[Merged by Bors] - Support recording multiple CommandBuffers in RenderContext

crates/bevy_core_pipeline/src/core_2d/main_pass_2d_node.rs

@@ -101,7 +101,7 @@ impl Node for MainPass2dNode {
             };
 
             render_context
-                .command_encoder
+                .command_encoder()
                 .begin_render_pass(&pass_descriptor);
         }
 

crates/bevy_core_pipeline/src/core_3d/main_pass_3d_node.rs

@@ -186,7 +186,7 @@ impl Node for MainPass3dNode {
             };
 
             render_context
-                .command_encoder
+                .command_encoder()
                 .begin_render_pass(&pass_descriptor);
         }
 

crates/bevy_core_pipeline/src/fxaa/node.rs

@@ -78,7 +78,7 @@ impl Node for FxaaNode {
             Some((id, bind_group)) if source.id() == *id => bind_group,
             cached_bind_group => {
                 let sampler = render_context
-                    .render_device
+                    .render_device()
                     .create_sampler(&SamplerDescriptor {
                         mipmap_filter: FilterMode::Linear,
                         mag_filter: FilterMode::Linear,
@@ -88,7 +88,7 @@ impl Node for FxaaNode {
 
                 let bind_group =
                     render_context
-                        .render_device
+                        .render_device()
                         .create_bind_group(&BindGroupDescriptor {
                             label: None,
                             layout: &fxaa_pipeline.texture_bind_group,
@@ -120,7 +120,7 @@ impl Node for FxaaNode {
         };
 
         let mut render_pass = render_context
-            .command_encoder
+            .command_encoder()
             .begin_render_pass(&pass_descriptor);
 
         render_pass.set_pipeline(pipeline);

crates/bevy_core_pipeline/src/tonemapping/node.rs

@@ -72,12 +72,12 @@ impl Node for TonemappingNode {
             Some((id, bind_group)) if source.id() == *id => bind_group,
             cached_bind_group => {
                 let sampler = render_context
-                    .render_device
+                    .render_device()
                     .create_sampler(&SamplerDescriptor::default());
 
                 let bind_group =
                     render_context
-                        .render_device
+                        .render_device()
                         .create_bind_group(&BindGroupDescriptor {
                             label: None,
                             layout: &tonemapping_pipeline.texture_bind_group,
@@ -112,7 +112,7 @@ impl Node for TonemappingNode {
         };
 
         let mut render_pass = render_context
-            .command_encoder
+            .command_encoder()
             .begin_render_pass(&pass_descriptor);
 
         render_pass.set_pipeline(pipeline);

crates/bevy_core_pipeline/src/upscaling/node.rs

@@ -63,12 +63,12 @@ impl Node for UpscalingNode {
             Some((id, bind_group)) if upscaled_texture.id() == *id => bind_group,
             cached_bind_group => {
                 let sampler = render_context
-                    .render_device
+                    .render_device()
                     .create_sampler(&SamplerDescriptor::default());
 
                 let bind_group =
                     render_context
-                        .render_device
+                        .render_device()
                         .create_bind_group(&BindGroupDescriptor {
                             label: None,
                             layout: &upscaling_pipeline.texture_bind_group,
@@ -108,7 +108,7 @@ impl Node for UpscalingNode {
         };
 
         let mut render_pass = render_context
-            .command_encoder
+            .command_encoder()
             .begin_render_pass(&pass_descriptor);
 
         render_pass.set_pipeline(pipeline);

crates/bevy_render/src/camera/camera_driver_node.rs

@@ -98,7 +98,7 @@ impl Node for CameraDriverNode {
             };
 
             render_context
-                .command_encoder
+                .command_encoder()
                 .begin_render_pass(&pass_descriptor);
         }
 

crates/bevy_render/src/renderer/graph_runner.rs

@@ -58,18 +58,12 @@ impl RenderGraphRunner {
         queue: &wgpu::Queue,
         world: &World,
     ) -> Result<(), RenderGraphRunnerError> {
-        let command_encoder =
-            render_device.create_command_encoder(&wgpu::CommandEncoderDescriptor::default());
-        let mut render_context = RenderContext {
-            render_device,
-            command_encoder,
-        };
-
+        let mut render_context = RenderContext::new(render_device);
         Self::run_graph(graph, None, &mut render_context, world, &[])?;
         {
             #[cfg(feature = "trace")]
             let _span = info_span!("submit_graph_commands").entered();
-            queue.submit(vec![render_context.command_encoder.finish()]);
+            queue.submit(render_context.finish());
         }
         Ok(())
     }

