feat: add device-side subtitle overlay using FreeType for rendering Chinese text

- Updated Cargo.toml to include freetype-rs for font rendering.
- Modified message.rs to introduce a new Message variant for subtitles.
- Enhanced HttpPlugin to send subtitle messages to the live2d plugin.
- Implemented text rendering in the live2d plugin using FreeType for Chinese characters.
- Added OpenGL shaders for rendering text overlays.
- Created a new text.rs module for handling text rasterization and texture rendering.
- Updated renderer.rs to integrate subtitle rendering logic.

src/plugins/live2d/plugin.rs

@@ -9,10 +9,11 @@ use crate::core::plugin::{Platform, Plugin, PluginContext, PluginInfo};
 use anyhow::{Context, Result};
 use std::path::PathBuf;
 use std::sync::atomic::{AtomicBool, Ordering};
-use std::sync::Arc;
+use std::sync::{Arc, Mutex};
 use std::thread::JoinHandle;
+use std::time::{Duration, Instant};
 
-use super::renderer::Live2DRenderer;
+use super::renderer::{Live2DRenderer, Subtitle, SubtitleState};
 
 pub struct Live2DPlugin {
     ctx: Option<PluginContext>,
@@ -21,6 +22,8 @@ pub struct Live2DPlugin {
     worker: Option<JoinHandle<()>>,
     /// 渲染停止信号
     stop_flag: Arc<AtomicBool>,
+    /// 字幕共享状态（http 插件写入，渲染线程读取）
+    subtitle: SubtitleState,
 }
 
 impl Live2DPlugin {
@@ -30,6 +33,7 @@ impl Live2DPlugin {
             renderer: None,
             worker: None,
             stop_flag: Arc::new(AtomicBool::new(false)),
+            subtitle: Arc::new(Mutex::new(None)),
         }
     }
 }
@@ -97,6 +101,16 @@ impl Plugin for Live2DPlugin {
             Message::Shutdown => {
                 self.stop_live2d();
             }
+            Message::Subtitle { text } => {
+                // 设备端字幕：写入共享状态，渲染线程每帧读取，超时自动消失
+                let ttl = Duration::from_millis(
+                    (text.chars().count().max(1) as u64)
+                        .saturating_mul(220)
+                        .saturating_add(2500),
+                );
+                *self.subtitle.lock().unwrap() =
+                    Some(Subtitle { text, expires_at: Instant::now() + ttl });
+            }
             _ => {}
         }
         Ok(())
@@ -139,7 +153,14 @@ impl Live2DPlugin {
             .clone();
 
         let renderer = Arc::new(std::sync::Mutex::new(
-            Live2DRenderer::new(&core_so, &live2d_base, &model_rel, width, height)?,
+            Live2DRenderer::new(
+                &core_so,
+                &live2d_base,
+                &model_rel,
+                width,
+                height,
+                Arc::clone(&self.subtitle),
+            )?,
         ));
         self.renderer = Some(Arc::clone(&renderer));