_file_location_resolver_open, ak_file_location_resolver_open_aob, 0x1E, ak_file_location_resolver_open, SCAN_CALL_INST);
 
     auto config = get_config<ModLoaderConfig>();
     for (const auto& mod : config.mods) {

src/modengine/ext/mod_loader/wwise_file_overrides.cpp

@@ -0,0 +1,120 @@
+#include <filesystem>
+
+#include "wwise_file_overrides.h"
+#include "archive_file_overrides.h"
+
+namespace modengine::ext {
+
+// This hook the IAkFileLocationResolver::open() method. It takes in a path 
+// and a so-called openMode. This openMode parameter is of type AkOpenMode 
+// which is an enum with 4 states: Read, Write, WriteOverwrite and ReadWrite.
+// Passing in any of these 4 invariants will cause this function to yield a 
+// FileOperator used for sourcing the file bytes. FromSoftware added another 
+// possible state to AKOpenMode, decimal 9. which will make this fn yield an 
+// EBLFileOperator, this implementation does all its fetching from the BDTs.
+// EBLFileOperator does not use the usual virtual path lookup that ME2 already 
+// hooks. Hence we need this hook here.
+//
+// In order to selectively make it read from disk again this hook checks if an 
+// override file exists and sets the openMode back from 9 to Read and replaces
+// the virtual path parameter string with an absolute path.
+//
+// This is a messy one though:
+// Figuring out if there is an override isn't straight forward. The hooked 
+// function gets invoked with a virtual path string ex: `sd:/50846376.wem`. 
+// Wwise uses subdirectories for localized content, meaning that the "simple"
+// WEM example makes Wwise look in `/50846376.wem` but also in 
+// `enus/50846376.wem` (or `ja/50846376.wem` for AC6 which has `ja` as an extra 
+// locale for some audio and BNKs). To make matters even worse, Elden Ring 
+// specifically sorts the WEMs into a subdir (`wem/`) and then another subdir 
+// based on the  first two digits of the WEM. So above example will spawn 
+// lookups in  `/wem/50/50846376.wem` and `enus/wem/50/50846376.wem`. In order 
+// to figure out if there is an override we will need to look in multiple 
+// directories per request. Luckily, aside from boot, this routine is called
+// quite infrequently.
+//
+// Also, worth pointing out that not all paths passed to this hook will have 
+// the `sd:/` prefix. So we cannot get away with the usual prefix / rewrite 
+// trick and will have to allocate a completely new string.
+
+namespace fs = std::filesystem;
+
+using namespace spdlog;
+
+std::optional<fs::path> find_override_file(const fs::path game_path)
+{
+    for (const auto& root : hooked_file_roots) {
+        trace(L"Searching for {} in {}", game_path.wstring(), root);
+
+        auto file_path = root / fs::path(game_path);
+        if (fs::exists(file_path)) {
+            return file_path;
+        }
+    }
+
+    return {};
+}
+
+const wchar_t* prefixes[3] = {
+    L"sd/",
+    L"sd/enus/",
+    L"sd/ja/",
+};
+
+std::optional<fs::path> check_paths(const std::wstring filename) {
+    for (auto prefix: prefixes) {
+        if (auto override = find_override_file(prefix+filename)) {
+            return override;
+        }
+    }
+
+    return {};
+}
+
+std::optional<fs::path> find_override(const std::wstring filename)
+{
+    // Check wem/<first to digits of filename>/<filename> too since ER uses 
+    // this format
+    if (filename.ends_with(L".wem")) {
+        auto wem_path = L"wem/" + filename.substr(0,2) + L"/" + filename;
+        auto wem_path_result = check_paths(wem_path);
+
+        if (wem_path_result.has_value()) {
+            return wem_path_result;
+        }
+    }
+
+    return check_paths(filename);
+}
+
+std::optional<std::wstring> normalize_filename(const std::wstring path) {
+    if (path.length() > 3 && path.substr(0, 4) == L"sd:/") {
+        return std::wstring(path.substr(4));
+    }
+
+    return {};
+}
+
+ScannedHook<decltype(&ak_file_location_resolver_open)> hooked_ak_file_location_resolver_open;
+
+void* __cdecl ak_file_location_resolver_open(UINT64 p1, wchar_t* path, UINT64 openMode, UINT64 p4, UINT64 p5, UINT64 p6)
+{
+    std::wstring lookup(path);
+    debug(L"sd.bhd entry requested: {}", lookup);
+
+    auto normalized = normalize_filename(lookup);
+    if (!normalized.has_value()) {
+        return hooked_ak_file_location_resolver_open.original(p1, path, openMode, p4, p5, p6);
+    }
+
+    auto filename = normalized.value();
+    auto override = find_override(filename);
+    if (!override.has_value()) {
+        return hooked_ak_file_location_resolver_open.original(p1, path, openMode, p4, p5, p6);
+    }
+
+    auto override_path_string = override.value().wstring();
+    return hooked_ak_file_location_resolver_open.original(p1, override_path_string.data(), 0, p4, p5, p6);
+}
+
+}

src/modengine/ext/mod_loader/wwise_file_overrides.h

@@ -0,0 +1,11 @@
+#pragma once
+
+#include "modengine/hook_set.h"
+
+namespace modengine::ext {
+
+void* __cdecl ak_file_location_resolver_open(UINT64 p1, wchar_t* path, UINT64 p3, UINT64 p4, UINT64 p5, UINT64 p6);
+
+extern ScannedHook<decltype(&ak_file_location_resolver_open)> hooked_ak_file_location_resolver_open;
+
+}