Skip to content

[Merged by Bors] - Reduce branching in TrackedRenderPass #7053

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Closed
wants to merge 7 commits into from
Closed

[Merged by Bors] - Reduce branching in TrackedRenderPass #7053

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
7 commits
Select commit Hold shift + click to select a range
f0fee58
Reduce branching in TrackedRenderPass
james7132 Dec 29, 2022
0ea8e45
Switch to using RenderContext::begin_tracked_render_pass
james7132 Dec 31, 2022
28f4ee5
Merge branch 'main' into less-branching-render-pass
james7132 Jan 4, 2023
2c2f871
Set an artificial limit to avoid overallocating the Vecs
james7132 Jan 4, 2023
ce58ddf
Update call sites
james7132 Jan 4, 2023
e525c85
Use wgpu-hal's constants instead of ours.
james7132 Jan 4, 2023
6a080ec
Merge branch 'main' into less-branching-render-pass
james7132 Jan 6, 2023
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
83 changes: 37 additions & 46 deletions crates/bevy_core_pipeline/src/bloom/mod.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -17,7 +17,6 @@ use bevy_render::{
},
prelude::Camera,
render_graph::{Node, NodeRunError, RenderGraph, RenderGraphContext, SlotInfo, SlotType},
render_phase::TrackedRenderPass,
render_resource::*,
renderer::{RenderContext, RenderDevice},
texture::{CachedTexture, TextureCache},
Expand Down Expand Up @@ -232,17 +231,15 @@ impl Node for BloomNode {
{
let view = &BloomTextures::texture_view(&textures.texture_a, 0);
let mut prefilter_pass =
TrackedRenderPass::new(render_context.command_encoder.begin_render_pass(
&RenderPassDescriptor {
label: Some("bloom_prefilter_pass"),
color_attachments: &[Some(RenderPassColorAttachment {
view,
resolve_target: None,
ops: Operations::default(),
})],
depth_stencil_attachment: None,
},
));
render_context.begin_tracked_render_pass(RenderPassDescriptor {
label: Some("bloom_prefilter_pass"),
color_attachments: &[Some(RenderPassColorAttachment {
view,
resolve_target: None,
ops: Operations::default(),
})],
depth_stencil_attachment: None,
});
prefilter_pass.set_render_pipeline(downsampling_prefilter_pipeline);
prefilter_pass.set_bind_group(
0,
Expand All @@ -258,17 +255,15 @@ impl Node for BloomNode {
for mip in 1..textures.mip_count {
let view = &BloomTextures::texture_view(&textures.texture_a, mip);
let mut downsampling_pass =
TrackedRenderPass::new(render_context.command_encoder.begin_render_pass(
&RenderPassDescriptor {
label: Some("bloom_downsampling_pass"),
color_attachments: &[Some(RenderPassColorAttachment {
view,
resolve_target: None,
ops: Operations::default(),
})],
depth_stencil_attachment: None,
},
));
render_context.begin_tracked_render_pass(RenderPassDescriptor {
label: Some("bloom_downsampling_pass"),
color_attachments: &[Some(RenderPassColorAttachment {
view,
resolve_target: None,
ops: Operations::default(),
})],
depth_stencil_attachment: None,
});
downsampling_pass.set_render_pipeline(downsampling_pipeline);
downsampling_pass.set_bind_group(
0,
Expand All @@ -284,17 +279,15 @@ impl Node for BloomNode {
for mip in (1..textures.mip_count).rev() {
let view = &BloomTextures::texture_view(&textures.texture_b, mip - 1);
let mut upsampling_pass =
TrackedRenderPass::new(render_context.command_encoder.begin_render_pass(
&RenderPassDescriptor {
label: Some("bloom_upsampling_pass"),
color_attachments: &[Some(RenderPassColorAttachment {
view,
resolve_target: None,
ops: Operations::default(),
})],
depth_stencil_attachment: None,
},
));
render_context.begin_tracked_render_pass(RenderPassDescriptor {
label: Some("bloom_upsampling_pass"),
color_attachments: &[Some(RenderPassColorAttachment {
view,
resolve_target: None,
ops: Operations::default(),
})],
depth_stencil_attachment: None,
});
upsampling_pass.set_render_pipeline(upsampling_pipeline);
upsampling_pass.set_bind_group(
0,
Expand All @@ -309,18 +302,16 @@ impl Node for BloomNode {

