[core, hle, video_core, memory] Improve multi-process, display layers, dynamic shader cache and rework overlay (#4238)

- [x] I have read and followed the [Contribution Guidelines](https://git.eden-emu.dev/eden-emu/eden/src/branch/master/CONTRIBUTING.md#code-contributions).
- [x] I have read and followed the [AI Policy](https://git.eden-emu.dev/eden-emu/eden/src/branch/master/docs/policies/AI.md)
- [x] I have read and followed the [Coding Guidelines](https://git.eden-emu.dev/eden-emu/eden/src/branch/master/docs/policies/Coding.md) to the best of my ability.

-------------------

- Dynamic shader cache reloading capability for qlaunch
- Multi-process improvements (thanks to @frank1734), instead of just using the main application we now respect caller process (also did it for HID devices while I was at it)
- Layer stack masks & shared buffer screenshot for video core, added different masks (screenshot, recording, etc.) this was discovered as an issue due to how in qlaunch the transition was not right between applications. May not be perfect but also fixes screenshots while using qlaunch
- Reworked overlay display management (input and visibility) - instead of random numbers as I've previously did, I decided to add an AppletZIndex enum for better readability. Also split capability of input by touch and gamepad.
- etc.

Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/4238
Reviewed-by: Samuel <lizzie@eden-emu.dev>
Reviewed-by: CamilleLaVey <camillelavey99@gmail.com>
Reviewed-by: MaranBr <maranbr@eden-emu.dev>

src/core/file_sys/content_archive.cpp

@@ -29,7 +29,7 @@ static u8 MasterKeyIdForKeyGeneration(u8 key_generation) {
     return std::max<u8>(key_generation, 1) - 1;
 }
 
-NCA::NCA(VirtualFile file_, const NCA* base_nca)
+NCA::NCA(VirtualFile file_, const NCA* base_nca, bool allow_missing_base)
     : file(std::move(file_)), keys{Core::Crypto::KeyManager::Instance()} {
     if (file == nullptr) {
         status = Loader::ResultStatus::ErrorNullFile;
@@ -110,7 +110,7 @@ NCA::NCA(VirtualFile file_, const NCA* base_nca)
         }
     }
 
-    if (is_update && base_nca == nullptr) {
+    if (is_update && base_nca == nullptr && !allow_missing_base) {
         status = Loader::ResultStatus::ErrorMissingBKTRBaseRomFS;
     } else {
         status = Loader::ResultStatus::Success;

src/core/file_sys/content_archive.h

@@ -1,3 +1,6 @@
+// SPDX-FileCopyrightText: Copyright 2026 Eden Emulator Project
+// SPDX-License-Identifier: GPL-3.0-or-later
+
 // SPDX-FileCopyrightText: Copyright 2018 yuzu Emulator Project
 // SPDX-License-Identifier: GPL-2.0-or-later
 
@@ -63,7 +66,7 @@ inline bool IsDirectoryLogoPartition(const VirtualDir& pfs) {
 // After construction, use GetStatus to determine if the file is valid and ready to be used.
 class NCA : public ReadOnlyVfsDirectory {
 public:
-    explicit NCA(VirtualFile file, const NCA* base_nca = nullptr);
+    explicit NCA(VirtualFile file, const NCA* base_nca = nullptr, bool allow_missing_base = false);
     ~NCA() override;
 
     Loader::ResultStatus GetStatus() const;

src/core/file_sys/fssystem/fssystem_indirect_storage.cpp

@@ -4,6 +4,7 @@
 // SPDX-FileCopyrightText: Copyright 2023 yuzu Emulator Project
 // SPDX-License-Identifier: GPL-2.0-or-later
 
+#include "common/logging.h"
 #include "core/file_sys/errors.h"
 #include "core/file_sys/fssystem/fssystem_indirect_storage.h"
 
@@ -99,6 +100,18 @@ Result IndirectStorage::GetEntryList(Entry* out_entries, s32* out_entry_count, s
     R_SUCCEED();
 }
 
+void IndirectStorage::ReportMissingOriginal(s64 offset, s64 size) {
+    if (m_reported_missing_original) {
+        return;
+    }
+    m_reported_missing_original = true;
+
+    LOG_ERROR(Common_Filesystem,
+              "Patch storage requests {:#x} bytes at {:#x} from a base storage that is not "
+              "present; this data will read as garbage",
+              size, offset);
+}
+
 size_t IndirectStorage::Read(u8* buffer, size_t size, size_t offset) const {
     // Validate pre-conditions.
     ASSERT(this->IsInitialized());

src/core/file_sys/fssystem/fssystem_indirect_storage.h

@@ -85,6 +85,9 @@ public:
     void SetStorage(s32 idx, VirtualFile storage) {
         ASSERT(0 <= idx && idx < StorageCount);
         m_data_storage[idx] = storage;
+        if (idx == 0) {
+            m_original_missing = storage == nullptr || storage->GetSize() == 0;
+        }
     }
 
     template <typename T>
@@ -130,6 +133,9 @@ protected:
 
     template <bool ContinuousCheck, bool RangeCheck, typename F>
     Result OperatePerEntry(s64 offset, s64 size, F func);
+    // Launching another game makes the original storage inaccessable.
+    // This is a helper for multi-nca games.
+    void ReportMissingOriginal(s64 offset, s64 size);
 
 private:
     struct ContinuousReadingEntry {
@@ -154,6 +160,8 @@ private:
 private:
     mutable BucketTree m_table;
     std::array<VirtualFile, StorageCount> m_data_storage;
+    bool m_original_missing{false};
+    bool m_reported_missing_original{false};
 };
 
 template <bool ContinuousCheck, bool RangeCheck, typename F>
@@ -272,6 +280,10 @@ Result IndirectStorage::OperatePerEntry(s64 offset, s64 size, F func) {
         if (needs_operate) {
             const auto cur_entry_phys_offset = cur_entry.GetPhysicalOffset();
 
