improve: reuse GPU layer pipelines across export preview frames; coalesce export progress updates

apps/desktop-gpui/src/editor_export.rs

@@ -943,7 +943,11 @@ impl EditorWindow {
             });
 
             loop {
+                let mut latest: Option<(u32, u32)> = None;
                 while let Ok((rendered, total)) = progress_rx.try_recv() {
+                    latest = Some((rendered, total));
+                }
+                if let Some((rendered, total)) = latest {
                     let _ = this.update(cx, |this, cx| {
                         if let Some(ui) = this.export.as_mut() {
                             ui.rendered = rendered;
@@ -1184,7 +1188,11 @@ impl EditorWindow {
             });
 
             loop {
+                let mut latest: Option<(u32, u32)> = None;
                 while let Ok((rendered, total)) = progress_rx.try_recv() {
+                    latest = Some((rendered, total));
+                }
+                if let Some((rendered, total)) = latest {
                     let _ = this.update(cx, |this, cx| {
                         if let Some(ui) = this.export.as_mut() {
                             ui.rendered = rendered;
@@ -1229,7 +1237,11 @@ impl EditorWindow {
                     });
 
                     loop {
+                        let mut latest: Option<f64> = None;
                         while let Ok(progress) = upload_rx.try_recv() {
+                            latest = Some(progress);
+                        }
+                        if let Some(progress) = latest {
                             let _ = this.update(cx, |this, cx| {
                                 if let Some(ui) = this.export.as_mut() {
                                     ui.upload_progress = progress as f32;

crates/editor/src/editor_instance.rs

@@ -8,8 +8,8 @@ use cap_project::{
 };
 use cap_rendering::{
     PrecomputedCursorTimeline, ProjectRecordingsMeta, ProjectUniforms, RecordingSegmentDecoders,
-    RenderVideoConstants, SegmentVideoPaths, SharedWgpuDevice, Video, ZoomTransformTimeline,
-    get_duration, spring_mass_damper::SpringMassDamperSimulationConfig,
+    RenderVideoConstants, RendererLayers, SegmentVideoPaths, SharedWgpuDevice, Video,
+    ZoomTransformTimeline, get_duration, spring_mass_damper::SpringMassDamperSimulationConfig,
 };
 use std::{
     collections::HashMap,
@@ -248,6 +248,7 @@ pub struct EditorInstance {
     meta: RecordingMeta,
     pub export_preview_active: AtomicBool,
     pub export_active: AtomicBool,
+    pub preview_layers: std::sync::Mutex<Option<RendererLayers>>,
     runtime_handle: tokio::runtime::Handle,
     audio_output: Arc<crate::AudioOutput>,
 }
@@ -655,6 +656,7 @@ impl EditorInstance {
             playback_active_rx,
             export_preview_active: AtomicBool::new(false),
             export_active: AtomicBool::new(false),
+            preview_layers: std::sync::Mutex::new(None),
             playback_epoch: AtomicU64::new(0),
             runtime_handle: tokio::runtime::Handle::current(),
             audio_output,
@@ -781,6 +783,7 @@ impl EditorInstance {
             meta: self.meta.clone(),
             export_preview_active: AtomicBool::new(false),
             export_active: AtomicBool::new(false),
+            preview_layers: std::sync::Mutex::new(None),
             runtime_handle: self.runtime_handle.clone(),
             audio_output: self.audio_output.clone(),
         });

crates/export/src/preview.rs

@@ -100,6 +100,7 @@ struct PreviewSource<'a> {
     render_constants: &'a RenderVideoConstants,
     segments: Vec<PreviewSegment<'a>>,
     total_duration: f64,
+    layers_cache: Option<&'a std::sync::Mutex<Option<RendererLayers>>>,
 }
 
 struct PreviewSegment<'a> {
@@ -130,6 +131,7 @@ async fn render_preview_with_base(
             })
             .collect(),
         total_duration,
+        layers_cache: None,
     };
     render_preview_frame(source, frame_time, settings).await
 }
@@ -184,6 +186,7 @@ pub async fn render_preview_with_editor(
             })
             .collect(),
         total_duration,
+        layers_cache: Some(&editor.preview_layers),
     };
     render_preview_frame(source, frame_time, settings).await
 }
@@ -219,6 +222,7 @@ async fn render_preview_frame(
         render_constants,
         segments,
         total_duration,
+        layers_cache,
     } = source;
     let project_config = &Arc::new(project_config.clone());
     let transition_mapping = project_config.timeline.as_ref().and_then(|timeline| {
@@ -286,11 +290,22 @@ async fn render_preview_frame(
     );
 
     let mut frame_renderer = FrameRenderer::new(render_constants);
-    let mut layers = RendererLayers::new_with_options(
-        &render_constants.device,
-        &render_constants.queue,
-        render_constants.is_software_adapter,
-    );
+    let mut layers = layers_cache
+        .and_then(|cache| {
+            let mut guard = cache.lock().ok()?;
+            guard.take()
+        })
+        .map(|mut cached| {
+            cached.reset_frame_state();
+            cached
+        })
+        .unwrap_or_else(|| {
+            RendererLayers::new_with_options(
+                &render_constants.device,
+                &render_constants.queue,
+                render_constants.is_software_adapter,
+            )
+        });
 
     let frame = if let Some((outgoing, kind, progress)) = transition_mapping {
         let outgoing_media = segments
@@ -392,6 +407,12 @@ async fn render_preview_frame(
         (total_bitrate * encoder_efficiency * duration_seconds) / (8.0 * 1024.0 * 1024.0)
     };
 
+    if let Some(cache) = layers_cache
+        && let Ok(mut guard) = cache.lock()
+    {
+        *guard = Some(layers);
+    }
+
     Ok(ExportPreviewResult {
         jpeg_base64: STANDARD.encode(&jpeg_buffer),
         estimated_size_mb,

crates/rendering/src/layers/cursor.rs

@@ -455,6 +455,7 @@ impl CursorLayer {
         let time_s = segment_frames.recording_time;
 
         let Some(interpolated_cursor) = &uniforms.interpolated_cursor else {
+            self.bind_group = None;
             return;
         };
 
@@ -565,6 +566,7 @@ impl CursorLayer {
             }
             let Some(tex) = self.cursors.get(&interpolated_cursor.cursor_id) else {
                 error!("Cursor {:?} not found!", interpolated_cursor.cursor_id);
+                self.bind_group = None;
                 return;
             };
             tex

crates/rendering/src/lib.rs

@@ -8116,7 +8116,7 @@ fn join_layer<T>(handle: std::thread::ScopedJoinHandle<'_, T>) -> T {
 }
 
 impl RendererLayers {
-    fn reset_frame_state(&mut self) {
+    pub fn reset_frame_state(&mut self) {
         self.display.reset_frame_state();
         self.camera.reset_frame_state();
         self.camera_only.reset_frame_state();