{
let mut upsampling_final_pass =
TrackedRenderPass::new(render_context.command_encoder.begin_render_pass(
&RenderPassDescriptor {
label: Some("bloom_upsampling_final_pass"),
color_attachments: &[Some(view_target.get_unsampled_color_attachment(
Operations {
load: LoadOp::Load,
store: true,
},
))],
depth_stencil_attachment: None,
},
));
render_context.begin_tracked_render_pass(RenderPassDescriptor {
label: Some("bloom_upsampling_final_pass"),
color_attachments: &[Some(view_target.get_unsampled_color_attachment(
Operations {
load: LoadOp::Load,
store: true,
},
))],
depth_stencil_attachment: None,
});
upsampling_final_pass.set_render_pipeline(upsampling_final_pipeline);
upsampling_final_pass.set_bind_group(
0,
Expand Down
11 changes: 3 additions & 8 deletions crates/bevy_core_pipeline/src/core_2d/main_pass_2d_node.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,6 @@ use crate::{
core_2d::{camera_2d::Camera2d, Transparent2d},
};
use bevy_ecs::prelude::*;
use bevy_render::render_phase::TrackedRenderPass;
use bevy_render::{
camera::ExtractedCamera,
render_graph::{Node, NodeRunError, RenderGraphContext, SlotInfo, SlotType},
Expand Down Expand Up @@ -63,7 +62,8 @@ impl Node for MainPass2dNode {
{
#[cfg(feature = "trace")]
let _main_pass_2d = info_span!("main_pass_2d").entered();
let pass_descriptor = RenderPassDescriptor {

let mut render_pass = render_context.begin_tracked_render_pass(RenderPassDescriptor {
label: Some("main_pass_2d"),
color_attachments: &[Some(target.get_color_attachment(Operations {
load: match camera_2d.clear_color {
Expand All @@ -76,12 +76,7 @@ impl Node for MainPass2dNode {
store: true,
}))],
depth_stencil_attachment: None,
};

let render_pass = render_context
.command_encoder
.begin_render_pass(&pass_descriptor);
let mut render_pass = TrackedRenderPass::new(render_pass);
});

if let Some(viewport) = camera.viewport.as_ref() {
render_pass.set_camera_viewport(viewport);
Expand Down
31 changes: 9 additions & 22 deletions crates/bevy_core_pipeline/src/core_3d/main_pass_3d_node.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,6 @@ use crate::{
core_3d::{AlphaMask3d, Camera3d, Opaque3d, Transparent3d},
};
use bevy_ecs::prelude::*;
use bevy_render::render_phase::TrackedRenderPass;
use bevy_render::{
camera::ExtractedCamera,
render_graph::{Node, NodeRunError, RenderGraphContext, SlotInfo, SlotType},
Expand Down Expand Up @@ -70,7 +69,8 @@ impl Node for MainPass3dNode {
// NOTE: Scoped to drop the mutable borrow of render_context
#[cfg(feature = "trace")]
let _main_opaque_pass_3d_span = info_span!("main_opaque_pass_3d").entered();
let pass_descriptor = RenderPassDescriptor {

let mut render_pass = render_context.begin_tracked_render_pass(RenderPassDescriptor {
label: Some("main_opaque_pass_3d"),
// NOTE: The opaque pass loads the color
// buffer as well as writing to it.
Expand All @@ -94,12 +94,7 @@ impl Node for MainPass3dNode {
}),
stencil_ops: None,
}),
};

let render_pass = render_context
.command_encoder
.begin_render_pass(&pass_descriptor);
let mut render_pass = TrackedRenderPass::new(render_pass);
});

if let Some(viewport) = camera.viewport.as_ref() {
render_pass.set_camera_viewport(viewport);
Expand All @@ -113,7 +108,8 @@ impl Node for MainPass3dNode {
// NOTE: Scoped to drop the mutable borrow of render_context
#[cfg(feature = "trace")]
let _main_alpha_mask_pass_3d_span = info_span!("main_alpha_mask_pass_3d").entered();
let pass_descriptor = RenderPassDescriptor {

let mut render_pass = render_context.begin_tracked_render_pass(RenderPassDescriptor {
label: Some("main_alpha_mask_pass_3d"),
// NOTE: The alpha_mask pass loads the color buffer as well as overwriting it where appropriate.
color_attachments: &[Some(target.get_color_attachment(Operations {
Expand All @@ -129,12 +125,7 @@ impl Node for MainPass3dNode {
}),
stencil_ops: None,
}),
};

let render_pass = render_context
.command_encoder
.begin_render_pass(&pass_descriptor);
let mut render_pass = TrackedRenderPass::new(render_pass);
});

