Fix: Alt backgrounds and some models not always loading after toggling alt mode

soh/soh/OTRGlobals.cpp

@@ -1415,6 +1415,14 @@ extern "C" void ResourceMgr_DirtyDirectory(const char* resName) {
     LUS::Context::GetInstance()->GetResourceManager()->DirtyDirectory(resName);
 }
 
+extern "C" void ResourceMgr_UnloadResource(const char* resName) {
+    std::string path = resName;
+    if (path.substr(0, 7) == "__OTR__") {
+        path = path.substr(7);
+    }
+    auto res = LUS::Context::GetInstance()->GetResourceManager()->UnloadResource(path);
+}
+
 // OTRTODO: There is probably a more elegant way to go about this...
 // Kenix: This is definitely leaking memory when it's called.
 extern "C" char** ResourceMgr_ListFiles(const char* searchMask, int* resultSize) {
@@ -1441,6 +1449,27 @@ extern "C" uint8_t ResourceMgr_FileExists(const char* filePath) {
     return ExtensionCache.contains(path);
 }
 
+extern "C" uint8_t ResourceMgr_FileAltExists(const char* filePath) {
+    std::string path = filePath;
+    if (path.substr(0, 7) == "__OTR__") {
+        path = path.substr(7);
+    }
+
+    if (path.substr(0, 4) != "alt/") {
+        path = "alt/" + path;
+    }
+
+    return ExtensionCache.contains(path);
+}
+
+// Unloads a resource if an alternate version exists when alt assets are enabled
+// The resource is only removed from the internal cache to prevent it from used in the next resource lookup
+extern "C" void ResourceMgr_UnloadOriginalWhenAltExists(const char* resName) {
+    if (CVarGetInteger("gAltAssets", 0) && ResourceMgr_FileAltExists((char*) resName)) {
+        ResourceMgr_UnloadResource((char*) resName);
+    }
+}
+
 extern "C" void ResourceMgr_LoadFile(const char* resName) {
     LUS::Context::GetInstance()->GetResourceManager()->LoadResource(resName);
 }
@@ -1565,6 +1594,11 @@ extern "C" void ResourceMgr_PushCurrentDirectory(char* path)
 
 extern "C" Gfx* ResourceMgr_LoadGfxByName(const char* path)
 {
+    // When an alt resource exists for the DL, we need to unload the original asset
+    // to clear the cache so the alt asset will be loaded instead
+    // OTRTODO: If Alt loading over original cache is fixed, this line can most likely be removed
+    ResourceMgr_UnloadOriginalWhenAltExists(path);
+
     auto res = std::static_pointer_cast<LUS::DisplayList>(GetResourceByNameHandlingMQ(path));
     return (Gfx*)&res->Instructions[0];
 }

soh/soh/OTRGlobals.h

@@ -86,8 +86,11 @@ uint32_t ResourceMgr_GetGameVersion(int index);
 uint32_t ResourceMgr_GetGamePlatform(int index);
 uint32_t ResourceMgr_GetGameRegion(int index);
 void ResourceMgr_LoadDirectory(const char* resName);
+void ResourceMgr_UnloadResource(const char* resName);
 char** ResourceMgr_ListFiles(const char* searchMask, int* resultSize);
 uint8_t ResourceMgr_FileExists(const char* resName);
+uint8_t ResourceMgr_FileAltExists(const char* resName);
+void ResourceMgr_UnloadOriginalWhenAltExists(const char* resName);
 char* GetResourceDataByNameHandlingMQ(const char* path);
 void ResourceMgr_LoadFile(const char* resName);
 char* ResourceMgr_LoadFileFromDisk(const char* filePath);

soh/src/code/z_room.c

@@ -277,6 +277,11 @@ void func_8009638C(Gfx** displayList, void* source, void* tlut, u16 width, u16 h
     bg->b.imagePal = 0;
     bg->b.imageFlip = CVarGetInteger("gMirroredWorld", 0) ? G_BG_FLAG_FLIPS : 0;
 
+    // When an alt resource exists for the background, we need to unload the original asset
+    // to clear the cache so the alt asset will be loaded instead
+    // OTRTODO: If Alt loading over original cache is fixed, this line can most likely be removed
+    ResourceMgr_UnloadOriginalWhenAltExists((char*) source);
+
     if (ResourceMgr_ResourceIsBackground((char*) source)) {
         char* blob = (char*) ResourceGetDataByName((char *) source);
         swapAndConvertJPEG(blob);