feature: chat (#36)

* fix(config): load config on demand in get/set instead of asserting

* feat(chat): implement in-game chat box with UTF-8 support

- Add ChatMessage struct and ChatBox widget for displaying and sending messages
- Introduce split_utf8() in text_tools for splitting UTF-8 strings by character count
- Add TimeTools utility (get_time_ticks) for message timestamps
- Update TextField with start_typing/stop_typing methods and set_typing()
- Integrate text input handling in WorldScene and WorldUIManager for chat
- Add utf8cpp library for robust UTF-8 validation and processing
- Add ChatBox rendering and input logic (src/ui/chat_box.cpp)
- Register ChatBox source in CMakeLists.txt
- Fix Renderer::render_lable to skip rendering if VAO is null
- Update credits to include utf8cpp library

* fix(ui): correct chat box layout with dynamic height and bottom anchor

* feat(chat): implement client-server chat messaging

Add protobuf definition for ChatMsg, new packet ID CHAT_MSG (4001), and
handle sending/receiving chat messages on both client and server side.
Wire up UI components (ChatBox, TextField) to allow message input and
display, including a message queue in ClientWorld for thread-safe
processing. Also add default initialization for ChatMessage::time.

* feat(chat): distinguish between send and cancel in chat input

* feat(ui): add background to Label widget and refactor debug overlay

* refactor(ui): decouple ChatBox from image dependencies, allow custom TextField backgrounds

TextField's background is now a generic `Widget` pointer, enabling use of any widget (e.g., `Rect`, `Image`) as background. `ChatBox` no longer creates its own `TextField`; it accepts one via `set_text_field`. Removed `set_d_image` and `set_default_image` in favor of `set_background`. Added a shared default image constant in `default_image.hpp`. Updated `host_game_ui.cpp`, `join_game_ui.cpp`, and `world_ui_manager.cpp` to construct backgrounds accordingly.

* refactor(ui): move width, height, and fill properties to base Widget

Consolidate width, height, and fill (fill_parent, fill_width, fill_height) into the base Widget class. Replace per-widget set_fill(bool) with set_fill_parent(bool), set_fill_width(bool), and set_fill_height(bool).

* refactor(ui): generalize Label background, add ChatBox width method

* feat(chat): implement message expiration after 5 seconds

* feat(ui): add word wrap for chat messages with font width measurement

* feat(audio): implement voice chat using Opus codec

Add voice chat support with Opus encoding/decoding, push-to-talk (V key), and new audio recording infrastructure.

* feat(audio): implement voice chat with Opus codec and streaming audio source

Add AudioStreamSource for continuous PCM playback. Refactor voice send/receive to encode with Opus and stream to a dedicated source instead of per-frame sources. Enable voice transmission over network.

* feat(audio): add spatial voice source with underwater effects

Update voice source to support spatial positioning, low-pass filter, and reverb effect for underwater immersion. Adjust source pool size and low-pass filter parameter. Correct receive_voice parameter type.

* feat(settings): add player voice volume and voice input type options

- Add player voice volume slider and voice input type combo in settings UI.
- Add localization strings for player voice and voice input types.
- Add config overloads for const char* default values.
- Implement voice input types (PTT, always, off) in world scene.
- Refactor WorldScene member order and add load_config method.
- Update audio engine to use player voice volume.
- Downgrade some logging to debug.

* fix(event): delegate error UI events to each handler

Move error UI event check from top of handle_event into each individual
event handler (mouse_move, mouse_button, mouse_wheel, key, text_input).
Also flatten window resize dispatch: all sub-handlers are called regardless
of previous handler return values, and the method always returns false.

* feat(chat): add colored system messages for player join/exit

* chore(logging): reduce verbosity for audio loading and input events

* fix(settings): fix typo in config key "vloume"

* feat(ui): add microphone icon when recording voice

* feat(voice): limit voice message range to 48 units

* chore(logging): downgrade text input log level to debug

* feat(credits): add license identifiers and reorganize license files

* feat: add sensitive word filter for chat messages

Implement AC automaton-based filtering using a sensitive lexicon loaded from a JSON asset file. The filter is applied to both player names and chat messages before broadcasting, and can be toggled via the `sensitive_filter` config option.

* feat(server): add config option to disable voice chat

* fix: correct utf8 validation, add missing include, remove debug log

include/Cubed/audio/audio_engine.hpp

@@ -1,7 +1,9 @@
 #pragma once
 
 #include "Cubed/audio/audio_fade.hpp"
+#include "Cubed/audio/audio_recording.hpp"
 #include "Cubed/audio/audio_source.hpp"
+#include "Cubed/audio/audio_stream_source.hpp"
 #include "Cubed/audio/sound_manager.hpp"
 #include "Cubed/audio/source_pool.hpp"
 #include "Cubed/config.hpp"
@@ -10,13 +12,15 @@
 #include <AL/alc.h>
 #include <glm/glm.hpp>
 #include <memory>
+#include <opus/opus.h>
 #include <string>
 #include <unordered_map>
 namespace Cubed {
 
-class ClientWorld;
+class NetworkClient;
 
 class AudioEngine {
+
 public:
     AudioEngine(Config& config);
     AudioEngine(const AudioEngine&) = delete;
@@ -41,11 +45,23 @@ public:
 
     float& bgm_target_volume();
 