if let Some(viewport) = camera.viewport.as_ref() {
render_pass.set_camera_viewport(viewport);
Expand All @@ -148,7 +139,8 @@ impl Node for MainPass3dNode {
// NOTE: Scoped to drop the mutable borrow of render_context
#[cfg(feature = "trace")]
let _main_transparent_pass_3d_span = info_span!("main_transparent_pass_3d").entered();
let pass_descriptor = RenderPassDescriptor {

let mut render_pass = render_context.begin_tracked_render_pass(RenderPassDescriptor {
label: Some("main_transparent_pass_3d"),
// NOTE: The transparent pass loads the color buffer as well as overwriting it where appropriate.
color_attachments: &[Some(target.get_color_attachment(Operations {
Expand All @@ -169,12 +161,7 @@ impl Node for MainPass3dNode {
}),
stencil_ops: None,
}),
};

let render_pass = render_context
.command_encoder
.begin_render_pass(&pass_descriptor);
let mut render_pass = TrackedRenderPass::new(render_pass);
});

if let Some(viewport) = camera.viewport.as_ref() {
render_pass.set_camera_viewport(viewport);
Expand Down
28 changes: 12 additions & 16 deletions crates/bevy_pbr/src/render/light.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1770,23 +1770,19 @@ impl Node for ShadowPassNode {
continue;
}

let pass_descriptor = RenderPassDescriptor {
label: Some(&view_light.pass_name),
color_attachments: &[],
depth_stencil_attachment: Some(RenderPassDepthStencilAttachment {
view: &view_light.depth_texture_view,
depth_ops: Some(Operations {
load: LoadOp::Clear(0.0),
store: true,
let mut render_pass =
render_context.begin_tracked_render_pass(RenderPassDescriptor {
label: Some(&view_light.pass_name),
color_attachments: &[],
depth_stencil_attachment: Some(RenderPassDepthStencilAttachment {
view: &view_light.depth_texture_view,
depth_ops: Some(Operations {
load: LoadOp::Clear(0.0),
store: true,
}),
stencil_ops: None,
}),
stencil_ops: None,
}),
};

let render_pass = render_context
.command_encoder
.begin_render_pass(&pass_descriptor);
let mut render_pass = TrackedRenderPass::new(render_pass);
});

shadow_phase.render(&mut render_pass, world, view_light_entity);
}
Expand Down
1 change: 1 addition & 0 deletions crates/bevy_render/Cargo.toml
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -50,6 +50,7 @@ image = { version = "0.24", default-features = false }

# misc
wgpu = { version = "0.14.0", features = ["spirv"] }
wgpu-hal = "0.14.1"
codespan-reporting = "0.11.0"
naga = { version = "0.10.0", features = ["glsl-in", "spv-in", "spv-out", "wgsl-in", "wgsl-out"] }
serde = { version = "1", features = ["derive"] }
Expand Down
30 changes: 17 additions & 13 deletions crates/bevy_render/src/render_phase/draw_state.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -5,14 +5,16 @@ use crate::{
BindGroup, BindGroupId, Buffer, BufferId, BufferSlice, RenderPipeline, RenderPipelineId,
ShaderStages,
},
renderer::RenderDevice,
};
use bevy_utils::tracing::trace;
use bevy_utils::{default, tracing::trace};
use std::ops::Range;
use wgpu::{IndexFormat, RenderPass};
use wgpu_hal::{MAX_BIND_GROUPS, MAX_VERTEX_BUFFERS};

/// Tracks the current [`TrackedRenderPass`] state to ensure draw calls are valid.
#[derive(Debug, Default)]
pub struct DrawState {
struct DrawState {
pipeline: Option<RenderPipelineId>,
bind_groups: Vec<(Option<BindGroupId>, Vec<u32>)>,
vertex_buffers: Vec<Option<(BufferId, u64)>>,
Expand All @@ -26,12 +28,10 @@ impl DrawState {
bind_group: BindGroupId,
dynamic_indices: &[u32],
) {
if index >= self.bind_groups.len() {
self.bind_groups.resize(index + 1, (None, Vec::new()));
}
self.bind_groups[index].0 = Some(bind_group);
self.bind_groups[index].1.clear();
self.bind_groups[index].1.extend(dynamic_indices);
let group = &mut self.bind_groups[index];
group.0 = Some(bind_group);
group.1.clear();
group.1.extend(dynamic_indices);
}

pub fn is_bind_group_set(
Expand All @@ -48,9 +48,6 @@ impl DrawState {
}

pub fn set_vertex_buffer(&mut self, index: usize, buffer: BufferId, offset: u64) {
if index >= self.vertex_buffers.len() {
self.vertex_buffers.resize(index + 1, None);
}
self.vertex_buffers[index] = Some((buffer, offset));
}

