docs

Author: IceSentry

crates/bevy_render/src/picking.rs

@@ -80,16 +80,13 @@ fn map_and_send_buffer_async(query: Query<&ExtractedGpuPickingCamera, With<Extra
                 Err(err) => bevy_log::error!("Failed to map entity buffer: {err}"),
             });
 
-            // Buffer is mapped and ready to be sent
+            // This waits until the Buffer is mapped
             rx.recv().await.unwrap();
 
             // Send the buffer to the main world
-            let entity_buffer = &buffers.entity_buffer;
             let buffer_view = buffer_slice.get_mapped_range();
-            // Immediately copy the data to CPU to avoid holding the mapped view for long
+            // Copy the data to the CPU
             let entity_data = Vec::from(&*buffer_view);
-            drop(buffer_view);
-            entity_buffer.unmap();
 
             // Because the channel is bounded to 1 entry, the channel will sometimes be full.
             // This isn't ideal but not blocking makes it faster which is preferred.
@@ -245,6 +242,7 @@ pub fn entity_as_uvec2(entity: Entity) -> UVec2 {
     UVec2::new(bits as u32, (bits >> 32) as u32)
 }
 
+/// The textures used to draw the entity for each rendered mesh
 #[derive(Component, Clone)]
 pub struct EntityTextures {
     pub main: CachedTexture,
@@ -282,6 +280,7 @@ impl EntityTextures {
     }
 }
 
+/// This creates the required buffers for each camera
 fn prepare_gpu_picking_buffers(
     render_device: Res<RenderDevice>,
     mut cameras: Query<
@@ -294,6 +293,9 @@ fn prepare_gpu_picking_buffers(
 
         let buffer_dimensions =
             BufferDimensions::new(size.x as usize, size.y as usize, ENTITY_TEXTURE_FORMAT);
+        // TODO We currently create one buffer per frame. This isn't ideal.
+        // We should have a way to only create a buffer when required. Unfortunately, the async nature of
+        // the buffer map api makes it hard to know how many buffer we'll need since we need at least one per frame.
         let entity_buffer = render_device.create_buffer(&BufferDescriptor {
             label: Some("Entity Buffer"),
             size: (buffer_dimensions.padded_bytes_per_row * buffer_dimensions.height) as u64,