use bevy::{
prelude::*,
reflect::TypePath,
render::{
render_asset::RenderAssets,
render_resource::{
binding_types::{sampler, texture_2d},
*,
},
renderer::RenderDevice,
texture::{FallbackImage, GpuImage},
RenderApp,
},
};
use std::{num::NonZeroU32, process::exit};
fn main() {
let mut app = App::new();
app.add_plugins((
DefaultPlugins.set(ImagePlugin::default_nearest()),
GpuFeatureSupportChecker,
MaterialPlugin::<BindlessMaterial>::default(),
))
.add_systems(Startup, setup)
.run();
}
const MAX_TEXTURE_COUNT: usize = 16;
const TILE_ID: [usize; 16] = [
19, 23, 4, 33, 12, 69, 30, 48, 10, 65, 40, 47, 57, 41, 44, 46,
];
struct GpuFeatureSupportChecker;
impl Plugin for GpuFeatureSupportChecker {
fn build(&self, _app: &mut App) {}
fn finish(&self, app: &mut App) {
let Some(render_app) = app.get_sub_app_mut(RenderApp) else {
return;
};
let render_device = render_app.world().resource::<RenderDevice>();
if !render_device
.features()
.contains(WgpuFeatures::SAMPLED_TEXTURE_AND_STORAGE_BUFFER_ARRAY_NON_UNIFORM_INDEXING)
{
error!(
"Render device doesn't support feature \
SAMPLED_TEXTURE_AND_STORAGE_BUFFER_ARRAY_NON_UNIFORM_INDEXING, \
which is required for texture binding arrays"
);
exit(1);
}
}
}
fn setup(
mut commands: Commands,
mut meshes: ResMut<Assets<Mesh>>,
mut materials: ResMut<Assets<BindlessMaterial>>,
asset_server: Res<AssetServer>,
) {
commands.spawn(Camera3dBundle {
transform: Transform::from_xyz(2.0, 2.0, 2.0).looking_at(Vec3::new(0.0, 0.0, 0.0), Vec3::Y),
..default()
});
let textures: Vec<_> = TILE_ID
.iter()
.map(|id| asset_server.load(format!("textures/rpg/tiles/generic-rpg-tile{id:0>2}.png")))
.collect();
commands.spawn(MaterialMeshBundle {
mesh: meshes.add(Cuboid::default()),
material: materials.add(BindlessMaterial { textures }),
..default()
});
}
#[derive(Asset, TypePath, Debug, Clone)]
struct BindlessMaterial {
textures: Vec<Handle<Image>>,
}
impl AsBindGroup for BindlessMaterial {
type Data = ();
fn as_bind_group(
&self,
layout: &BindGroupLayout,
render_device: &RenderDevice,
image_assets: &RenderAssets<GpuImage>,
fallback_image: &FallbackImage,
) -> Result<PreparedBindGroup<Self::Data>, AsBindGroupError> {
let mut images = vec![];
for handle in self.textures.iter().take(MAX_TEXTURE_COUNT) {
match image_assets.get(handle) {
Some(image) => images.push(image),
None => return Err(AsBindGroupError::RetryNextUpdate),
}
}
let fallback_image = &fallback_image.d2;
let textures = vec![&fallback_image.texture_view; MAX_TEXTURE_COUNT];
let mut textures: Vec<_> = textures.into_iter().map(|texture| &**texture).collect();
for (id, image) in images.into_iter().enumerate() {
textures[id] = &*image.texture_view;
}
let bind_group = render_device.create_bind_group(
"bindless_material_bind_group",
layout,
&BindGroupEntries::sequential((&textures[..], &fallback_image.sampler)),
);
Ok(PreparedBindGroup {
bindings: vec![],
bind_group,
data: (),
})
}
fn unprepared_bind_group(
&self,
_: &BindGroupLayout,
_: &RenderDevice,
_: &RenderAssets<GpuImage>,
_: &FallbackImage,
) -> Result<UnpreparedBindGroup<Self::Data>, AsBindGroupError> {
panic!("bindless texture arrays can't be owned")
}
fn bind_group_layout_entries(_: &RenderDevice) -> Vec<BindGroupLayoutEntry>
where
Self: Sized,
{
BindGroupLayoutEntries::with_indices(
ShaderStages::FRAGMENT,
(
(
0,
texture_2d(TextureSampleType::Float { filterable: true })
.count(NonZeroU32::new(MAX_TEXTURE_COUNT as u32).unwrap()),
),
(1, sampler(SamplerBindingType::Filtering)),
),
)
.to_vec()
}
}
impl Material for BindlessMaterial {
fn fragment_shader() -> ShaderRef {
"shaders/texture_binding_array.wgsl".into()
}
}