+    void set_client(std::weak_ptr<NetworkClient> client);
+
+    void send_voice(const std::array<int16_t, AudioRecording::FRAME_SAMPLES>&);
+    void receive_voice(std::span<const char> opus, const glm::vec3& pos);
+
+    AudioRecording& audio_recording();
+    const AudioRecording& audio_recording() const;
+
 private:
     using FadeMap = std::unordered_map<std::string, AudioFade>;
     bool m_init{false};
     ALCdevice* device{nullptr};
     ALCcontext* context{nullptr};
+    OpusEncoder* m_encoder{nullptr};
+    OpusDecoder* m_decoder{nullptr};
+    AudioRecording m_recording;
+    std::weak_ptr<NetworkClient> m_client;
     glm::vec3 listener_pos;
     std::unique_ptr<AudioSource> m_bgm;
     FadeMap m_fade_map;
@@ -56,6 +72,9 @@ private:
     bool m_underwater = false;
     float m_music_volume = 1.0f;
     float m_sfx_volume = 1.0f;
+    float m_player_voice_volume = 1.0f;
+
+    std::unique_ptr<AudioStreamSource> m_voice_source;
     std::unique_ptr<AudioFilter> m_low_pass_filter;
     std::unique_ptr<AudioEffect> m_underwater_effect;
     std::unique_ptr<AudioEffectSlot> m_underwater_slot;

include/Cubed/audio/audio_recording.hpp

@@ -0,0 +1,33 @@
+#pragma once
+
+#include <alc.h>
+#include <array>
+#include <cstdint>
+namespace Cubed {
+class AudioEngine;
+class AudioRecording {
+public:
+    static constexpr int SAMPLE_RATE = 48000;
+    static constexpr int FRAME_MS = 20;
+    static constexpr int FRAME_SAMPLES = SAMPLE_RATE * FRAME_MS / 1000;
+    AudioRecording(AudioEngine& engine);
+    AudioRecording(const AudioRecording&) = delete;
+    AudioRecording(AudioRecording&&) = delete;
+    AudioRecording& operator=(const AudioRecording&) = delete;
+    AudioRecording& operator=(AudioRecording&&) = delete;
+    ~AudioRecording();
+
+    void update();
+
+    void init();
+    void start();
+    void stop();
+    bool is_recording() const;
+
+private:
+    AudioEngine& m_engine;
+    ALCdevice* m_capture = nullptr;
+    bool m_recording = false;
+    void send_voice(const std::array<int16_t, FRAME_SAMPLES>& pcm);
+};
+} // namespace Cubed

include/Cubed/audio/audio_source.hpp

@@ -5,6 +5,7 @@
 
 #include <AL/al.h>
 #include <glm/glm.hpp>
+#include <memory>
 namespace Cubed {
 
 enum class AudioState { INITIAL, PLAYING, PAUSED, STOPPED };
@@ -21,8 +22,9 @@ public:
     void set_pitch(float pitch);
     void play();
     void play_2d(const AudioBuffer& buffer);
+    void play_2d(std::unique_ptr<AudioBuffer> buffer);
     void play_3d(const AudioBuffer& buffer, const glm::vec3& pos);
-
+    void play_3d(std::unique_ptr<AudioBuffer> buffer, const glm::vec3& pos);
     void stop();
     void pause();
     float duration() const;
@@ -42,6 +44,8 @@ public:
     void clear_effect_slot();
 
 private:
+    std::unique_ptr<AudioBuffer> m_buffer;
+
     ALuint m_source = 0;
     float m_target_volume = 1.0f;
     float m_duration = 0.0f;

include/Cubed/audio/audio_stream_source.hpp

@@ -0,0 +1,46 @@
+#pragma once
+
+#include "Cubed/audio/audio_effect_slot.hpp"
+#include "Cubed/audio/audio_filter.hpp"
+#include "glm/ext/vector_float3.hpp"
+
+#include <al.h>
+#include <array>
+#include <cstdint>
+#include <span>
+#include <vector>
+
+namespace Cubed {
+class AudioStreamSource {
+public:
+    static constexpr int NUM_BUFFERS = 4;
+    AudioStreamSource();
+    AudioStreamSource(const AudioStreamSource&) = delete;
+    AudioStreamSource(AudioStreamSource&&) = delete;
+    AudioStreamSource& operator=(const AudioStreamSource&) = delete;
+    AudioStreamSource& operator=(AudioStreamSource&&) = delete;
+    ~AudioStreamSource();
+
+    void push_pcm(std::span<const int16_t> pcm, ALsizei sample_rate);
+
+    void stop();
+    bool is_playing() const;
+    void reset();
+
+    void set_volume(float volume);
+    void set_pitch(float pitch);
+    void set_pos(glm::vec3 pos);
+    void set_filter(const AudioFilter& filter);
+    void clear_filter();
+    void set_effect_slot(const AudioEffectSlot& slot);
+    void clear_effect_slot();
+
+private:
+    ALuint m_source = 0;
+    std::array<ALuint, NUM_BUFFERS> m_buffers{};
+    std::vector<ALuint> m_free_buffers;
+    bool m_playing = false;
+
+    void unqueue_processed();
+};
+} // namespace Cubed

include/Cubed/audio/source_pool.hpp

@@ -4,7 +4,7 @@
 namespace Cubed {
 class SourcePool {
 private:
-    std::vector<AudioSource> m_sources;
+    std::vector<std::unique_ptr<AudioSource>> m_sources;
 
 public:
     explicit SourcePool(size_t size);
@@ -15,9 +15,10 @@ public:
     SourcePool& operator=(SourcePool&&) = delete;
 
     void update();
+    [[nodiscard]]
     AudioSource* acquire();
 
-    std::vector<AudioSource>& sources();
+    std::vector<std::unique_ptr<AudioSource>>& sources();
 };
 
 } // namespace Cubed