crates/bevy_render/src/renderer/mod.rs

@@ -17,7 +17,9 @@ use bevy_ecs::prelude::*;
 use bevy_time::TimeSender;
 use bevy_utils::Instant;
 use std::sync::Arc;
-use wgpu::{Adapter, AdapterInfo, CommandEncoder, Instance, Queue, RequestAdapterOptions};
+use wgpu::{
+    Adapter, AdapterInfo, CommandBuffer, CommandEncoder, Instance, Queue, RequestAdapterOptions,
+};
 
 /// Updates the [`RenderGraph`] with all of its nodes and then runs it to render the entire frame.
 pub fn render_system(world: &mut World) {
@@ -278,20 +280,68 @@ pub async fn initialize_renderer(
 /// The [`RenderDevice`] is used to create render resources and the
 /// the [`CommandEncoder`] is used to record a series of GPU operations.
 pub struct RenderContext {
-    pub render_device: RenderDevice,
-    pub command_encoder: CommandEncoder,
+    render_device: RenderDevice,
+    command_encoder: Option<CommandEncoder>,
+    command_buffers: Vec<CommandBuffer>,
 }
 
 impl RenderContext {
+    /// Creates a new [`RenderContext`] from a [`RenderDevice`].
+    pub fn new(render_device: RenderDevice) -> Self {
+        Self {
+            render_device,
+            command_encoder: None,
+            command_buffers: Vec::new(),
+        }
+    }
+
+    /// Gets the underlying [`RenderDevice`].
+    pub fn render_device(&self) -> &RenderDevice {
+        &self.render_device
+    }
+
+    /// Gets the current [`CommandEncoder`].
+    pub fn command_encoder(&mut self) -> &mut CommandEncoder {
+        self.command_encoder.get_or_insert_with(|| {
+            self.render_device
+                .create_command_encoder(&wgpu::CommandEncoderDescriptor::default())
+        })
+    }
+
     /// Creates a new [`TrackedRenderPass`] for the context,
     /// configured using the provided `descriptor`.
     pub fn begin_tracked_render_pass<'a>(
         &'a mut self,
         descriptor: RenderPassDescriptor<'a, '_>,
     ) -> TrackedRenderPass<'a> {
-        TrackedRenderPass::new(
-            &self.render_device,
-            self.command_encoder.begin_render_pass(&descriptor),
-        )
+        // Cannot use command_encoder() as we need to split the borrow on self
+        let command_encoder = self.command_encoder.get_or_insert_with(|| {
+            self.render_device
+                .create_command_encoder(&wgpu::CommandEncoderDescriptor::default())
+        });
+        let render_pass = command_encoder.begin_render_pass(&descriptor);
+        TrackedRenderPass::new(&self.render_device, render_pass)
+    }
+
+    /// Append a [`CommandBuffer`] to the queue.
+    ///
+    /// If present, this will flush the currently unflushed [`CommandEncoder`]
+    /// into a [`CommandBuffer`] into the queue before append the provided
+    /// buffer.
+    pub fn add_command_buffer(&mut self, command_buffer: CommandBuffer) {
+        self.flush_encoder();
+        self.command_buffers.push(command_buffer);
+    }
+
+    /// Finalizes the queue and returns the queue of [`CommandBuffer`]s.
+    pub fn finish(mut self) -> Vec<CommandBuffer> {
+        self.flush_encoder();
+        self.command_buffers
+    }
+
+    fn flush_encoder(&mut self) {
+        if let Some(encoder) = self.command_encoder.take() {
+            self.command_buffers.push(encoder.finish());
+        }
     }
 }

examples/shader/compute_shader_game_of_life.rs

@@ -215,7 +215,7 @@ impl render_graph::Node for GameOfLifeNode {
         let pipeline = world.resource::<GameOfLifePipeline>();
 
         let mut pass = render_context
-            .command_encoder
+            .command_encoder()
             .begin_compute_pass(&ComputePassDescriptor::default());
 
         pass.set_bind_group(0, texture_bind_group, &[]);