[wgpu-core] Document and improve naming in PendingWrites.

Author: jimblandy

wgpu-core/src/device/queue.rs

@@ -188,18 +188,25 @@ impl<A: HalApi> EncoderInFlight<A> {
 #[derive(Debug)]
 pub(crate) struct PendingWrites<A: HalApi> {
     pub command_encoder: A::CommandEncoder,
-    pub is_active: bool,
+
+    /// True if `command_encoder` is in the "recording" state, as
+    /// described in the docs for the [`wgpu_hal::CommandEncoder`]
+    /// trait.
+    pub is_recording: bool,
+
     pub temp_resources: Vec<TempResource<A>>,
     pub dst_buffers: FastHashMap<id::BufferId, Arc<Buffer<A>>>,
     pub dst_textures: FastHashMap<id::TextureId, Arc<Texture<A>>>,
+
+    /// All command buffers allocated from `command_encoder`.
     pub executing_command_buffers: Vec<A::CommandBuffer>,
 }
 
 impl<A: HalApi> PendingWrites<A> {
     pub fn new(command_encoder: A::CommandEncoder) -> Self {
         Self {
             command_encoder,
-            is_active: false,
+            is_recording: false,
             temp_resources: Vec::new(),
             dst_buffers: FastHashMap::default(),
             dst_textures: FastHashMap::default(),
@@ -209,7 +216,7 @@ impl<A: HalApi> PendingWrites<A> {
 
     pub fn dispose(mut self, device: &A::Device) {
         unsafe {
-            if self.is_active {
+            if self.is_recording {
                 self.command_encoder.discard_encoding();
             }
             self.command_encoder
@@ -232,9 +239,9 @@ impl<A: HalApi> PendingWrites<A> {
     fn pre_submit(&mut self) -> Result<Option<&A::CommandBuffer>, DeviceError> {
         self.dst_buffers.clear();
         self.dst_textures.clear();
-        if self.is_active {
+        if self.is_recording {
             let cmd_buf = unsafe { self.command_encoder.end_encoding()? };
-            self.is_active = false;
+            self.is_recording = false;
             self.executing_command_buffers.push(cmd_buf);
 
             return Ok(self.executing_command_buffers.last());
@@ -262,23 +269,23 @@ impl<A: HalApi> PendingWrites<A> {
     }
 
     pub fn activate(&mut self) -> &mut A::CommandEncoder {
-        if !self.is_active {
+        if !self.is_recording {
             unsafe {
                 self.command_encoder
                     .begin_encoding(Some("(wgpu internal) PendingWrites"))
                     .unwrap();
             }
-            self.is_active = true;
+            self.is_recording = true;
         }
         &mut self.command_encoder
     }
 
     pub fn deactivate(&mut self) {
-        if self.is_active {
+        if self.is_recording {
             unsafe {
                 self.command_encoder.discard_encoding();
             }
-            self.is_active = false;
+            self.is_recording = false;
         }
     }
 }