Expand Down Expand Up @@ -98,9 +95,16 @@ pub struct TrackedRenderPass<'a> {

impl<'a> TrackedRenderPass<'a> {
/// Tracks the supplied render pass.
pub fn new(pass: RenderPass<'a>) -> Self {
pub fn new(device: &RenderDevice, pass: RenderPass<'a>) -> Self {
let limits = device.limits();
let max_bind_groups = limits.max_bind_groups as usize;
let max_vertex_buffers = limits.max_vertex_buffers as usize;
Self {
state: DrawState::default(),
state: DrawState {
Copy link
Contributor

@IceSentry IceSentry Jan 2, 2023 •
edited
Loading

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I may be missing something, but does this means we always allocate a big buffer for every render pass? Is it small enough that it doesn't matter. The previous impl looked like it would just allocate memory when necessary, if you only need 2-3 bind groups this seems wasteful.

Is it just that the speed up is worth the small memory increase?

Copy link
Member Author

@james7132 james7132 Jan 2, 2023 •
edited
Loading

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

The latter. The actual size of these Vecs aren't that big (1-2KB at most), and is a static upfront cost compared to the scaling cost of branching on every RenderCommand (not just every entity) that uses it.

The actual limits here are also usually quite small. 16 for both vertex buffers and bind groups, IIRC.

Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Alright, makes sense then, might be worth adding a small note in a comment I guess, but I'll approve anyway

Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

The actual limits here are also usually quite small. 16 for both vertex buffers and bind groups, IIRC.

Some devices may report u32::MAX for those limits instead of an actual value, #6841 for example for max_storage_buffers_per_shader_stage. I don't know if that's also the case for max_bind_groups or max_vertex_buffers but that's a possibility

Copy link
Member Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

After talking about this with cwfitzgerald about this on Discord, it seems like the limits for vertex buffers and bind groups are generally pretty low (max a few hundred). It seems like the limit is hard set in wgpu-hal mostly to avoid reallocations from Vecs.

In the worst case, we should set a reasonable upper limit ourselves (i.e. 1024) which we use min with the Device provided limits to be 100% sure it's not overallocating.

Original discussion: https://discord.com/channels/691052431525675048/743663924229963868/1059900749636702309

Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Yeah, after reading the discussion I had the same conclusion.

Copy link
Member Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Ended up using wgpu-hal's public constants MAX_VERTEX_BUFFERS and MAX_BIND_GROUPS so we're not keeping them out of sync.

bind_groups: vec![(None, Vec::new()); max_bind_groups.min(MAX_BIND_GROUPS)],
vertex_buffers: vec![None; max_vertex_buffers.min(MAX_VERTEX_BUFFERS)],
..default()
},
pass,
}
}
Expand Down
18 changes: 8 additions & 10 deletions crates/bevy_render/src/render_resource/resource_macros.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -124,7 +124,7 @@ macro_rules! render_resource_wrapper {
macro_rules! define_atomic_id {
($atomic_id_type:ident) => {
#[derive(Copy, Clone, Hash, Eq, PartialEq, Debug)]
pub struct $atomic_id_type(u32);
pub struct $atomic_id_type(core::num::NonZeroU32);

// We use new instead of default to indicate that each ID created will be unique.
#[allow(clippy::new_without_default)]
Expand All @@ -134,15 +134,13 @@ macro_rules! define_atomic_id {

static COUNTER: AtomicU32 = AtomicU32::new(1);

match COUNTER.fetch_add(1, Ordering::Relaxed) {
0 => {
panic!(
"The system ran out of unique `{}`s.",
stringify!($atomic_id_type)
);
}
id => Self(id),
}
let counter = COUNTER.fetch_add(1, Ordering::Relaxed);
Self(core::num::NonZeroU32::new(counter).unwrap_or_else(|| {
panic!(
"The system ran out of unique `{}`s.",
stringify!($atomic_id_type)
);
}))
}
}
};
Expand Down
16 changes: 16 additions & 0 deletions crates/bevy_render/src/renderer/mod.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,8 @@ pub use render_device::*;

use crate::{
render_graph::RenderGraph,
render_phase::TrackedRenderPass,
render_resource::RenderPassDescriptor,
settings::{WgpuSettings, WgpuSettingsPriority},
view::{ExtractedWindows, ViewTarget},
};
Expand Down Expand Up @@ -279,3 +281,17 @@ pub struct RenderContext {
pub render_device: RenderDevice,
pub command_encoder: CommandEncoder,
}

impl RenderContext {
/// 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),
)
}
}
Loading