e6405bb7b4
# Objective
- Reduce the number of rebindings to enable batching of draw commands
## Solution
- Use the new `GpuArrayBuffer` for `MeshUniform` data to store all
`MeshUniform` data in arrays within fewer bindings
- Sort opaque/alpha mask prepass, opaque/alpha mask main, and shadow
phases also by the batch per-object data binding dynamic offset to
improve performance on WebGL2.
---
## Changelog
- Changed: Per-object `MeshUniform` data is now managed by
`GpuArrayBuffer` as arrays in buffers that need to be indexed into.
## Migration Guide
Accessing the `model` member of an individual mesh object's shader
`Mesh` struct the old way where each `MeshUniform` was stored at its own
dynamic offset:
```rust
struct Vertex {
@location(0) position: vec3<f32>,
};
fn vertex(vertex: Vertex) -> VertexOutput {
var out: VertexOutput;
out.clip_position = mesh_position_local_to_clip(
mesh.model,
vec4<f32>(vertex.position, 1.0)
);
return out;
}
```
The new way where one needs to index into the array of `Mesh`es for the
batch:
```rust
struct Vertex {
@builtin(instance_index) instance_index: u32,
@location(0) position: vec3<f32>,
};
fn vertex(vertex: Vertex) -> VertexOutput {
var out: VertexOutput;
out.clip_position = mesh_position_local_to_clip(
mesh[vertex.instance_index].model,
vec4<f32>(vertex.position, 1.0)
);
return out;
}
```
Note that using the instance_index is the default way to pass the
per-object index into the shader, but if you wish to do custom rendering
approaches you can pass it in however you like.
---------
Co-authored-by: robtfm <50659922+robtfm@users.noreply.github.com>
Co-authored-by: Elabajaba <Elabajaba@users.noreply.github.com>
60 lines
1.9 KiB
Rust
60 lines
1.9 KiB
Rust
use crate::{
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render_resource::{GpuArrayBuffer, GpuArrayBufferable},
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renderer::{RenderDevice, RenderQueue},
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Render, RenderApp, RenderSet,
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};
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use bevy_app::{App, Plugin};
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use bevy_ecs::{
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prelude::{Component, Entity},
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schedule::IntoSystemConfigs,
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system::{Commands, Query, Res, ResMut},
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};
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use std::marker::PhantomData;
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/// This plugin prepares the components of the corresponding type for the GPU
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/// by storing them in a [`GpuArrayBuffer`].
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pub struct GpuComponentArrayBufferPlugin<C: Component + GpuArrayBufferable>(PhantomData<C>);
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impl<C: Component + GpuArrayBufferable> Plugin for GpuComponentArrayBufferPlugin<C> {
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fn build(&self, app: &mut App) {
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if let Ok(render_app) = app.get_sub_app_mut(RenderApp) {
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render_app.add_systems(
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Render,
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prepare_gpu_component_array_buffers::<C>.in_set(RenderSet::Prepare),
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);
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}
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}
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fn finish(&self, app: &mut App) {
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if let Ok(render_app) = app.get_sub_app_mut(RenderApp) {
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render_app.insert_resource(GpuArrayBuffer::<C>::new(
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render_app.world.resource::<RenderDevice>(),
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));
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}
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}
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}
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impl<C: Component + GpuArrayBufferable> Default for GpuComponentArrayBufferPlugin<C> {
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fn default() -> Self {
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Self(PhantomData::<C>)
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}
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}
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fn prepare_gpu_component_array_buffers<C: Component + GpuArrayBufferable>(
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mut commands: Commands,
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render_device: Res<RenderDevice>,
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render_queue: Res<RenderQueue>,
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mut gpu_array_buffer: ResMut<GpuArrayBuffer<C>>,
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components: Query<(Entity, &C)>,
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) {
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gpu_array_buffer.clear();
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let entities = components
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.iter()
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.map(|(entity, component)| (entity, gpu_array_buffer.push(component.clone())))
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.collect::<Vec<_>>();
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commands.insert_or_spawn_batch(entities);
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gpu_array_buffer.write_buffer(&render_device, &render_queue);
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}
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