+            if (cur_entry.storage_index == 0 && m_original_missing) {
+                this->ReportMissingOriginal(cur_offset, cur_size);
+            }
+
             if constexpr (RangeCheck) {
                 // Get the current data storage's size.
                 s64 cur_data_storage_size = m_data_storage[cur_entry.storage_index]->GetSize();

src/core/file_sys/nca_metadata.h

@@ -48,11 +48,11 @@ struct ContentRecord {
     std::array<u8, 0x10> nca_id;
     std::array<u8, 0x6> size;
     ContentRecordType type;
-    INSERT_PADDING_BYTES(1);
+    u8 id_offset;
 };
 static_assert(sizeof(ContentRecord) == 0x38, "ContentRecord has incorrect size.");
 
-constexpr ContentRecord EMPTY_META_CONTENT_RECORD{{}, {}, {}, ContentRecordType::Meta, {}};
+constexpr ContentRecord EMPTY_META_CONTENT_RECORD{{}, {}, {}, ContentRecordType::Meta, 0};
 
 struct MetaRecord {
     u64_le title_id;

src/core/file_sys/registered_cache.cpp

@@ -567,20 +567,45 @@ VirtualFile RegisteredCache::GetFileAtID(NcaID id) const {
 }
 
 static std::optional<NcaID> CheckMapForContentRecord(const ankerl::unordered_dense::map<u64, CNMT>& map, u64 title_id, ContentRecordType type) {
-    const auto cmnt_iter = map.find(title_id);
+    auto cmnt_iter = map.find(title_id);
+    u8 id_offset = 0;
+
     if (cmnt_iter == map.cend()) {
-        return std::nullopt;
+        const auto program_index = title_id & AOC_TITLE_ID_MASK;
+        if (program_index == 0) {
+            return std::nullopt;
+        }
+
+        cmnt_iter = map.find(title_id & ~AOC_TITLE_ID_MASK);
+        if (cmnt_iter == map.cend()) {
+            return std::nullopt;
+        }
+
+        id_offset = static_cast<u8>(program_index);
     }
 
     const auto& cnmt = cmnt_iter->second;
     const auto& content_records = cnmt.GetContentRecords();
     const auto iter = std::find_if(content_records.cbegin(), content_records.cend(),
-                                   [type](const ContentRecord& rec) { return rec.type == type; });
-    if (iter == content_records.cend()) {
+                                   [type, id_offset](const ContentRecord& rec) {
+                                       return rec.type == type && rec.id_offset == id_offset;
+                                   });
+    if (iter != content_records.cend()) {
+        return std::make_optional(iter->nca_id);
+    }
+
+    if (id_offset != 0) {
         return std::nullopt;
     }
 
-    return std::make_optional(iter->nca_id);
+    const auto fallback_iter =
+        std::find_if(content_records.cbegin(), content_records.cend(),
+                     [type](const ContentRecord& rec) { return rec.type == type; });
+    if (fallback_iter == content_records.cend()) {
+        return std::nullopt;
+    }
+
+    return std::make_optional(fallback_iter->nca_id);
 }
 
 std::optional<NcaID> RegisteredCache::GetNcaIDFromMetadata(u64 title_id,

src/core/file_sys/submission_package.cpp

@@ -12,6 +12,7 @@
 #include "common/hex_util.h"
 #include "common/logging.h"
 #include "core/crypto/key_manager.h"
+#include "core/file_sys/common_funcs.h"
 #include "core/file_sys/content_archive.h"
 #include "core/file_sys/nca_metadata.h"
 #include "core/file_sys/partition_filesystem.h"
@@ -65,10 +66,12 @@ u64 NSP::GetProgramTitleID() const {
     }
 
     auto program_id = expected_program_id;
-    if (program_id == 0) {
-        if (!program_status.empty()) {
-            program_id = program_status.begin()->first;
-        }
+    if (program_id == 0 && !program_status.empty()) {
+        program_id = std::min_element(program_status.cbegin(), program_status.cend(),
+                                      [](const auto& lhs, const auto& rhs) {
+                                          return lhs.first < rhs.first;
+                                      })
+                         ->first;
     }
 
     program_id = program_id + program_index;
@@ -273,8 +276,7 @@ void NSP::ReadNCAs(const std::vector<VirtualFile>& files) {
                     // If the last 3 hexadecimal digits of the NCA's TitleID is between 0x1 and
                     // 0x7FF, this is a multi-program update NCA. Otherwise, this is a regular
                     // update NCA.
-                    if ((next_nca->GetTitleId() & 0x7FF) != 0 &&
-                        (next_nca->GetTitleId() & 0x800) == 0) {
+                    if ((next_nca->GetTitleId() & AOC_TITLE_ID_MASK) != 0) {
                         ncas[next_nca->GetTitleId()][{cnmt.GetType(), rec.type}] =
                             std::move(next_nca);
                     } else {